cc  >> Hi, I'm Cathy Vrentas from  the UW Biotechnology Center.  And I'd like to welcome everyone  to another Wednesday Night at  the Lab, held every week at 7:00  PM here at the Biotechnology  Center on campus.  So today we're going to be  hearing from Dr. Wan-Ju Li.  who is an assistant professor in  orthopedics and rehabilitation,  as well as biomedical  engineering on campus.  And he wears many hats because  he also trains students in  research in cellular and  molecular biology, as well as  stem cell and regenerative  medicine.  He did his Ph. D.  work in solid tissue engineering  at Thomas Jefferson and most  recently did post-doctoral work  at the National Institutes of  Health.  And what he's going to be  telling us today is about his  work and tissue engineering  specifically on muscle and  skeletal tissue and looking at  ways to engineer tissue both in  the body and also in the lab.  So join me in welcoming  Dr. Wan-Ju Li.  [APPLAUSE]  >> Thank you. 

 Can everybody hear me?  Thank you, Kathy.  First of all, I would like to  thank Tom, the organizer  inviting me here.  It's my pleasure to have the  opportunity to come here to talk  to you.  Today I'm going to, first of I  can also tell who I am.  I'm Wan-Ju Li.  And I am a principal  investigator in muscular tissue  engineering and regenerative  medicine here in UW Madison  orthopedics.  And I'm going to talk about some  very interesting topic, and the  topic is the growing tissue in  the laboratory.  It sounds like science fiction.  It's science fiction about two  or three decades ago but it is  no longer science fiction.  It becomes a reality today. 

 In the laboratory we actually  engineer and grow a tissue in  the laboratory on the bench.  So I'm going to talk about the  subtitle is tissue engineering  based orthopedic regenerating  matters.  I'm going to talk about what is  tissue engineering and how is  that going to help to cure the  diseased in orthopedics.  How is that going to help the  orthopedic patients.  First, I would like you to look  at this slide.  What makes the differences to  the peoples in these two  pictures.  The answer is osteoarthritis.  And many people think arthritis  is a disease but actually  osteoarthritis is not a disease.  It's a natural aging process  which cause joint degeneration.  So it happens to many parts of  the joints in your body. 

 So osteoarthritis, serious  problem, definitely impact the  quality of the life.  And also more and more people,  especially the baby boomers when  they get aged, they have a  problem.  They have a problem in the  joints.  They suffer from osteoarthritis.  So I want to show you this  graph.  This graph showing the very  interesting data.  You can see arthritis and  rheumatism over heart trouble,  as well as diabetes, become the  leading cause of the disabled  among patients.  And this slide also shows you in  1990 and you can see this color  stayed.  Label was the gray colors.  They have the population about  15% to 18% of a population who  suffers from the OA or some sort  of arthritis. 

 And this problem become even  more severe by 2020.  You can see all this states  which previously marked with  gray colors become lighter.  This black color states.  They have a problem.  And all this have a more  patients overpopulation.  More than 18% of a population  who also suffers some sort of  arthritis.  Also, other states from the west  coast and part of northeast, the  states also joined a trend of  arthritis.  They have a population of about  15% to 18% of people who  suffered osteoarthritis.  So you can see this is the  problem to the whole entire  nation, not just to the  individual.  So we can see how we are going  to tackle the problem. 

 How can we solve the problem  together?  This is my job as a scientist.  So what exactly osteoarthritis?  Osteoarthritis, OA, is the most  common form of arthritis.  It occurs when the thin layers  of cartilage inside a joint  breaks down.  The rough ends of the bone come  in contact with each other.  The result can be pain, swelling  and stiffness.  So over time, loss of joint  mobility may occur.  If this problem without  treatment osteoarthritis can  totally harm a joint.  And also osteoarthritis commonly  occurs in hips, knees and spine,  even in the finger and toe.  So you can see it could possibly  happen to all parts of your  joints.  I want to give you warning, I'm  sorry I have to do this first. 

 I have to give a warning first  before I hear this.  It may be not present to most of  you.  And you can look at this picture  here.  It shows you arthritis joints  versus a normal joint.  What is the differences.  On the left panel this is a  normal joint.  You can see the smooth cartilage  surface on the joint.  On the right hand side is  osteoarthritis joint.  You can see all the cartilage is  degraded and it becomes rough  surface.  So this is problematic to most  of the people. 

 It causes the trouble.  And also make the people feel  pain.  That is the problem.  So how are we going to solve the  problem?  Before I do that, I would like  to give you a story.  This is the real story about an  arthritis patient.  This story is written by the  person called Jo.  Not Joe the plumber, the other  Jo.  The Jo has been living with  osteoarthritis for 15 years when  she felt their independence  slipping away she knew she had  to take stock of her life.  She writes, "Osteoarthritis  affects every part of my life.  My favorite past time is making  wooden toys. 

 Unfortunately, I now also  experience pain in my finger  joint.  My aim now is to keep my hands  moving and try to lessen the  damage so that I can continue to  enjoy my hobby as long as  possible."  She continued, "I enjoy  walking as I am a country girl  at heart.  But it's increasingly becoming  agony even to -- to the  supermarket.  I feel passionately about a need  for good quality care for  patients with osteoarthritis  across the country."  So you can see how significant  a problem and how that impact a  person's life when this  individual has osteoarthritis.  Before we continue to talk about  this I want to give you some of  the idea what is cartilage.  So how is cartilage happens when  people have osteoarthritis.  This is the patient's, this the  is normal structure of cartilage  tissue.  So as you can see, this  cartilage is composed of three  major parts.  One is the cell, we call it --.  That's the major cell type which  produce the cartilage tissue. 

 And then the other is collagen,  as well as we -- glycin.  We call it -- matrix.  So the matrix is also very  important.  It provides the mechanic loaded  to the construct or to the  tissue.  The third one, it's also an  important component, it's water.  So water also provides a very  important job to resist loading.  So as you can see here cartilage  is composed by three different  components.  And, unfortunately, what  happened when a patient got  osteoarthritis, cartilage is a  structure with a very low number  of the cells, only 5% to 10% of  the cartilage is the cell which  means you don't have that much  repair cells when the damage  occurs to help out to repair the  cartilage defect.  And the other thing is cartilage  has no block, no lymphatic  vessels.  And there's no highway which  means there's no repair factor,  transfer or transplant in there. 

 So there's no soldier.  There is no weapon.  Of course, the battle it doomed  to fail.  That's a reason why cartilage is  so difficult to repair when you  get hurt or when you start to  progress with the  osteoarthritis.  So I want you to look at what  could be the possibility caused  osteoarthritis.  Of course, genetic and --  imperfection.  That's the main reason.  And the other reason is, if you  have a trauma or an injury in  the early stage in your life  than you might end up with  arthritis later in your life.  And the third one is aging.  Like what I say is the aging  process. 

