Category Archives: Medical

Biopolymers Used Inside Body

source: http://www.pr-inside.com/solvay-advanced-polymers-launches-solviva-tm-r263374.htm

Solvay Advanced Polymers Launches Solviva(TM) Biomaterials Available for Use in Implantable Medical Devices


2007-10-24 12:21:47 -Solvay Advanced Polymers announced today at the K-Show the launch of its Solviva(TM) family of biomaterials offered for use in implantable medical devices. No other supplier has more polymers available for use in implantable applications than Solvay Advanced Polymers with its Solviva line of biomaterials.

Solviva Biomaterials are comprised of: Zeniva(TM) PEEK (polyetheretherketone) – one of the most chemically resistant plastics available, exhibiting high strength and stiffness along with excellent toughness and fatigue resistance

Proniva(TM) SRP (self-reinforced polyphenylene) – the stiffest and strongest unreinforced thermoplastic available, offering exceptional chemical resistance and hardness

Veriva(TM) PPSU (polyphenylsulfone) – offers unsurpassed toughness combined with transparency and excellent chemical resistance

Eviva(TM) PSU (polysulfone) – offers practical toughness in a strong, transparent polymer

“We are very proud to leverage our technology in creating this family of products,” commented Roger Kearns, President & CEO of Solvay Advanced Polymers. “The ability to supply our customers with biomaterials that are the foundation for products that may help to extend and improve the quality of life in critical healthcare applications is tremendously rewarding. We look forward to a successful rollout and further enhancement to our line in the near future.”

The launch of Solviva Biomaterials is the culmination of more than 18 months of planning and extensive investments by Solvay Advanced Polymers in its production facilities, biocompatibility testing and the installation of one of the industry’s most stringent production processes. Specifically, those efforts include meeting the relevant aspects of the current Good Manufacturing Practice (GMP) guidelines of the Food & Drug Administration’s 21CFR Part 820 Quality Systems Requirements and ensuring manufacturing operations are in compliance with relevant aspects of the ISO 13485 Quality Management System for the manufacture of medical devices.

“We have invested a considerable amount of resources into ensuring that the Solviva biomaterials line meets or exceeds the critical regulations required of a supplier,” explained Shawn Shorrock, Global Market Manager, Healthcare for Solvay Advanced Polymers.

Solvay Advanced Polymers’ heritage as a supplier to the healthcare industry goes back more than three decades, and today includes widespread use of its ultra and high-performance polymers for orthopedic applications, cases and trays, medical devices and dental instruments. The company’s sulfone polymers are also used globally in the manufacture of membranes for kidney dialysis.

Solvay Advanced Polymers is currently in active product trials for its line of Solviva biomaterials with several medical device manufacturers including worldwide leader, Zimmer(R) Medical (www.zimmer.com). For more information on the Solviva line of biomaterials, visit www.solvivabiomaterials.com.

About Solvay Advanced Polymers

Solvay Advanced Polymers, LLC produces more plastics with more performance than any other company in the world. This gives design engineers worldwide more ways to solve top design challenges in automotive, healthcare, electronics, aerospace and other demanding industries. Learn more about the full line of Solvay Advanced Polymers’ SolvaSpire family of ultra polymers at www.solvayadvancedpolymers.com.

Solvay is an international chemical and pharmaceutical Group with headquarters in Brussels. It employs some 29,000 people in 50 countries. In 2006, its consolidated sales amounted to EUR 9.4 billion, generated by its three sectors of activity: Chemicals, Plastics and Pharmaceuticals. Solvay (Euronext : SOLB.BE – Bloomberg: SOLB.BB – Reuters: SOLBt.BR) is listed on the Euronext stock exchange in Brussels. Details are available at www.solvay.com.

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Medical Plastics: Avoiding Biological Interface Reactions

 Source: http://www.cemag.us/articles.asp?pid=160
Surface Modification of Plastics for MEDICAL DEVICE APPLICATIONS -
By: June-Jim Schepple,Jeff Dykhouse
June 1999

Plastics, polymers, and resins have become widely accepted for in vivo and in vitro medical applications. Many of these materials have properties that lend themselves well to the manufacture of medical appliances or devices; they are relatively inexpensive and easily molded or formed into complex shapes, and bulk physical properties may be selected from a wide range of parameters such as rigidity and temperature stability. Unfortunately, fabrication procedures that require bonding are difficult to achieve, and biological interface reactions within the body or in the laboratory can limit their in vivo and in vitro performance.

Gas plasma technology offers a technique for easing these limitations by modifying the surfaces of these polymers. By altering just the first few atomic layers, the surfaces of most medical polymers can be rendered wettable so that adhesive bonding can be achieved to troublesome materials such as polyolefins, silicones, and fluoropolymers. In a similar fashion, more exotic processes such as plasma grafting and polymerization can produce totally new custom surfaces without loss of the desirable characteristics of the bulk material.

Plasma is a low pressure, gaseous “glow discharge” process that has been used in the aerospace, semiconductor, and electronics industries for more than 30 years for cleaning, etching, and surface treatment of various materials. Plasma treatment does not affect the bulk of the materials and plasma treated parts are generally visually and physically indistinguishable from untreated parts.

Plasma is now routinely used for controlling the wettability of test tubes and lab vessels, for pre-bonding preparation of angioplasty balloons and catheters, for treating blood filtration membranes, and to manipulate surface conditions of in vitro structures to enhance or prohibit culture cell growth.

PLASMA BASICS

Given enough energy, any gas can be excited into a “plasma,” which is a mixture of ions, electronics, excited species, and free radicals. There are many temperature and pressure conditions where this phenomenon will occur, but for practical considerations, radio frequency or microwave energy is commonly used, enabling these processes to take place at low temperatures (25-100¡C) and low pressure (0.1-1 torr), where surface reactions with polymers are feasible without bulk interactions.(1,2)

Plasma “treatment” usually refers to a plasma reaction that either results in modification of the molecular structure of the surface or atomic substitution. Even with be-nign gases such as oxygen or nitrogen, plasma treatment can create highly reactive species at low temperatures. High energy ultraviolet light is emitted in the process, which along with the high energy ions and electrons provide the energy necessary to fracture polymer bonds and initiate chemical reactions at the surface. Only a few atomic layers on the surface are involved in the process, so the bulk properties of the polymer remain unaltered by the chemistry, while the low process temperature eliminates concerns about thermal modification or distortion of the bulk. Unique reactions can be promoted by appropriate choice of reactant gases, and unusual polymer byproducts and structures can be formed.

