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The Inventivity Pod
Ceramic Material That Can Grow With Bones

In 1969, Professor Larry Hench developed a glass that can grow with bones. His close friend and colleague, David Greenspan, helped Professor Hench develop the material into BioGlass, a product that is used in orthopedic and dental bone graft materials. David, a native of Brooklyn, wanted to be a drummer but turned to glass blowing instead. His big insight into entrepreneurship? “Never lie to yourself.” *This episode was originally released on September 25, 2018.*




Intro: 0:01
Inventors and their inventions. Welcome to Radio Cade a podcast from the Cade Museum for Creativity and Invention in Gainesville, Florida. The museum is named after James, Robert Cade who invented Gatorade in 1965. My name is Richard Miles. We’ll introduce you to inventors and the things that motivate them. We’ll learn about their personal stories, how their inventions work, and how their ideas get from the laboratory to the marketplace.

Richard Miles: 0:39
Glass that lives. That’s the subject of our Radio Cade podcast today and in the studio with me, I have David Greenspan. David, welcome.

David Greenspan: 0:47
Thank you very much. It’s a pleasure to be here and it’s great to see the Cade Museum alive and well.

Richard Miles: 0:52
Thank you. Thank you. All right. Before we talk about you, David, which is, I know probably your favorite subject, right? Of course. Let’s tell the listeners a bit about BioGlass, which is the invention that you’re associated with. Just explain to me in very simple terms, what is the core technology underneath it and sort of how does it work and then we’ll come back later and talk about the applications in the market and that sort of stuff.

David Greenspan: 1:15
Bioglass is a bio material and there are lots of biomaterials you can think of. Metals for hips, knees, materials for wound healing, gauze, bandages, all biomaterials heart valves, some are synthetic some are natural. Bioglass is a form of glass and of course glass itself as a chemistry has lots of different compositions, lots of different properties within that category. BioGlass is unique because when it’s implanted, and originally it was used as a bone regenerative material. When it’s implanted in bone, it actually reacts like sugar dissolves. Well, much more slowly BioGlass the atoms, the Ions in BioGlass will react and actually stimulates bone healing and that was the core Aha moment.

Richard Miles: 2:05
I see.

David Greenspan: 2:06
So basically that was the concept and the original material and from that and from learning about how this glass reacts and how you could change the composition slightly and change, the reactions, the field kind of broadened out into applications well beyond just trying to help bone healing.

Richard Miles: 2:25
So that sounds both fascinating and incredibly complicated at the same time because unlike what your earlier examples about a metal hip, there you’re basically just taking an object, sticking it in the body and it replaces the previous object, but BioGlass really sounds quite different in that it is actually interacting with the body itself.

David Greenspan: 2:44
Yeah, it is different and when professor Larry Hinch actually invented the material, the first experiments, and he had a whole series of thought processes, which actually we can explore that, but it actually wasn’t… she wasn’t… I’m going to make a material that’s going to bond to bone. It was I’m going to make a more compatible material that we can put in the body. There’s a great quote by Isaac Asimov that I’m going to butcher right now, but basically he said the most profound moment in science is not “Eureka”, but “gee, that’s interesting” and that’s what it was. I mean, in the late sixties when Larry invented this, we were trying to make a material that the body wouldn’t reject.

Richard Miles: 3:24
I see.

David Greenspan: 3:25
And what he found as a result of the first experiment was that the material actually attached to the bone and that set an entirely new path for everybody coming later who was developing biomaterials.

Richard Miles: 3:38
You make a great point. Referring to Larry. Larry was the actual inventor, this Larry Hinch. We both knew Larry, you knew him, much better than I did. Um, and like a lot of inventors, Larry was an interesting guy, let’s shall we say, can you give our listeners a snapshot of maybe Larry’s career, but also his personality.

David Greenspan: 3:57

Larry, was just in awe about the world and everything and he was curious. And that’s the best thing that I learned from Larry is there’s always another question to ask. You do an experiment. You get some information. That information that you get should lead you to ask three or four more questions. He was curious about everything. You knew him. I knew him. He was like a big grown up kid. And his interests were much more than just beyond science and biomaterials and bone regenerative medicine. I mean, he painted of course Boing Boing the Bionic Cat series of books that he wrote and authored, it wasn’t enough for him to write the book, but then he thought that he could make science kits for kids in seventh, eighth, ninth grade to do experiments based on the subject matter of the book. He was an incredible thinker. He was kind, generous, wonderful, and just had a love of life. Truly a PhD, a Renaissance Man, arts, painting, music, all of that.

