Tissue adhesive, biomedical polymers

Materials are indexed quite adequately. The broad MeSH heading Biomedical and Dental Materials includes such narrower terms as Alloys, Biocompatible Materials, Polymers, and Tissue Adhesives. More precise narrower terms au-e also provided, for example, the many different types of polymers (e.g., cyanoacrylates, elastomers, plastics, and silicones). 

Hydrophobicity of biomedical polymers influences the biocompatibility depending on the particular application such as tissue engineering, blood contacting devices, and dental implants [35]. Polymers are dynamic structures and can switch their surface functional groups depending on the environment. For example, polymeric biomaterials need to have a hydrophilic smface for most of the applications, so that the cell-adhesive proteins present in the serum will be adsorb and promote cell adhesion and proliferation. This is achieved by snrface treatment procedures such as... 

PPy is the first and most extensively studied and used CP for biomedical and tissue engineering applications [241-245]. It was one of the first known polymers biocompatible to cells both in vitro and in vivo and promoting their adhesion and growth in vitro. PPy implants have also shown to be compatible with minimum or no response from tissues. The electrical stimulation of PPy has also been found to... 

Moreover, tyrosinase-catalyzed activity is not limited only to protein substrates. Burke et al. have focused their work on the modification of biocompatible polymers such as poly(ethylene glycol) with DOPA in an effort to impart adhesive qualities to the polymers for biomedical application. Although PEG itself is not adhesive, it represents a candidate budding block for a synthetic tissue adhesive because of its high water solubility, low immunogenicity and toxicity, and availability of end groups easily modifiable with amino acids and peptides [61]. Burke et al. [12] synthesized several linear and branched PEG molecules with end groups modified by DOPA residues and have characterized their oxidation-induced... 

PEAs are a branch of relatively new polymers. Research in the biomedical field is just starting to investigate possibilities in areas such as controlled drug release systems [215], hydrogels [216], tissue engineering [217,218], and other uses like adhesives and smart materials, together with the main families of functionalized PEAs that have been developed to date [214]. 

A wide variety of natural and synthetic materials have been used for biomedical applications. These include polymers, ceramics, metals, carbons, natural tissues, and composite materials (1). Of these materials, polymers remain the most widely used biomaterials. Polymeric materials have several advantages which make them very attractive as biomaterials (2). They include their versatility, physical properties, ability to be fabricated into various shapes and structures, and ease in surface modification. The long-term use of polymeric biomaterials in blood is limited by surface-induced thrombosis and biomaterial-associated infections (3,4). Thrombus formation on biomaterial surface is initiated by plasma protein adsorption followed by adhesion and activation of platelets (5,6). Biomaterial-associated infections occur as a result of the adhesion of bacteria onto the surface (7). The biomaterial surface provides a site for bacterial attachment and proliferation. Adherent bacteria are covered by a biofilm which supports bacterial growth while protecting them from antibodies, phagocytes, and antibiotics (8). Infections of vascular grafts, for instance, are usually associated with Pseudomonas aeruginosa Escherichia coli. Staphylococcus aureus, and Staphyloccocus epidermidis (9). 

Biomaterials. Adsorbed polymers find many apphcations as surface modifiers in biomedical apphcations. By choosing a combination of hydrophobic and hydrophilic copolsrmers, surfaces can be modified to make them biocompatible (65) (see Biomolecules at Interfaces). In the area of tissue engineering (qv), adsorbed layers with specihc amino acid sequences can be used to promote cell adhesion and proliferation. The recent developments in the design of biochips to analyze specihc DNA molecules also take advantage of this technology. Polymer adsorption on patterned surfaces can be used to mimic pattern recognition. This effect can be used to develop sensors and molecular-scale separation processes (66). 

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