In many instances, plasma cleaning with benign gases such as oxygen or nitrogen provides adequate surface activation for enhanced wetting and adhesive bonding. With other targeted end results or substrate materials, it may be necessary to utilize reactants which result in “grafting” or surface chemistry modification to achieve the desired results.
It is frequently possible to select reactants that form volatile byproducts upon reaction of the plasma with the substrate material. These, upon desorbtion from the surface of the treated material, are removed by the vacuum pump, resulting in etching of the surface without the necessity for further scrubbing or neutralizing.

SURFACE MODIFICATION

Oxidizing species such as air, oxygen, water vapor, or nitrous oxide are often used to remove organics, leaving functional oxygen-containing groups on the surface. These groups greatly enhance wetting, improve adhesive bonding, and, in some instances, create acidic surfaces.(3,4) In at least one instance, sterilization of components has been reported with the use of strong oxidizers such as ozone or hydrogen peroxide vapors.

Reducing gas species such as hydrogen or methane-often diluted with argon, helium, or nitrogen-may be used to remove organics from surfaces sensitive to oxidation. This chemistry may also be used to partially substitute hydrogen atoms for fluorine or oxygen in polymer surfaces. The noble gas species, such as argon or helium, are chemically inert, so they do not combine or become part of the surface chemistry. Instead, they transport energy to break chemical bonds in polymer chains. Broken polymer chains result in “dangling bonds,” which recombine with other reactive sites, resulting in significant molecular restructuring and cross-linking. The creation of dangling bonds allows for chemical “grafting” reactions to occur. This process is involved in several of the biomedical applications.(5)

Active gases, such as ammonia, are used to create amino groups on the surface. This type of functionality has an influence on important surface properties such as pH and Lewis basicity.

Fluorinated species such as Tetrofluoromethane (CF4), Sulfur Hexafluourine (SF6), and perfluorohydrocarbons may be used to induce substitution of fluorine atoms for hydrogen atoms in the surface structure. Teflon-like structures may be created, resulting in a very hydrophobic, chemically inert surface with significant chemical stability.

Polymerization, or deposition, processes may include reactions utilizing a wide variety of gases, including some of the organic or organo-metallic compounds, which deposit nonvolatile polymer films.6 In many instances these reactant gases maybe toxic, corrosive, or otherwise hazardous and require special handling such as heated gas transfer plumbing and measurement instrumentation, reactor exhaust scrubbing, and trapping of reaction byproducts. Polymerization processes will generally necessitate frequent cleaning of the reaction chamber, since all surfaces ex-posed to the plasma will be coated.

BIOMEDICAL DEVICE APPLICATIONS

Surface Wetting.  Plasma treatment of polyethylene or polypropylene disposable Petri or Assay dishes greatly enhances wetting. Contact angles as low as 22û have been demonstrated on these materials after only a few minutes of oxygen plasma exposure (see Table 1). When these parts are properly packaged after treatment, the contact angle has been seen to be stable for several years.

Conversely, many medical polymers can be made extremely hydrophobic. Teflon-like films and other similar surface treatments can be easily accomplished on most polymers using fluorinated gases. For example, small diameter tubes can be treated so that when immersed in aqueous solutions they do not draw fluid by capillary action.

One of the simplest techniques used to evaluate plasma surface treatment is a wetting angle test using a contact goniometer. Surface roughness and substrate cleanliness need to be tightly controlled to obtain quantitative data. Standard wetting solutions are often used to obtain accurate surface energy values.

Most untreated polymers are only poorly wettable. Initial contact angles may vary from 60-100û. Table 1 shows a sample of some typical contact angle measurements:

Table 1.
Typical wetting angles,
before and after
Oxygen plasma treatment.(7)

Before After
Hydrocarbons
Polyptopylene 87° 22°
Polyethylene 87° 22°
Polyamide (nylon) 73° 15°
Polyimide 79° 10°
Polycarbonate 75° 33°
Fluorocarbons
Tefzel 92° 53°

PFPE

96° 68°

After 5 min. of oxygen plasma treatment, the contact angle decreases significantly.

Adhesive Bonding. Many intravascular devices, such as balloon catheters, are assembled by adhesive bonding of polyethylene components. Chemical surface activation or mechanical surface roughening techniques provide only modest bonding performance, with bond failures noted after as few as eight repetitive inflations. With plasma treatment, up to 40 repetitions are achievable. Typical bond strength data are shown in Table 2.(7)

Table 2.
Typical lap-shear bond
strengths (psi), without and
with plasma treatment.

Without With
Polypropylene 370 1380
Polyethylene
(low density)
370 1450
Polyethylene
(high density)
315 3125
Nylon 850 4000
Polystyrene 570 4000
Polycarbonate
(Lexan)
410 928
Tefzel 410 3200

An oxygen plasma not only removes organic residues but also chemically reacts with the surface to form strong covalent carbon-oxygen bonds, which are much more polar and more reactive than the initial carbon-hydrogen bonds. The increased polarity of the surface accounts for the substantial increases in wettability and adds a degree of covalent bonding to the surface-adhesive interface. (Note that other gases may be used to attain similar results in instances where oxidizing species may be harmful to components of the assembly.)

The bond strength ultimately realized will certainly be affected by:

1. Initial cleanliness of the surface(s).
2. Wetting of the surface by the adhesive.
3. Cross-linking effects.
4. Chemical interaction of the adhesive with the surface.

Any mold release compounds, unpolymerized monomers, plasticizers, or additives that may have migrated to the surface must be removed either by plasma cleaning or washing before surface modification is attempted. Immediate assembly is usually advised after the surface has been prepared. Once the surface has been optimized and bonded, the bond is permanent and does not degrade over time.