Richard Miles: 4:53
I remember my wife Phoebe and I went and visited him I guess probably about five years before he died and he was showing us around his condo at the time and he was just, like you said, a little boy. I can’t remember what he was showing us, but there were various toys and devices and whatnot. And he was thrilled to be showing them off. And I remember he… didn’t he also record his own song. Uh…

David Greenspan: 5:12
Yes he did

Richard Miles: 5:13
I think you can find it on Youtube, right? About a mechanical part.

David Greenspan: 5:17
Yes. Yes, he did. And in fact there was a conference for bioceramics, bioglass and bioceramics and Larry was one of the co-founders. It was an international conference that rotated between Europe and America and the Far East, Japan or China. And at one of the first ones, which I was lucky enough to attend, the three Bill Bonfield and Tadashi Kokubo and Larry decided that at the banquet, the Europeans and the Americans and the Japanese and folks from the Far East and Australia would each get up and do a song and that became a regular thing at the banquets. So yeah, he was gregarious. He loved life and…

Richard Miles: 5:56
It was quite amazing. All right, let’s talk about you for a second you’re a Brooklyn boy and tell us sort of growing up, what were you like as a kid? What were your interests in any role models or were you just sort of like at aimless troublemaker?

David Greenspan: 6:08
I was a…

Richard Miles: 6:09
I understand it’s not mutually exclusive. You could be both, but go ahead.

David Greenspan: 6:12
I was… the first six years of my life, I grew up in the projects. We didn’t have a lot of money and so the projects were a little rougher than a really nice suburban sort of household and I kinda shied away, but when we did finally… my parents saved enough. We got into a house. It was a huge park that had a dozen baseball fields, three football fields. I was out the back door and they wouldn’t even bother calling me for dinner.

Richard Miles: 6:38
We’re still talking about Brooklyn.

David Greenspan: 6:39
Still Brooklyn Marine Park, Brooklyn born and raised, went to James Madison high school, Bader Ginsburg, Chuck Schumer, lots of other famous people. Graduated from James Madison. I had a large extended nuclear family and so growing up I did the normal getting into a little bit of trouble. I wasn’t a truant or anything and it was nothing conscious, but I just knew I had to do well in school, but my mother also thought “Oh, you should do music. You should learn art.” And I used to like to draw, so my first love was always sports, but my second first love was painting. I got to take art lessons from a professional artist who was a friend of my mother’s and she was kind of impressionist and so I studied that and I loved it and time would pass.

Richard Miles: 7:21
And you’re a drummer in a rock band currently.

David Greenspan: 7:23
Yeah, I played music so I had instrumental music in junior high school so that I got to play in the orchestra and the band and I love drumming and got together with friends, you know, it’s the 60s, 64 65 and…

Richard Miles: 7:34
So when they kicked Pete Best out of the Beatles, you’re on the shortlist.

David Greenspan: 7:37
I was ready. I was ready.

Richard Miles: 7:37
You never got the call.

David Greenspan: 7:40
One of one of my early most humbling experiences was we got to cut a demo record BT Puppy Records, the tokens in the happenings owned the little record company in Manhattan and we cut a demo and listened to what we sounded like and that’s when I realized music was not in my future.

Richard Miles: 7:58
It’s a nice way of putting it. But you did decide that glassblowing was in your future and how did that happen and how did that end up into ceramic engineering?

David Greenspan: 8:05
So being from New York, we would go on vacation, the summers in the Finger Lakes region in western New York is beautiful. So for everybody who hasn’t been up there go. And there’s a little town, Corning, New York, and you’ve probably heard Corning Glassworks, they had a museum a Glass Museum and part of that back then was Steuben glass company was blown crystal and it was gorgeous. So we’re in the museum. I’m at that point still painting, doing art.

Richard Miles: 8:30
So you’re in high school, at this point.

David Greenspan: 8:32
Just high school and there they were doing glassblowing. We watched them for 15 or 20 minutes and my parents said let’s go get lunch. And I said nope. And they said, come on David. And I said, you bring me back something. And they did. They went, they went to get lunch and I sat there for an hour and a half and decided right then and there I wanted to be a glass blower. Watching glass being blown was the most fascinating thing to me.

