OK.

Kesha Thank you.

It's a it's a great pleasure to
be here at a very enjoyable day.

All meeting up with all friends
making acquaintance with individuals.

I had never met before and

I was very impressed with what
I saw about the department.

Especially the size.

I'm from Ohio State's a big place.

The Ohio State University.

I tend to be a little bit rebellious and

leave the off of what I'm
going to talk today about.

Of work that I began about seven or
eight years after I started my career.

It was constant in the beginning
was all about polyurethanes and

about polymer physics of polyurethanes
of the year of micro face separation and

physical properties.

And gradually got caught up
with medical school colleagues

in whether I could supply
samples of materials that

they heard were very interesting
in terms of blood compatibility.

From my laboratory so I would give them
samples and they would do some testing and

before long we talked about well
maybe we could write a proposal and

it turned out that
the the big mistake the McG.

The government made was the first
time ever proposals and I got funded.

And that launched me and
along with a long career in dealing with

interactions of blood material or

blood components with polyurethanes
that's going to be about sixty or

seventy percent of women tell you about
today and I'll try and transition to work.

We've been doing more recently.

That's not on polyurethanes but
on a related topic at Ohio State so.

Biomaterials are certainly evolved
since I began working in the field.

For the most part the early
applications of polyurethanes were

to take commercial materials and
see whether if they were cleaned up.

That they could serve in a medical
application so cellulose acetate which is

textile fibers even a sausage sausage
cake casing it processed appropriately

can be used as a dialysis membrane is
this use of complement activation another

other features that have to be dealt with
but basically it's cellulose acetate.

Polyethylene tariff were.

The early vascular graphs but before
then they were often woven fabric some

filmed form their mylar etc
It's a workhorse polymer.

The fact that you could have woven
tubes let these heroic surgeons

mostly in Texas just are using them
as artificial blood vessels and

as long as the vessel isn't too small.

They are fine.

Not only a woven decor.

But also cortex tough for
stuff on it's when you get to smaller

diameters that blood compatibility
issues rear their head and there's even

after all these years of research in
the area is still no real good solution.

So it's like looking for
the philosopher's stone still a lot

of work going on and I'll tell
you about what we tried to do and

how that research is evolved
to where we are today.

I got interested because I certainly
was working with poly theory thanes.

They're very good in support.

Where in terms of their high modulus
of holding power of the typical

type techs the fiber is
a spandex as you know it and

began to be used in catheters Bloom
pumps and pacemaker insulation and

they're still I think.

Decent application of
poly a three year thanes

up particularly in catheters these days.

I could mention a few other polymers
a silicone rubber poly dimethyl

Psylocke saying of lubricants gaskets etc
and i Phone the distant all additives.

But catheters breast implants into being
finger joints and there was a whole big

upset many many years ago about
whether the a lingo a silicone

material that's used as the liquid
inside of the sill of silicone sacks.

It would cause essentially
a disease response.

It never was quite proven but
silicone brought breast plans were

off the market for a long time and
there I guess they're slowly coming back.

P.V.C. we know as vinyl seat covers and

the hard form without plasticizer in your
basement that white cold water piping.

That's polyvinyl chloride.

In it's plasticized form.

Probably you know what is tied on
to being a were there the kind of

tubing that it appears in the infusion
sets in hospitals the blood bags and

the the sailing bags are typically.

Polyvinyl chloride that's plasticized and

there's a lot of sort of
like uncertainty of that.

Is that appropriate material
because the plasticizer leaks

out into the blood if it's a blood bag.

And.

It's very hard to replace P.V.C. because
of cost and effectiveness of the blood is

stored to a little greater effect than
if you try to make the blood bag out of

a more hot hydrophobic say rubbery
material or or block polymer material.

And finally we have polyethylene
low dielectric constant

used in the insulation first and
then cheating and so on.

Of polyethylene wash bottles in
the lab terms of that property but

if you make it very high molecular weight.

It has very good abrasion resistance and

it can be used as as the coating of
the Cup material in the artificial hip.

The problem with all polymers in many of
these applications like finger joints in

the hip is that they tend to produce small
particles that come off with with wear and

cause inflammation and
problems and repeated surgeries.

But what are what are basically saying is

we have these materials
that look like when you.

Off the shelf and
they don't quite come up to standard.

So the Via materials
field has been evolving.