In-vivo and in-vitro applications. To increase biocompatibility in vivo, the issue of thrombogenesis (the propensity of a surface to form or initiate clotting) must be addressed. Many unmodified materials encourage protein binding and thus initiate the process of clot formation. To combat this process, antithrombonin (anticlotting) coatings are often applied to the surface, but when dealing with polymers these antithrombonin coatings often fail to effectively bond to the target surface.

Using an active gas plasma, surfaces may be modified by heparinizing or by grafting of antithrombotic functional groups, which achieve effective chemical bonding to previously inert material surfaces. Process variables are dependent upon a range of factors including selection of the base materials, composition of the antithrombotic, and the expected product lifetime.

Animal test results of the procedure on surface modified and heparin coated polyure-thane catheters revealed no protein attachment after a 30-day indwelling. Simultaneous testing on surface modified but uncoated polyurethane catheters disclosed only slight protein attachment, while unmodified and uncoated catheters show severe thrombus formation.

In tests performed on plasma modified blood filters, results showed substantial reduction in platelet retention compared to untreated materials.

Attachment of in vitro cultures. It is sometimes necessary to manipulate surface conditions of in vitro structures so as to encourage or enhance culture cell growth. In specific cases where cell attachment is necessary to ensure proliferation, plasma modified in vitro culture cell containers yielded dramatic improvement over untreated containers. Testing has confirmed that, by using gas plasma surface modification procedures, materials such as PET, polyethylene and K-Resin can yield substantially higher performance than in the untreated state.

REFERENCES

1 J.R. Hollohan and A.T. Bell, Techniques and Applications of Plasma Chemistry, John Wiley & Sons, New York, NY, 1974

2 Chapman, Glow Discharge Processes, John Wiley & Sons, New York, NY, 1980

3 T.J. Hook, J.A. Gardella, and L. Salvati, Journal of Materials Research, 2, 132, 1987

4 D.S. Everhart and C.N. Reilly, Annals of Chemistry, 53, 665, 1981

5 M. Szycher and W.J. Robinson, Editors, Synthetic Biomedical Polymers, Technomic, Westport, CT, 1980

6 R. d’Agostino, Editor, Plasma Deposition, Treatment, and Etching of Polymers, Academic Press Inc., San Diego, CA, 1990

7 E.M. Liston, Journal of Adhesion, 30, 198, 1989

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Filed under General Knowledge, Medical

Plastic Used To Hunt Cancer

 source: http://www.abc.net.au/science/news/stories/2007/1837304.htm

Plastic nanospheres to hunt out cancer

ABC Science Online

Friday, 9 February 2007

cells

Nanospheres could help take the sting out of chemotherapy by delivering anticancer drugs more effectively and safely, say Australian researchers.

Dr Martina Stenzel, a polymer scientist from the University of New South Wales (UNSW), will present her team’s research at the Australasian Polymer Symposium in Hobart next week.

When anticancer drugs are injected into the blood, they are recognised as toxic foreign agents and quickly disposed of.

This means people undergoing chemotherapy have to put up with numerous intravenous injections to keep the drugs at an effective concentration.

This method of delivering drugs also has nasty side-effects because the whole body is affected.

“You poison your whole body with these things,” says Stenzel.

“The cancer may be [destroyed] but the patient has to recover from the treatment itself.”

So Stenzel says the holy grail of drug delivery is to find a way of getting a drug straight to the cells it’s supposed to be treating, and ensuring it is released slowly over a period of time at the right concentration.

Search and destroy mission

Stenzel and colleagues at the UNSW’s Centre for Advanced Macromolecular Design are among the first to explore the delivery of drugs in nanospheres, tiny plastic spheres.

These would contain, say, a week’s worth of drug that, once injected into the bloodstream would quickly seek out cancer cells and slowly release the drug directly into them.

Stenzel and team have been experimenting with about 50 different nanospheres, between 10 and 100 nanometres in diameter.

Each sphere is made of specially designed polymers. There’s a hydrophilic (water loving) coating to help get them through the bloodstream and a hydrophobic (oil loving) interior that can soak up the drug.

On the outside they are coated with special molecules, called ligands, that recognise and latch onto particular types of cells.

While further research is required to find the best ligands to target cancer cells, over healthy cells, the researchers have so far had some interesting results.

While some nanospheres seem to be toxic to human cells and kill them before they get a chance to deliver the drug, others latch onto the cells, or are taken up by them.

Once attached or inside the cell, the nanospheres release the drug slowly as planned.

Releasing the drug

Stenzel says in some cases the drug can simply slowly diffuse out of the nanosphere, in other cases, they have shown the nanospheres can dissolve in response to heat or acidity.

Cancer cells are slightly warmer than healthy cells and more acidic.

Stenzel says the ideal would be for biodegradable polymers to be used so the nanospheres don’t build up in the body.

But the nanospheres can’t be too biodegradable or they won’t survive the trip through the bloodstream to their target.

Stenzel and team recently received two Australian Research Council Discovery Grants for the research and are talking to a commercial partner.

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Choosing Plastic For Medical Forceps

 source: http://www.grantadesign.com/products/ces/medcase.htm

CES Medical Polymer Selector – Case Study

Selection of plastic for medical forceps

This case study demonstrates how the CES Medical Polymer Selector, drawing on the Medical Plastics data module, could be used to establish the best material from which to make medical forceps.

The material must be USP Class VI or ISO 10993 certified, steam sterilizable, and adequately impact resistant. When applied to the medical plastics data, these criteria narrow the choice to 44 out of 628 materials.