Richard Miles: 8:55
Do you remember what about it that was really compelling?

David Greenspan: 8:57
The fact that you could take something that’s red, hot, yellow, glowing shape it mold it put a puff of air, into it and it expands and then it cools down and it’s malleable and you can make all these beautiful forms and you could see through it and it’s shiny, and then at the end of the line some of the pieces would have engravings and you’d watch these artists engrave. It was pure art and that trip was obviously the seminal moment in my life. It’s sad.

Richard Miles: 9:26
So later on, where did you go to college?

David Greenspan: 9:29
When I got back, I announced to my whole family I was going to be a glassblower and there were three coronaries because nice Jewish kid from Brooklyn should be a doctor or a lawyer, you’re going to starve if you’re an artist. And I did really well in school. School was pretty easy for me and I had a cousin said, “I know a college that gives courses in glass blowing.”

Richard Miles: 9:49
This is on the down low…

David Greenspan: 9:52
Yes… and so she said, go to glove Joy’s college catalog. I don’t know if anybody remembers. They used to have these big catalogs that had all the schools. So we went to the library. Alfred University, upstate New York, right near the Finger Lakes, not too far from Corning is a private university, but they had a College of Ceramics, so it was New York State College of Ceramics, but it was administered by Alfred University and the Premier College for ceramics. They have the best number one ceramic art college in the world, I believe. Still do and they…

Richard Miles: 10:21
Was there a formal relationship with Corning. Did Corning’s name fund some of this or no?

David Greenspan: 10:25
No, this was started by a potter because they had terracotta clay at Alfred, but it became this worldclass college and I said, okay, well if I can’t be an artist there’s this technical stuff, and back then in the late sixties it was rocket nose cones. This metal oxide semiconductors was just very new, so there was all this new science and technology around ceramic materials in general and that led me to Alfred.

Richard Miles: 10:51
So Brooklyn boy goes to college in upstate New York and here we are in North Central Florida. Something happened in between. How did you end up in Gainesville working with Larry Hinch?

David Greenspan: 11:02
Well, of course this is the late sixties, so there’s the whole Vietnam thing. I wasn’t sure I wanted to go work in industry. I’ve loved research, you know, a senior projects and doing research and what I was doing was trying to develop materials for an early artificial kidney so that kind of brought in the biomedical stuff and I was looking around to do graduate work in glass and there’s a very limited number of people that do work in glass. And Larry Hinch was at the time looking at developing glass that would withstand radiation damage in outer space because we had a space program and they were going to get astronauts up into space and they had windows but the windows would fog. So he was working on that and there was some very specific technical properties about glass. Glass is normally an insulator. Think back to early 1900s. There were all these electrical insulators that were made from glass because it doesn’t conduct well. Larry, a lot of other people found that you could change the elements in the glass composition and you could conduct electricity slightly or do other things. And Larry was working on that in the late sixties and so that fascinated me. So I applied to there and to a few other schools, Clemson University and Virginia Polytechnic Institute, which is Virginia Tech now. Basically why I came down to is I got the best research assistantship offer from the University of Florida and Larry’s work was interesting so I said I’m going to go there. So I get to the university and I sit down with Dr. Hinch and I say, well I’d like to work on these style electric properties of glass. And he said, well I don’t have any more funded research there but I have this new thing that we just started and it’s a ceramic biomaterial. It wasn’t called BioGlass in 1972 when I started was a ceramic biomaterial. He said you could work on that. He said, but if you want to work on the other stuff, you could do a teaching assistantship. So I could teach labs and then do my studies and then do my research or I could have a research assistantship and not bother with the 20 hours a week of labs and grading papers, so I said yes, I’ll do that. Dr Buddy Clark, who is still at University of Florida in the College of Dentistry was I think the first PhD student and I was the second working on the development of BioGlass.

Richard Miles: 13:16
So from what you describe, David, it sounds like this is a technology that industry would love. Did BioGlass immediately start making a bunch of money or… tell us about the commercialization. Now I do know Larry really didn’t make any money off of his invention for a number of different reasons, but explain to me what happened after it was established as a thing who bought it?

