Multinuclear nuclear magnetic resonance spectroscopic and high-performance liquid chromatographic characterization of silica, grafted with specifically deuterated 4-((propylamino)methyl)benzoic acid.

Specifically deuterated 4-((propylamino)methyl)benzoic acid-grafted silica (PAMBA-silica) was prepared by benzylation of propylamino-grafted silica (PA-silica) by either in situ reduction by sodium cyanoborodeuteride (NaCNBD3) of the Schiff base, formed by the reaction between PA-silica and 4-formylbenzoic acid, or by NaCNBD3 reduction of the isolated Schiff base. The PAMBA-silicas, which contain amine and carboxylic acid functionalities, were characterized by elemental analysis, (13)C, (29)Si, and (2)H solid state NMR, and HPLC. Solid state (13)C NMR revealed that PAMBA-silica prepared by the in situ method consists of di-benzylated, mono-benzylated, and unreacted amino-groups while PAMBA-silica prepared by the two-step synthesis consists of only mono-benzylated and unreacted amino-groups.

Encapsulated neural stem cell neuronal differentiation in fluorinated methacrylamide chitosan hydrogels.

Neural stem/progenitor cells (NSPCs) are able to differentiate into the primary cell types (neurons, oligodendrocytes and astrocytes) of the adult nervous system. This attractive property of NSPCs offers a potential solution for neural regeneration. 3D implantable scaffolds should mimic the microstructure and dynamic properties found in vivo, enabling the natural exchange of oxygen, nutrients, and growth factors for cell survival and differentiation.

Specific immobilization of biotinylated fusion proteins NGF and Sema3A utilizing a photo-cross-linkable diazirine compound for controlling neurite extension.

In this study we report the successful synthesis of N-(2-mercaptoethyl)-3-(3-methyl-3H-diazirine-3-yl) propanamide (N-MCEP-diazirine), with sulfhydryl and amine photoreactive ends to allow recombinant protein tethering to chitosan films. This regimen allows mimicry of the physiological endeavor of axon pathfinding in the nervous system where neurons rely on cues for guidance during development and regeneration. Our strategy incorporates strong covalent and noncovalent interactions, utilizing N-MCEP-diazirine, maleimide-streptavidin complex, and two custom biotinylated-fusion proteins, nerve growth factor (bNGF), and semaphorin3A (bSema3A).

3D differentiation of neural stem cells in macroporous photopolymerizable hydrogel scaffolds.

Neural stem/progenitor cells (NSPCs) are the stem cell of the adult central nervous system (CNS). These cells are able to differentiate into the major cell types found in the CNS (neurons, oligodendrocytes, astrocytes), thus NSPCs are the mechanism by which the adult CNS could potentially regenerate after injury or disorder. Microenviromental factors are critical for guiding NSPC differentiation and are thus important for neural tissue engineering.

Fluorinated methacrylamide chitosan hydrogel systems as adaptable oxygen carriers for wound healing.

In this study a series of novel, biocompatible hydrogels able to repeatedly takeup and deliver oxygen at beneficial levels have been developed by conjugating various perfluorocarbon (PFC) chains to methacrylamide chitosan via Schiff base nucleophilic substitution, followed by photopolymerization to form hydrogels. The synthesized fluorinated methacrylamide chitosan (MACF) hydrogels were confirmed by high resolution (19)F NMR. Synthesized MACF hydrogels were tested for their ability to takeup and then release oxygen for future use in dermal wound healing.