Sustained immobilization of growth factor proteins based on functionalized parylenes.

Protein molecules immobilized on biomaterial surfaces are performed based on oriented conjugation or replaced mimicking peptides. The sustainable immobilization of growth factor proteins using functionalized parylene coatings is demonstrated in this study. Site-specific and nonspecific immobilization approaches are realized to conjugate bone morphogenetic protein (BMP-2). The binding affinities and conformational changes of BMP-2 are confirmed by QCM and SPR characterizations. Osteoinduction of stem cells is examined by ALP activity on the BMP-2 modified surfaces. Finally, immobilizations and equally sustained biological functions of vascular endothelial growth factor (VEGF) and a mimicking peptide of KLTWQELYQLKYKG (QK) are also examined and confirmed.

Peptide-modified zwitterionic porous hydrogels for endothelial cell and vascular engineering.

Hydrogels allow control of gel composition and mechanics, and permit incorporation of cells and a wide variety of molecules from nanoparticles to micromolecules. Peptide-linked hydrogels should tune the basic polymer into a more bioactive template to influence cellular activities. In this study, we first introduced the generation of 2D poly-(sulfobetaine methacrylate [SBMA]) hydrogel surfaces. By incorporating with functional peptide RGD and vascular endothelial growth factor-mimicking peptide KLTWQELYQLKYKG (QK) peptides, endothelial cells attached to the surface well and proliferated in a short-term culturing. However, the mechanical property, which plays a crucial role directing the cellular functions and supporting the structures, decreased when peptides graft onto hydrogels. Manipulating the mechanical property was thus necessary, and the most related factor was the monomer concentration. From our results, the higher amount of SBMA caused greater stiffness in hydrogels. Following the 2D surface studies, we fabricated 3D porous hydrogels for cell scaffolds by several methods. The salt/particle leaching method showed a more reliable way than gas-foaming method to fabricate homogeneous and open-interconnected pores within the hydrogel. Using the salt/particle leaching method, we can control the pore size before leaching. Morphology of endothelial cells within scaffolds was also investigated by scanning electron microscopy, and histological analysis was conducted in vitro and in vivo to test the biocompatibility of SB hydrogel and its potential as a therapeutic reagent for ischemic tissue repair in mice.

Oxidation of catechin and rutin by pentaammineruthenium(III) complexes.

The reaction of catechin and rutin with Ru(NH(3))(5)L(3+) (L = N-methylpyrazinium (pzCH(3)(+)), pyrazine (pz), and isonicotinamide (isn)) complexes underwent a two-electron oxidation on the catechol ring (B ring) with the formation of quinone products. The kinetics of the oxidation, carried out at [H(+)] = 0.01-1.0 M and pH = 4.0-7.6, suggested that the reaction process involves the rate determining one-electron oxidation of the flavonoids in the form of H(2)X (k(0)), HX(-) (k(1)), and X(2-) (k(2)) by Ru(NH(3))(5)L(3+) complexes to form the corresponding semiquinone radicals, followed by the rapid scavenge of the radicals by the Ru(III) complexes. The specific rate constants (k(0), k(1), and k(2)) were measured and the results together with the application of the Marcus theory were used to estimate the self-exchange parameters for the one-electron couples of the flavonoids, H(2)X/H(2)X(+*), HX(-)/HX(*), and X(2-)/X(-*).