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>> You know it's just terrific to be here. It's really really pleasure and honor and. The last time I looked at this building was a hole in the ground. So it's amazing to see this this incredible structure and the structures populated by it's a great group here so it's it's real nice to be able to tell you something about what our Engineering Research Center is doing.

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We actually have an area Engineering Research Center N.S.F. center is you web sure many of you know we actually have quite a bit of activity these days and tissue engineering also and so I could have talked about that but I thought it might be more interesting to hear what is going on at the University of Washington in biomaterials and I'll try and make this case about the I think the very close.

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Maybe intimate relationship between biomaterials and and tissue engineering. So let's see I got the Nano word in this title and actually it's a pretty good way. If you're given a poster of talk in a meeting or something and you want to get a double your audience just put the Nano word in doesn't matter if it's relevant and I just put it in so well made the audience smaller.

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OK So you know as you travel around the that's the sort of a circuit that many of us in via materials go on around the world and bioengineering and there's lots of talk is nano this and and all that and I just want that is where these nano ideas came from at least my thoughts and then and how relevant are they to the to my central interest which is bio compatibility and maybe how we can explore to use these nano ideas that's really were gone in this talk and let me let me give some interesting credit to where I think some of the earliest work in nano came.

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From And this woman that actress pocalypse she is a self proclaimed housewife lived in Germany and in fact took care of some elling relatives in our house but was fascinated by science and did a bunch of interesting experiments in her kitchen with soap bubbles and soap films and was a careful observer and Agnes packages actually wrote a letter describing her observations to Lord rarely in England the letter was in German really had a translator read the letter and published a letter intact in nature which is you know something you can look up to for experiments you might have done in your kitchen in any event what her what her work really did was describe nano scale thin film structures and she she had based upon just sort of observations careful observations and measurements done a pretty good job of understating the dimensions the Nano dimensions of these sort of things.

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So you know this was a true nano technologist well before her time. If I wanted to put one person before her interest me would be Ben Franklin but I didn't have time to get into benefactors contribution to this. In any event if one continues on this progression of where nano came from you talk about J. Willard Gibson gives in his exposition on therm with an admixture describe what an interface or surfaces and he described this is exquisitely well that there's nothing more to be done the wood Jay will it gives describe theoretically in his work which was published in that journal we all read which is the transactions of the Connecticut Academy of Sciences actually took a while for Gibbs to be recognized published in a.

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Not not the best place but Connecticut I think they like it so. So anyway Gibbs gives described. Sort of a surface in an interface and again the dimensions were nano and then we had people going into the beginning of the twentieth century is it Monday in. Hungry describe Kahlo oids in Irving lying here in New York described in limited films working with Catherine Blodget Langer Blodgett type films.

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So these were all nano sort of inventions or gone a long time ago but kind of that we were to where this modern nano thing come from. Well obviously people attribute a lot of this to Richard Feynman's. Seminal talk at Cal Tech in one thousand nine hundred fifty nine and Fineman said you know the principles of physics as far as I can see do not speak against the possibility of maneuvering atom by things atom by atom.

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It's not an attempt to violate any laws. FINEMAN stimulated our ideas from work that really was going on. Nano engineers as a said were doing it. Well back a bit of the time event Franklin. But in any event Fineman opened their eyes to the possibility and then some place who in one thousand fifty nine in the year two thousand Bill Clinton also Cal-Tech gave a talk which was incredible talk for a president of the United States Bill Clinton is a visionary talk.

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Bill Clinton started imagine the possibilities of compressing the entire Library of Congress into a volume the size of a sugar cube imagine the possibilities of nano machines treating blood and things like that just to hear these words from a US president was really quite quite remarkable. But what went on between fifty nine and the year two thousand.

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Well. Wasn't that the Nano community was asleep between fifteen and two thousand the molecular biologists and molecular bio engineers were quite busy what molecular biologists was doing were discovering and even using a remark. No machines and. I don't know if people seen this amazing piece of work but basically there's an A.T.P. ace molecular motor molecular motor has six protein subunits and a protein like Shaft in it.

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This is going on in every one of our bodies the shaft. Turns I believe it. Seventeen times a second powered by A.T.P. it's an absolute remarkable structure and nobody people have isolated it studied it. Nobody really knows how it works. We don't have an idea yet but it's incredible man a machine and one group actually fabricated a little nickel pillars on a nano scale connected into the shaft to make a little motor that spins around this is a example of a real supporter of nano machine maybe something we'd like to do and then sort of the science fiction writers and of people have seen this this image of just won a prize but it's an absolutely remarkable image of maybe what we're daydreaming about a nano some sort of remarkable Gelug nano machine that's going to come along and do some sort of interesting process for most of us would say why would we want to inject something in a red blood so we don't exactly know where we made a great image.

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This is obviously an artist's conception of the future and it says something interesting about nano. But we do have people like like Ned Seaman who is taking D.N.A. and Ned Seeman doesn't really care about the fact that there are codes and signals and coded in D.N.A. He thinks it's an E. construction tool and he uses the ability and C.N.A. and tape it to connect to make incredible molecular nanostructures So just another example of the molecular and cell biologists I think doing remarkable things in nano before we use the Nano.