David Greenspan: 13:38
Sure. I think first 30 years later, overnight success. The concept that Larry put forward, that a synthetic material can be implanted in the body and stimulate repair was so far into everybody working in the field. Nobody believed it. I mean it literally took 15 years to convince other biomaterial researchers that it was real and it worked and because we didn’t know how or why. But in fact, by 1973, Larry had posited his five-stage reaction for bioactive glass. First it releases sodium and then silicon ions dissolve a little bit and then they reprecipitate on the surface and then that causes calcium-phosphate to precipitate and then collagen comes in there and it bonds to the bone and then it crystallizes to hydroxyapatite, which is bone mineral and all that’s well and good, but that’s not really the answer, but it was put out there and as you know, if you put it out there enough it becomes real.

Richard Miles: 14:34

David Greenspan: 14:35
So it was really tough. But sticking with it, finally, we found applications that were necessary where there was an unmet need basically and that’s what you have to do. It’s fine to have a material, but you need the unmet need and that was in dental bone grafting and…

Richard Miles: 14:52
That was already you said 15 years in…

David Greenspan: 14:54
Yeah 15 years… mid to late eighties. There had been an attempt with a startup company to actually commercialize it, but the people were less than upstanding and the company failed miserably and university got the technology back and then another group of investors came in who were more reasonable. Larry actually drove that and we actually started properly going through all the FDA regulations and all the processes to get a material into the marketplace.

Richard Miles: 15:22
And this was for dental…

David Greenspan: 15:24
Dental, bone graft, yes.

Richard Miles: 15:25
Eventually became a toothpaste as well. Or was it different?

David Greenspan: 15:29

That was different. This was called perio glass, so it… take the BioGlass, crush it up into a powder and for people who that have periodontal disease, they have bone loss between the teeth and your teeth can fall out and it causes a lot of problems. So he put a little bit of this in that pocket where the bone is resorbed and you suture the gums up over it, cleaned it all out and it helps regrow the bone and save the teeth. And at the time there were other calcium phosphate, hydroxyapatite bone mineral types of products being used for that. So basically the synthetic bioglass was pulled along in this developing market for the periodontist and the oral surgeons who were looking for better solutions. And that’s what it always is.

Richard Miles: 16:13
So I got to ask David, and you can take the fifth amendment on this one, but was the University of Florida any help during this process at all? Or were they just sort of on the sidelines or…

David Greenspan: 16:22
It’s a complicated question. They tried to…

Richard Miles: 16:25
I said you can take the fifth on this.

David Greenspan: 16:26
No, no, no, no. Hindsight’s always 20 20. At the time they were doing, I think what they felt was best. They were looking not proactively, but if somebody came, they were willing to license technology. Larry always had a hand in continuing to do research that was funded by the company, so companies that licensed the technology to commercialize it had a component that was giving Larry money directed towards some of what the company wanted to do, but back in the seventies and the eighties and of course there’s a very famous case of another inventor who invented some electrolyte drink and the university didn’t know what to do. So we were all very naive back then.

Richard Miles: 17:05
That’s one of the reasons I was asking. I couldn’t help but be struck by the timing in that. You said it was 1972 right…

David Greenspan: 17:10
When he invented, yeah…

Richard Miles: 17:11
And that’s right when the University of Florida chose to sue Robert Cade, the namesake of this podcast over Gatorade, and so I imagined that wasn’t the best environment maybe to…

David Greenspan: 17:22
But the university didn’t know they licensed. I mean the first license was to an orthopedics implant company, Howmedica. And the university did have a licensing agreement. It wasn’t as favorable to the university as it might have been. It wasn’t prohibitive to the company, but the university is so much better these days at knowing that… a lot of them. Yeah.

Richard Miles: 17:42
Tell us about now what applications is bioglass currently being used and I know of at least one NovaMin, the toothpaste. I know there’ve got to be other ones.

David Greenspan: 17:51
So BioGlass was something that we trademarked while I was still a graduate student. We needed a name I can remember… was in the conference room on a Friday afternoon in the materials building and there was a lot of beer and a lot of graduate students and we were looking for names for this ceramic biomaterial and bioglass one, and from that one composition, people started playing with others. So 45, S5 Bioglass’s one particular composition. There are a lot of others. The first materials were solid implants to replace the three smallest bones in the middle of the year, the malleus, the incus, and the stapes based middle ear prosthesis. Very successful clinically, not a big market, was not successfully commercialized. Perio glass was. Following that was Nova Bone, which… for orthopedics and there’s a very large market there in spine fusion. Probably 85 percent of bioactive glass used in orthopedics is used for spinal fusion surgeries. Beyond that is Novamin, very, very, very fine particle of that same composition used for tooth desensitization, but there are also other compositions and other companies. Biomin is a British company that is using bioactive glass in toothpaste. There’s a company, most eyeglass that produces a board, not a silicate glass, but a Bor, a glass which is bioactive has the same sort of properties that’s used in treating chronic wounds. It’s FDA approved. There are other glasses, bioactive glasses that have silver, which is an antimicrobial used in wound healing and a few other applications. Most of it is hard tissue, some wound healing, and a lot of oral applications.