With these constraints satisfied, the material needs to be both strong and stiff in bending, for the lowest cost and lowest volume. We can investigate these objectives through the use of a materials selection chart:

Materials selection chart - click for a higher resolution image

This chart, created in the CES Selector software, shows the trade-off between lowest cost and lowest volume of material. It allowed the following analysis:

  • Our initial thought was to use unfilled PEEK (PEEK Classix). The chart shows PEEK is a valid option, but it is neither low cost nor low volume, so not an optimal choice
  • Unfilled polypropylene copolymer is the cheapest option, but the forceps handles will need to be bulky to have adequate stiffness and strength
  • The forceps could be made just one-tenth of the bulk with PEEK carbon fiber composite (e.g. Endolign). However, this material is much harder to process than other options
  • Carbon fiber filled LCP (Vectra) and glass filled PPS (Fortron) offer 0.2 and 0.3 of the volume of polypropylene respectively
  • An intermediate choice is PPO/PS alloy (medical grade Noryl) with about twice the bulk of LCP or PPS, but a third of the material cost

Post-script: Surgical Innovations Group chose Ticona’s Fortron (40% glass filled PPS) for their forceps design. LCP-based materials gave too poor a surface finish. (source: Composites Technology, Dec 2003)

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Teflon Could Defeat Medical Superbugs

source: http://www.delawareonline.com/apps/pbcs.dll/article?AID=/20070821/BUSINESS/708210311/1003/BUSINESS

Teflon being tested for use with antibiotic

It might let humans use frog-skin poison

Posted Tuesday, August 21, 2007

The same chemical property that keeps eggs from sticking to frying pans may let antibiotics produced by frogs fight off drug-resistant infections in humans, researchers said.

Scientists added Teflon, a nonstick coating made by DuPont for cookware and medical equipment, to molecules of a bacteria-killing substance found on frog skin. In its natural form, the substance, called an antimicrobial peptide, can be broken down in the human body, where it attaches to cells, releases toxic components and dissolves before it has a defensive effect.

The Teflon versions of the antibiotic can stay intact in the body longer and may be safe to use. New drugs with antimicrobial peptides, which kill a wide spectrum of bacteria, may offer treatment to patients infected with drug-resistant “superbugs,” scientists say.

“Right now, if you are unlucky and have these superbugs, we don’t have an antibiotic that will treat you,” said E. Neil Marsh, a chemistry professor who conducted the research at the University of Michigan in Ann Arbor. Marsh discussed his findings today at the American Chemical Society’s 234th national meeting in Boston.

“This is one area of medicine that we’re actually going backwards in,” he said in a phone interview. “Things that used to work won’t work anymore.”

Marsh collaborated with fellow University of Michigan chemistry professor, Ayyalusamy Ramamoorthy, to make the nonstick antibiotics. Ramamoorthy had been studying antimicrobial peptides, an immune system defense used by all plants and animals and strongest in those most exposed to bacteria.

Frogs produce high levels of the toxic substance to prevent infection on their moist skin. The lethal poisons on some rainforest frogs are “close cousins of an antimicrobial peptide,” Marsh said.

Scientists have been studying the peptides for over 25 years and have struggled to find a way to limit their toxic effects in humans. Marsh’s Teflon version may be the solution.

The manmade material gets its non-stick quality from the element fluorine, which won’t react or bond with almost any other substance, including those inside the human body. That property will possibly make the new antibiotics safer for humans, Marsh said.

Scientists must conduct further experiments using Teflon antibiotics, which could be tested in humans in three to five years, he said.

Teflon is a trademark of DuPont for fluoropolymer resins resistant to high temperatures, chemical reactions, corrosion and stress cracks, according to the company’s Web site.

Polytetrafluoroethylene, or PTFE, is inert to virtually all chemicals and is considered the most slippery material in existence, according to the company.

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Plastic Replaces Hand

source: http://blog.wired.com/gadgets/2007/07/super-realistic.html

Super Realistic Bionic Hand

By Charlie Sorrel July 18, 2007 | 8:14:16 AM

Hand
If Luke Skywalker hadn’t lived so long ago, and so very far away, he might have gone to Touch Bionics for his replacement hand. The i-Limb is supposedly the world’s most advanced bionic hand. It works on the usual myoelectric system, which uses electrodes to detect electrical signals from muscles and translate them into movement, but Touch Bionics have brought some innovations to the game.

A problem with robotic hands is the lack of tactile feedback. The human hand can feel when it has a good grip. A bionic hand keeps going, and can crush delicate objects. The i-Limb hand has stall-detection, which tells the hand when it has exerted enough pressure. The hand is also modular, so that a doctor can “swap out fingers” in minutes instead of sending the whole unit in for repair. There is also the brilliantly named “Thumb Parking” function, which stops it getting tangled when dressing, for example.

Most amazing of all, though is how natural these things look. The photo above features an i-Limb hand. Can you tell which it is? Touch Bionics also offer the a plain plastic version, which they say is popular with military personnel. It’s not quite Terminator 2 style, though; it has a thin plastic sheath to protect against dust and water and to provide grip. But it still looks a lot nicer than the traditional pirate’s hook.

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Body Parts Turned Into Plastic

 source: http://toledoblade.com/apps/pbcs.dll/article?AID=/20070812/NEWS32/70812013

Article published Sunday, August 12, 2007

University of Toledo doctor turns flesh into plastic learning tool

Neuroscience professor pioneers technique to preserve organs, tissue

Photo

Dr. Carlos Baptista, left, and Dr. Jeffrey Gold discuss defects in a child’s heart that Dr. Baptista is considering for the process of transforming into a plastic organ that can be studied.
( THE BLADE/AMY E. VOIGT )

Zoom | Photo Reprints


Since 1978 this tiny heart, not much bigger than a golf ball, soaked in formaldehyde.

That was the year its owner succumbed to a congenital defect that made its lifetime a sad and swift defeat.

Dr. Jeffrey Gold examines the heart, probes its sole ventricle — there should have been two — that did double duty for this infant gone nearly 30 years now. He notes the lacking connection between the heart and the lungs.

He examines the accordioned Dacron tube, as wide as a finger, sewn in to make up for nature’s missing connection.

About once a month, Dr. Gold — the dean of the medical school and 25 years a cardiac surgeon — meets Dr. Carlos Baptista in the Gross Anatomy Laboratory in the basement of the Block Health Science Building on the campus of the former Medical College of Ohio — today the University of Toledo college of medicine.

Together, the men work their way through bucket after bucket of tiny hearts like this one.

Dr. Gold diagnoses defects that killed these infants, noting the special features of each. Dr. Baptista takes note of it all, asks questions, makes comments, assuring that he thoroughly understands each postmortem diagnosis.