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Word. Well we have some sort of scaling relationships we're going to think about here. We're going to protein is a terrific nano machine and in fact Charles Stanford It's one of the. Classic pioneers in protein biochemistry and published very widely in the sixty's very influential work in the one nine hundred sixty S. just came out with a new book called protein protein machines or something like that very interesting philosophy on proteins as machines but in any way we have proteins clearly a nano scale structure and then D.N.A. D.N.A. We have chains that are roughly two nanometers wide but can be microns long and interesting with scaling in D.N.A. and we use D.N.A. and devices these are some linearize D.N.A. chains are actually done in our laboratory in a flow field and then people are putting these into so-called memes devices and people even memes are micro electrical mechanical systems but people are doing flow micro flow systems and even thinking about nano flow systems and these are again more likely at a nano scale or a micro scale but we're for example putting coatings on these things that are indeed nano scale dimension coatings they do things in these channels.

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And these things go into devices D.N.A. type chip again now in the micron scale and finally up to medical devices which are clearly Micron scale or exist me a centimeter scale in the case of devices like this and. How do these relate to. Nano well as I see it.

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The ability to use nanotechnology to modify the surface of a medical implant device maybe with proteins is the key. I think to the future and it's. We think it's clearly a nanotechnology. When we started our Engineering Research Center. We didn't use the Nano word. Little did I know we could have gotten even more funding up and used it but so it anyway.

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I think we're doing nano and and how can we use these nano concepts in designing biomaterials that's where I want to go. So let me give a quick introduction to modern biomaterials and ask how nanotechnology can help and I always like to introduce modern biomaterials with this image this is where I think the field of biomaterials in its modern sense started and looks like kind of a usual picture to launch into this idea but this plane flew over the European theater in World War two and.

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You know there were aviators machine gun us assigned to sit here and you know we're just the last place you really want to be sitting with the enemy coming down with machine guns firing is right out in front as you might imagine the injury rate was extremely high for these these tore sides that they got assigned to that spot and after the war a British British surgeon was examining the eyes of aviators that got massive sprays of shards of plastic often in their eyes and the eye is an interesting window into the body.

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So the aviator just or the surgeon just looked into the aviator's eyes and looked in there and saw these shards of plastic that were accidentally implanted years before into these eyes and they were just sitting there and he's looking in that they're not inciting a reaction. The conventional wisdom at that time.

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This is a very striking observation conventional wisdom was anything like a splinter or a foreign body would incite a reaction. And here they were just sitting there so he said this plastic must be bio compatible and he went to I see I cooperation and bought a sheet of the stuff and fabricated implant lenses for the I with it and this is this is what I think it was the first real observation of what we call bio compatibility.

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Today and that observation. Again roughly fifty years ago is led to an injury to injury lead to an industry with quite a range of common medical implants and I just have a few of them you know just kind of glibly illustrate your finger joints are the the infamous breast implant or heart valve or a hip joint or artificial heart or here's this this plastic lens that was made out of in fact to this day.

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Many of them are still made of the exact same material that they gunnery Cabot canopy was made out of polymath and with actually the same kind of polymath with accolades. So from a very interesting observation industry has arisen and in fact the industry has reached the point where it's entered sort of the public consciousness and this is something I found in a newspaper personal ads as mint condition mail nine hundred thirty two high mileage good condition some hair many new parts including hip knee cornea valves doesn't run to walks well.

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So you know people just think very casually these days about all these replacements it's not something that only only scientists and physicians know. And another field again just to show these relationships that has sprung up as tissue engineering obviously that's the major focus here and a field of great scientific and technological excitement.

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Like I said by materials are important. Even with tissue engineering on the horizon and so I've shown this diagram to illustrate the connections and and you know if you look at really the relationship biomaterials now is one hundred billion dollar market. Tissue engineering is still kind of near zero.

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Everybody says it's going to dominate the whole field. Obviously a tissue a living tissue construct has many many advantages over synthetic buying material but a. The moment it's kind of quiet from an economic standpoint and biomaterials help millions of well are a few people that I have skin products and but in tissue engineering a biomaterials biomaterials they used both a look into modern biology.

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Biomaterials has had steady growth over over forty years with with really no sign of slowdown and the tissue engineering course is showing explosive growth and continues to do so. So there's interesting relationships between these two fields. But to get back to buy materials which again go into most tissue engineered constructs.

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We've had some success. We have. Worldwide millions of devices. I'm not going to read down the list but there are millions of devices that go into humans the U.S. health care market in one thousand nine hundred eight exceeded a trillion dollars And it's it's actually pushing towards two trillion very rapidly.

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If you look at the federal estimates of where the health care market is going and we have millions of lives saved in the quality of life improved for millions more pretty impressive record but. Another way to look at this is to ask how a biomaterials really do work and.