To more purposeful design of the chemistry
and I thought I was doing that

in my research I'll show you some
examples with surface modification and

with the integration of biologicals
particularly thinking we can make hybrid

organs with bio material with
cells that would grow on it and

aspects of that and by mimicry is
a very active area of research.

So I want to talk about the interaction
of blood with biomaterials of for

those of you working in the area.

This may be too primitive but for those of
you who are working more traditional areas

of chemical engineering I think go
a little review it is helpful but

with respect to blood it's
a very complex fluid.

It's two phase about forty percent red
blood cells that's the amount of crit

got a lot of proteins.

We only know in detail even today a small
fraction of the total fro proteins and

what their structure function relations
are like albumen in fiber and

it's in fiber necked in its outer.

And and in addition to small particles in
here that you can see these little circles

those opposed to be platelets
of the are the red.

So this thing.

The red blood cells is about eight or

ten microns this is a three
micron platelet and

in our research the platelet aggregates
were very very much a high flow rates

the controlling of feature of viability
in terms of clot formation on surfaces.

There are issues that engineers Arkan
are interested in that I'll talk about

today like the convection diffusion and
reaction that surfaces which play a role

in the performance of the material
when placed in blood.

But if the fact of the matter
is you put blood through

a material like an artificial blood
vessel the first thing is going

to happen is protein will absorb and.

Some of these formed elements that are of
their call like the platelets will come

down and
act become activated on the surface.

And what we observed in our experiments
I want to show you experimental data if

you will that confirm
a hypothesis of what happens

particularly high flow rates is
that you get proteins or first.

Then the platelets come out they recognize
that some of these proteins are not

natural.

They're in the in the sense they've
been denatured the plate would spread so

in contrast endothelial cells were
to talk about later which you

want to spread because that's a sign that
they're going to pollute right and so on.

You want to keep the platelets from
activating because it's an irreversible

process with with with the platelets that
cause chemicals to come out of them and

make the surface above them very sticky
to subsequently arriving platelets and

you can build up a a clot a clump or
clot of aggregated platelets and

in the interest to seize fibrinogen
a protein that's present in a significant

abundance in blood and rises to fiber and
holds the whole structure together.

What we observed and I guess it's a.

Emory professors would do is almost
simultaneously in a different model.

Harker and Hanson was what the team.

In baboons I want to show
you experiments in canines.

Was that you can get them off

of these surfaces a kind of
passivation that occurs so.

There are a lot of questions that arise
and the whole idea of making a better

buying material which is the first
part of my talk was how could you

minimise the extent of this process
of thrombus and then thrombus

a removal and of course it's bad that
these thrombus particles come off because.

They large in the capillary bled beds.

If it's your brain.

That gives you a stroke.

So a lot of you are too old to
remember the artificial heart but

that that failure of the artificial
heart was due to stroke formation and.

In in the poor implants
the recipients that received it.

So we want to somehow minimize this but
the the all talk about that process.

After we say a little bit about the role
of IT or proteins This is a very also

a good many of the comments are still
valid today we don't know enough about

the role of INS or proteins how we can
design a surface that my preferentially

alter in a positive way for
us the protein composition.

The role of minor proteins when I began
in this field fiber Nekton was a minor

protein it was just being
characterized effectively an hour.

We know a lot more about it.

Veteran act and comes on the scene there
may be other proteins out there yet

to be fully characterized that
play a controlling factor

cell binding interactions or something.

We're trying to exploit today this is the
it's maybe now it's twenty five years but

they're in it to the into green
lie again interaction has come to

be known to be fairly important and
why is it that when

we do Ass A's in biology very
often you use albumin or

casing solution to passive A to
the surface to to minimize

nonspecific consortiums what is what is
unique about I'll be human to do that.

OK And
is it because albumin has virtually no.

Carbohydrate.

In it and so on and then.

Protein denature ration and if indeed
we have this thromboembolism that

results in a surface that looks passive
aided blood compatible for a while.

Is this enough the surgeons when
they're doing artificial graft.

In say the abdominal aorta will often

depending on their technique
they will precaution.

With the patient's blood
the graft washed out the clock and

then implanted they think
they get a better result.

But I don't know if there have been
any definitive studies as to whether

it really helps but
there is a passivation it takes place.

OK.

The platelets are very
interested in places but

I don't want to spend
much time on this but.

Chemical engineers were very early
in looking at platelet transporter

the surfaces.