 Nobody can escape from the aging  process.  That's the three main reasons  caused osteoarthritis.  And osteoarthritis affects  almost 60 million people in the  United States.  You can see this is a big  problem.  So want to give you more detail  about cartilage pathology.  So there are two types of  arthritis.  One, if the cartilage defect  only happens on the cartilage  site, it did not go down, it's  called chondralation which means  it happens only to the surface  of the cartilage.  But if this is happening, the  problem will continue to  progress.  There's no stopping.  It will continue to progress to  the second stage which we call  osteochondralation. 

 The difference is this lesion  will continue to penetrate it  down to the sub-chondral bone.  So you can see the bone part is  exposed to the air so that is  the major reason and make you  pain.  So this is the process of the  progression of articular  cartilage pathology.  So what's the treatment?  I just talk to you and what  could be the problem?  How is that happen?  And what is the current  treatment?  Everybody knows the current  treatment, the ultimate  treatment is the joint  replacement, right?  The joint replacement is the end  stage of replacement or  treatment we call.  Which means when all the  treatment is felt we have to use  the last resort which is the  joint replacement.  But before that we have several  ways to try to stop or slow down  the progress.  One is called osteochondral  autograph.  Let me explain to you what does  that mean here.  Osteochondral autograph which  means you harvest a piece of the  osteochondral plug from your own  joints at non-weight bearing  area and then transfer this  piece of a graft down here which  is your defect sites.  When you transfer it from here  to here, you caused another  trouble because you create  another defect right here. 

 And also the problem is we don't  have that many spot for you to  transfer because you are looking  for the good healthy cartilage  to transfer.  This is limited spot for you to  get it enough transplant down  here.  So that's the first problem of  the osteochondral autograph.  The second treatment, what  people do is instead of getting  the whole plug, people get a  cell.  So what they do is they use the  instrument and take in some of  the tissue and then digest this  tissue, release the cell.  Remember what I told you  earlier, the cell from cartilage  is chondrocyte.  So the chondrocyte will be  transplanted and then put into,  actually what they do is they  get the digestion down and they  finished it and then transferred  these cells into the defect site  by covering periosteal  membranes, they inject in the  cells there.  The biggest problem is the cell  are free-form.  Once they get down there they  won't stay there.  They can continue may be   absorbent. 

 Maybe they're trouble to  somewhere else.  So the effect was not effective  because there's no way they can  be fixed securely at a defect  site right here.  So what can we do about it?  Both treatment before the total  joint replacement are not very  effective because they cause  donor site mobility, as well as,  they are only good for the focal  lesion.  Once you have the bigger lesion,  like a large defect, these two  treatments are not useful.  So we want to develop a new  treatment for the bigger defect  in place.  Here comes the science.  Everybody say okay, you tell me  there is a problem.  What if we are good at thinking  big as a scientist, so what if  we can create or produce a piece  of a cartilage for you in my  lab?  What if I can make a new bone  for you in my lab?  What if I can even create or  fabricate a whole joint for you  and that you can replace it, and  what if just like we have are a  problem in the defect site or  defect parts in our car, there  is a problem in the tire, we'd  replace tire.  There's a problem in engine, we  replace engine.  Just like you'd have a problem  with the car parts, we'd replace  the car parts. 

 That's what we're trying to do.  Can we do that?  The answer is yes.  Before I answer you with my  scientific data I want to tell  you there are several different  kind of animals in nature which  can do the job which we cannot  do as a human.  Lower animal such as earth worm,  --, salamander, they are good  and regenerate their injured or  missing parts.  If they have parts of their body  missing, they can regenerate it  without any problems.  So normally it takes a couple  days to a couple weeks, they can  regenerate their limb without  any problem.  As a human being, we can't.  We are limited.  We have are a certain limitation  in terms of regeneration.  But we can regenerate it --. 

 For example, if we have a cut on  our skin we will be able to  regenerate or repair the cut.  But we cannot regenerate the  missing part of our limb or  finger or joint.  That's something we cannot do.  So as a scientist, I want to  help.  How can we help?  Here comes the concept of tissue  engineering.  So the tissue engineering, if  you read it will be reversed  exactly the meaning of the  tissue engineering.  Tissue engineering meaning  engineered tissue.  How are we going to engineer  tissue?  I'm going to give you an idea  how this is being done.  First, we isolated cells from  the patient.  Okay, these cells can be tissue  specific cell such as  chondrocyte, cartilage cells. 

 Bone tissue has a bone cell  called osteoblast.  We harvest those cells, as well  as, mesenchymal stem cell or  embryonic stem cell.  We grow those cells and when we  can actually spend those cells  and make it a huge quantity.  Once we get enough quantity of  the cell what we do is we seed  these cells in this  three-dimensional poured  structures, we call it scaffold.  Just like -- you have are a  template called scaffold.  So scaffold can reshape into  desired shape.  For example, I can make it into  nose shape, ear shape.  Then I'm putting the signal to  the cell because the cell has to  already be put in here.  So this whole piece is called  cellular construct.  Then we can remove this whole  cellular construct into the  environment, cultured  environment. 

 We call it bioreactor.  And this bioreactor just  providing the kind of  environment, that environment is  similar to your body  environment.  If you walk, you have the median  circulate in your body.  This piece of device doing  exactly as that.  So this device is used to  replace your body environment  but instead of being stored in  your body they are sitting  outside.  So once you have this all done  and remember this material  normally we have a biodegradable  polymer which means it would  degrade eventually.  So cells sitting in the  biodegradable structures  eventually biodegradable polymer  will be replaced by the nature  produced -- matrix which is your  natural material such as  collagen.  So the whole piece from  artificial tissue turns into the  natural tissue.  Then it's a functional tissue,  we can put it back to the body.  Okay, sounds very, very  scientific. 

 Let me give you a best example.  You'll understand this easily.  I like to use this example of  the human living in the house.  Let's look at this.  Cell is a human.  They all living in the house.  In a house you want to get a  good house.  You want to have a temperature  control, you want to have a  humidity control.  So you also want your ceiling  high so a lot of window so  you'll feel enjoyed.  So you'll stay in the nice  designed house with a lot of  space. 

 And also providing signal.  This signal can be chemical  signal or mechanical signal,  which is entertainment to you.  So I'm providing entertainment,  as well as, the food.  Make you happy.  If you are happy in the  scaffold, cells are happy in the  scaffold they start to produce  the matrix.  If I'm happy in my house I do  most creative, constructive  activity.  Then I will do something and  make the tissue.  That's what I like to use.  The best example is this: Many  of you have seen this before, in  1995 -- from Harvard university  who just invented the first  tissue engineer here.  What he did is he used the  scaffold, which is what I just  described to you, and that is  the tissue has been made into an  ear shape. 

 Then he put the chondrocyte cell  which is the ear cells.  And then put in there, put on  the back of the mouse.  Use the mouse as a nutrition  provider.  So this piece of tissue comes  out after a certain period of  time.  So to get this piece of tissue,  that's a real ear.  So I can give this ear to the  people who maybe need an ear  reconstruction or something.  So we can use the same concept  and do it and then try to  regenerate your cartilage joint.  So that's what I'm trying to do  here.  So I want to repeat again, there  are three very important factors  decide successful of the tissue  regeneration.  Number one is the cell source. 

