Bioactive Polymer

Bioactive Polymers

INTRODUCTION Bioactive polymer made of synthetic or artificial polymers substituted

with

specific

chemical

functional

groups

carried

by

the

macromolecular chain are designed to develop specific interactions with living systems. When a polymeric material is exposed to a biological environment, there is a natural tendency to induce different reactions such as blood coagulation, complement activation and cell interactions. Polymer scientists have synthesized a large number of polymers and have evaluate their behavior when they are in contact with biomolecules, viruses, bacteria, body fluids, cells and whole organisms. Bioactive polymers are used to repair, restore or replace damaged or diseased tissue or to interface with the physiological environment. They are basically three main types of polymers used in a biological environment. • Polymer used as bio materials, e.g. in organ replacement and bone surgery. • Polymers serve as matrices in devices that permit control release of an active substance over along period of time. • Soluble polymers: synthetic polymers that themselves display biological activities.

Uses of bioactive polymers: C.O.E.& T., Akola

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Bioactive Polymers

Bioactive polymers in medicines and surgery are currently widely used and include intracorporeal, paracorporeal and extracorporeal (inside, interfacing or outside the body, respectively) Applications are given below: Intracorporeal Materials Temporary devices: •

Surgical dressings

•

Sutures

•

Adhesives

•

Polymeric intermedulary nails

•

Polymer - fiber composite bone plates

Simple semipermanent devices: •

Tendons

•

Reinforcing meshes

•

Heart valves

•

Joint reconstruction & bone cement

•

Tubular devices

•

Soft-tissue replacement materials for cosmetic reconstruction

•

Drug delivery implants.

Complex devices simulating physiological processes: •

Artificial kidney/Blood dialysis

•

Artificial lung/Blood oxygenator

•

Artificial pancreas/Insulin delivery system

•

Artificial heart

According to a soon-to-be-released updated report from Business Communications Company, Inc. the U.S. biocompatible materials market is

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Bioactive Polymers

estimated at $8.2 billion in sales at the manufacturer's sales level in 2003. Fueled by greater demand from the aging population and the relatively short medical device product life cycles (as compared to other medical products) this market is forecast to grow at a 7.7% AAGR (average annual growth rate) through 2008 reaching nearly $1.9 billion. The biocompatible materials market is a niche market comprised of polymers, metals, advanced ceramics, natural materials, pyrolytic carbon, composites and coatings. The industry requires superior grade materials in relatively small volumes when compared to the volume of these materials consumed in other industries.

PVC accounts for 80% of polymer consumption; other polymers commonly consumed are silicone, polyurethane, polycarbonates, polyester and polyethylene. Emerging polymer applications include biodegradable polymers, bioactive polymers (polypeptides), hydrogels, molecular imprinted polymers, conductive polymers and biopolymers. Many of these are being applied to meshes, foams, sponges or hydrogels to stimulate tissue growth.

MARKET DATA C.O.E.& T., Akola

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Bioactive Polymers

U.S. Market Size for Biocompatible Materials in Medical Devices, through 2008 ($ Millions) Materials Polymer Metals Other materials * Total Medical Device market using biocompatible materials

AAGR %

2003

2008

7,200 162.5 834.5 8,197.0

10,500 212.8 1,178.4 11,891.2

2003-2008 7.8 5.5 7.1 7.7

38,000.0

57,380.0

8.6

* Includes advanced ceramics, natural materials, pyrolytic carbon, natural materials, companies and coatings. Source: BCC, Inc.

U.S. Market Size for Biocompatible Materials in Medical Devices, through 2008 ($ Millions)

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Bioactive Polymers

FEATURES OF BIOACTIVE POLYMERS Some of important properties should be required for bioactive polymers are as follows.  Biocompatibility.  Mechanical, Physical and Chemical Properties.  Purity.  Fabrication.  Stability.  Tolerability.  Sterilizability.  Foreign body reaction.

 Biocompatibility: Acceptance of an artificial important by the surrounding tissue and by the body as a whole.

 Physical, Chemical & Mechanical Properties: These must be capable with the proposed and for eg.. in the design of heart , the flexing characteristics of the polymer have often been overlooked.