They don't have use according to the
molecular diffusion parameters that you

would see for its size to
the surface they diffuse much more

rapidly because of the two
face flow we have these big

red blood cells tumbling along and
you have these much smaller

platelets that are given a transverse
impulse toward the surface.

So the platelets in tube flow
are basically rained down on the surface

with enhanced diffusion
coefficients because of that

of the tumbling right bloke blood
felt that blob of blood flow and.

This was very much.

The domain of chemical
early chemical engineers

who appoint fluid mechanics issues and
and sort of studying the fundamentals of.

Blood flow.

So platelets at that.

Here they aggregate.

They form from by and there's also a lot
of chemicals release inside a platelet

there's a sense there are some amount
of fiber nectar there's some amount of

thrombus Spondon etc There is an A.T.P.
and this is these factors.

That cause the activated platelet

to be sticky to subsequently
arriving of platelets.

And something that that I mentioned that
I don't have an answer to at this point

it's a it's an interesting subject.

I read most of the work I'll
show you is in vivo X. of evil.

OK so with an animal model but
what is the relevance to the dog.

To the bad bone at Parker Hanson
studied to human etc

The species difference in terms of how
you evaluate materials is still very very

much of an open area for validation.

Of the best that would shape or whatever.

If you really want to make
a new vascular graft for its.

Valuation some people prefer mini pigs.

Because of this more similarities to
the human to human logical condition.

So this is our gift to.

The.

Blood evaluation technique we created

with my surgeon friends at Wisconsin and
X. be both shant.

The shunt can take on will see
a little higher magnification

character to have several
materials in it so

you can evaluate several
compositions of the same time.

The dog is not anti coagulated So
you have whole blood the blood pressure of

the dog pushes the blood flow through and
periodic Lee you clamp and

remove the stems section put
a new test section in and

we use radio labeling at this time from E.

M. for platelets ID and for protein and
which study as a function of time.

The deposition on the surface.

This is a little higher magnification

of the what we call the series shot so
this allowed us to test.

Three or four materials and duplicate or
triplicate in a single animal so

that if you wanted to look at animal to
animal variations in one week we could

do three of these kinds of experiments and
instead of taking six weeks.

If you only did one
material in one animal.

So we were counting and taking for
scanning electron microscopy a little

sample here counting the deposition and
what we found.

And I was I.

We were alone in this but
it really surprised me and

if you understand how to
interpret this data of but

here's the example I'm not going to
show too much of this kind of data.

Except to say we have P.V.C.
our plasticized P.V.C. and

Apollo birthing that Johnson and Johnson
kind of licensed the technology from

Du Pont which is a kind of spandex recipe
of what was called by armor at the time.

And.

The but

I expected that when we were counting the
platelets on the surface that we would see

a plateau we would sound like a Langmuir
isothermal it would rise up to a plateau.

But both.

Platelets and the fiber in it in
which we measure it separately and

are going to show that
go through a maximum and

the height of the maximum could
be used in a qualitative way

as a measure of the blood compatibility so
P.V.C. is not very good.

OK in this nonet and I quite related
animal but the buyer looks interesting.

And if it with the sort of.

Anecdotal information that polyurethane.

If it didn't bio degrade so we had to
be a poly either your thing would be

more blood compatible and and
useful in medical applications.

So.

One of the things that you can see in
this model the tubing is transparent and

this is not a very good S.C.M. in.

Having been reproduced several times but
this is about one hundred micron

size thrombus on P.V.C.
at about that peak time.

It's peeled back on itself.

It's ready to come off the surface and
it's visible to the naked eye.

You can see these white pinpoints it
once you but flush the bulk blood out

of the slum by and the difference between
P.V.C. and a polyurethane is where

you still have platelets run by instead
of one hundred microns is five or ten

the plate with a little bit less activated
a little more rounded and this would

be defined in as very qualitative ways
is a more bio blood compatible surface.

Now polyurethanes are the segment
of materials there's

the they have a soft segment in this case
a poly ether which resists hydrolysis

paramedic ice assign a and
it's a two step reaction out of

essentially gives you a block polymer
you have rubbery segments and

rigid your thing materials here this
is like a Euro thing in your ear.

This would be typical of the that by a
recipe which is which has a main content.

And we sent out after this work to change
every variable that you could imagine.

Three or four Ph D. theses maybe
five on changing the soft segment

from of the poly ether to more hydrophobic
polytheists the polyethylene oxide.