 So what kind of the cell you  want to use, that's very  important.  So you want to use the  chondrocyte cell or multi  differentiated stem cell.  That's the cell type you want to  use.  A second one is the signal.  What kind of a signal because  the signal tells the cell what  to do.  So the signal can be chemical,  can be mechanical.  Remember when we walk and your  body weight creates certain  motion on your joints, that's a  mechanical signal.  Those are mechanical signal  exercise your joints, tell your  joints we need to be strong to  resist loading.  That's why you have all this  healthy cartilage.  When people are laying down they  never have opportunity to walk,  they lose their strength of the  their cartilage, as well as the  bone. 

 Why?  Because they lose their  mechanical signal.  So that's very important to know  you have the right signal to  make a healthy tissue.  Then you have a scaffold.  Again, we want to design a good  house for these people there,  right?  So what kind of structure I want  to design.  I can have a synthetic, I can  have a natural polymer which we  can use to do the scaffold.  And also the structure depends  on how strong you want it to be  and what kind of a tissue you  want to replace.  Bone tissue requires stronger  material.  Soft tissue like skin and  cartilage require less strong  material.  So you can see the differences  between the mechanical property  of a structure we decided that  will be the successful tissue  engineering or not.  So you can see three different  factors are very important. 

 And I'm going to talk about each  one of these factors  individually and tell you what  we do in our laboratory.  Okay, so I want to also  emphasize why tissue  engineering-based orthopedic  regenerative medicine become the  future of orthopedics.  In the future, I can tell you  orthopedics is no longer, you go  into the hospital, they find out  the problem and then they just  seal you, you're done.  You miss part of your joints,  right?  It won't be like this anymore.  It will become the preventive  orthopedics.  Which means preventive medicine.  If I have the problem earlier, I  will get that problem fixed  right away before it becomes  more serious problem.  That's orthopedics.  How this can be done?  It will be done by stem cell.  By gene therapy. 

 So last year American Academy of  Orthopedic Surgeons, they have a  meeting.  The section is called 21st  Century Triple-Play Stem Cell  Tissue Engineering and Gene  Therapy.  In this meeting they conclude  the use of the a stem cell may  have the power to transform  orthopedic surgery now and in  the future.  So you can see they already  start to realize the trend of  orthopedic futures.  So we are doing that now in our  school and other universities,  as well.  So I want to also mention in  clinical is any product  available now in orthopedics you  can use?  Yes, the answer is yes.  There's a company called Osiris  and this company has developed a  product called OsteoCell.  This OsteoCell product is a stem  cell product which is currently  used in orthopedic application.  So you can see this product has  a market here $15 million.  And also that was 83% of  increase from 2006. 

 It's getting more and more  popular, more and more people  realized the stem cell based  product is going to be the  future of the product to treat  orthopedic related problems.  All right, I'm going to talk,  that was the general  introduction about what is  tissue engineering.  What can we do using the tissue  engineering to treat orthopedic  problem.  And what happened to my  laboratory.  This is happening in UW Madison  now.  So UW Madison Orthopedic and  Rehabilitation Department, which  is the department I'm in, I'm  actually trying to do this.  This is my research goal, very  clear.  We try to use cutting-edge  nanotechnology to develop stem  cell based tissue engineering  for muscular/skeletal tissue  regeneration.  People always like my topic of  my research goal.  Because it covers some of the  fancy words. 

 For example, nanotechnology.  Stem cell.  Regenerated medicine.  But I want to tell you not  because I try to impress you or  impress the rest of the public  so I use these kinds of fancy  words.  No.  I'm going to talk to you, I'm  going to introduce you what  happened in my laboratory.  We do actually use all of this  technology and try to us this  technology to regenerate the  tissue.  Here you go.  All right, first thing we're  talking about nanotechnology.  What kind of nanotechnology am I  using?  We are using the nanotechnology  called electrospinning. 

 Electrospinning is a technology,  it's not me who invented it.  This technology invented in  1938.  That was 60 years ago.  But first when they were  invented they were used for  textile industry, as well as, a  filter paper industry.  What I try to do is make a very  small fiber fabric.  So I can tell you how this is  working.  But we are a first group who use  this technology in tissue  engineering.  We publish more than 25 papers  related to this technology and  we have a very careful  investigation using this  technology for tissue  engineering.  Okay, so this is a graph telling  you what happened.  Actually, I have bring the  product. 

 Here in case of want to see it.  I hope I can find it.  I should take it out earlier.  I did actually bring it here,  hopefully.  Sorry.  For some reason, I cannot find  it.  That's okay.  Later maybe I can try to find  it.  I actually put in.  There are many different  compartments in my bag. 

 But anyway what I'm trying to  see here is this is a  technology.  I tried to explain to you what  happened.  We have the polymer solution put  in here and then we applied 30K  volts which is very high voltage  right here.  Created electrical static force  right here.  This electrical static force  coming down bring the fiber to  the target and the target will  be the -- target and the --  target can be used to collect  the fibers and this is called  electrospinning.  Because of all this very  complicated physics going here,  if you're interested, I can talk  to you after the presentation.  So this is a structure.  If you look at it, it's a very  small fibers.  The size of the fiber is 50  nanometer to 300 nanometers.  And this size of nanometers of  fibers is similar or the same  order of the collagen fibers. 

 So it is very easy to understand  why we want to use these fibers.  Because we want to trick cells.  We want to fool cells.  When we take cells out we want  to tell them you are still in  your native environment, just do  whatever you were doing in the  body.  So the first thing we have to do  is, of course, give them the  real stuff or the structure  similar to what they live in.  Their native environment Which  is the collagen fiber  environment like what I said.  Collagen environment is what we  try to provide.  So the similarity between  collagen fiber and nanofiber  which create very, very  interesting cell matrix  interaction.  That interaction really give the  signal to the cell and make the  cell start to produce normally.  That's what happened. 

 I try to explain in the prime  language.  And then you also have smaller  fibers.  Some of the professors here know  you have, maybe general public  also knows, the small fibers  provides the higher surface  area.  Which means you can have more  surface area to accommodate more  cells.  So you have more cells in the  one unit.  That's why high surface area  needed.  And provided mechanical property  because a smaller fiber are more  stronger if you have a bundle.  So there's a whole thing  together will actually bring our  hypothesis.  Our hypothesis is if I have this  matrix which is a nanofiber  scaffold it might actually act  as the biological preferred  structures support physiological  function of the cell for tissue  engineering.  In other words, this is the  happy cells living in the  environment I provide. 

 That's what I'm trying to say.  I want to prove that's the case,  all right?    Okay, so what's this?  This is actually the SEM picture  showing you what I just said.  I keep telling you how similar  between the fiber I make versus  the collagen fibers.  I want to show you on the left  panel here is the material I  made which is the synthetic  electrospun nanofiber.  And then right hand is the  collagen fiber.  So you can see the similarity in  terms of their size and  structures.  And this is so important.  My student investigated this  very detailed signal that passed  inside of the cell why this  cells liked these structures.  That's a different story.  So I'm not going to cover this  today. 

