In vivo biocompatibility

PANI would be typically functionalized with selected dopants via either noncovalent or covalent approaches. In addition, nanostructured PANI materials, such as nanorods, nanowires and nanofibers, offer the possibilities to improve the performance of the PANI-based devices (Huang et al., 2003). PANI has demonstrated its biocompatibility in vivo and sparked great interests in tissue engineering. The biocompatibility of PANI can be further improved by the introduction of biocompatible elements without sacrificing its electric conductivity. 

Furthermore, these scaffolds have been shown to be both biodegradable and biocompatible in vivo. Results indicated that PPF is biocompatible within both soft and hard tissues, minimal fibrous encapsulation of the scaffolds occurred, and tissue response appeared to improve with implantation time. A progressive reduction in inflammatory cell density and a continued organization of connective tissue with the interstitial space was observed, even if scaffold microstmcture did not seem to play a key role. ... 

Williams, D.E (1994) Molecular biointeractions of biomedical polymers with extracellular exudate and inflammatory cells and their effect on biocompatibility, in-vivo. Biomaterials. 15, 779-785. 

Key words degradable metals, biocompatibility, in vivo corrosion, in vitro corrosion, magnesium implant. 

Miniaturized catheter-type ISE sensors, such as the implantable probe shown in Figure 5-20 represent the preferred approach for routine clinical in-vivo monitoring of blood electrolytes. For these intravascular measurements the reference electrode is placed outside die artery (in die external arm of die catheter), tints obviating biocompatability and drift problems associated with its direct contact with the blood. 

In vivo biocompatibility was assessed through subcutaneous implantation in Sprague-Dawley rats. PLGA was used as a control polymer. PGS and PLGA implants with the same surface area/volume ratio were implanted in dorsal subcutaneous pockets. A fibrous capsule around PGS (45 pm thick after 35 days implantation) appeared later than that around PLGA (140 pm thick after 14 days implantation). After 60 days of implantation, the implant was completely absorbed with no signs of granulation or scar formation. ... 

Various in vivo studies have been performed to assess the biocompatibility of PEG/PBT copolymers upon implantation in soft and hard tissues." ... 

M., McConnell, R., Lange, N., and Langer, R., Poly(anhy-dride) administration in high doses in vivo Studies of biocompatibility and toxicology, J. Biomed. Mat. Res., In Press. 

The term "bioenertness" is a relative one since few if any synthetic polymers are totally biocompatible with living tissues. The terra is used here on the basis of preUminary in vitro and in vivo tests, together with chemical evaluations based on analogies with other well-tested systems. Two different types of polyphosphazenes are of interest as bioinert materials those with strongly hydrophobic surface characteristics and those with hydrophilic surfaces. These will be considered in turn. 

Probably the most promising polymeric drug carrier system involves polysaccharide molecules. These are natural polymers and are often biodegradable to products that are useful to the host or easily eliminated by the host. Dextrans have been the most extensively used polysaccharide for macromolecular prodrug preparations (79). These materials are biocompatible and the in vivo fate is directly related to their molecular weight. Moreover these macromolecules can be easily targetted to the hepatocytes with D-mannose or L-fucose (20). 

Mutlu, G.M. et al. (2010) Biocompatible nanoscale dispersion of single-walled carbon nanotubes minimizes in vivo pulmonary toxicity. Nano Letters, 10 (5), 1664-1670. 

---