Biocompatible material

Functionalization is a central to many studies exploring the potential of polypeptide fibers as biocompatible materials, and fibers are often decorated with short bioactive tags that originate from the extracellular matrix (ECM). These tags can be displayed on protein fibers at much higher densities than that which occurs in nature and can also be displayed in unique and complimentary combinations. 

There are two main ways to incorporate bioactive tags the first is to include the sequence prior to assembly (see Sections 4.1 and 4.2 above for other examples). The second is to link the sequence following assembly either by covalent capture or by chemical cross-linking. Fibers that display these tags not only have typical dimensions of ECM proteins but can interact with cells in a similar way to the ECM. 

A range of functionalized and unfunctionalized self-assembling fibrous structures have been tested for their biocompatibility and ability to provide cells with a favorable micro- and nanoenvironments for soft tissue engineering. In this section, studies that focus on amyloid fibrils, on peptide amphi-philes, on ionic complementary peptides, and on dipeptide structures are reviewed. Hard tissue engineering, composites, and coating are also explored followed by macroscopic structures and networks that can be created from fibrous protein structures. 

Fibrils have broad potential for many of the bioapplications listed above. While some amyloid fibrils have negative associations with protein misfold-ing diseases, other fibrils demonstrate positive functions such as the fibrils that thought to occur in mammalian cells (Fowler et al., 2006) reviewed in 

Section 2.1 above). These functional fibrils suggest that designed fibrils can be developed as compatible materials. Toxicology will be a potential issue for all structures that self-assemble on a nanoscale. However, the natural building blocks used to construct protein fibers may increase the biocompatibility of these structures compared to other man-made materials. Polypeptide self-assembly also represents a route for generating ECM-like structures that are not only simpler than their natural equivalents but also easier to prepare. 

---

The ability of these peptidomimetic collagen-structures to adopt triple helices portends the development of highly stable biocompatible materials with collagenlike properties. For instance, it has been found that surface-immobilized (Gly-Pro-Meu)io-Gly-Pro-NH2 in its triple-helix conformation stimulated attachment and growth of epithelial cells and fibroblasts in vitro [77]. As a result, one can easily foresee future implementations of biostable collagen mimics such as these, in tissue engineering and for the fabrication of biomedical devices. 

Polyamines and their ammonium salts have been of interest because they are known to have potential applications as chelating agents (1-3), ion exchange resins (4-6), flocculants (7,8), and other industrial uses (9). Recent biomedical applications have constituted another important use of polymeric amines they have been investigated for use as biocompatable materials, polymeric drugs, immobilization of enzymes, cell-culture substratum and cancer chemotherapeutic agents (10-12). 

In the past few years, a large number of experimental and theoretical studies have focused on metal oxide surfaces with the aim of gaining insight into their catalytic, photocatalytic, and gas-sensing activity [68]. Owing to its thermodynamic stability and relatively easy preparation, the rutile Ti02(l 10) surface has evolved into one of the key models for metal oxide surfaces. For example, it has been extensively used in the research of biocompatible materials, gas sensors, and photocatalysts [69]. 

Halloysite is a biocompatible material but its biodegradability is unclear. Therefore, its usage in medicine may be restricted for dermatological and dental applications or those associated with medical implants [11-14]. 

Invent biocompatible materials for organ replacements and for artificial bones and teeth. 

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. 

J. Xu et al. [283] have shown that immobilization of enzymes can be done using a specially designed composite membrane with a porous hydrophobic layer and a hydrophilic ultrafiltration layer. A polytetrafluoroethylene (PTFE) membrane with micrometer pores as an excellent hydrophobic support for immobilization was employed for the porous hydrophobic layer, and a biocompatible material of polyvinyl alcohol (PVA) which provided a favourable environment to retain the lipase activity was used to prepare the hydrophilic... 

Artificial materials are of growing importance in the fields of medicine and biology. Tissue Engineering, a new and modem interdiseiplinary seientific field, has been developed to design biocompatible materials in order to substitute irreversibly damaged tissues and organs. 

Artificial materials designed for the biomedical use should be biocompatible, i.e. free of adverse effects on cells and tissues, such as cytotoxicity, immimogenicity, mutagenicity and carcinogenicity. Biocompatible materials can be constructed as bioinert, i.e. not allowing adsorption of proteins and adhesion of... 

It is beyond the scope of this Chapter to discuss all kinds of various coating techniques, properties of the supports, properties of the coatings and the various fields of application of the composites in catalysis, separation techniques, materials science, colloid science, sensor technology, biocompatible materials, biomi-metic materials, optics etc. The scope had to be restricted to the fundamental properties of ultrathin organic layers on solid supports followed by some examples, outlining the benefit of the tailored functional surfaces such as SAM and polymer brushes for catalysis. 

Lutz JF (2008) Polymerization of oligo(ethylene glycol) (meth)acrylates toward new generations of smart biocompatible materials. 1 Polym Sd Part A Polym Chem 46 3459-3470... 

Polyelectrolytes have been widely investigated as components of biocompatible materials. Biomaterials come into contact with blood when used as components in invasive instruments, implant devices, extracorporeal devices in contact with blood flow, implanted parts of hard structural elements, implanted parts of organs, implanted soft tissue substitutes and drug delivery devices. Approaches to the development of blood compatible materials include surface modification to give blood compatibility, polyelectrolyte-based systems which adsorb and/or release heparin as well as polyelectrolytes which mimic the biological activity of heparin. 

The selection of a scaffold material is both a critical and difficult choice. There are many biocompatible materials available metals, ceramics, and polymers. 

PLLA, PLGA copolymers, and PGA have proven to be biocompatible materials and are FDA approved for several applications. However, one drawback to their use as scaffold materials for organ regeneration is the acidity caused by the release of lactic and glycolic acid, which at high concentrations becomes toxic to surrounding tissues. Initially, the amount of acid released... 

Vinyl group (polymer) Hydro-gel, Water holding substance Biocompatible material... 

Biocompatible materials consisting of poly(ester-amides), (I), were prepared by DesNoyer et al. (2) and used in cardiovascular medical devices. 

These intermediates were then amidated with selected aminobenzene sulfonic acids. Materials produced in this process were used as biocompatible materials and in drug delivery devices. 

---