 Polymer Purity : Industrial reins are highly variable in nature from manufacture to manufacturer. A variety of other materials incidental to the polymer process such as residual initiators, initiator fragments, solvents, plasticizers, trapped free radicals, inhibitors, lubricants, heat sand light stabilizers, fillers, parting agents, anti oxidants, degradation products, curing agents, residual monomers and allow

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Bioactive Polymers

molecular weight oligomers may be present. There may be variations in the molecular weight and in the mol. Wt. distribution, as well linkages and branching. 

Ease of fabrication: The desired device should be capable of fabrication without damages in

properties,

surface

characteristics,

crystallinity,

surface

oxidation,

or

contamination by processing aids such as oils, solvents or like that.

 Stability: Bioactive polymers should not be adversely affected by the normal physiological environment. No biodegradation that could compromise function over the short or long term should occur, and no process should release toxic to the environment.

 Tolerability: Bioactive polymers should not exhibit toxic or irritant qualities, or elicit adverse physiological responses locally or systemically. Toxicity can also be affected by the rate of release of the substance and the biological processing and removal of the substance.

 Sterilizability: The physical, chemical, mechanical and biochemical characteristics of the device or material must not undergo any change during sterilization. This is often not as easy as it may seem. Light, heat, radiation, or chemical treatment may be used during this process.

 Foreign body reaction: The polymer should cause only minimal, if any, foreign body interaction, inflammation, encapsulation or cell change response in the surrounding tissue. It also should not cause tissue or other reaction rmote from the site of implantation and should be free of response.

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Bioactive Polymers

Materials used as bioactive polymers The following materials using as bioactive polymers.  PEUU’s [Poly(ether urhane urea )s]  Silicons  TFE polymers  PVC  Polyolefins  Polycarbonate  PMMA  Polyesters  Cellulose  Polyvinyl alcohol  Epoxy resins

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Bioactive Polymers

Comparison with Other Materials PROPERTIES Flexibility

Glass

Metal

plastics

Poor

Poor

Excellent

Clarity

Excellent

Poor

Good

Design Versatility

poor

poor

Excellent

Barrier Properties

Excellent

Excellent

Good

Excellent

Poor

Good

Poor

Good

Excellent

Poor

Poor

Excellent

Poor

Poor

Excellent

Chemical Resistance Saleability Performance weight/vol. Ratio Cost/

Performance

Ratio

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Bioactive Polymers

Application of bioactive polymer  Application of bioactive polymers in artificial heart. Numerous polymeric systems have been explored for use in cardiovascular systems. For example the materials used in artificial heart studies include Polyvinyl Chloride (PVC), silicone rubber (silatic), Polyurethane, Biomer and polyolefin rubber. However among polyurethanes the most promising materials appear to be some of the polyether urethane ureas. Your heart is the engine inside your body that keeps everything running. Basically, the heart is a muscular pump that maintains oxygen and blood circulation through your lungs and body. In a day, your heart pumps about 2,000 gallons of blood. Like any engine, if the heart is not well taken care of it can break down and pump less efficiently, a condition called heart failure.

The AbioCor is the first artificial heart to be used in nearly two decades.

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Bioactive Polymers

Until recently, the only option for many severe heart failure patients has been heart transplants. However, there are only slightly more than 2,000 heart transplants performed in the United States annually, meaning that tens of thousands of people die waiting for a donor heart. On July 2, 2001, heart failure patients were given new hope as surgeons at Jewish Hospital in Louisville, Kentucky, performed the first artificial heart transplant in nearly two decades. The AbioCor Implantable Replacement Heart is the first completely self-contained artificial heart and is expected to at least double the life expectancy of heart patients.

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Bioactive Polymers

 Application of bioactive polymers in artificial Lung An artificial implantable lung that uses tiny hollow fibers and the heart’s own pumping power to oxygenate blood is showing promise in pre-clinical studies, and may reach clinical trials in about a year for lung failure patients awaiting a lung transplant. The materials used in artificial lung studies include Polyvinyl Chloride (PVC), silicone rubber (silatic), Polyurethane, Biomer and polyolefin rubber. However among polyurethanes the most promising materials appear to be some of the polyether urethane ureas.

