Publications by authors named "Ramakrishna R Ponnapati"

A folic acid sensor was prepared via an electropolymerized molecularly imprinted polymer (E-MIP) film of a bis-terthiophene dendron on a quartz crystal microbalance (QCM). The cyclic voltammetry (CV) electrodeposition of the imprinted polymer film was monitored by electrochemical QCM or E-QCM, enabling in situ monitoring and characterization of E-MIP film formation and the viscoelastic behavior of the film. A key component of the E-MIP process is the use of a bifunctional monomer design to precomplex with the template and function as a cross-linker.

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In this study, a series of electrochemically active oligo(ethylene glycol) (OEG) linear-dendrons have been synthesized and grafted onto electrode surfaces by cyclic voltammetry (CV) to improve protein resistance. Dendronized molecules with peripheral carbazole functionality and branching architecture enabled tethering of the poly(ethylene glycol) (PEG) or OEG group with a predictable number of electrochemical reactive groups affecting OEG distribution and orientation. It is possible that ample spacing between the OEG chains affects the intrinsic hydration of these layers and thus surface protein resistance.

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This paper introduces a novel and versatile method of grafting protein and cell-resistant poly(poly ethylene glycol methyl ether methacrylate) (PPEGMEMA) brushes on conducting Au surface. The process started with the electrochemical deposition and full characterization of an electro-active chain transfer agent (CTA) on the Au surface. The electrochemical behavior of the CTA was investigated by cyclic voltammetry (CV) while the deposition and stability of the CTA on the surface were confirmed by ellipsometry, contact angle, and X-ray photoelectron spectroscopy (XPS).

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In this work, we report an electrochemical surface plasmon resonance/waveguide (EC-SPR/waveguide) glucose biosensor that could detect enzymatic reactions in a conducting polymer/glucose oxidase (GO(x)) multilayer thin film. In order to achieve a controlled enzyme electrode and waveguide mode, GO(x) (negatively charged) was immobilized with a water-soluble, conducting N-alkylaminated polypyrrole (positively charged) using the layer-by-layer (LbL) electrostatic self-assembly technique. The electrochemical and optical signals were simultaneously obtained from the composite LbL enzyme electrode upon the addition of glucose as mediated by the electroactivity and electrochromic property of the polypyrrole layers.

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