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Again these in tracking lenses these I implants based upon that observation with the shards of plastic. Yes we're putting in seven million per year worldwide. But there's a twenty five to fifty percent re operation rate on these these devices which is a huge cost to the health care system trauma to the patient obviously the hip and knee prostheses.

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Were developed by a British surgeon in the fifty's and the surge on Charlie the original Charlie hip implant lasted ten to fifteen years and you look at the modern data which come from for example Sweden all Center study on hip and knee implants and and they report ten to fifteen year life times two on the average through.

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The whole country and through many many years of data. So there's still a lot of room obviously to to improve these sort of things vascular graps blood vessel prostheses were developed in the sixty's in fact originally from parachute cloth of all things but the vascular grafts were developed as poor structures to heal to infuse cellular regrowth and reconstruction and to this day we still don't get healing on bascule graps heart valves calcifying thrombosis perky Janie's devices through the skin a supposed to seal to the skin.

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They just don't. Stimulatory electrodes and capsule eight catheters have problems with thrombosis infection leading to thousands of deaths a year blood cardiovascular stents clot and close contact lenses lead to the discomfort and even permanent eye injury dental implants loosening listen the list goes on and on there are yes successes with their biomaterials but there are profound problems too.

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And so these are problems of much concern but interesting where we have problems we also have opportunities opportunities are suggested to do some new things and we have to ask why the complication rate and what can we do about it. So it sort of a central premise of the biomaterials field has been that the surface of the material dictates the biological reaction classic sort of mildly draws a bio material and the surface adds orbs a layer of proteins the absorption is almost instantaneous within seconds from biological fluid and then cells come along and interrogate the material so what do they see they really don't see the bio material they see some say some proteins that were driven by the surface.

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And so we have to ask how does the surface that attracts the proteins dictate healing. And so we can sort of expand that diagram and again we have a bio material in the materials and planted that's really an injury. Implantation is an injury and then the by material goes into some body fluids and has a protein absorption layer and then some cells come along like the neutrophil and macro fires to interrogate the by amateur and these cells in response to the material are going to release some soluble components cytokines protein components typically which would go and talk to cells and one of the things they seem to do is talk sort of talk back to the macro fires and induce the macro fires to form a giant cell and the giant cell tries to encapsulate the implant in order to consume the implant to digest it really can and through a series of other molecules and cellular processes leads to the final result which is a bio material that scene in a in a capsule in a in a capsule or bag Calatinus capsule and.

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As a pretty dramatic scanning electron micrograph showing the tough one device and you can see this dense foreign body capsule in a much looser tissue outside but this capsule is the interesting thing we get these may even be macro factors at the interface but it's a little hard to tell for S.C.M. So anyway to reduce it back to cartoons again we have our implant and you know if you want that a real definition of bio compatibility can look to the F.D.A. You can look to academics generating definitions ask a surgeon ask a surgeon what what he or she would think is a bio compatible bio material and if this green thing the material is found within one month is found within a thin relatively a cellular Kalash in a sack and the reaction site is quiescent the surgeon would say this is.

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Compatible and the interesting thing is it doesn't matter if this biocompatible biomaterials titanium polyethylene terrace Alitalia your thing. Or silicone rubber a polyethylene a poly lactic acid all of them heal in exactly the same reaction. So we had this model the surface dictates the biological reaction yet the surface of these things is all essentially.

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The surface a beach is quite different. Yet the healing reaction is essentially identical in every case what why is this how could this be. Instead we were wondering about the veracity of this idea. It seemed very radical and biomaterials to say that the surface didn't matter so we decided to test the concept theirself within our Engineering Research Center and we had what we call the U.S. implant group but this is this is one part of that experiment.

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There was a hypothesis that said that the amount of the protein fibrin isn't that it's the implant dictated the foreign body reaction. The more fiber in engine the more violent or more extreme the foreign body reaction or the inflammatory reaction actually is a very reasonable hypothesis was good reasons to to think it was you know a good idea that.

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So we tested it out. Each of these bars is a different Bion material. I don't want to go into details about what they all are some of them will be featured later in this talk but each of them is a different buying material and this is the amount of fibrinogen and Zorba and one of the materials it's a titanium treated by a process called a cuckoo book process that actually makes it bind to bone.

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It's sort of the tremendous amount seven hundred square centimeter of five bridge and. And then the other ones are on just a more compressed scale but they range from something around eighty down to ten. So we have seven hundred down to ten nanograms per square centimeter fibrinogen a huge range of five bridge and.

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To these are serious and we would predict this would correlate with a different foreign body reaction or healing in fact when we implanted them all certainly within the error. They were they were all the same there's one material that can be statistically different from some of the others.

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This is an osteopath and immobilize material talk about this one a little bit later but basically they all healed. This is the foreign body capsule thickness. They all feel just about the same and in spite of huge differences in the surface properties so. What do you conclude when you get to this point.