A heart-lung bypass machine can be used for major operations but it could not be used to keep a patient alive who has a long-term lung problem or while

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Bioactive Polymers

their lungs are recovering from some form of damage. Also, an artificial ventilator will not be of any use if the patient's lungs are unable to take in the oxygen required. To try and solve this problem, the University of Pittsburgh Medical Center, in the United States, is developing an artificial lung that can sit inside a blood vessel and oxygenate blood as it moves past a series of porous membrane tubes attached to an external oxygen supply. Called the Intravenous Membrane Oxygenator (IMO), it is intended to treat patients with life-threatening lung problems. This could be due to some form of trauma or it could be used with patients who have lung infections like pneumonia. Their lungs cannot take in sufficient oxygen and the IMO is designed to add extra oxygen to the blood before it gets to the patient's lungs. In this way the damaged lungs are assisted until they are able to recover.

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Bioactive Polymers

 Application of bioactive polymers in artificial kidney Artificial kidney is another example of an interesting development in the field of biomaterials. Artificial kidney is often referred to as haemodialysis unit which removes waste products from the blood with polymeric semipermeable membrane. Which purifies the blood against artificial liquids in a process known as hemodialysis or peritoneal dialysis. In peritoneal dialysis, silicone elastomer or polyurethane elastomer is generally used as caterers to access the peritoneal cavity A polyester cuff surrounds the segment of each catheter. In haemodialysis, the dialyser is normally made of several thousand hollow polymer fibers mounted in a polyurethane potting . The dialysis tubing is generally made of PVC. The membranes used are generally based on cellulose or cellulose derivatives.

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Bioactive Polymers

Advantages & Disadvantages The major advantages and few disadvantages of bioactive polymers are as follows.

 Advantages • The bioactive polymers must be capable of good response from body surrounding body tissue. • They will not cause of inflammation. • They will not produce infection. • They will not responsible for thrombogenesis. • No adverse immunological response or neoplasm induction or promotion. • The artificial heart and valve, kidney, lung saves the life of the patient by improving the function of organ.

 Disadvantages • Sometimes growth of bacteria takes place on the surface of implant. • Implant will be cause of cancer due to foreign body reaction. • Bioprosthetic valve fail due to calcification (Calcium from the blood stream form deposits on the implant). •

Bioprosthetic valves are also susceptible to mechanical fatigue. Artificial heart, kidney, lung is more expensive and also involves great risk of life.

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Bioactive Polymers

Scope Recent advance in material science and surgery now make it possible to rebuild many parts of the human body. Some polymers have mechanical properties that resemble those of natural tissues, making them suitable as bioactive polymers. Polymer engineering coupled genetic engineering to produced material that interact and control biological system. The synthetic polymer industry has expanded and polymeric materials with a vast spectrum of properties are available.

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Bioactive Polymers

Conclusion Thus ,from the discussion we concluded that Polymers are most important and largest family of materials being used in medical technology such as used in conventional medical technology and ,surgery and drug delivery. Polymers have been used in the augmentation and repair of the human body with much success. Bioactive polymers must be capable of being used in or on human body without eliciting rejection response

from surrounding body tissues.

They must passed stringent tests to assured that they will not cause of inflammation, infaction, thrombogenesis, adverse immunological response of neoplasm induction or promotion.

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Bioactive Polymers

Bibliography (1) Nass And Mark, “Encyclopedia of polymer Sci. & Engg.” Vol 2, Second Edition, Pg-No. 243-280 (2) Nass And Mark, “Encyclopedia of polymer Sci. & Engg.” Vol 9, Second Edition, Pg-No. 459-461,488-491 (3) J.A.Brydson “Plastics materials.” Sixth Edition, Mar-Apr 1999, Pg-No. 345-370

Web Sites http://www.expasy.ch/spdbv/mainpage.htm. http://www.msi.com. http://www.povray.org. http://www.chemistry.mcmaster.ca/faculty/brook/bio.html http://www.uroplasty.com/ http://www.biomedical.com/

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Bioactive Polymers

CONTENTS • Introduction • Market Data • Features of bioactive polymers • Bioactive polymers • Comparison with other material • Application of bioactive polymers • Advantage & Disadvantage • Scope • Conclusion • Bibliography

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