Biocompatible materials continued

Combat medicine poses special problems. Chemical science and technology can aid in the rapid detection and treatment of injuries from chemical and biological weapons and other new weapons such as lasers. We need to develop blood substitutes with a long shelf life, and improved biocompatible materials for dealing with wounds. For the Navy, there are special needs such as analytical systems that can sample the seawater to detect and identify other vessels. We need good ways to detect mines, both at sea and on land. Land mines present a continued threat to civilians after hostilities have ended, and chemical techniques are needed to detect these explosive devices. 

Gold is a metal that continues to be precious in the market place, in exploration, in medicine and in science and technology (1). Its unique chemical properties ensure that it continues to be researched and applied in many established and in many new fields, including the treatment of arthritis (2), as advanced biocompatible materials in medicine (3,4) in the nanoengineering of optical properties as gold nanoshells (5) and in biosensing (6). 

Artificial kidney designs will likely continue to experience incremental improvements in the materials and hemodynamic areas. New developments in biocompatible materials, superior transport methods for toxin removal, and improved patient management techniques will allow further maturation of hemodialysis and hemofiltration therapy. For example, considerable benefits could be realized from selective toxin removal without concomitant elimination of beneficial proteins. It has been suggested that future devices might utilize the absorption removal pathway with affinity methods as a primary technique to eliminate specific uremic toxins (Klinkmann and Vienken, 1995). 

Our increased understanding of what contributes to biocompatibility wUl also allow us to redefine it once again or to be more specific when publishing new data on biocompatible materials, among which bioresorbable polymers for medical applications surely play a major role with their continuous growth. Finally, more precise prediction tools will enable faster translation from basic science to the clinic and ultimately to the benefit of patients. 

To this day, we still hear people claim that in vitro testing of materials alone shows that they are suitable for use in chronically implanted devices. Others continue to say that I proved the materials are biocompatible and biostable, so I don t have to do any device testing. This statement can be very far from the truth. In vitro testing has its place, primarily to screen materials and processes for further testing. In some cases where no suitable in vitro test exists, one may be forced to develop accelerated in vivo materials tests. Once the preliminary testing is accomplished, however, one must test the device per se in animals. A biocompatible material does not necessarily make a biocompatible device. The same may be said about biostability. These statements are true because shape, size, surface finish, interactions between the materials in the device, etc., all can affect its biocompatibility and biostability. But even well-performed animal studies may not unveil previously unknown mechanisms, because animals do not perfectly mimic the human in vivo environment. An excellent example of this is the subclavian crush in humans (clamping a lead between the clavicle and first rib), which is impossible to discover in animals with no clavicles. With the right protocol for the device in question, only postmarket surveillance appropriate for the device in question can determine for certain that the device does or does not meet expectations. 

Nichols S, Koh A, Storm WL, Shin JH, Schoenfisch MH (2013) Biocompatible materials for continuous glucose monitoring devices. Chem Rev 113(4) 2528-2549... 

Both of these formulations can be applied to tissue by pouring or spraying on wounds. Both formulations are particularly conducive for pressure-spray or pump-spray applications. They both form continuous impermeable films over moist tissue, are water-proof after application, have long shelf stability, and are biocompatible. The siloxane-based material appears to have no stinging effect on excised tissue, and it does possess a very low surface energy that is difficult for environmental contamination and bacteria to attach. These materials are inexpensive compared to cyanoacrylates. 

Stiff lightweight structures such as aircraft wings are made from sandwiches of continuous sheets filled with foams or honeycombs. Open porous structures can form frameworks for infiltration by other materials leading to application of biocompatible implants. Open pore structures are used as supports for catalysts. 

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