To changing the ratio of ice to sign
a to Pollio so you make harder or

softer polymers to change in
what's called the chain extend or

in this case is shown butane
dial this is a dime E. and

we had a whole series of studies and
I never could yet any performance in this

model that exceeded that of that very
first material I tested by armor.

So we were at a loss.

It was kind of interesting work for
the graduate students and

a lot of polymer synthesis and related
characterization that led to papers.

But it was frustrating.

And I want to tell you about.

Well the polyurethanes are interesting
materials because of that

their micro domain structure.

They're they're like nano reinforced
materials they have these hard domains

which might have a dimension here of fifty
to one hundred I think storms are very

long they can be interconnected knots
what gives you the toughness and spandex.

Is what gives you the high abrasion
resistance in a skateboard wheel or

off the off the road truck tire
which are made from polyurethanes So

it's a very interesting
material in this respect.

But it's a two faced material because
you have this Michael Fay separation and

there are many questions that arise
which we won't deal with today about

what's at the air or water interface.

When you using this in a biomedical
application because that is particularly

since the the robbery phase if
you will is of above it's T.G.

there's a lot of flexibility and you can
get mobility and rearrangements when

you go from air characterization or vacuum
characterization to putting the material

in buffer solution before you would
do an implant where it's very spaced.

So what worked in a very interesting
way is when we started to make

some fairly harsh modifications
of the polyurethane and

make polyurethane ion immerse and
particularly

the self unaided variety where we would
abstract the earthing hydrogen with

sodium hydroxide and then propane Sultans
a very reactive dangerous chemical.

But you could soften ate
the material clean it up and.

We saw for
the first time in this polyurethane an eye

on a murders of very icy and
hence response.

The minimal response in
the animal model that I had.

So the poly if the earth aims we would.

Characterize this is five
percent of the of the N.H.

groups are replaced with self in a ten
fifteen and twenty as a show you later.

If you go much above twenty
it becomes water soluble so

what you're making particularly
after equilibrium what

moisture absorption after forty eight
hours or so isn't an ionic Hydra Joe.

So it's a soft gel like material that we
could code on the inside of our test tubes

or our test segments which were
polyethylene which were oxidized so

that polymer solutions of this kind
of material would wet the surface and

give us a coating of poly your Earth.

Cell phone had polyurethane for
testing in the animal model.

And here for the first time if this is
sort of like the controlled pollies that

you're at then behaves like biome or.

Appear that we started
to see much lower and

it turns out with my cross
screen which I won't show you

much more rounded platelets on the surface
and you would think that the strong

acid would be very sign of toxic you
know the platelets or anything but

in the presence of the whole blood of the
animal with all those proteins present.

There's a screening reaction and

there's something very unusual in which it
wasn't only my lab that looked at this.

John brash and in in Canada working on
very similar kinds of chemistries and

being surprised by the tolerance
of platelets toward the surface.

I think part of the of the mechanism.

Is that there is some interference
with other four parts of the.

Quagga lation mechanism.

This is Brahman time partial time
activated partial formal placid time

whatever and
our controls were polyvinyl also.

Canine blood or
whatever clots at about the second.

Experiments and as we put these material.

Then at about fifteen makes permille So
these are water soluble already.

OK so I can put them in and then you know
you shake it and measure how long it takes

the clot and we can immediately see that
we go to a fairly long clotting time so

it's doing something to interfere
with blood coagulation and

we did some other studies that I won't
talk about that showed that it seems

to be some aspect of fibrinogen
Plimer zation that is inhibited

by the presence of these
strong acid functionalities.

So we were kind of excited about this.

It wasn't the end because it's a hydrogen.

Of the last phase of my
polyurethane work was this was

at the time when our G D was
still a little bit novel.

OK but looking at the integration

law again receptor interaction and
saying OK.

I give up can't make a normal
polymer material blood compatible.

What if we could grow endothelial cells on
the surface form a monolayer if you will

and that's the natural lining
of cells in a blood vessel.

Would that solve my problem.

And in theory it was should work but

a lot of people who are working on
this and it's a very big challenge

in terms of not having you making
an artificial blood vessel.

When you saw one into somebody most of
the cells you put on this way by seeding

a whatever slough off in
your back to ground zero.

So just say it's not the end but

an analogous way of putting a soften
a group on the surface you could put

a carbon a carb oxalate group and
this is probably a lacto.