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We have to sort of ask the question what's we know these materials are all different but what is the similarity between all these wildly different materials that make them heal the same. Well our hypothesis is that they all have what we call uncontrolled. Interface will proteins the proteins that I talked about just glom down on the surface they come down almost instantaneously is no control.

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We as the engineers have no control over this process you stick it in proteins glom down each material have different proteins. But it's a mixture of proteins the proteins are up down denatured and they're out of our control. And that's the commonality Yes each of these materials does have different proteins at the surface but the protein is a mixture sort of a mess something that nature never uses can we conclude that the surface properties do not matter.

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Well if you looked at that set you'd say surface properties don't matter but I think it's not a good conclusion for one thing biology does all its work at surfaces it interfaces you may think that that in fact processes happen in the bloodstream. In solution but it's essentially not true.

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Practically every process in the body happens on the surface of a cell or on the surface of an extra cellular matrix protein. It's where I think ninety percent of the reactions going on in living organisms occur. Not in free solution. They're surface in into facial properties somehow biology makes a difference.

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Biology makes a difference with surfaces it's just our synthetics that are doing it and also all in vitro biomaterials all the biosensors and diagnostics to directly exploit surfaces and as long as we're in vitro we do see big differences in surfaces. So surfaces are important but in different ways from what we originally thought.

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So the U.N. program our Engineering Research Center has a goal at the moment by materials heal in a capsule in the future. We'd like to see biomaterials heal in a normal. Reconstructed revascularization a reconstruction of the anatomy interestingly normal wounds you get a wound within your body this moon heals just this way it is excellent ability to reconstruct anatomy and wounds but our biocompatible biomaterials are incredibly effective at turning off normal wound healing and we're asking the question why.

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So how can we get around this foreign body reaction. It's we think it's triggered by the nonspecific proteins. Maybe we think macro fire cell this interrogating cell is involved normal wound healing follows a different course. Namely the inflammation in normal wound healing is resolved on healing inflammation for an implanted F.D.A. approved vial compatible bio material inflammation is never resolved.

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It's there forever as long as the implants in there's always some evidence of active cells and inflammation. So there's a Porton difference right there. The central U.S. strategy has really three components to it. One of them says that if proteins are the problem. Maybe we can use stealth material.

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Fallowing sort of invisible materials that resist the pick up of protein. If we can use these at the other extreme what we really want to do is encourage the specific interactions that turn on normal healing there are processes that turn our normal wound healing and can we as engineers learn about those unexploited use those processes to make what we call engineered surfaces.

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But in between these two extremes what we want to do is prevent the nonspecific interactions always why we been doing it for fifty years and by materials we know exactly what they give us. They kind of work for clinical implants but we have to go beyond this. I think it's time to just get beyond this especially thinking as an engineer.

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So we have our idea of an engineered by a material with the biology well understood. We can use the correct receptor interaction and the bioengineers to sort of in charge of this reaction rather than some stochastic process. We're going to use molecules and to find orientation conformationally stabilized and maybe we'll need some bland non interactive regions in part of our design might be one of our design tools.

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To get there. This is a set of analytical tools that we use a lot. We're dealing with surfaces the surfaces are on a nano scale the surfaces have. Nanograms or peak of grams of material that comprise them we need some very sensitive methods to measure these surfaces. So there's a set of tools you'll hear me mention them I don't have time in this lecture to go into them things like ask.

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Sims comic force microscope contact angles is a kind of error tool chest of Beth to deal with these surfaces. Let me show you some data with one of the surfaces we worked a lot with. It's an attempt to make a protein resistant or non fouling surf. BAS and we call it a stealth surface and we use a molecule called polyethylene glycol and many of you are probably familiar with people.

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Peggle a proteins to make the proteins invisible to the body. This is the chemical structure very simple molecular structure. And P.E.O. or P.G. surfaces are found to resist protein and cell pick up that's the observation. So we decided we're trying to find a way we can make these surfaces that we readily put on real world medical devices and our monomers to do this or are some materials called This is a structure it has this.

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C H two C.H. two motif in it repeated four times and the ether is on the end. Basically it's a commercial solvent of UNITA tank or a load of it you can get the stuff it's cheap and easy and reasonably safe and what we do with this is we volatilize it and we put it into a glow discharge zone all this is not all that different what goes on in a fluorescent tube but it's a pretty energetic ionized environment we volatilize are gone.

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Put it in here and then we put a bio material in there and we deposit a twenty nanometer coating on our bio material of this. Let's say energetically reconstructed climb that goes into the vapor phase here. Well let's see what these coatings do. Talk a lot about the characterization we spent years learning about the chemistry I'm not going to discuss it other than to say they look very polyethylene glycol like in this experiment our sort of control material Stephano we're doing is taking a piece of Teflon and coating it with this gone layer and teflon placed into fibrin engine and this is fiber engine from plasma so we have.

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The Plaza Mo blood in the plasma. Combined are two words Interesting you both coined from the same scientist Perkins who also describe the conduct of fibers in the heart. So as interesting history there too. In any event plasmas. The teflon placed in plasma. One hundred sixteen non-aggressive a square centimeter five bridge in and then we treat the staff line with are gone.