 But I just want to tell you what  we found here is this is the  very small nanofiber which has a  very small diameter similar to  collagen fiber.  So we want to use this structure  to culture the cell.  So this study will just prove  why I'm saying is what I say.  This is a study, we try to  compare two different sites.  So when you say this is better,  you have to prove it.  How are you going to prove it?  You use a different cell.  You use different size of fiber.  So I use the fiber made of --  acid which is a biodegradable  polymer.  The polymer is the set, the  difference is this guy is 20  micron, much, much bigger fiber.  And this is a 300 nanometer,  smaller fiber. 

 So the fiber sizes are  different.  And were put in cells.  What are you trying to look at  here.  I will try to point it out here.  This is a sheet on the surface  of the material is the cell.  And this is the couple of the  cells sitting on the material.  What's the differences between  these two?  This cell are differentiated  chondrocyte which means they  change, they're no longer  chondrocyte.  They're no longer cartilage  cells.  But in this case they are still  cartilage cell.  They are the spherical  three-dimensional cartilage  cell. 

 If you take your cartilage out  of your body and look at the  cell inside, they should look  like this.  Is that clear?  So that's what happened here.  Then I want to talk about a stem  cell.  Everybody talking about stem  cell.  Of course, I'm also doing the  stem cell long before I come  here.  Stem cell, there are two  different kinds of stem cell.  The stem cell I'm using is  called mesenchymal stem cell.  And this mesenchymal stem cell  is adult stem cell.  Normally you can find it in the  bone marrow and a lot parts of  your body.  For example, fat. 

 You can find the mesenchymal  stem cell in fat.  Indeed, that's the case.  Fat, bone marrow, muscle, a lot  of tissue contains the  mesenchymal stem cell.  And this stem cell is the one  when you have any kind of injury  they will send the signal.  They are the troops, they are  the soldiers march to the target  and help you to rebuild your  tissue.  So we have a technology we can  isolate this -- stem cell and  this stem cell can be  differentiated into the  different cell type which is  bone cartilage, cardiac, stroma,  tendon and --.  What's the differences between  this cell?  There are functional differences  but they will be constructed  into the different kind of a  cell type by the different  signal and that signal is called  growth factor.  So say that again, mesenchymal  stem cell by different signal we  can differentiate them and  instruct them become a different  tissue.  That's what happened here.  So how are we going to do this  has been documented. 

 People use that in many  different applications.  So what we try to do is focus on  bone and cartilage.  This is what I'm trying to do.  All right, so this study, just  to give you an idea, remember  I've used nanofiber.  People say you have to prove  it's good.  So what I'm trying to do is I  use nanofiber to tell people we  have the better differentiation.  Remember I try to do mesenchymal  stem cell differentiation so  what I want to do, if they can  differentiate better in my  structures, in my nanofiber  structures, which means I have a  more successful data.  So what we try to do is we  culture these cells in the  monolayer culture, monolayer  meaning flat, no up and down, no  fibers.  And the other is the fiber.  What we are looking here is the  color intensity. 

 The color intensity indicated  the presence of that specific  tissue.  Meaning, if you have are a blue  color here which is the  indication of a protein glycin,  remember that's a part of your  cartilage tissue, and you have  calcium here, which is a part of  your bone, and you have a fat  tissue here, which is a part of  your fat, so all this color  here, the stronger the color is,  the more tissue that kind of a  tissue is in that structure.  So it's easier to tell.  We have the nanofiber  structures.  It can make the tissue  differentiated from the  mesenchymal stem cell become all  this cartilage tissue, bone  tissue, as well as the fat  tissue more effectively.  So that's what I'm trying to say  here.  So that proves again the  structure really can actually  make the cells become more like  that type of cells I'm looking  for.  All right, so I got the cell  work out.  I have the house built.  I know from a previous study  that tissue likes to be growed  in the house I built which is  nanofiber structures, right?  So I like it. 

 So what happened to other  signal?  Remember that three component.  I want cell, I want signal, I  also want growth factors as well  as the environment which is a  bioreactor.  So this is a study what we tried  to do.  So we have the fiber, remember.  And we put the cells on it and  then you have a cell.  And I want to give them growth  factor.  This is the growth factors.  growth factor is part of your  body molecule which will go to  whatever the target is help to  differentiate that specific  tissue.  In this case, -- beta and --,  you don't have to remember  what's this, but just remember  they are two different growth  factor important for the  cartilage development.  So we're put in there and try to  tell the cell you guys become a  cartilage tissue with the  instruction under this growth  factors. 

 And then put them together and I  want to test that if I put that  into the bioreactor which is a  dynamic culture condition  similar to our body environment,  what happened?  Versus I put it into the test  tube which is just the static,  no any circulation of a medium,  what happened?  So I want to know what is the  differences?  That's what happened here.  So I want to show you this very  cool video.  Okay, this video, I want you to  focus on this little tiny thing.  There are four pieces of a white  spot there.  Those are engineered tissue.  So I will tell you more detail.  Let's pay attention and focus on  the video first.  It's about one minute.  I found it actually right here,  the material.  So focus on this. 

 So this guy are providing  circulation to the large piece  of engineered tissue.  So this is the engineered  tissue.  Thinking about you're going to  the fried chicken store to eat a  fried chicken.  At the end of the bone there's a  white piece, that's what we have  here.  Okay, that's a cartilage.  And we can make that.  And why?  I want to show you.  This is so exciting.  Every time I talk about this I  get so excited about this.  Let's look at this. 

 This is amazing.  So this is actually a close up.  You can close up to see this is  the case.  And then that's another piece in  the dynamic versus a static.  The difference is one is the  dynamic culture condition.  The other one is just sit there  and is all static environment.  Let's look at what happened.  Look at this.  Can you imagine this 42 days ago  is, okay let me pass this.  So I'm suppose to hold this to  you, have the camera just take a  close shot. 

 And then I'm going to pass it.  You can touch it.  It's a biodegradable lactic  acid.  Don't worry about it, it's not  toxic.  So I want you to look at this.  This is a fiber, you can see.  You're welcome to touch it.  This is a fiber.  So that's what I'm talking about  the nanofibers right here.  So this is made up of lactic  acid. 

 So a little bit sticky.  So let me pass it and everybody  has a sense kind of feel it.  It's very exciting stuff.  Okay, it's very sticky.  Nanofiber about 300 nanometer.  Okay, so you can pass it.  And make sure the last person  has the opportunity to touch it.  Don't get all the way around and  the first couple person.  Okay, so let me explain this.  Okay, here. 

 This is actually the material we  make.  Can you imagine 42 days ago it's  a fluffy fibers.  The best way to say it's the  cotton ball.  Just like a cotton ball.  Then 42 days later you get this  piece of the cartilage with the  real tissue.  And all this material inside is  the real cartilage tissue.  Okay, it's no longer fibers.  So because we have a very  optimize, we have optimized the  produces so we can grow a piece  of cartilage like this.  And then I want to also show you  the differences between these  two.  This one provides, because of  the environment, circulation, as  well as mechanical stimulation. 