It's a dangerous chemical both
propane salt on appropriate a lot.

Tone ring compounds are very reactive and

they're carcinogenic you have to be very
careful using them but once they react.

In when the Ring opens.

It's a pretty safe compound and

we did both by blocking
the secondary means on here and

in a one step reaction which I show
you here you can with a car box later

material work with the diameter and
put it.

Am i bond on air and
have R R G D which is the law again for

the inner going on on and
you'll feel yourselves.

And if this works.

There are many questions
such as accessibility.

Again this is on the N.H.
group has been car box elated.

So it's on these hard segments.

Certainly in a Prius systems it's
here if you do Esca or X. ray for

electron spectroscopy it's kind
of hard to see the nitrogen

excess nitrogen content
say from the peptide and

there's certainly about going to be some
of this mobility in here which one can can

study by of using techniques
that freeze the structure and

work in X. ray for the lecture on
spectroscopy cryogenic conditions.

Now does it work.

The answer is yes.

Here it's about from five to of.

The to forty the controls which are the
base polymer the poly easier thing to call

box related polyurethane is down here and
the negative R G E peptide is down here.

Very few cells in here and
when you put R G D With S

which is sort of like a fiber Nekton and
with our G.D.B. which is

a characteristic of the R G D
in Richard I can you get on.

Large amount of cells and
which will be the continuing theme today.

The biggest effect the seen
in serum free media so

this is an in vitro experiment
you just groan sells for

four hours on the surfaces and
and yes R G D works.

Anybody can do.

R G D stuff and you'll get.

R G D on the service and what you see
on the controllers this is the poly

easier thing to call box laid our
genie is that once you put our G.D.

on the surface you get a spread and
the feel yourself so

just opposite of platelets which with
you you you want to stay rounded.

A better result from a endothelial cell
experiment is to get them to spread

because then they'll start reproducing and
you get the cobblestone layer.

That's characteristic of the interior
of a of the artificial Hattori.

And the R G D V lots of spread cells.

But what happens when you
do experiments and serum.

Now it's much more healthy
environment to do sell it.

He's going to have serum present.

OK We're just putting men from buffer or
whatever if you don't.

If you go much more than four hours
the cells are going to start to die.

So serum is required for
any kind of long term.

Cell surface studies.

So that's the challenge and

of course if you think of implant
situation you're going to get the proteins

from the body which are very similar
to many of the ones and in the serum.

And what you see is that you lose a
fraction of the effect a good fraction so

now the control surfaces which before
we're down around five are up to

I don't know fifteen to eighteen.

We still see some effect here
in the R G D vu still the best.

But you can see from the from
the micrographs that.

Even the control surfaces have
somewhat spread endothelial cells

of course more with the R G D S N R G D V
in the material and this theme about.

The complication that occurs when serum is
present and serum has this fiber neck and

has fiber engine and
it has a piece of proteins is

is something that haunts us as I go to
the next part of my talk which is more

much more recent work on
trying to essentially attract.

Low concentration stem cells.

That might add Zorba or
grow on a vascular graft material so

affinity surfaces for these human
blood outgrowth endothelial cells.

So what are we trying to do.

Well first of all that what we were
going to go away from polyurethanes and

the system I've used in
recent years is is not.

The typical scaffold like material
although it can be made into a scaffold is

a non-biodegradable polymer
of acrylic monomers typically

hex almost accurately method with
accolade and as we'll see you could use

meth acrylic acid particularly if you want
to use the acid group to to attach and

mean to to the to the material
by AM I bond formation.

It's by a stable it's
biocompatible acrylics to be used

of contact lens kind of applications for
a long time.

And by changing the ratio of monomers you

can make fairly soft materials or
hard materials.

So this is the structure and

of which shows change in
the concentration but basically.

We started to work with human blood out.

Both the H.B.O. he sees and
the cells they are present in

low concentrations in what they form
from stem cells that are present

in the body in the peripheral blood at
low concentrations of their adult cells.

And they are a bear to culture and
what we did in this study

is to first obtain the H.B.O. we seize and

second look for the analog of our G.-D.

which would bind to these cells using
a technique called phase display.

So we're looking for peptides and
no one has ever thought of using

by using the H.B.O. he sees as essentially
the finity matrix as it's called

so phase display is makes use
of common authorial chemistry.

