Biomedical subjects

Wenqiang Huang

Publications and source records attributed to Wenqiang Huang.

5 recordsLinked to original sources

PubMed2006

Catalytic properties of carboxylic acid functionalized-polymer microsphere-stabilized gold metallic colloids.

Polymer-microsphere-stabilized gold metallic colloids have been prepared by a novel strategy of simple and convenient reduction of the metallic salt through the stabilization of the active carboxylic acid group on the gel and surface layer of the microsphere. The nature of the interaction between the carboxylic acid and Au nanoparticles was studied in detail by XPS. Preliminary results indicate that polymer-microsphere-stabilized gold colloids are active catalysts for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride as reductant. The catalytic properties of the stabilized catalyst for recycling were also investigated.

Adsorption↗

PubMed2006

Core-corona polymer composite particles by self-assembled heterocoagulation based on a hydrogen-bonding interaction.

Poly(ethylene glycol dimethacrylate-co-acrylic acid) (poly(EGDMA-co-AA)) small microspheres were effectively self-assembled on poly(ethylene glycol dimethacrylate-co-4-vinylpyridine) (poly(EGDMA-co-VPy)) surfaces to form a core-corona structure with a raspberry-like polymer composite by a hydrogen interaction mechanism through an affinity complex between the carboxylic acid group and pyridine group. The control of coverage of the poly(EGDMA-co-AA) corona on the surface of poly(EGDMA-co-VPy) was studied in detail via adjustment of the nature of the mass ratio between the core and corona. The effects of the pH and solvent used on the morphology of the self-assembled core-corona polymer composites were investigated. The nature of the interaction between the core and corona polymer particles was identified as hydrogen bonding with FT-IR spectroscopy.

Acrylates↗

PubMed2005

Raspberry-like composite polymer particles by self-assemble heterocoagulation based on a charge compensation process.

Nano-sized poly(ethylene glycol dimethacrylate-co-acylic acid) (poly(EGDMA-co-AA)) were effectively self-assembled on poly(divinylbenzene-co-styryl methylpyridinium chloride) (poly(DVB-co-StMPyCl)) surfaces to form the raspberry-like composite by a charge compensation mechanism through the affinity complex between carboxylic group and pyridinium group. The effects of pH and salt electrolyte on the morphology of the self-assembled polymer composites were investigated. The resulting heterocoagulates were highly stable in water and acid solution. These heterocoagulates were reversible through the self-assembly in acidic or neutral media and the dissociation in the basic medium due to the charge compensation through the strong affinity complex between hydroxide anion and pyridinium group cation. The resulting heterocoagulates were characterized with scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). As a result, a new method for tuning the structure of a charge compensation directed polymer composite was developed.

Composite Resins↗

PubMed2003

A new strategy for solid phase synthesis of a secondary amide library using sulfonamide linker via radical traceless cleavage.

A new strategy for solid phase synthesis of a secondary amide library using sulfonamide linker via radical traceless cleavage is reported. Polystyrylsulfonyl chloride (1) reacted with primary amines to afford polystyryl-supported N-alkyl sulfonamides (2), which were acylated with acid chlorides and followed by radical cleavage with TiCl4/Zn to afford secondary amides. It was interestingly found that the products released from acyl alkanesulfonamide resins are closely dependent on the substituents of benzene rings of alkyl or acyl groups on the resins. When the substituent on benzene ring of N-benzyl group of sulfonamides is an electron rich MeO-group, the products released from sulfonamide resins are dependent on the substitution position on benzene ring: para-MeO- to yield 1,2-bis (p-methoxylphenyl)ethane and N--p-methoxylbenzyl benzamide (30:1); ortho-MeO- to give 1,2-bis (o-methoxylphenyl)ethane and N--o-methoxylbenzyl benzamide (1:15); and meta-MeO- only to release N--m-methoxylbenzyl benzamide. Neither N-benzoyl sulfonamide resins on benzene ring with electron-drawing para-O2N-, nor the one with electron-donating para-H2N- could release any amide product, while the N-benzoyl sulfonamide resins on benzene ring with para-acetamido group released para-acetamidobenzamides. The conjugation effect to stabilize the radical groups in the radical cleaving process was observed.

Amides↗

PubMed2002

Molecular recognition through the exact placement of functional groups on non-covalent molecularly imprinted polymers.

To investigate the extent of the placement of functional groups in the non-covalent molecularly imprinted polymers contributing to selectivity, three kinds of molecularly imprinted methacrylic acid-ethylene glycol dimethacrylate copolymers were prepared at higher polymerization temperature (60 degrees C) using 2-L-phenylalanylamino-pyridine, 3-L-phenylalanylamino-pyridine, or 4-L-phenylalanylamino-pyridine as a template molecule, respectively. The enantiomeric recognition performance of these molecularly imprinted polymers (MIPs) in the high-performance liquid chromatography (HPLC) mode was investigated. The polymers exhibited efficient enantiomeric resolution of the racemic mixture of their printing molecules and could hardly resolve the enantiomers of other substrates that were structurally analogous to the imprinting molecules, but different from spatial interaction sites on the polymer with the methacrylic acid residues. Our results showed that the shape and spatial orientation of functionality of imprinted binding sites were critical for recognition and the recognition properties of MIPs were greatly influenced by the minor difference of N position on the pyridine ring and caused by the distance accuracy of functional groups in the binding sites. The implication of these findings with respect of the mechanism of recognition was discussed.

Chromatography, High Pressure Liquid↗