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We have some of them that have zero fiber engine pick up now we just can't do any better than that. This is pretty good non fouling ability this is measured with radio labeled fiber engine which is a very sensitive method. We can't measure any pick up. That's good.

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We really learned how non fouling these are using a technology called Surface plasma resonance and what this methodology does is really measure a change in refractive index of a surface with great accuracy. And so if a surface is bare gold and we start adding some buffer which is a function of time we're going to add some buffer and as soon as we add some bovine serum outman we see a huge increase huge change in the surface refractive index it plateaus as we reach a monolayer of album and on the surface and then we add the buffer stream again and try and wash it off.

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We can't it's irreversibly absorbed we take this gold put it into our plasma react and put on a coating of Glaum and now we have our buffer we add the B.S.A. small signal. We had buffer goes right back down to baseline. This is called Tri go on three of those ethylene glycol units textured lime.

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That's the yellow bar even less pick up when we add the protein as soon as we had the buffer right back down to baseline. These are pretty non fouling materials. We looked at it. He should've pseudomonas originalists a bacteria sticky biofilm forming bacteria is a nuisance. Surgical problems.

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And a lot of data on this. It's from a pretty complicated experiment but if you look at the extremely low pick up with these colony forming units this pseudomonas original also. We've also learned to take this coating and use it with a graphic methods to photo pattern and I'm not going to go through the steps but it is a pretty conventional photo with a graphic process to make patterns.

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And some recent work with a professor in our electrical engineering department in a few two postdocs in our group we patterned the school line and you can't really see anything in the films of twenty nanometers sixty there's nothing to see on the surface but what we've done is indicated with these dotted lines where we patterned it and everything inside the dotted lines.

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We have removed the gone bare glass and then we take this particular bacteria and we just see the surface and let let the bacteria sit there for twenty hours and then just be batted around by brownian motion and seventy hours later we're Where do we see the bacteria.

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It's it's on the on the glass where we've removed the climb back to the movie here this let's see if this works. Looks good so these are images taken at every two hours and again we're just watching Brownian motion move these bacteria around and you know where they where they're starting to wind up I'm going to go through the whole movie.

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A lot of frames in here but eventually they all wind up on the bare glass and not on the climb. So this looks like the sort of material we really wanted so we started looking at Manas site is a site is the precursor to the macro. And sure enough when we develop surfaces that have extremely low fi British an addition they also.

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Monocytes density. So this looked like a pretty good material it inhibited these very sticky monocytes from sticking to its protein inhibit all the cells we tried so second grade material. So one of our Ph D. students being share Shannon planted these and we got actually quite a surprise that which is opening up some new horizons for us but this is an F.P.P. implant F.T.P.'s fluorinated ethylene Pro Plan tough one.

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Implant the control and use the touch of the line implant and this blue is the stain collagen and in fact if we look at the thickness of the college and capsule for the Teflon and the F.P.P.. Excuse me for the Teflon and the textured lime they're essentially identical.

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So the ability to resist protein pick up is is our conclusion is we still think these non fallowing surfaces they can be very useful and biomaterials of the future. They may be necessary but they're not sufficient to give the healing that we need. So we need some active turn on for the healing we'd like to see and this leads into the next area we're working on which is sort of the clues to healing and we have a bunch of things that have shown potential to heal is a few things that have been seen in the literature for example hydroxy appetite heals very nicely into bone.

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It's the sort of healing we mean like to see some interesting work with porous structures and fibers and I'll show some of this but in the blue area here they're all they're interesting molecules that are always present in healing wounds and as soon as the wounds are healed.

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These molecules are gone. They're only present or wound healing and this set of molecules is really something we're focusing quite a bit of our energy on at the present time so I talked about prosody and. It's interesting that these are two identical materials Here's one material here's another.

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Or implanted for a month in a mass. This is called a mixed test or a cellulose with very poor small Poor's or with much larger pores. But the chemistry is identical. And if one looks at the the small poor material is a dense fibrous body capsule. There are active macro five years at the interface between the capsule and the implant classic foreign body response just change the pore size in this material we get a very very different healing reaction a very open reaction there are a number of blood vessels going through this this capsule and how did we achieve this this very different healing reaction just change the prosody that was pretty easy.

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That's an interesting clue which working on. So one of my Ph D. students is making a whole new class of materials that have very controlled poor sizes these are very small poor materials at the moment but he's making larger poor materials too but he does this by templating the materials with microspheres and then extracting out the microspheres to get these very interesting open structures.

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Another interesting experiment in healing that's coming out of our Engineering Research Center. PROFESSOR JOHN SANDERSON a group is a lecturer spinning fibers and she's noticed that as the fiber diameter goes down to below five microns this is the foreign body capsule thickness after a month of implantation and the foreign body goes down to zero the foreign body reaction goes down to zero when the fiber gets below five microns.