You can buy a library of
a billion of of of these things in

our case it would go down the peptides
on these phage molecules and

if you can concentrate them on
your target in this case an H.B.O.

we see and look for the strong winding

elements at the end of the day
when you have your strong binders.

You can use genetic techniques
to determine the amino acids

sequence of the deck of peptides
that are that are in this like and.

So that's what we did it took about
a year to learn the technique

to do these experiments and
we discovered a couple of interesting.

Peptides this one of the techniques that
we used was we knew we didn't want our

ally dance to bind to regular endothelial
cells so what you do is a kind of

prescreening So there's a lot of
incubation center free if you gave.

PH changes that release the lie Ganz and
a cyclic med that meant

a method of growing up
the the phage in E.-Coli.

So it's a it's a very
straightforward process but

one that takes skill and
learning so we have.

Incubate the Phase two billion of them
with Hugh vex these the open circles.

OK.

And then centrifuges whatever
that get rid of as many

of the a billion cells
you know like a seven or

a thousand that bind to you have X.
and take the super nape and

put it in here and then put a pc's in
that you separated by a very primitive.

And tedious process and precipitate them
and you expect that these like dance.

Of have these like Gans on on the on
the hugh backs would be strongly bound

to the E.P. see at least in this first
round of what is called Bio panning OK so

is prescreening throwing away
these screening with a P.C.

and then collecting the valuable
materials changing the PH to release

the lie Ganz growing them up in equal I so
you get high

enough concentration again and repeating
the other process without this step.

So that's called Bio panning and it looks
like a car to form this you have many

different like and so you do
the colored particles are Deca peptides

randomly created by molecular
biological technique and

you you go down to get the strong
binders and you grow them up.

And do this.

About three times and fall.

Anneli you get.

There are literally thousands or

hundreds of thousands of choices after
the third there's still a lot around

you you you play them out they
grow colonies called phages.

Face forming units and they're all
monoclonal in those individual.

Colonies and you cut you you sequence them

to get back information about what
peptide was in that colony and

we analyzed like forty of
the of these at random

to get a series of of
peptide possibilities and

to make a long story short we found
a whole bunch that were interesting and

I'm going to show most of the end
of the data on on this T.P.S.

Deca peptide So the idea is just
like R G D You take a T.P.S.

you functionalize it to get it into into.

The polymer if you want to use
a meat chemistry will see you use.

The Sistine to create
a change transpiration and

do plumbers ation with it.

And then see if they can somehow harvest.

Or potentially harvest H.B.O. You see
when they're immobilised this way so

we did that we created you can you know
go to a peptide sequence place and

you know the T.P.S.
we had three glycine spacers Syrian and

then then Sistine which we
used in our plumber zation.

It has the SH in it which is a very
powerful functional group for

interrupting a vinyl plumber zation and
making a chain and.

So we're going to end up in with this kind
of synthesis with the peptide at the ends

of of the chain as shown at
the bottom of the slide here.

It's not it's you don't
get high concentrates But

the other stories when we when we when
we did this on our crew of polymers.

We found.

Again and here's the.

Sort of like the bottom
line it was successful.

Our T.P.S. would bind H.B.O. He sees sort
of fiber neck to bite H.B.O. series.

It was selected against Hugh VAX so T.P.S.
doesn't bind you back.

So we had selective binding.

Of this it may not be enough

in terms of what whatever
the surface concentration was.

But we were kind of
excited about this result.

So is is could you make of vascular

graft with T.P.S. could it harvest
these rare cells in the body.

That would polyphony rate and

become endothelial like an effect of
it in terms of a bit of a lining.

The problem was.

If you did the same experiment with.

Serum.

The whole effect was ablated.

Or you know it and you're going to have
these kinds of proteins around that

any kind of in vivo situation.

So we were we was interesting study
was you know you get papers you can

do people get their Ph D.'s etc.

Most of this work is done by post-doc
though so ph the Wasn't wrist but

the bottom line was you know
it's this little disappointing.

And that leads me to the most recent
work we've been doing which was trying

to just engineer around the problem
which creates other problems etc of

incorporating non filing
character on our material

surfaces along with the like and
for the cell binding.

And I'll show you a little bit in my
talk really with a few slides here.

We're not going to have Carbon Silicon
acid side groups no math acrylic acid

just a skull polymer and
instead of meth acrylic

acid polyethylene glycol with AK relate.

It's not.