Then Dr. Baptista turns these hearts into tools. He is one of the pioneers of a process that turns organs and body parts into perfect, everlasting plastic.

Back in his office, the associate professor of neuroscience pulls a fist-size adult heart from a file cabinet.

“Hold it up to the light,” he instructs. He points to a small section of the wall that divides the heart’s upper chambers. Faint daylight glows through it.

“You can see how thin it is,” he says.

Suddenly it all becomes clear: Why children are sometimes born with a hole in this septum; why older people can develop a breach in this paper-thin shield.

“You are appreciating something we want students to see,” he says.

The heart is human and it is plastic, the product of Dr. Baptista’s science, and his art.

The workshop
Students seeing Dr. Baptista saunter across the parking lot near the Howard Collier Building — his face too young for his 53 years and too young for the gray hair he’s had since his 20s — know he may be carrying a body part: a leg, a brain, a bucket of infant hearts.

Photo

Dr. Carlos Baptista, an associate professor of neuroscience, preserves specimens in acetone.
( THE BLADE/AMY E. VOIGT )

Zoom | Photo Reprints

He steps into the air-conditioned offices of a small out-building across East Campus Drive from the main campus, passes through a couple tall-ceilinged storage rooms before, finally, unlocking a tall gate. It is uncomfortably warm in this part of the building, not much cooler than the swelter outside.

This is his workshop: Three small windowless rooms with block walls. Many homes have larger bathrooms. The setting is positively unclinical. On the floor of one room are three large plastic tubs, the kind one might use to store toys. Dr. Baptista pulls back the lid of the first tub. Inside is a breast with an obvious tumor, there is a heart, there is a stomach, there are ovaries. The sharp smell of nail polish remover — it’s acetone — scrapes the back of the throat as it rises from the tub. Even the light switches in this room are special: They don’t spark. Acetone is flammable, explosive, toxic.

These tanks begin the process of turning body parts into plastic.

It’s an unlovely technique, but what brews here is education. These body parts will be touchable. They won’t smell. They’ll last nearly forever. And they’ll educate hundreds of students studying to be doctors. They’ll also form a lending library for cardiologists studying the defects that occur sometime in infant hearts.

Holding the small heart he examined with Dr. Baptista, Dr. Gold explains: “Think about the power for a surgeon or cardiologist to spend time looking at these things when you can handle them, look inside them, touch them, when you’re not in the operating room having to make critical life decisions in minutes.”

A simple process
The process of making flesh plastic is stunningly simple.

The organ or body part is dissected to show some interesting feature: the tangle of arteries in a hand, the blossom of a tricuspid valve inside the heart, or the hole worn away in an ulcerated stomach. Then, with many other organs, it soaks in acetone. Slowly, the acetone replaces any water in the tissues. It also turns body fat to liquid.

Next, the organ is placed in a vacuum chamber full of liquid silicone. The chamber is inside a large freezer kept at minus 13 degrees Fahrenheit. Every few days, Dr. Baptista increases vacuum pressure in the chamber. Slowly, the acetone is drawn out, replaced by the silicone.

Finally, gas cures the now silicone-impregnated specimen. Silicone molecules crosslink into a durable plastic in every cell.

“It’s precious. It’s like jewelry,” he says of these donated organs, now ready for classroom discussion.

“The process is very simple,” says Dr. Baptista, who taught himself how to plastinate organs in the 1980s while working as a professor in Brazil. “It’s simple in the manner that you follow instructions. Then the refinement, that is the art and the science combined. It is like cooking. Some people say they can cook, and they can cook. Other people can do the cooking very well. This process has this: You have to put in your art.”

A 30-year-old technique
The general recipe for turning organs to plastic is 30 years old. It was developed by Gunther von Hagens, the German anatomist who went on to create the traveling Body Worlds exhibitions, where flayed humans in exotic poses of dancers and runners display muscles, organs, and vessels for the inspection of the curious.

In those commercial displays, organs and muscles are brightly colored, injected with special dyes. But the medical school models for the most part are monochrome: gray after long years in formaldehyde or a yellowish color for fresher flesh.

The idea of preserving human remains is ancient. While Egyptians developed a mummification process as part of religious belief, there’s some suggestion that the knowledge of mummification — which included removal of the brain and internal organs — may have played a role in the development of medical practice.

“Even in Egypt … they were also doing surgery,” says Ronald Wade, who directs the University of Maryland school of medicine anatomical services division.

“They were doing brain surgery.”

Mr. Wade was among the first in the United States to plastinate body parts. He directs the state of Maryland’s body donation program, which distributes some 1,500 cadavers each year to medical schools.

“I grew up in a funeral home,” Mr. Wade says. “Death is my life.” It’s clearly a favorite joke. He said it a few times.

Mr. Wade says early efforts to preserve human remains for study arose with the Age of Enlightenment in the 18th century, as dissection became a part of medical education and the body-thieving practices of “resurrection men” a shadowy adjunct to physician studies.

By the early 1800s, Mr. Wade says, Scottish anatomist Allen Burns was experimenting with preservation techniques that had a great deal in common with preserving food. The University of Maryland now holds the Burns specimens.

Many of the preserved organs were cured in salt and sugar, ‘‘just like you would dry beef,” Mr. Wade says. “They dried them out, and they were very light and delicate, just like beef jerky.

“When I came to the University of Maryland, they were shown in cabinets. Some were stuck together because the sugar was starting to come out.”

Burns was fascinated with the vascular system and injected hearts with a kind of red mortar “almost like cement,” Mr. Wade says. “I have hearts he injected that are 8 pounds, 16-pound hearts. They’re hard as a rock. They’re also very delicate.”

On this background, plastination was a huge leap forward.

It came from methods used for preparation of microscopic slides, Mr. Wade said. Its creator, Mr. von Hagens, “took it macroscopic. If you can do this for little fishes, why not big worms?”

Another teaching tool
Although Dr. Baptista plastinates body parts for other institutions, which helps cover the cost of his tiny operation, the ones he does for UT come from the university’s anatomical donation program.