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So in fact might even say nano scale fibers seem to be almost invisible to the body and Joan is now making mats and materials of these these fibers for implantation is there question. These are polypropylene in this case I think Joan would think that it's independent of the material it's the size effect which is what.

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Same with the poor size effective. So the geometry and poor size does seem thousand very profound effects on healing. The other class I mentioned these interesting proteins that are present wounds of whole major cellular proteins a lot of people talk about extracellular matrix A lot of people talk about cells list of the proteins that exist between the extracellular matrix in the cells cells don't really interact with collagen interact with proteins on college and college and wonder what a delivery of proteins and so these are very important.

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And they've been named by one of our colleagues in our era see Paul born in the call made for cellular proteins they are present during healing wounds this is the purple brown color is a Spain for us The upon one of these materials and at seven days one sees considerable asked The upon and healing piece of TAF on twenty eight days it's essentially gone the wounds healed.

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So there are present and healing. And in some recent experiments what we've done is and this is our. Ph D. student Stephanie Martin has immobilized the osteopath into the material in this case is poly Hema just like a soft contact lens and if the poly Hema is implanted.

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This is actually as a lysine immobilize on the surface of poly Hema just to be a mobilization control for the Asti upon a twenty eight days we see a dense foreign body capsule the blue is the foreign body capsule Here's the Hema. And there are some some features in that these features really don't have a lot of definition we're not sure exactly what they are but they're not terribly interesting to histology.

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But the Asti upon immobilised Hema the capsule is riddled with with blood vessels more vascular as in we've ever seen a foreign body capsule before so it's interesting the odd. Pond seems to encourage the vascularity that we want but also does not seem to inhibit the foreign body capsule.

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So the Asti upon as a protein seems to do half we want. But then we have another observation or another protein called thrombus Spondon and this protein what we've done in this experiment is to use a knockout mouse that has thrombus upon the knocked out and looked at the we have to materials of silicone rubber and oxidize silicon rubber and we look at the vascularity it we look at the capsule thickness and it turns out that.

[00:40:40]
In the thrombus pond the knockout mouse first of all we get ten times more vascularity and the capsule the foreign body capsule it actually looks like a gothic or in the thrombus man the knockout mouse but if you look at the history of this capsule and I didn't include those slides in this talk again it's a very open the fuse capsule Yes we measure it is thicker.

[00:41:00]
But there's very little college in it. It's a very very different morphologically from this one. So it seems like the thrombus Spondon is sort of the enemy with Rama spawn is present in the wild type mouse we get this dense foreign body capsule with a thrombus Spondon is absent we get a much more vascularity and a much looser capsule.

[00:41:20]
So what we're trying to do now the in fact one of the goals one of the engineering goals and in our Engineering Research Center is to develop a sort of a systems approach to use an osteopath on which increases vascularity and the thrombus upon them which reduces the capsule.

[00:41:35]
How can we use these both to generate the sorts of signals we need to turn on a normal vascularized healing rather than a capsule in a capsule or healing and so badly running out of time here. Someone has zipped through a bunch of slides and just kind of tell you generally what I'm doing when it's time to go into the details but why.

[00:42:00]
One of the ways we're talking about delivering these protein signals that we need. It's called templating we do is go through a series of steps where we literally make a material with pits we use the original protein as a template and have pits in the material and these pits have recognizability for the proteins and interesting the purple color or this pink color is sugar.

[00:42:25]
So the surface of the implant becomes a sugar surface that has that recognition sort of stamped into it. Templated into it that allows the sugar surface to recognize proteins. The idea is that the template protein aligns the sugar or hydrogen bonding Iran the sugar which is cross-linked in place in this binding pocket and we have some evidence that the process we use has the fidelity to make pits the size of proteins these are these are glutamine sympathies pits exam with a transmission electron microscope.

[00:42:56]
You see from the histogram that are pits are just about the same size as the protein. So we have the fidelity to make these nano pits and we can use a family again to sort of look at what our surfaces look like obviously rougher fibrinogen has coarser pits and if you want to use your imagination you might even think you could see some fiber energy in there but I won't push that point in any of it will we get with these pitted surfaces is a remarkable degree of recognition and in this experiment we're comparing lysozyme Arriva nucleus both fourteen kill adult and proteins the same size protein and basically rival a nucleus pits rep recognize rival nucleus about twenty to one over lysozyme where lysozyme pits recognize lysozyme override a nucleus about thirty to one.

[00:43:48]
So these surfaces have remarkable selective A-T. and they're just they're just sugar in this work was published in Nature in one nine hundred ninety nine and we are. Some students continuing this process with things like fiber Nekton now to show this this recognition of fact we used a process called micro contact printing we made a rubber stamp at a micron scale and the ink for our rubber stamp is protein and in this experiment we stamped their stamp with strep the strep avid and protein stamped it on my I couldn't make the sort of pattern of strep Ave that's the green back till that with bovine serum Outman.