Fouling polyethylene oxide
were non protein resistant.

And another one that we've used
to good effect soulful but

self-will Betaine Zwicker I'm so

here again is off friend the sulfate and
these two One is what are on this is

completely neutral both of them resists
protein absorption and you can see

that in this curve of fluorescents
measurement so when I was at Wisconsin.

All we did was radiation all the protein
we radio label that we counted and

I'm glad we learned.

To get away from that the the use of
radioisotopes is getting more and

more tedious and there are very
elegant and useful fluorescent methods

to measure protein is off and
that's how we did that here.

Here's a positive control tissue culture
polystyrene this is the piece here is

this is the base hydrophobic polymer.

Five percent or more percent of
polyethylene oxide and fifteen percent

basically gives very little protein
absorption is case fibrinogen.

And here is on the sulphur Petain we does
with our ion is the symbol Z. again you

have to go up to about fifteen percent or
at least in this sensitivity of experiment

see virtually no protein absorption
from really and in vitro experiment.

They also show good resistance
to cellular attachment.

Now there's there's no like in on these
these are just of the same materials we

did the protein is or

to study your culture polystyrene
you can always grow things on here.

This is a huge VAX this is the base

polymer five percent polyethylene oxide
NO percent fifteen percent in the same

We get very few adhere to it here and.

You this is just
a fluorescents are confident

Mike microscope images showing that.

We get fewer and fewer cells that here and
you can even find self reste

regions on the Z fifteen in panel D. so.

Waking interesting materials.

It turns out that probably were we were
placing ourselves at a disadvantage using

chain transfer chemistry to have
a Sistine terminated material.

Now with polyethylene
oxide ly Ganz we would

what we did in this image if occasional C.
using sucks intimate chemistry.

Is you can buy only go polyethylene
oxide that has an N.H.S.

at the end that will bind to the mean and
of your peptide

don't you'll have to put sustain on there
and the pending on how much you put in.

You can get now.

Sigh groups of pure Polya not side or just
a little bit substitution of the law again

and get the much higher concentrations and
if it's only at the chain and.

So we did that.

Of a C.T. as a symbol for
a change transfer and

this is the P fifteen very few cells are
or are going to hear with no lie again.

If you put some R G D now so we don't
have our expense of peptide in here but

our G.D. now you'll get more and

if you have a higher concentration
that we're able to put in with.

With either a bit emanation or
of N.H.S. chemistry.

You can you can get both in
principle protein resistant and

sell adherence surface.

Relatively short term contact I
think two to four hours or so

where you get pictures like this where
having trouble sustaining viability.

At longer times of a culture in for weeks.

So here's a cell density of us more and

more quantitatively define the P.
fifteen by itself.

PIFF P fifteen it has R G D
by a change transfer and

probably a factor of three higher R G D
concentration using socks intimate so

the idea would be we
this is our test model.

If this works or
what can we do it with the H.B.O.

He sees why we're interested in this.

Finally the protein resistance
can be shown pretty explicitly

hears of three sets of of
experiments without proteins blow.

The pink is with Prius or
fibrinogen and the yellow is

with the blocking over serum albumin and
if you have no lie again.

OK if I burn it is going
to help you a little bit.

But if you have you're lying and
then you get twice or

three times the amount
of cells that hearing.

And this is that the example
on tissue culture polystyrene.

Now these materials a linear polymers so
you can you can do and this sort of like

when the end you can make them by Electra
spinning you can make a spongy mass.

If there hydrophilic you're going
to get a kind of swelling and

kind of more cheesy structure this a D.
is just the H twenty which is basically no

polyethylene oxide and you can make fibers
like everybody makes fibers here but

these would serve and
what we had that the last grant I had was

sort of giving up on the heroic
desire to make a vascular graft.

But make another device
which would be interesting

in terms of the analytical chemistry for
stem cells.

We called it cell trap and I think
this is my last saw the last slide or

next to last line.

We would make a scaffold like
this put our Arwa Ganz on it and

have our rare cells which are red.

Along with other forms of cells and
say I'm looking for the the live dance for

the H.B.O. he sees.

And then use magnetic B.
technology with like hands for

you know CD thirty four whatever for
these cells pull down the cells.

Have them attach the scaffold
get rid of everything else and

expand it into a Instead of way across a
to two Culture H.B.O. he sees is a month.

So if you want to characterize a disease
state by how many of these H.B.O.

season it is conjecture.