 It makes the surface of the  cartilage smooth.  That's what we expect to see.  And the other one, if you look  at it carefully, actually it's a  little bit rough but it's still  a tissue but not a smooth  tissue.  So that makes the differences  under the two different  environment.  Culture in the dynamic versus  the static.  They get a different kind of a  surface.  But looking at this graph here,  this D which means the dynamic  culture, S means a static.  What I want to tell you is after  42 days this whole piece  increased 12 times weight.  Which means if they are one  gram, 42 days later they are  12-grams.  If they are 100-gram, 12 days  later they are 1200-gram. 

 So that's much, much more which  means they have something  growing inside.  We hope that's a cell.  Let's look at if that's a cell  or not.  We have verification we can tell  you they are cartilage tissue.  So let's look at it.  So, by the way, I want to tell  you we have a two patent  technology protected.  This is under the protection.  There are several biomedical  engineering company or the  pharmaceutical company have  contacted us and they try to see  they can purchase this  technology.  Hopefully, my personal hope is  once they purchase it they can  really use this technology to  improve the quality of the  patient's life.  That would be great. 

 But I want to tell you we have a  two related patented technology  related to what we have just  showed you.  This material engineered  cartilage we produced.  Okay, so when I look at this  material, and also the tissue,  it looked like a cartilage,  right?  So it's like a cartilage.  How about microscopically?  So people doing the testing on  the cartilage, they want to know  how about histologically.  Can I section it, look at the  cell inside.  Are they real chondrocyte or  not?  That's what we are saying here.  I want so show you here.  Focus on this.  This is the first time being  done.  Actually haven't been done  before. 

 What we try to do is we grow the  cells.  All these red dots here are  cells.  If you look at carefully these  cells are spherical.  This is very important future  for the cartilage.  Chondrocyte cells are supposed  to be round shape.  If they are round shape, they  are likely a chondrocyte cells.  And also inside there's a space  called a cuna.  This is an anatomic future which  is open structure cell sitting  there.  Why is it important?  Because this anatomic future is  the future of a cartilage.  If we see this in anatomic  futures we can say this is a  cartilage. 

 That's what I'm trying to say  here.  And also the blue color here is  the color indication of the  protein glycin.  Like I say, they have to be  surrounded by many, many  different protein glycin.  When you guys go to the  wholesale place, a lot of people  I know they take a supplement  and that's called --, the  company, I did not try to sell  this product.  But what I try to tell you is a  supplement, they have are a lot  of stuff which the is protein  glycin or glucosamine.  Glucosamine is part of this so  they can actually eat it and  then supply it, this  glucosamine.  So this glucosamine, you can buy  it.  We make it into your joints, and  this engineered cartilage has a  lot of glucosamine here or  protein glycin here which is  indicated by the blue color.  So that's very important.  And also if you look at this by  the SEM you can see the layer of  the tissue which is on the top  of the fiber. 

 It never happens before when we  have a fiber, only fiber.  But now you can see all this  engineered tissue has been  layered on the top of the fiber.  That's important.  So microscopically, they look  like a cartilage.  Doesn't necessarily say that's a  real cartilage.  What do we do as a scientist?  We have to check the ID.  This is what we do for checking  the ID.  So the ID which means they have  this ID they are cartilage.  So what happened here?  Don't worry about this thing.  So I just want to tell you  collagen type 2, collagen type  9, collagen type 10 which is  another --, these are important  for the chondrocyte cell. 

 If they are showing, the cells  showing this molecule, they are  chondrocyte.  They are the chondrocyte cell.  So we is successfully making the  cartilage from the mesenchymal  stem cell.  So we check their ID.  Yes, they are cartilage cells,  they are chondrocyte.  So that's what I'm trying to  show you here.  And right here I just give you  -- quantitatively compare the  dynamic culture engineered  cartilage has more those markers  I'm looking for.  Which means they produce more  matches compared to the static  one.  That's what I'm trying to say  here.  I'm trying to use the plain  language to explain it to you. 

 This is very easy to tell by  this kind of explanation.  Okay, so we make it.  What happens if I want to do  this cosmetic purpose?  I have tried to do this for the  repair of engineered cartilage  for the people who has the  osteoarthritis.  What if some people want to have  a nose jobs, ear jobs?  They want to have a higher nose.  Can we do that?  We can actually do that.  This is actually the work we did  for fun.  We tried to shape this  engineered cartilage.  We make it into a square.  We make it into a square, and  also we can make it into a  triangle.  Any shape we want, any size we  want. 

 This is what happened in my  laboratory.  So we make elastic cartilage for  cranial facial reconstructive  purpose.  That's what we're trying to do  here.  So I just want to tell you we  can make a cartilage.  We also can make any size of a  cartilage.  We also can make any shape of a  cartilage.  That's what we're trying to do  here.  Okay, so the next study is, one  of the biggest problem is we  successfully make an engineered  cartilage.  We can make it, so what?  What's the most important thing  is you want to implant it into  the patient.  The biggest problem of the  implantation is the implant  doesn't integrate well with the  host tissue. 

 Once you implant there you want  them to communicate, the  engineered tissue or artificial  tissue implant with the host  tissue.  They have to talk.  They have to form some kind of  integration.  So that way the engineered  tissue can stay there long  enough time.  So what we try to do here, what  I want you to understand, how is  my invention going to integrate  with the host tissue.  So what we do is we make a  tissue like what I described to  you and then we take that  engineered tissue, we punch the  hole and insert a native tissue  inside.  Make it like a doughnut.  So you have an engineered tissue  outside, native tissue inside.  So I want to understand what  happened to this integration  interface between engineered and  host tissue so I can understand,  okay, they are integrated well  or not.  This is what I'm trying to do  here. 

 Here you go.  So we did actually have the very  successful result.  You can see right here on the  top it's hard to see from this  resolution but up here is the  engineered tissue.  On the bottom right here is the  native tissue.  So you can almost not able to  see obvious interface between  them.  Only this one.  So which means there's no gap  between that.  They have a very good  integration.  Those integration is very well  between these two piece.  No space, no gap. 

 So they are cross taught.  They have the cell cross the  other side and the other cell  has the other side cross over.  So that's what happened here.  And also we want to test it by  the strength by pushing them  out, try to mechanically  separate it and see what  happened.  If they are true integration,  you have a problem, you really  have to spend a lot of efforts  and try to pull them.  If they are not true  integration, you can simple  separate it by using the two  hands that's easy to separate  it.  So that's what we are trying to  do.  This is called push-out study.  So we pushed it.  We get very good result. 