Every year, some 120 to 130 bodies are donated to the university, said Mark H. Hankin, PhD, the director of the program that began the year after the medical school’s 1967 founding.

Plastinated specimens won’t replace the tradition of training students with real human bodies, says Carol Bennett-Clarke, PhD and associate professor in neurosciences — where the anatomy program resides. Rather, such specimens offer another teaching tool.

“We actually don’t have any intention of replacing cadaver dissection,” she says. “Our real intention is to make it more time-efficient.”

She and Dr. Baptista used plastinated hand dissections to investigate how effective they were as a teaching tool.

One group of students performed a traditional dissection of the hand during a three-hour laboratory period. A second group studied predissected hands to learn anatomy.

Testing before and after the hand-anatomy laboratory showed that the two groups learned the material equally well. But the group using the plastinated specimens learned faster.

The research group selected hand dissection because it is a difficult thing to do.

“Students find that it’s particularly time intensive, and not really rewarding,” Ms. Bennett-Clarke says. “The structures of the hand are very, very tightly knit with each other. And it takes a very patient and somewhat skilled person to dissect.”

In the three-hour lab typically assigned for hand dissection, student success rates fall about 50 percent.

“Wasting three hours of time for a 50 percent yield, that’s not really time well spent for them,” she says. “There’s just an explosion of information we need to present to the medical student,” and in this instance, plastination squeezes in learning a little more efficiently.

Emerging from obscurity
Dr. Baptista has labored almost unknown in the neurosciences department at the medical school. Many others there have no idea that a UT professor has plastinated body parts in Toledo since 1987.

But there are signs his star is rising. Plans are afoot to take him out of the tiny rooms where he works and put him into a larger laboratory space.

It’s ironic that the University of Michigan visited him when it was establishing its plastination laboratory and now possesses far posher facilities and the full-time assistance of technicians. Dr. Baptista generally works alone.

Just last week, two other universities contacted him for assistance in plastinating specimens. Other professionals in the field know and respect his work.

Mr. Wade of the University of Maryland says, “There are very few people that have developed the expertise and experience in this process. Carlos is one of them.”

And if you’ve ever visited the Chicago Museum of Science and Industry, the plastinated sections of a head displayed there are his work. In fact, the head MRI that accompanies the display is actually an MRI of Dr. Baptista’s head.

“Who can say they have their head in a museum?” Dr. Baptista jokes. “Nobody could say that.”

Contact Jenni Laidman at:jenni@theblade.comor 419-724-650

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Did Chinese Steal Vespel Secrets?

source: http://www.bloomberg.com

China’s Spying Overwhelms U.S. Counterintelligence (Update2)

By Jeff Bliss

 

U.S. Chamber of Commerce President Thomas Donohue

April 2 (Bloomberg) — In a Santa Ana, California, courtroom, 66-year-old engineer Chi Mak listens to federal prosecutors describe how he and his family stole secrets from his employer, L-3 Communications Holdings Inc. The alleged target: data about Navy submarine engines that run silently to avoid detection.

U.S. intelligence officials say the Mak case is unusual — not in the nature of the charges brought against him, but that charges were brought at all.

For every person caught and accused of passing U.S. military and trade secrets to China, they say, scores of others go undetected. Taking advantage of an outmanned counterintelligence effort drained and distracted by the wars in Iraq and against al-Qaeda, current and former officials say, China has systematically managed to gain sensitive information on U.S. nuclear bombs and ship and missile designs.

“Iraq and the struggle with terrorism are sucking resources across the board,” says Joel Brenner, the top counterintelligence official in the office of Director of National Intelligence Michael McConnell. Meanwhile, “the Chinese are really making a run at us.”

Adds Keith Riggin, a former senior official at the Central Intelligence Agency who focused on China issues: “If the American people knew the number of officers going against the Chinese, they would be appalled.” He says his frustration with the lack of resources was one reason he ended a 24-year career in 2006.

`Troublesome’

While 140 foreign intelligence services are trying to penetrate U.S. agencies, China’s is the most aggressive, Brenner says. He describes China’s activities as “an intensifying and troublesome pattern.”

Chinese officials say the U.S. allegations are meritless.

“I wonder why people always feel threatened by others and treat others as thieves,” Qin Gang, a spokesman for the Foreign Ministry, said at a March 15 press briefing in Beijing. “It indicates these people have a chip on their shoulders and have fragile psychologies.”

While the Federal Bureau of Investigation tripled the size of its China unit in 2001, plans for further expansion were scotched when the Iraq war began, says Rudy Guerin, a China expert who retired from the bureau last year. David Szady, the FBI’s former assistant director for counterintelligence, says the FBI should hire another 1,500 agents, and most should be used against China’s espionage within the U.S.

More Agents

Stephen Kodak, an FBI spokesman, declines to say how many more might be necessary. At the same time, he adds that “the bureau would always welcome additional assets.”

Central Intelligence Agency spokesman Paul Gimigliano says his agency has enough resources, and that “it would be wrong to suggest that other priorities have diluted the attention we pay to China. Over the past five years, the opposite has been true.”

The FBI spent $2.2 billion on counterterrorism and counterintelligence programs last year; the CIA budget is classified. The U.S. won’t disclose how many counterintelligence agents are working on China-related issues.

U.S. officials say there’s overwhelming evidence that China has a well-thought-out plan to employ thousands of professional spies and amateurs to get sensitive U.S. military and business data, sometimes directly from sympathetic employees, sometimes through a joint venture or third party.

Submarine Data

Mak, his wife, brother, sister-in-law and nephew were indicted on charges of conspiring to export U.S. defense articles to China’s government. In court papers, prosecutors say he copied submarine data from L-3′s Anaheim, California-based Power Paragon unit onto compact discs and enlisted the other family members to encrypt the information and help smuggle it to China. Brenner says the disks also contained information on the U.S. Navy’s next-generation DD(X) warship.

Under questioning, Mak admitted sending information to Chinese operatives since 1983 on technology that included radar systems of Aegis cruisers, which are used to defend against multiple missile attacks, Brenner says.