[00:44:31]
So now we have bovine serum Alderman islands instruct avin and we use this is the template to make an imprint the sugar imprint and then we dip it in a strip Abbott and bovine answer Malvern solution. And this is an A.F.M. image of. Biotin. Two which was attached to ten nanometer gold microspheres and the biotin goes to strip avid and you can see where goes it goes in the spaces between these holes in the stamp.

[00:45:01]
So the surface is all sugar one part of the surface likes album and one part like stripped Avenue and this might suggest a method to make a surface on a bio material that doesn't involve a mobilizing and expensive fragile protein said we can just use sugar but the problem is our proteins are every which way they're up they're down the side ways.

[00:45:23]
Those proteins we put a mike in to make these imprints what we really desire something like this. So you can make a really good imprint that would bind the protein with the for example the interesting binding a reactive sider or lie again binding site was facing out. So we'd have real control of the proteins at the surface.

[00:45:41]
And we're using the Sims methodology surface analysis methodology study the orientation of proteins. I'm going to skip through a group of slides here now and go just to the conclusion of the story but basically using protein peaks and sims to get to where we want to go and using so.

[00:46:00]
Multi various statistics and. Let's just go right to the end of the story here. Basically we can distinguish using the Sims if the protein is up if the protein is down or the protein is randomly absorbed by this clustering of different multivariate. Correlates of the points and we think that if we had the proteins.

[00:46:21]
We know now that we can align antibodies all ins in such an orientation and if we can do this if we can use this alignment in this way which we found we can. We can get a monoclonal to a different region on a protein have the protein stick in an oriented fashion on this I.G.G. and then template that.

[00:46:44]
So that's one of the places we go and we're also mobilizing type on college and on surfaces which does bind the proteins in a very specific way. And so instead of having random proteins on our biomaterials of by amateurs might have the type one college in which then binds the osteopath in a very controlled way.

[00:47:03]
And these experiments are ongoing. Now this idea of protein delivery just just look at what a virus does with its coat proteins it delivers the proteins with the organization and specificity. We're just trying to copy the way nature does its protein delivery the precision with which it does and we have a vision maybe someday we can take just showing where the hip joint here coated with nano pits implanted in bone the device concentrates the proteins the we as the bioengineer want to bring to the surface and leads to improved healing.

[00:47:35]
This is a sugarcoated medical device and the patient's own proteins are used for healing. So these are some of the ideas that lead to what we're calling an engineered by a material organized ordered by a material sort of describe that. And I see an interesting progression of course we used biomaterials for a long time and I think we can have biomaterials in the classic sense the silicon robbers and the Titaniums and all.

[00:48:00]
At least for another twenty years or sure we'll be seeing them widely used in medicine but maybe by two thousand and ten or so maybe these precision nano surfaces will start appearing in medicine and controlling the healing response. I think tissue engineering is certainly the wave of the future and then beyond that is going to come true.

[00:48:18]
Regenerative Medicine that's going to for obvious reasons replace all that. So this is a quote from Voltaire look at this is early eighteenth century the art of medicine consists in amusing the patient while nature cures the disease. I think the intrinsic healing mechanisms in our body are really what's important and the physicians job is keeping the patient happy while the body does the healing.

[00:48:43]
I think a real future of this is a cartoon obviously but maybe some of you read about this experiment of putting electrodes in the brain of a monkey and having the monkey control the cursor on a computer with just the electrodes implanted in its brain. This has incredible potential for example to allow a paraplegic to walk just controlling with the person's brain.

[00:49:08]
Maybe some prosthetic device in the legs. The potential is incredible. We're doing things with this idea what's the problem is the electrodes in capsulated the moment over if we can get healing electrodes I think we can make devices like this that really work for long periods of time.

[00:49:25]
So let me finish up this is this is about half of our YOU WERE program and you couldn't just couldn't get everybody together at the same time for the photograph. But anyways a lot of people that obviously have to be thanked for all this work that went into it and.

[00:49:41]
So thanks to my students staff colleagues for the work. Thanks to Bob for the nice invitation to give us a seminar here in a quiet please take some questions. THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU. Great. Now. Yeah yeah. In that case you basically just faces errors or is it sort of.

[00:50:22]
You know it's at the surface it's a mobilisation technology will see the CARBONELL diameter is all pretty classical mobilization technology as we describe it it looks like it's pretty effective but the molecules were very sick. We called sloppily handled they weren't control for you in Taishan or confirmation stabilize they're just gone down there at the still work.

[00:50:44]
So we think we can do much better but the they weren't out on tethers for example or they weren't the fusible that's what you mean for Genesis for Horace you know those of very good questions. There's actually a lot of a lot of fundamental biological data on the processes stimulated by one of the things it does do is sort of calm inflammation it seems to reduce the inflammatory the magnitude of the inflammatory response and we think by reducing the classic macrophage activation we think by reducing that it gives more opportunity for normal healing or reconstruction.

