Oxidative chemical vapor deposition (oCVD) of patterned and functional grafted conducting polymer nanostructures
ABSTRACT We present a simple one-step process to simultaneously create patterned and amine functionalized biocompatible conducting polymer nanostructures, using grafting reactions between oxidative chemical vapor deposition (oCVD) PEDOT conducting polymers and amine functionalized polystyrene (PS) colloidal templates. The functionality of the colloidal template is directly transferred to the surface of the grafted PEDOT, which is patterned as nanobowls, while preserving the advantageous electrical properties of the bulk conducting polymer. This surface functionality affords the ability to couple bioactive molecules or sensing elements for various applications, which we demonstrate by immobilizing fluorescent ligands onto the PEDOT nanopatterns. Nanoscale substructure is introduced into the patterned oCVD layer by replacing the FeCl3 oxidizing agent with CuCl2.
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ABSTRACT: Triangular silver nanoparticles ( approximately 100 nm wide and 50 nm high) have remarkable optical properties. In particular, the peak extinction wavelength, lambda(max) of their localized surface plasmon resonance (LSPR) spectrum is unexpectedly sensitive to nanoparticle size, shape, and local ( approximately 10-30 nm) external dielectric environment. This sensitivity of the LSPR lambda(max) to the nanoenvironment has allowed us to develop a new class of nanoscale affinity biosensors. The essential characteristics and operational principles of these LSPR nanobiosensors will be illustrated using the well-studied biotin-streptavidin system. Exposure of biotin-functionalized Ag nanotriangles to 100 nM streptavidin (SA) caused a 27.0 nm red-shift in the LSPR lambda(max). The LSPR lambda(max) shift, DeltaR/DeltaR(max), versus [SA] response curve was measured over the concentration range 10(-)(15) M < [SA] < 10(-)(6) M. Comparison of the data with the theoretical normalized response expected for 1:1 binding of a ligand to a multivalent receptor with different sites but invariant affinities yielded approximate values for the saturation response, DeltaR(max) = 26.5 nm, and the surface-confined thermodynamic binding constant K(a,surf) = 10(11) M(-)(1). At present, the limit of detection (LOD) for the LSPR nanobiosensor is found to be in the low-picomolar to high-femtomolar region. A strategy to amplify the response of the LSPR nanobiosensor using biotinylated Au colloids and thereby further improve the LOD is demonstrated. Several control experiments were performed to define the LSPR nanobiosensor's response to nonspecific binding as well as to demonstrate its response to the specific binding of another protein. These include the following: (1) electrostatic binding of SA to a nonbiotinylated surface, (2) nonspecific interactions of prebiotinylated SA to a biotinylated surface, (3) nonspecific interactions of bovine serum albumin to a biotinylated surface, and (4) specific binding of anti-biotin to a biotinylated surface. The LSPR nanobiosensor provides a pathway to ultrasensitive biodetection experiments with extremely simple, small, light, robust, low-cost instrumentation that will greatly facilitate field-portable environmental or point-of-service medical diagnostic applications.Journal of the American Chemical Society 09/2002; 124(35):10596-604. · 10.68 Impact Factor
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ABSTRACT: Conducting polymers (CPs) were first produced in the mid-1970s as a novel generation of organic materials that have both electrical and optical properties similar to those of metals and inorganic semiconductors, but which also exhibit the attractive properties associated with conventional polymers, such as ease of synthesis and flexibility in processing. The fact that several tissues are responsive to electrical fields and stimuli has made CPs attractive for a number of biological and medical applications. This review provides information on desirable CP properties specific to biomedical applications and how CPs have been optimized to generate these properties. The manuscript first introduces different types of CPs, their unique properties and their synthesis. Then specific information is provided on their modification for use in applications such as biosensors, tissue engineering, and neural probes. Although there remain many unanswered questions, particularly regarding the mechanisms by which electrical conduction through CPs affects cells, there is already compelling evidence to demonstrate the significant impact that CPs are starting to make in the biomedical field.Progress in Polymer Science. 01/2007;
Article: Nanostructures in biodiagnostics.Chemical Reviews 05/2005; 105(4):1547-62. · 41.30 Impact Factor