Mak and his relatives pleaded innocent to the charges. His lawyer, Ronald Kaye, says he was taking the disks for a conference with fellow engineers, and that the information about the Navy engine was obsolete. The engineer also got approval from his supervisor to make presentations at the conference, Kay says.

`Asset to His Country’

Mak “was not only an asset to the company but a profound asset to his country,” he says. Mak’s relatives will go on trial in May.

U.S. officials say China’s effort encompasses industrial secrets as well as national-security ones. Brenner cites the case of Gary Min, a DuPont Co. chemist who admitted obtaining information on company products, including materials used in airplane construction, that prosecutors valued at $400 million.

Authorities say that between August and December 2005, Min, 43, downloaded 22,000 confidential abstracts from the Wilmington, Delaware-based company’s electronic library. The documents included information on all DuPont’s major product lines as well as emerging technologies.

Some of the searches focused on Vespel, a synthetic resin used to coat car, airplane and oil pump parts, and Declar, a plastic material used in the automotive and energy industries and in airplane interiors, according to court papers.

Shredded Documents

U.S. law-enforcement authorities said that when they searched Min’s Grove City, Ohio, home, they found computers containing confidential files, garbage bags filled with shredded company documents and the remains of DuPont papers that had been burned in the fireplace. In court documents, DuPont said the information would be “highly valuable” on the open market in “foreign countries, specifically China.”

A call to Min’s lawyers wasn’t returned. Min hasn’t been charged with being a Chinese spy.

Brenner says his office is still assessing the damage from another case involving Katrina Leung, who the FBI had used for 20 years as a double agent to obtain information from the Chinese, and who prosecutors in turn accused of being a Chinese agent herself.

Authorities accused Leung, 52, of taking documents from James Smith, head of the FBI’s Chinese counterintelligence operation in Los Angeles, over the course of a nearly 20-year affair with him.

Peter Lee

Some of those documents related to “Royal Tourist,” the FBI code name for the investigation of Peter Lee, an employee of defense contractor TRW Inc. Lee, who was accused of giving radar technology being developed to track submarines to Chinese scientists, pleaded guilty in 1997 to willful transmission of national defense information to a person not entitled to receive it.

While the case against Leung was dismissed in 2005, Smith pleaded guilty to making a false statement to the FBI about his relationship with her. Smith was one of the FBI’s most seasoned China experts, a resource the agency has struggled to replace, intelligence officials say.

The CIA also hasn’t been able to replace its veteran China experts when they retire, Riggin says. “We’re losing huge experience in this area.”

With the CIA occupied with preventing U.S. government secrets from falling into the wrong hands, Riggin and others say, companies doing business in China are especially vulnerable to losing non-defense information. U.S. businesses are paying particular attention to the first intellectual-property suit brought in a Chinese court by Santa Clara, California-based Intel Corp., the world’s biggest semiconductor maker.

Intel Suit

In the suit, Intel said Shenzhen Dongjin Communication Tech Co. Ltd. illegally used its software, which Dongjin had obtained through a third party, for network communication cards in its own products. Shenzhen Dongjin has countersued, accusing Intel of being an illegal monopoly.

Spokesmen for Shenzhen Dongjin haven’t responded to e-mails and phone calls for comment. A ruling may come as early as next month, says Intel spokesman Chuck Mulloy.

Whatever the ruling, U.S. companies face an uphill battle to keep secrets secret, says Thomas Donohue, president of the U.S. Chamber of Commerce, the nation’s largest business group.

“If you’re going to make a huge move toward innovation, well, get ready in this system to lose it,” he told reporters March 26 in Beijing. “Because somebody’s going to steal it.”

To contact the reporters on this story: Jeff Bliss in Washington jbliss@bloomberg.net .

Last Updated: April 2, 2007 11:07 EDT

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No More Med Lead – Thanks Plastic

source: http://www.jeccomposites.com/composites-news/3753/GE-Plastics-HSG.html

GE Plastics HSG Composites offer alternative to lead in radiation shielding applications

GE lead alternative - © GE Plastics

© GE Plastics

GE Plastics has launched a new line of thermoplastic materials with high specific gravity (HSG) that may replace lead in many healthcare applications that call for radiation shielding. Medical equipment and devices that produce x-rays and gamma rays must be shielded to protect operators, clinicians, patients, and sensitive electronic components from tube leakage and room scatter. GE’s LNP Thermocomp HSG radiation shielding, high-density compounds enable x-ray shielding solutions without the use of known toxic substances, while providing greater design freedom and higher-volume manufacturing with lower total part cost through the use of injection molding.

“Lead continues to present health and disposal challenges to manufacturers of radiation-shielding products,” said Clare Frissora, market director, Healthcare, GE Plastics. “We’re very pleased to offer a new alternative to lead that can enable these manufacturers to design safer solutions. Our LNP Thermocomp HSG x-ray shielding compounds also provide the opportunity for design and cost advantages over lead in a wide range of healthcare applications.”

Due to increasing regulation of lead for toxicity and environmental risks, manufacturers are seeking new replacement materials. For example, the European Union’s Restriction of Hazardous Substances (RoHS) directive calls for the near-elimination of lead in most electrical and electronic equipment. In addition, lead has design drawbacks. Lead-encapsulated glass plates for protection against x-rays must be very thick, limiting usage and design options. Further, lead shielding can have “hot spots” – areas where x-rays can penetrate.

GE’s LNP Thermocomp x-ray shielding compounds have been shown to shield radiation up to the effectiveness of lead without leakage or hot spots. They are based on tungsten – a non-hazardous HSG material – in nylon 6. LNP Thermocomp HSG x-ray shielding compounds can be made with enhanced stiffness, strength, and impact resistance for demanding injection-molding applications.

GE Healthcare chose an LNP Thermocomp HSG x-ray shielding compound for several applications within its OEC 9800 x-ray machine, which is designed for procedures such as cardiac, vascular, and orthopedic surgeries. The shielding material is used in the collimator, which absorbs stray radiation and limits the x-ray exposure dose. With LNP Thermocomp HSG compound, GE Healthcare gained many advantages over lead beyond compliance with environmental regulations. The transition from machined and stamped lead to injection-molded engineering resins may help enable tighter tolerance specifications and greater part consistency, enhancing the performance and safety of the x-ray equipment. Avoiding secondary operations required with lead, plus combining multiple components in one part, reduced total manufacturing time, system cost, and complexity.