[00:51:31]
So it may work in may increase the angiogenesis by reducing the influence of the massive inflammation. Yeah. In making the porous materials. Yeah you know. The classic problem and were we sort of have some interesting approaches one of them is to is to make these materials would you know how you might flour a bread board before you put bread in to keep from sticking we put our microspheres we make it microspheres we put our microspheres down on our bread board and put this dull of polymer down on it.

[00:52:20]
So we have clear inroads into the material without the skin. It's tricks you've got to do tricks to get around that skin but it's term of the family wants a form and it's a problem for porous materials. These are polymath them with accolade and actually it was kind of hard to find a source of soluble most microspheres across like we needed soluble ones that we could dissolve and we finally found some sources for them.

[00:53:19]
Yeah you know. Well you know the immobilized protein surfaces are as stable as the proteins which is stable and unstable both in shear For example the the covalent immobilizing these are you know stable against the shear forces but maybe the shear can the nature of the proteins we don't know that for sure.

[00:53:41]
Of the sugar surfaces they found sugar in the tombs of the Pharoahs intact Sugar Sugar is very stable actually if nothing eats it. And so we're hopeful that we could make implants that could be stored for long periods of time with sugar on the surface. Well I'm not sure exactly.

[00:54:24]
You know to take an example of material that maybe you say would never or a device would never get integrated Let's take a pacemaker. OK. The Pacemakers are given considerable problems by the stick capsule surgeon as the dig through them when they have to replace or work on the pacemaker.

[00:54:39]
They fought the leads get heavy fire or some capsule ation if we could reduce this just just even reduce it. I think we'd already make a contribution to surgery and medicine also a lot of device centered infection is associated with the lack of vascularity with this vascularity the body has mechanisms to deal with infection.

[00:54:57]
You cut off the vascularity the body doesn't have a way to deal with infection. So we think if we can improve the vascularity around the site is where we're going I don't know if we can ever totally eliminate the foreign body capsule. But we know we can reduce its thickness its density and improve its vascularity And that's kind of where we're heading and that would go for I think all medical devices implanted devices of synthetic materials could benefit from this technology.

[00:55:23]
In fact there's no reason to believe that the increase vascularity and the reduced inflammatory response wouldn't be good for a tissue engineering matrix to a tissue entering scaffold should benefit from a similar kind of protein control in technology. Where. I would say you know. It's a really good question and you know if the answer is.

[00:55:59]
Maybe the diabetic doesn't heal well because the diabetic doesn't have enough mass to upon again these these implants are like Affinity columns for osteopath and your unprincipled surgeon could dip into some and then implanted and that might improve the healing. I think we have to know and this is an ongoing question and we.

[00:56:21]
People right now are enjoying Research Center working the stats why buybacks don't heal or why they heal so poorly we don't know exactly but if we knew that we might be able to develop biomaterials strategies around that Helena last year has played. Yeah well I think there's no doubt that as the Upon is very important in the healing of normal wounds in normal individuals and so we feel it could also help to heal biomaterials but maybe a diabetic was short an osteopath and we don't we don't know for sure.

[00:56:59]
You know we don't know for example the impulse to extremely good question and it's a question that that is on the table. It's very hard to do the analysis. Once the body puts all that stuff on we don't know what's happening underneath very hard to figure out what's happening inside inside or at the surface of an implant that's been implanted for a long period of time so we don't know exactly.

[00:57:21]
You know this two things we have two ideas we have one that proteins may stay there and stabilize things. Another that once they've done their work. They may get digested and vanish and. If they've done the work that's probably fine too. The proteins. Yeah the body has great mechanism recycling proteins.

[00:57:45]
Yeah. Again we don't really know for a fact. How long those proteins on bio material stick around is just not known and it's just analytically a very very difficult problem to get at. That. Scrap that it was. Yeah. And actually we did it. We got some very very impressive results with fiber Nekton So our first thought was to use small durable proteins like the lysozyme and rob a nuclear.

[00:58:39]
Those were good cases and they worked out but we've done it with with fiber in addition I.G.G. albumin now fiber Nekton is the latest set of data to come out and you know it seems to work. There's no doubt that the more we damage the confirmation of the proteins the less active our surfaces are so some of the techniques to stabilize and organize proteins that surfaces are going to lead to we believe to much better imprints.

[00:59:16]
At the moment all the work is all this work is based on to be to Micah and there's some evidence in the literature the mike is not terribly the nature and for proteins that's and it's also molecular smooth. That's the advantages of mica. OK Well good. Good questions.

[00:59:48]
In fact one of our Ph D. students who's going to be just submitted an abstract of society to buy materials a meeting this year is coating the inside of tubes with these gone plasma coatings and in fact we're working with Mike Sefton and the Toronto group on assessing play reactivity with these these materials.

[01:00:09]
This is a very interesting area because Tom Foreman has this theory that again fiber engine pick up is directly related to plate that activation and these don't pick up any fiber energy and we know that but we know they have this interesting interaction with neutrophils I was telling you about earlier.

[01:00:25]
So we're kind of fastened to see how they're going to react with blood and we should have some real data so new it is a major technological accomplishment to be able to coat long tubes and we can do it now.