 So this study just showing you  this condition we're giving you  the best condition.  Which means you culture in the  dynamic culture and then make  that dynamic culture engineered  cartilage put into the dynamic  culture condition for  integration study gets the best  result.  That's what I'm trying to do  here.  So that kind of indicated or  suggested our body providing the  mechanical loaded was the  dynamic circulation unimportant  for integration.  That's what I'm trying to say  here.  All right here is the real  stuff.  A lot of pharmaceutical  companies are looking for this  piece of data.  Before they try to buy the  patent from us.  First of all, I haven't sell the  patent so don't expect I will --  but this is hopefully is the  case we can use this as a kind  of a technology we can use that  for the future orthopedic  application.  I can explain it to you. 

 But before I say this, this is a  very typical process people do.  You make a tissue.  You study the tissue inside the  chamber, we call it in vitro.  Inside the container.  Then you got a very good result  by optimizing this material,  getting the good composition,  make cartilage look like a  cartilage, function like a  cartilage.  That's not enough.  But most importantly is you have  to make this really put into the  body.  But you cannot find a person and  say are you willing to be my  guinea pig I can put into your  body.  No, you can't.  First what you want to do is you  want to use the animal. 

 The animal, unfortunately, will  have to, even I'm not a big fan  of animal study but this is what  we have to do before we have can  do a human study in the patient.  So this is what we do.  But we have option to use a  different animal.  You can use a rat.  You can use a rabbit.  You can use a goat and sheep and  pig.  We use a pig.  The reason is a rat has very,  very tiny joints.  I cannot operate on them.  It's very hard to find the  joints. 

 Then we have a rabbit.  And rabbit is good but a rabbit  has a different anatomic  geometry.  Their joint is not straight  down.  Their joint is kind of a bent.  So the rabbit joint cannot  really represent the human  joints.  And then the other option is the  pig and pig is a good size and  normally it will give you a very  reasonable similarity between  the pig joints versus the human  joint.  That's what we're trying to do  here.  Okay, so we have the pig and  then we try to create a defect  artificially.  So what we do is, unfortunately,  we just have to kind of create  it using the instrument create  an artificial defect right here.  We move an eight millimeter  defect right here on the joints. 

 And then we put this engineered  cartilage back here and insert  the material right there and  cross the wound and release the  pig.  Have the pig walking under  normal condition for six months.  So that six months they have no  restrictions, they do regular  activity.  So what happened six months?  We opened the joint.  We can see focus on this area.  It used to be a hole right  there.  A big hole, a big defect.  Completely repaired.  So you can see the defect is  gone.  The repair is successful. 

 So what we proved here is it's  not just an engineered cartilage  we made.  It looks like engineered  cartilage.  What we put in there actually  repaired the defect site.  And then if you look at the  color of the defect versus the  color of the host tissue which  is here look very similar.  That indicated they may be the  similar type of the tissue.  And the regenerated material  maybe is the real cartilage.  I will tell you are they real or  not.  But look at this  microscopically.  They look like a cartilage  defect has been repaired.  That's the case. 

 And if you focus on here, you  can see this used to be a hole  and then it's gone.  So it completely recovered.  This study is trying to  understand if I can use beside  chondrocyte cell, remember 5% of  the cell in the joint is  chondrocyte, very low.  So what if I can use other  patient's cell like a --.  I want to have a surgery.  I can use my brother's cells, my  friend's cells.  Can I do that?  In this case, I use the human  cell in the pig.  Can I do that?  This is a study we're trying to  do.  So I want to tell you we found  it very, very interesting result  this work just published in the  Journal of the Tissue Engineer  and Regenerative Medicine.  What happened here is we proved  this mesenchymal stem cell has  no any immune reaction to the  cells. 

 Human cell gets to the pig.  There's no reaction.  I don't know exactly why we are  doing further investigation.  But it has been well documented.  mesenchymal stem cell has immune  regulation also called immune  separation.  So what happened is they are too  young or too preliminary or too  early stage of a cells so they  end up they are not developing  any kind of a surface marker  which will be recognized by the  other patient's immune system.  So they will be kind of escape  around this territory without  being recognized.  That's what I'm trying to say  here.  So this has to be further  investigated.  But I'm trying to tell you is  you can see that X here is a  human cell try to repair pick  defect. 

 And then we found it very  successful.  Actually it's better than the  pig chondrocyte cell trying to  repair chondrocyte defect.  So what I'm trying to say here  is mesenchymal stem cell is  better doing than chondrocyte  cell.  And we also can use the  different species and even  different patients without any  problem showing here.  So that's what I'm trying to say  here.  So this is the result we show.  And then I want to show you  focus on right here.  You can also get another piece  of data right here showing you  it used to be a cartilage defect  right here and then the defect  is gone.  It's no longer a hole here.  There's no hole. 

 It's basically, it's just  repaired cartilage.  This part of a tissue is totally  regenerated in that six months.  That six months give the pig  enough time for the chondrocyte  cell, for the mesenchymal stem  cell turn into the chondrocyte  and repair the defect right  there.  And then that doesn't happen to  the defect only which means we  created a defect.  We do nothing about it.  And there's no soldier right  here.  Only structure, only house,  house right here.  And this case is the different  tissue, different cells.  So what I'm trying to say here,  to sum up what I'm trying to do  here is we have the mesenchymal  stem cell which did a good job  compared to other conditions.  Okay, so here is the functional  test. 

 We did a previous study, I just  showed you the previous slide  shows the histology look like  all this repair job was done  okay, was done very well  actually by the mesenchymal stem  cell.  But what if they are  functionally good.  Do we want to know are they  strong enough to stand  mechanical loaded.  We just want to have a piece of  the cartilage also functionally  good.  So what we try to do here is we  test the mechanical loaded on  the material on the tissue it  regenerated which is the  mesenchymal stem cell  regeneration.  So we can see the equilibrium  stressed has a highest numbers  compared to other group.  Which means over the time this  tissue based on mesenchymal stem  cell can stand loaded for a  longer period of time compared  to other conditions.  That's what I'm trying to say  here.  Okay, don't worry about  equilibrium.  But that's the case if we make  the tissue from mesenchymal stem  cell it can stand loading longer  than the rest of the tissue it  generated from other tissue. 

 All right, so my laboratory has  focused a lot of work on  regeneration of cartilage.  But we also focus on other  because my lab is muscular  skeletal tissue engineering.  So we do, besides engineer  cartilage, we also do -- and we  also do the long bone.  Try to repair bone defect.  We also tissue engineer tendon  and try to repair tendon and  ligament tears.  That's what we try to do.  And these applications are  currently investigated in my  laboratory.  All right, so very close to the  end of my talk so I want to give  you a piece of information about  bone.  So what we try to do here is  using the similar idea  regenerated bone tissue.  So what we did is we add the  bone powder. 

 A bone powder provides a lot of  important growth factors and  that will tell the mesenchymal  stem cell to differentiate it.  So what we do is we have a cell,  fiber, bone powder, mix  together, grow in the bioreactor  get this piece of bone.  So we can make a bone, we can  make a cartilage.  What else we can do?  So we modify the structures.  Modify the way we do the  nanofiber.  We add rotating drum right here.  By spinning of this rotating  drum we can actually make the  fiber become a live structures.  It's no longer just a fiber you  guys just see those are the  fiber basically non-oriented.  They have all the different  directions fiber orientation.  There's not specific oriented  fibers. 

