Biocompatibility defined

A commonly used definition of a biomaterial, endorsed by a consensus of biomaterials experts, is a nonviable material used in a medical device, intended to interact with biological systems. An essential characteristic of biomaterials is biocompatibility, defined as the ability of a material to perform with an appropriate host response in a specific application. The goal of biomaterials science is to create medical implant materials with optimal mechanical performance and stability, as well as optimal biocompatibility. 

A device that is to be placed in contact with living tissue or biological fluids must be made of material that is biocompatible. However, biocompatible is not a precisely defined term or a measurable property. In general, biocompatibil-... 

Silk fibers or monolayers of silk proteins have a number of potential biomedical applications. Biocompatibility tests have been carried out with scaffolds of fibers or solubilized silk proteins from the silkworm Bombyx mori (for review see Ref. [38]). Some biocompatibility problems have been reported, but this was probably due to contamination with residual sericin. More recent studies with well-defined silkworm silk fibers and films suggest that the core fibroin fibers show in vivo and in vivo biocompatibility that is comparable to other biomaterials, such as polyactic acid and collagen. Altmann et al. [39] showed that a silk-fiber matrix obtained from properly processed natural silkworm fibers is a suitable material for the attachment, expansion and differentiation of adult human progenitor bone marrow stromal cells. Also, the direct inflammatory potential of silkworm silk was studied using an in vitro system [40]. The authors claimed that their silk fibers were mostly immunologically inert in short and long term culture with murine macrophage cells. 

The term biocompatibility needs some explanation and has to be defined for each application separately. The historical definition was based on unimpaired cell growth in the presence of the test article [12]. More recent definitions of the biocompatibility of implantable devices ask for the ability of the device to perform its intended function, without eliciting any undesirable local or systemic effects in the host. 

These dendrimers expand the repertoire of polymers available for study. Current investigations are primarily limited to linear polymers that possess ill-defined solution structures and fewer hydroxyl groups for further modification. The introduction of biocompatible building blocks (e.g., glycerol and lactic acid) augments the favorable and already known physical properties of dendrimers. These properties are likely to facilitate the design of new materials for specific biomedical and tissue engineering applications. 

The commercial production carried out by various companies is estimated to be ca. 2000 tyear-1 worldwide [7]. Due to the common solubility in water and various other solvents (e.g. DMSO, formamide), the biocompatibility, and the ability of degrading in certain physical environments, dextran is already successfully applied in the medical and biomedical field [8]. The physiological activity of dextran and its derivatives, indicated also by a very large number of publications in this area of research, is in contrast to inadequate structural analysis of both dextran and their semi-synthetic products. Only a few publications, in contrast to extensive studies in cellulose and starch chemistry [9,10], deal with the defined functionalisation and characterisation of dextran for adjusting desired features. 

The response reaction of the host to a foreign material remaining in the body for an extended period of time is a concern. Thus, any polymeric material to be integrated into such a delicate system as the human body must be biocompatible. Biocompatibility is defined as the ability of a material to perform with an appropriate host response in a specific application [79]. The concept include all aspects of the interfacial reaction between a material and body tissues initial events at the interface, material changes over time, and the fate of its degradation products. To be considered bio compatible, a biodegradable polymer must meet a number of requirements, given in Table 2. 

Poly(esters) are the best defined widely used biodegradable and biocompatible materials. There are a number of different grades of poly(lactic acid) (PFA), poly(glycolic acid) (PGA), and copolymers of lactic and glycolic acids (PFAGA) with respect to molecular weights and compositions. One of the major advantages... 

The problems that occur with in vivo experiments are not completely solved. The points where the implanted electrodes cause tissue damage are rapidly regenerated and covered by conjunctive tissue or even by antibodies from electrode rejection. The formation and growth of conjunctive tissue is influenced by the form and nature of the electrode material. A material s biocompatibility is defined as its ability to perform with an appropriate host response in a specific application51. Therefore it is important to develop biomaterials for in vivo sensor applications, since neither the conjunctive tissue nor the antibody layer on the electrode is conducting, and a large decrease in electrode response after implantation is observed. 

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