Richard Miles: 19:28
Wow. So quite a few opportunities out there.

David Greenspan: 19:31
Oh yeah.

Richard Miles: 19:33
So David, here’s your chance to dispense pearls of wisdom. If you were to come across, and I’m sure you probably have come across, say academic researchers who remind you of yourself years ago or maybe remind you of Larry and let’s say they’ve done the same thing. They have a technology and they’re going to take it to market. They’re all excited. What are one or two things you would say definitely do this and then one or two things you’d say definitely don’t do that.

David Greenspan: 19:57
Well, the first thing I tell people is, look, I’m 68 years old. I’ve been at this for 43, 44 years now from the time I was a graduate student. I don’t think I have any advice that I can give you cause I’ve been through a lot, but the biggest, most important thing is as you’re developing it, there were so many pressures. Don’t fool yourself. Okay?

Richard Miles: 20:17
Always tell yourself the truth.

David Greenspan: 20:18
Always tell yourself the truth. It’ll be what it’ll be. The second thing is that it is a process, right? And that you really, really learn from your failures and as a species we’re not too good about admitting we’re wrong or that our beliefs might not be correct, right? But step back because it’s just a process. You won’t know it going forward, but 30 years later when you look back, you’ll go “ah ha”, we always think when we have a failure, it’s the end of the world. So occasionally it is okay, I’m sorry, but most of the time it’s not. If you think your idea is good and if you’ve really been honest with yourself and you’ve vetted it, don’t worry when you fail, if you fail, you should find out the reasons and overcome that and there’s gotta. Be a way of overcoming it. If your technology is good, if it’s true, if it’s going to be because…

Richard Miles: 21:11
And that’s the first part. If you haven’t lied to yourself right now…

David Greenspan: 21:14
If you haven’t lied to yourself, the worst thing you can do in research is create a dozen experiments, all of which succeed perfectly just according to your theory. That means you haven’t had the right hypothesis otherwise. It’s not research. If everything I did was going to be successful, then I have all the answers that’s going nowhere. That’s not researched. The beauty and the fun of it. I’ve managed lots of people and people would come to me with studies that were abject failures and I would get like really excited and everybody thought I was crazy, which is true, but that’s another story. In all seriousness, I get excited when something went wrong because we would sit down and go, okay, let’s figure out what happened, how and why it’s not going to be easy, it’ll be stressful, but we’ll learn something from it and we’ll advance.

Richard Miles: 22:02
Well, that sounds pretty wise to me. I got to say they would. So I think we’re going to figure out a way to track down the individual listeners of this episode and if any of them make it big, we’re going to make sure some royalties go your way we’re charging you for that advice.

David Greenspan: 22:14
You know, it’s… that should be the joy of science. Every results should lead you to ask two or three new questions and oftentimes I see people who get a result “Okay, I got the result.” I sit back with my arms folded and say, “okay, so?” and I get these curious looks. I said, “so doesn’t that bring any other questions to mind”? and it should if you think about where you were 30 years ago, oh, there’s some great advance. That’s the end. It’s never the end.

Richard Miles: 22:44
Well unfortunately it is the end of this episode. So perfect segue. Anyway, David, thanks very much for being on the show. Hope to have you back and it was really a pleasure talking to you.

David Greenspan: 22:54

Outro: 22:57
Radio Cade would like to thank the following people for their help and support. Liz Gist of the Cade Museum for coordinating Inventor Interviews. Bob McPeak of Heartwood Soundstage in downtown Gainesville, Florida for recording, editing, and production of the podcasts and music theme. Tracy Columns for the composition and performance of the Radio Cade theme song featuring violinist Jacob Lawson. And special thanks to the Cade Museum for Creativity and Invention located in Gainesville, Florida.

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