If you have diabetes you may have more or
less of them or

if you're young or old you.

It could be a useful diagnostic
this might cut down the time.

If you could make such a device
from weeks to perhaps.

Say five or six days or maybe less.

So we call the cell trap we have
done a lot of work with magnetic B.

deal of worry a little bit about if
you've got beats contaminating your cells

are they really going to grow a nice
confluent a level of enable you

to to sort of back calculate
a concentration in that person's blood.

But that's that's where I had my last and
I grant.

To try to make this device.

So let me just close by
thanking my graduate students.

You know I'm very proud sort of like as my
career is sort of like drawing to a close

to have had about sixty
Ph D.'s to sixty one

actually Ph D.'s about forty
percent were in the biomedical

area shown here just a start of this
whole thing using the animal model.

Jay was for a time to C.T.O.
of the three M. company.

He now has all of the three M.
Asia very successful engineer

in advanced materials company.

Post-doc of mine is that some.

You may know Rich Dickinson
is the chairman of Florida.

And right now the student who did the last
little bit of work with the H.B.O.

he sees as Daniel Heath.

Gen-Y. and rust and Shankman.

So I try to give you a little
feeling in terms of a conclusion.

It's basically we've gone more and

more toward trying to get a biological
solution that involves both cells and

materials in a kind of synergistic
fashion but that the the goal

will issue of a blood compatible
material or for that may or twisting

it around to say the the effective
use of stem cells in some way for

this technology whether it as a something
that can endothelial as a surface.

By differentiating to endothelial cells or
or a diagnostic that

would allow you to characterize
a patient's state of illness by rare

cell analysis is what what sort of
been the last bit of this research.

So I'll stop now and
ask if there are any questions.

Thank you.

Lots were hoping but but really really
have no quantitative information.

What we were hoping to T.B.S. is not going
to work with endothelial cells T.P.S. can

work with H.B.O. He sees so if G.P.S. can
somehow get these on the surface and after

four or five days in culture if they pull
it rated form the cobblestones at cetera.

That would be a homerun.

But there's no guarantee that it would
work in fact I worry if indeed I

have to use gel technology to
defeat nonspecific absorption.

Whether or not.

That is a slough resistant
surface it probably isn't.

So I'm not I'm not I don't want over
promise on this technology has been fun to

do the work of but
it's a challenge to really say that

there's a path forward to you know I
don't think an intelligent reviewer.

Would help us with another round
of this kind of research but

who knows they may come to pass.

I think that might be the mechanism
although I found a lot of things.

That along the way that really
deserve serious examination.

Just the idea of passivation
of clotting a surface and

removing the clot what's there.

That is it is is a surface that might
be resistant to clotting at that point.

Just covered by membrane
fragments from the platelets and

that's sort of a fossil lip it's there
are or resistant to the further reaction.

And it.

It takes a lot of energy to focus on
what could be a Monday in a kind of

observation not too useful the same
thing with respect to to be human.

It's used very casually.

But monolayer versus multilayer
exhaustion the nature ation

a lot of those very subtle they could be

very subtle effects that would enable us
to understand a little bit more completely

why you can prevent

non specific it's option by a coating
of this particular protein.

So I don't know.

What.

I think

it much.

I think it's desirable to think that you
could make a synthetic that would serve

slightly more effectively than gore tex or

polyester because it's more
intelligently designed and tested but

whether or not it could tolerate
the low blood flows in a small they.

Amator arteries and certainly
the challenge is to get it in a vein.

It just may not be possible work for for

example could you get that to work if
there was an advance in anti-coagulation.

So that the patient could and
right now even with these large graphs

generally are on their on the blood
thinner for their whole life.

You might be able to get
a other prove meant.

So that the challenger they all they talk
about is like getting below the knee.

For diabetic patients
which they would avoid

if they could do a graft
there ovoid amputation.

And virtually nothing works.

So if you if you're combination
of slightly better material or

a little bit a bit better at acquiring
that regime might be clinically useful.

But it's I don't know about.

Whether I if you know starting over
whether I would try that's very probably

my polymer background which would
suggest it's a cleaner route

than to try to put the cells on but
but it's it's like.

The whole field of biomaterials
has gone more biological and

this is a outcome and

I think it is it should be allowed to play
itself out there should be more research.

Maybe some breakthroughs in and
and and and that would be great.

One.