Hydrophilic polymers, polymer brushes biocompatibility

In this work, we wiU discuss the characteristic size-exclusion effect and excellent protein repeUency of concentrated brushes on the basis of our experimental data previously reported with poly(2-hydroxyethyl methacrylate) (PHEMA) brushes. PHEMA is a hydrophilic, biocompatible polymer, but the biocompatibility of PHEMA cast film is reported to be not as good as e.g., poly(2-methacryloxyethyl-phosphorylcholine) and poly(2-metho-xyethylacrylate) cast films. Hence any favorable results on the PHEMA brushes could be ascribed more to the structural,... 

As with normal hydrocarbon-based surfactants, polymeric micelles have a core-shell structure in aqueous systems (Jones and Leroux, 1999). The shell is responsible for micelle stabilization and interactions with plasma proteins and cell membranes. It usually consists of chains of hydrophilic nonbiodegradable, biocompatible polymers such as PEO. The biodistribution of the carrier is mainly dictated by the nature of the hydrophilic shell (Yokoyama, 1998). PEO forms a dense brush around the micelle core preventing interaction between the micelle and proteins, for example, opsonins, which promote rapid circulatory clearance by the mononuclear phagocyte system (MPS) (Papisov, 1995). Other polymers such as pdty(sopropylacrylamide) (PNIPA) (Cammas etal., 1997 Chung etal., 1999) and poly(alkylacrylicacid) (Chen etal., 1995 Kwon and Kataoka, 1995 Kohorietal., 1998) can impart additional temperature or pH-sensitivity to the micelles, and may eventually be used to confer bioadhesive properties (Inoue et al., 1998). 

Markedly, surface-initiated ATRP provides the opportunity to use a variety of functional monomers, to tailor the composition and thickness of the brushes, and to prepare multiple functional surfaces. For example, Zhang et al. prepared poly(methyl methacrylate) (PMMA), poly(acrylamide) (PAAM), and their diblock copolymer (PMMA/PAAM) on the surface of PET film by surface-initiated ATRP [59]. The results indicated that the surface properties of PET film were greatly improved by grafted polymer, the surface of PET film modified by PAAM was hydrophilic, and the surface of PET film modified by diblock copolymer was amphiphilic. This kind of modified PET film may be applied as biocompatible materials, amphiphilic functional film, or conductive film. 

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