Topic
Surface modification
About: Surface modification is a research topic. Over the lifetime, 35544 publications have been published within this topic receiving 859567 citations.
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TL;DR: Lower limiting film thicknesses and surface coverages for films prepared in aqueous conditions is attributed to growth of inherently more blocking films and is supported by examination of the response of the Fe(CN)6(3-/4-) couple at NP-modified surfaces.
Abstract: Electrochemical reduction of the diazonium salts of 4-nitrobenzene and 4-nitroazobenzene-4‘- has been investigated in aqueous acid and acetonitrile media at carbon surfaces. Using pyrolyzed photoresist films as the substrate, we have examined the deposited films using electrochemistry and atomic force microscopy (AFM). Film thicknesses were measured by scratching through the film with an AFM tip. The procedure employed two AFM cantilevers with different lengths, located on the one device. When the shorter cantilever engages the surface in tapping mode, the longer cantilever (which is not resonating) imbeds into the surface with a constant force. For both modifiers and modification media, film thicknesses increase with deposition time to a limiting value. With equivalent modification conditions, films prepared in aqueous acid medium have lower limiting thicknesses than those prepared in acetonitrile. For nitrophenyl (NP) films, the same trends are found when calculating surface coverages from the charge as...
399 citations
TL;DR: This strategy for surface functionalization of an electrically conductive polymer, chlorine-doped polypyrrole, which has been widely researched for various electronic and biomedical applications, is developed and can be extended to immobilize a variety of molecules to PPyCl for numerous applications.
Abstract: The goal in biomaterial surface modification is to retain a material's bulk properties while modifying only its surface to possess desired recognition and specificity. Here we develop a unique strategy for surface functionalization of an electrically conductive polymer, chlorine-doped polypyrrole (PPyCl), which has been widely researched for various electronic and biomedical applications. An M13 bacteriophage library was used to screen 10(9) different 12-mer peptide inserts against PPyCl. A binding phage (phiT59) was isolated, and its binding stability and specificity to PPyCl was assessed using fluorescence microscopy and titer count analysis. The relative binding strength and mechanism of the corresponding 12-mer peptide and its variants was studied using atomic force microscopy and fluorescamine assays. Further, the T59 peptide was joined to a cell adhesive sequence and used to promote cell attachment on PPyCl. This strategy can be extended to immobilize a variety of molecules to PPyCl for numerous applications. In addition, phage display can be applied to other polymers to develop bioactive materials without altering their bulk properties.
397 citations
TL;DR: Biocompatible ferrofluid containing dye-functionalized magnetite nanoparticles that can serve as fluorescent markers enable optical tracking of basic processes at the cellular level combined with magnetophoretic manipulation and should be of substantial value to researchers engaged in both fundamental and applied biomedical research.
Abstract: A method is presented for the preparation of a biocompatible ferrofluid containing dye-functionalized magnetite nanoparticles that can serve as fluorescent markers. This method entails the surface functionalization of magnetite nanoparticles using citric acid to produce a stable aqueous dispersion and the subsequent binding of fluorescent dyes to the surface of the particles. Several ferrofluid samples were prepared and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), BET surface area analysis, transmission electron microscopy (TEM), and SQUID magnetometry. In addition, confocal fluorescence microscopy was used to study the response of the fluorescent nanoparticles to an applied magnetic field and their uptake by cells in vitro. Results are presented on the distribution of particle sizes, the fluorescent and magnetic properties of the nanoparticles, and the nature of their surface bonds. Biocompatible ferrofluids ...
396 citations
TL;DR: The mechanical properties above the glass-rubber transition were found to be drastically enhanced for the nanocomposites as compared to the neat polypropylene matrix as well as the dispersion quality when investigation of the films was performed in the nonlinear region.
396 citations
TL;DR: A zwitterionic poly(carboxybetaine acrylamide) (polyCBAA) biomimetic material was employed to create a unique biorecognition coating with an ultralow fouling background, enabling the sensitive and specific detection of proteins in blood plasma.
Abstract: A crucial step in the development of implanted medical devices, in vivo diagnostics, and microarrays is the effective prevention of nonspecific protein adsorption from real-world complex media such as blood plasma or serum. In this work, a zwitterionic poly(carboxybetaine acrylamide) (polyCBAA) biomimetic material was employed to create a unique biorecognition coating with an ultralow fouling background, enabling the sensitive and specific detection of proteins in blood plasma. Conditions for surface activation, protein immobilization, and surface deactivation of the carboxylate groups in the polyCBAA coating were determined. An antibody-functionalized polyCBAA surface platform was used to detect a target protein in blood plasma using a sensitive surface plasmon resonance (SPR) sensor. A selective protein was directly detected from 100% human blood plasma with extraordinary specificity and sensitivity. The total nonspecific protein adsorption on the functionalized polyCBAA surface was very low (<3 ng/cm2 ...
396 citations