 But we can orient this fiber.  Why that is important?  This is the reason why it's  important.  We have a lot of tissue which  has an isotropic mechanical  property.  What does that mean an  isotropic?  Which means in a certain  direction it requires higher  mechanical demand such as  tendon, right?  The tendon has the specific  orientation which requires  certain type of the mechanical  loaded specifically recorded for  this direction.  And then we can also make it  muscle.  Muscle also has specific  orientation of fibers.  And also meniscus.  So all this we try to do is we  want to build the nice house  which is constructive to the  cell.  So what we do is we make it  nanofiber into the small  oriented fibers bundled.  So we can put cells and we can  reconstruct the tendon muscle  and meniscus. 

 So one day when the football, as  well as the baseball player who  got injured they actually wait  for the engineered tissue I can  isolate a mesenchymal stem cell  from them and then put it into  my tissue construct and grow it  for six months or even 42 days,  depends on how big you want your  tissue to be, and then I can  call the patient back and have a  piece of engineered tissue for  them to implant.  So they don't need to get a  piece of tissue from a cadaver  or from other part of their body  in order to get a healthy  tissue.  We can do the engineered tissue  without any problem.  So before I go to the last part,  I want to tell you this is going  to be what I picture about  tissue engineering.  Everybody have heard tissue  engineering based treatment.  And most importantly I think a  lot of people coming to me and  ask me, hey, my wife is looking  for the opportunity to save  umbilical blood stem cells  right?  Have you heard this?  Umbilical blood stem cells.  So there is a cell bank and they  will preserve your cells for you  and for future use.  Can we do that?  It is possible but what happens  in the future is I think people  when they have the opportunity,  what they are trying to do is  when they were first born in the  hospital, there is a certain way  we can get your stem cell.  We can save your stem cell in  the cell bank.  Everybody will have their own  stem cell cell bank in the  hospital. 

 Then they will go home and  happy.  50 years later they say doctor I  have a problem with my joint, I  have a problem with my tendon I  want to get it fixed.  Okay, go back to your hospital  which has stored your  mesenchymal stem cell or other  stem cell and then pull out  those cells and give it to me as  a tissue engineer and then I  will send that person to CT or  some other type of image system  checking the defect size and  with that defect size  information, I will be able to  make engineered tissue according  to whatever the information they  got from the image.  And then I make a tissue like  what I just showed you.  Three months later I call that  patient back, your cartilage  tissue is ready.  So you can come back and store.  So that's what can be done.  So that's what I think will be  the future of tissue  engineering.  And, of course, this is not  science fiction.  But to be realized this kind of  progress I just mentioned, it  will take time. 

 It's not going to happen  tomorrow.  So a lot of time after I give a  talk what happens is a lot of  people come to me and they say  hey Dr. Li I think this is very  good.  I like your invention, can I go  talk to my doctor tomorrow and  then try to tell them or  convince them can I just get  your invention restore in my  knee or can you just put your  invention in my knee and try to  solve the problem for me.  This is not the case that will  be in the next couple years.  Because we are still looking for  the opportunity to optimize our  system.  Also, there are a lot of  regulatory effect.  You want to make sure this is  safe for the patient.  Before we can do that, we have  to do a lot of animal study to  prove this is safe.  So it will take some time but  eventually I think it is going  to benefit all of us, including  myself.  That will be the future of  tissue engineering so I hope  that will be the case. 

 I really enjoyed coming here and  do work.  And then I want to mention what  I'm trying to say.  This work is done by many, many  different type of persons.  Meaning the different scientists  has the different background.  Some of them are the cell  biologists.  Some of them are the material  engineer.  So my laboratory is not a  traditional so-called  biomaterial or biomedical  engineering or even a cell  biology lab.  My lab has all kind of people.  We have these people including  physician, surgeon, we all work  together as a team.  I recently moved to the new  building called WIMR, Wisconsin  Institute for Medical Research. 

 That is the institute encouraged  the interdepartmental  collaboration.  Even people has the  multidisciplinary background,  they work together under the  same roof.  That's what we're trying to do  there.  So my lab has all kind of  people.  They all work together trying to  get this dream come true and  that's what we are doing in our  laboratory.  And then finally I want to thank  my advisor or my mentor.  In -- when I was working there  as the postdoc, I was working in  the cartilage, biology and the  orthopedic branch under  Dr. Rocky -- who is my mentor  for several years.  And also I recently just moved  here.  Actually this is going to be my  anniversary moving to Wisconsin.  Before I moved here I was  actually moving here January 21  or 22, 2008. 

 That's exactly almost like a one  year anniversary before I take  this position as assistant  professor.  But I enjoy coming here and it's  my pleasure to have the  opportunity to talk to you  today.  Thank you.  [APPLAUSE]  >> Any questions?  >> Yes?  >> In the example of your  cartilage that you grew and you  showed its formation of  junctions with the native  cartilage, do you have any data  on how many days or how long it  takes for that junction to  become mechanically secure?  >> Okay, the question is how  many days it takes to get the  engineered cartilage and host  tissue cartilage integrated  together with the meaningful  integration meaning they are  mechanically strong and  biologically strong.  In that specific case, we tried  42 days.  And it can be probably shorter,  but we never actually tried a  different numbers of days.  I am guessing at least 21 days  is needed, three weeks, but, in  this particular case, we do six  weeks and we found it meaningful  or mechanically strong enough  integration between these two  pieces.  Any other questions?  >> So basically you're just kind  of like cloning --?  >> Coding?  >> Cloning.  >> Cloning.  Not really. 

 We did not do any cloning job.  What we are trying to do is  create it.  Cloning is basically you use  something which you have a  template.  You try to create it from the  original template.  Become the identical stuff with  your template.  But what we try to do is open  another door.  We make it another tissue which  is exactly different than what  we have before.  Nothing to do with what we  usually used in the tissue.  What we try to do is we have  several parts of the material,  put them all together and they  become another type of the  material which has nothing to do  with the other three.  You see what I'm trying to say. 

 So this is good question but I  don't know exactly how am I  going to answer you correctly.  But this is not cloning.  This has nothing to do with  cloning.  This is a regeneration.  And -- processed, we try to make  it from nothing to something.  Or from something we put it  together has no meaning at the  beginning but when we put them  together they become meaningful.  Each one of those.  They work together and become a  tissue we want.  That's what I'm trying to say  here.  >> Have there been developments  in getting the mesenchymal stem  cells to differentiate into the  cell type that you want?  Is that fairly new?  >> The question is the  differentiation between  mesenchymal stem cell into the  different cell types. 

