Biomedical subjects

Bhavana A Deore

Publications and source records attributed to Bhavana A Deore.

4 recordsLinked to original sources

PubMed2006

A novel layer-by-layer approach for the fabrication of conducting polymer/RNA multilayer films for controlled release.

Poly(anilineboronic acid) (PABA)/ribonucleic acid (RNA) multilayer films were prepared under neutral condition using a layer-by-layer deposition of PABA and RNA. RNA was used both as a polyelectrolyte for multilayer formation as well as dopant for PABA. Photoelastic modulated infrared reflection absorption spectroscopy measurements suggest that PABA interacts covalently with RNA through the formation of a boronate ester, a boron-nitrogen dative bond, as well as electrostatic interactions of anionic phosphates with cationic amines. The deposition procedure was monitored with UV-vis absorption spectroscopy, showing a linear dependence of absorbance with the number of PABA/RNA bilayers deposited. The multilayer films were further characterized using X-ray photoelectron spectroscopy and ellipsometry, which yielded a PABA/RNA bilayer thickness of approximately 10 nm. The PABA/RNA multilayer films are redox-active at neutral pH, consistent with the formation of a self-doped polymer. Electrochemical control of PABA under these conditions allows potential-induced controlled release of RNA from a multilayer at neutral pH, suggesting that this may serve as a novel method for controlled release of RNA under physiological conditions.

Aniline Compounds↗

PubMed2005

Substitution and condensation reactions with poly(anilineboronic acid): reactivity and characterization of thin films.

Poly(anilineboronic acid) thin films are treated under various conditions to achieve substitution or condensation reactions involving the boronic acid moiety. These reactions are studied with polarization modulated infrared reflection absorption spectroscopy, cyclic voltammetry, and UV-vis spectroscopy. The results suggest the single-step formation of substituted polyanilines, such as poly(hydroxyaniline), halogenated polyanilines, and mercury chloride-substituted polyaniline. A condensation reaction of poly(anilineboronic acid) with cis-diol compounds in aqueous solution, as well as with phenylenebisboronic acid and salycilamide in THF, indicates the formation of boronic esters. The latter reactions appear to be a good entry point for the formation of complex or supramolecular polymer structures.

Journal Article↗

PubMed2004

A switchable self-doped polyaniline: interconversion between self-doped and non-self-doped forms.

A novel strategy for the synthesis of a substituted polyaniline that can be switched between a self-doped and non-self-doped state is presented. The approach uses the complexation between boronic acid-substituted aniline, a diol (d-fructose), and fluoride to generate an anionic monomer. Under these conditions, chemical polymerization results in a self-doped, water-soluble, conducting polyaniline under neutral aqueous conditions. The self-doped polymer can be simply and reversibly converted to an insoluble non-self-doped form by reducing the concentration of fluoride. Characteristics of the polymerization reaction and the resulting polymer are discussed.

Journal Article↗

PubMed2002

Characterization of overoxidized polypyrrole colloids imprinted with L-lactate and their application to enantioseparation of amino acids.

Overoxidized polypyrrole colloids imprinted with L-lactate were prepared to evaluate the performance of the overoxidation pseudo-template technique developed by the authors. A polypyrrole colloid that had been prepared from a mixture of monomer (pyrrole), dopant (L-lactate), steric stabilizer (poly(vinylpyrrolidone)) and oxidizing agent (peroxodisulfate) was electrochemically overoxidized at +1.5 V vs Ag/AgCl to create a complementary cavity for recognition of the molecules, which were structurally similar to dopant, through dedoping. As a target molecule for enantioselective uptake into the overoxidized colloid, we selected alanine, which is structurally different from the template (lactate) only in one side chain (alanine, -NH2; lactic acid, -OH). The overoxidized polypyrrole colloid showed higher affinity for L-alanine than for D-alanine, and an uptake ratio (L/D) of as high as 11 +/- 4 was observed under optimum conditions. Uptake reached equilibrium in 10 min, thanks to the high surface area and short diffusion length in the colloidal particle. Further, to confirm the complementarity of the cavity, the effect of side chain size on uptake of several alpha-amino acids was examined to indicate that the uptake amount decreased with increasing molecular volume of the L-amino acids.

Alanine↗