Polymers applications in medicine

R. Dersch, M. Steinhart, U. Boudriot, A. Greiner, and J. H. Wendorff, Nanoprocessing of polymers applications in medicine, sensors, catalysis, photonics. Polymers Adv. TechnoL, 16, 276-282 (2005). 

Modjarrad and Ebnesajjad, Handbook of Polymer Applications in Medicine and Medical Devices ISBN 9780323228053... 

Modjarrad, K., Ebnesajjad, S. [2013]. Handbookof Polymer Applications in Medicine and Medicai Devices. Elsevier. 

In order to be successful as part of a medical device a polymer has to resist both biological rejection by the patient s body and degradation. The human body is an enviromnent which is simultaneously hostile and sensitive, so that materials for application in medicine must be carefully selected. The essential requirement is that these materials are biocompafible with the particular part of the body in which they are placed. The extent to which polymers fulfil this requirement of biocompafibility depends partly on the properties of the polymer and partly on the location in which they are expected to perform. For example the requirements for blood biocompafibility are stringent since blood coagulation may be triggered by a variety of materials. By contrast, the requirements for materials to be used in replacement joints in orthopaedic surgery are less severe and materials as diverse as poly (methyl methacrylate) and stainless steel can be used with minimal adverse reaction from the body. 

Microspheres made of various polymers biodegradable to nonharm-ful compounds that could be metabolized and/or removed from organisms found many applications in medicine as carriers of drugs or other bioactive compounds [1 ]. Besides chemical composition there are also other properties of microspheres that are of primary importance to their medical applications. In particular, average diameters and diameter distributions illustrated in Table 1 based on data published in [5] are the relationship between the diameters of microspheres and their localization in various cells and tissues of the human body. 

D-Glucose methacrylate (XXVI) is the last monomer. Its polymers have many potential applications in medicine, secondary oil recovery, etc (27,28). 

Abstract Synthesis of carbon adsorbents with controlled pore size and surface chemistry adapted for application in medicine and health protection was explored. Conjugated polymers were used as carbon precursors. These polymers with conjugated double bonds C = C have high thermal stability. Formation of sp carbon structures occurs via condensation and aromatization of macromolecules. The structure of carbon materials obtained is related to the structure of the original conjugated polymer, thus the porous structure of carbon adsorbents could be controlled by variation of the conjugated polymer precursor. 

Internal plasticizers are synthesized by copolymerization of suitable monomers. Polymeric non-extractable plasticizers, mostly copolymers having substantially lower glass transition temperatures due to the presence of plasticizing ( soft ) segments such as poly(ethylene-co-vinyl acetate) with approximately 45 % vinylacetate content, ethylene-vinyl acetate-carbon monooxide terpolymer, or chlorinated PE, are available for rather special applications in medicinal articles (Meier, 1990). In this case, the performance of the internally plasticized polymers is the principal advantage. However, copolymerization may account for worse mechanical properties. A combination with external plasticizers may provide an optimal balance of properties. For example, food contact products made from poly(vinylidene chloride) should have at most a citrate or sebacate ester based plasticizers content of 5 % and at most 10 % polymeric plasticizers. 

Applications in medicine take advantage of the combination of such properties as biocompatibility and degradability. Neither the polymers themselves nor their degradation products can set free toxic materials or cause tissue-damaging processes. 

Femtosecond laser irradiation of polymers allows direct structuring of polymers that are transparent at most laser wavelengths (e.g. Teflon), and reveal structures with high quality and a very small heat affected zone (HAZ). Similarities and differences between the ablation of polymers and dielectrics are shown, together with the influence of the pulse duration and band-gap of the materials. Various potential applications in medicine and biosensoric are discussed. 

An often applied method for the synthesis of hydrogels, especially for applications in medicine and pharmaceutics, is based on radiochemistry. The hydrogel can be formed by irradiation of monomers, polymers dissolved in water, or polymers in dry state. Electrons of different energies or y-rays are used as high-energy radiation. The possibilities of the radiation-chemical synthesis of smart hydrogels are discussed on different examples. The technique is applied to bulk polymers, to micro- and nanogel particles, and to patterned layers on different materials. The basics and fundamentals of irradiation techniques as well as the equipment are described. 

Amperometric electrodes that are extremely thin (<1 pm diameter) are called ultramicroelectrodes and have a number of advantages over conventional electrodes. Being narrower than the diffusion rate thickness, mass transport is enhanced, the signal-to-noise ratio is improved and the measurements can be made in resistive matrices such as nonaqueous solvents. These have huge applications in medicine as they can lit inside a living cell. Carbon fibre electrodes are coated in insulating polymer and plated with a thin layer of metal at the exposed tip to prevent fouling of the carbon itself. These can then be used to measure analytes of interest in various cells and membranes of the human body. 

This reaction was first reported by Hantzsch in 1890. It is the preparation of 2,5-dialkyl or 2,4,5-trialkylpyrrole derivatives from the condensation of of-halo-ketones, )0-ketoesters and ammonia or amines. Therefore, it is often known as the Hantzsch pyrrole synthesis or simply the Hantzsch synthesis. During this synthesis, ammonia or amine reacts quickly with y0-keto esters to form enamine esters or 3-amino crotonates that cyclize with of-halo-ketones to form pyrrole derivatives upon heating, and the regioselectivity strongly depends on the substituents on the starting materials. Thus, this reaction can directly start from 3-amino crotonates or enamines of 0-keto esters. Further extension of this reaction from aromatic amines results in the formation of indole derivatives, or carbazole derivatives if cyclized with a-halo-cyclohexanones. The synthesized pyrroles have wide application in medicinal chemistry, conducting polymers, molecular optics, sensors,etc. 

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