 Are they well documented or are  they new, are they just recently  discovered or they have been  well documented?  The answer is they have been  very well documented.  In the different laboratory in  the different part of the world,  in a different lab, they all  have the different kind of ways  to differentiate this  mesenchymal stem cell into  certain type of cells.  So what kind of instruction  signal, for example, like what I  need to make the mesenchymal  stem cell become cartilage or  what do I need to make the  mesenchymal stem cell become  bone tissue, they are well  discovered.  People all knows what molecule  are needed to make the  mesenchymal stem cell into the  cell type we want.  But the question is even you can  make it successfully, there's  always the room to improve.  To make it more stronger  mechanically, as well as  biologically.  And also this material are  supposed to be on three  dimensional otherwise it won't  form a reasonable structures.  We want structure.  We don't want just a piece of  the cell or a bunch of cells  just floating around.  We want them to become  structurally meaningful  interaction meaning this layers  of cell has to be meaningful to  me in terms of their location. 

 So what we tried to do here is  we make a three dimensional  structure on top of what they  already know, somebody published  how to make the cell become this  cell, on top of that, we  provided our input which is a  three dimensional structure more  important to make this  mesenchymal stem cell  effectively differentiated into  the cell type.  That's what our contribution is.  Just based on the mechanically  or chemically, that's not  enough.  We are interested in making it  into the structurally strong.  Which is the nanofibers job.  >> How long does the nanofiber  substrate last?  Does it go all the way into the  host when you plant it into the  pig?  >> Is it your question asking me  how long it takes to degrade in  the body?  That's a good question.  This biomaterial, or we call it  nanofiber, is made of lactic  acid.  There are many, many different  type of biodegradable you can  use.  Depends on the chemistry.  So you can design or you can  tailor the property of  degradation. 

 This particular one called  polylactic acid.  It takes about six months to  degrade.  And you have other option which  you can use called polyglycolic  acid which can degrade in two  weeks.  So by using this ratio of PLA,  which is polylactic acid and  polyglycolic acid, two weeks  versus six months, mix them  together, I can tailor the  degradation between two weeks  and six months.  Did you get me?  So what I'm trying to say here  is this material has been well  used.  A lot of time you go into a lot  of people maybe have surgery  already.  When you go to the surgery room,  those surgeons using some  so-called biodegradable suture  to suture the wound.  That is the material invented 30  years ago.  We use the same material what  they use to make a suture.  So this is suture-based  biodegradable polymer which is  not harmful, which is  biocompatible that will  eventually be degraded in the  body. 

 And then eventually when they're  degraded they become carbon  dioxide and water and can easily  be released from the body.  Non-harmful, non-toxic to the  body.  So degradation it takes about  six weeks, six months, I'm  sorry.  >> [INAUDIBLE]  >> Okay, at that  point of degradation, does other  cells fill into the space, the  void?  >> Yes.  That's the whole point.  Degradation and production of  matrix has to coordinate each  other.  If the degradation goes too  slow, they occupy the space, do  not release the space for the  cell.  It hurts the cell to produce  more matrix.  But if they degrade too fast,  the structure collapse too fast,  what happened is the cell will  fall apart.  They have nothing to hem. 

 And mechanically they will  become very week because the  degradation too fast caused the  problem of the degradation of  the mechanical properties.  It collapsed so the cell will  have a problem.  So you want to design the  material which will make the  cell produce the matrix exactly  the same rate of the degradation  of the polymer.  So it goes up, the other goes  down so eventually they make  even.  So that will be the best but  that's ideal situation.  Body won't allow you to do all  the job you want.  You tell it what you want to do  and they will end up being the  same what you want.  But we can try our best.  Okay, is there another question?  >> When you use the pig, for  your animal studies, I assume  they first have to be  anesthetized, is that right?  For the surgery?  >> Of course.  >> Of course. 

 >> Anesthesia, right?  >> Pardon?  >> Are you talking about putting  them to sleep?  Kind of a numbness.  Make sure they are not feeling  any pain.  We use a chemical to make sure,  we kind of numb the animal to  make sure they don't feel  anything.  >> And then when that wears off  and you release the animal, do  they scamper off or do they limp  off.  >> Well, first of all, I'm not a  pig, I don't know what they  feel.  But we have all this necessary  regulation for animal  protection.  Every time we do animal study we  do know what we have to comply  our regulation in terms of good  treatment to the animal.  So we make sure the animal don't  feel that much pain.  But there is something we can  do.  We give them some kind of  painkiller. 

 We also give them some kind of  fixation.  But this animal, amazingly to  me, we kind of do a surgery that  day, the next day they walk  normally without any problem.  That's something I can tell you  from my observation.  But if we see something happen  to this, if they kind of walk  differently, they walk normally,  we actually give them some kind  of painkiller and make sure they  don't feel bad.  That's what we can do.  This is all under the regulation  of animal protection.  This is in our project when we  started animal started.  All right?  So one more question?  The last one.  >> In the example you showed  where you had the disk of normal  tissue and then you cut a circle  to put the transplant in, in  some ways was a ideal situation  because the transplant was  surrounded by potentially  nurturing cells, but in the  joints of people who are my age  and older there are often very  large areas where you couldn't  really do that.  Do you have any experiments that  show that the transplanted  cartilage will just adhere to  the surface of the bone without  necessarily needing the  surrounding tissue?  >> Yes, this is actually one of  the biggest problems of the  engineered cartilage because  engineered cartilage is a piece  of a cartilage on top of the  host tissue. 

 How are we going to securely  attach that on the surface of  our original or host tissue.  It becomes a very essential  study.  People are trying to do that.  In my laboratory, we developed  another approach like what I  described before.  People use osteochondral plug  which means if you have a  cartilage with the bone part it  will make the insertion or the  implant fix in the specific  target more securely.  So we actually intend on  purposely design osteochondral  plug which means we make a  cartilage successfully using our  technology.  We also make a bone successfully  using our technology.  We combine them together become  osteochondral.  When we see patient who has  problem with cartilage, we  intentionally put the construct  down to the bone part.  What we do is we create a defect  all the way. 

 Even if they have intact bone,  they have a healthy bone but we  try to make it defect all the  way down to the bone part,  created a plug with the bone and  cartilage.  So when we have our engineered  cartilage, we pressed it there,  it has the support from  cartilage, as well as the bone.  So when we pressed it normally,  this approach can give us very  secure in fixation and normally,  without even suture, this whole  osteochondral plug will stay  there very well.  So that's what we're trying to  do here.  So your question will be  answered if we design the  cartilage with the bone part  which is osteochondral plug.  Normally this problem can be  easily solved.  It's not a big deal.  And also surgeons like it.  Surgeons like to have something  easy to handle.  Surgeons don't like to have a  complicated procedure. 

 When you ask them this is going  to take 20 minutes versus the  other guy that's going to take 2  minutes, which one are you going  to use?  They will tell you I'm going to  use that.  But this 20 minutes gives you  good result, they say I want to  use something fast and quick.  They don't have that much, you  know, time to waste.  So they are trying to open the  wounds and then put in there and  close the wound as soon as  possible.  So we also want to design a  construct which is easy to use  and a fast healing process.  All this has to be in  consideration of our product  design so that's what we're  trying to do here, all right?  Thank you, very much.  I appreciate it.  [APPLAUSE]