“Replacing lead with LNP Thermocomp HSG compound in our x-ray equipment may help us provide a higher level of safety for patients and caregivers,” said David Barker, engineering manager, GE Healthcare. “Part-to-part consistency made possible by injection molding facilitates uniform shielding, and gives designers precise control over the amount of radiation filtered through their devices. The fact that this compound is environmentally responsible and reduces overall system costs was a welcome bonus.”

GE Plastics is working with Thogus Products Company, a custom injection molder, to create new grades of the Thermocomp HSG material that match the specific gravity of lead, including a flexible version for specialized applications. The companies are also jointly working to develop an elastomeric grade with high elongation that will deliver exceptional design flexibility.

This composite offers the potential to replace other shielding materials for similar cost and performance advantages. Applications include: x-ray shielding devices and containers, housings, x-ray tubing components, dental x-ray equipment, and nuclear medicine containers.

Future applications for LNP Thermocomp HSG x-ray shielding compounds could benefit from the capabilities of GE’s Global Application Technology (GApT) centers, such as user-centric design elements, injection molding application-specific testing, and teardown analysis, which is used to disassemble existing units made of traditional materials such as metals (e.g., lead) and identify part consolidation opportunities attainable with thermoplastic injection-molded parts.

GE’s LNP Thermocomp HSG x-ray shielding compounds are commercially available. They are manufactured in the United States, and are available globally.

About GE Plastics
GE Plastics is a global supplier of plastic resins widely used in automotive, healthcare, consumer electronics, transportation, performance packaging, building & construction, telecommunications, and optical media applications. The company manufactures and compounds polycarbonate, ABS, SAN, ASA, PPE, PC/ABS, PBT and PEI resins, as well as the LNP line of high-performance specialty compounds. GE Plastics, Specialty Film & Sheet manufactures high-performance Lexan(1) sheet and film products used in thousands of demanding applications worldwide. In addition, GE Plastics’ dedicated Automotive organization is an experienced, world-wide competitor, offering leading plastics solutions for five key automotive segments: body panels and glazing; under the hood applications; component; structures and interiors; and lighting. As a Worldwide Partner of the Olympic Games, GE is the exclusive provider of a wide range of innovative products and services that are integral to a successful Games.

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Life, It Seems, Comes Down To Peeing In A Plastic Cup…

Where would medicine be without plastic?

This morning I had to drop in to the local vampire for blood work. I’m now at that age when the doctor insists on an annual physical rather than just suggesting one. I was there at 7:26am for a 7:30am show – and there were three older men there already, two sitting on the floor as if they were back in high school waiting for gym class to start. At 7:30 and 8 seconds the lab hadn’t opened yet and the class senior began beating on the door. A nurse popped her head out, inquired if there was a problem, and then grimaced knowing that this was probably an indication of the rest of her day. We herded in like a chain gang, showed our ID, and were handed our cups and then we all stood there waiting our turn to use the one wash room.

Styrene Urine Test Jar

And that’s when the plastic-guy inside me began his day – scanning the room for applications for polymers yet to be discovered.

The FIAlab SMA-Z Flowcell (for absorbance measurements) is a “Z” type flowcell constructed of chemically inert Teflon, Plexiglas (as pictured), Ultem, PEEK or high grade stainless steel. The SMA-Z Cell’s optical path length is available in 1.5, 5, 10, 50, 100 mm (other lengths are available with special orders).

There’s a certain ironic comedy, bordering on tragedy, for the learned plasticologist in a medical clinic. On one side of the room you have all these sophisticated separators and testing machines reeling out tendrils of polyethylene and vinyl tubing, hidden within ornate cabinets made from Kydex. If you look deep into the heart of the blood analyzers you catch a glimmer of translucent bronze – most likely Ultem. Engineered solutions at their finest.

This project required extremely close tolerances to be met in order to form a seal between two solenoids in a kidney dialysis medical device in which very tight tolerances are required to form an adequate fluid seal. The product is manufactured out of Ultem-1000 grade material, which required skilled material processing to deliver quality finished product.

Then, you look at what separates the farmer from their herd, the reception window – the most gawd-awful orangy-yellow faux-lead diamond pattern imprinted on cheap old styrene sheet – which I’m sure I’ve seen in 70′s era hutches. Would it have really blown the budget to spend another $10 and put in a sexy piece of matte-finished acrylic – maybe green edge Crystal Ice? Come on now, we just peed in a jar made from what we’re looking through!

So, what did Marie Curie’s lab look like when she was swooshing isotopes back and forth between glass test tubes and spilling them onto metal counters? Or watching radio-active chemical reactions happen behind regular old glass portals? Would she be amazed to learn how certain grades of acrylic can now withstand x-rays and gamma rays? That her table tops would be plastic too, perhaps blends of acrylic & PVC (Kydex). That her test tubes would sit in high density polyethylene trays rather than metal racks.

Plastic hasn’t just changed modern medicine, it’s evolved it into something different than it was. Plastic has made medicine accessible to more people – it’s made the business of medicine lighter, safer, and more cost effective. It’s inspired people to invent devices that would never have been conceived fifty years ago – that a tube can be made so precisely that it will fit inside an artery and take a doctor’s tool right to center of the heart avoiding the need to rip someone’s chest open (I guess if could have used the term invasive procedure here, but it wouldn’t be as dramatic). Plastic has given the possibility of life.

If you’re a budding young surgeon or medical technologist looking for materials to build your next tool, then please, give us a call at Warehoused Plastic Sales. We have expertise at our fingertips that can give you qualified engineering advice to help you identify the solutions you’ve been looking for.


Heart Catheter Using Teflon Tubing

Teflon/Polypropylene Heart Valve

The Heart Laser housing measures 28″ X 48″ X 62″ (711 x 1220 x 1575mm). Pressure-formed of KYDEX® Vinyloy™ 103 thermoplastic alloy, it won the Annual Thermoforming Institute Award of Excellence.

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