%0 Journal Article
%T Nonconjugated Polyelectrolyte as Efficient Fluorescence Quencher and Their Applications as Biosensors: Polymer-Polymer Interaction
%A Vidya Raj
%A Sreenivasan Kunnetheeri
%J ISRN Analytical Chemistry
%D 2014
%R 10.1155/2014/841857
%X A simple fluorescence quenching method for the quantitation in serum of an acute phase reactant, C-reactive protein (CRP), which can differentiate between viral and bacterial infections, is described, where material and reagent costs are minimal. The study harnesses a fluorescence quenching between a nonfluorescent polyelectrolyte containing a ligand (O-phosphorylethanolamine, PEA) and fluorophore (fluorescamine isomer 1) containing polyelectrolyte. The quenching was attributed due to strong polymer-polymer interaction through intermolecular hydrogen bonding. The nonlinear behaviour of Stern-Volmer plot indicates a binding induced quenching, that is, static quenching. However, fluorescence was found to increase in presence of C-reactive protein, due to the specific molecular recognition occurring between CRP and PEA, thereby excluding fluorophore containing chain. A definite correlation was found between concentration of CRP and fluorescence intensity and the method exhibited a linear relationship in the range of 40¨C360£¿ng/mL with a detection limit of 30 ¡À 2£¿ng/mL. The antibody free method was successfully applied for the analysis of CRP in human serum samples and the method showed good correlation with hospital measurements . Thus the fluorescence based polyelectrolyte biosensor is a potential system for rapid, and antibody free platform for CRP detection. 1. Introduction Polyelectrolytes based fluorescent sensors have been an area of intense research for the past few decades, due to the interest in area such as controlled drug release, surface coating, and chemical and biological sensing [1¨C5]. Conjugated polyelectrolytes have received particular attention for sensing proteins, due to their water solubility and fluorescence properties [6¨C9]. Conjugated polyelectrolytes contain a set of structural attributes that make them useful in optical and electronic detection of many chemical and biological targets [10]. Fluorescence methods are being used for a variety of investigations in biochemical, medical, and chemical research. Fluorescence based sensors may rely on changes in emission intensity, life time, and wavelength (excitation and emission). However, fluorescence quenching, in which decrease of emission intensity and/or life time is measured, is one of the most common techniques in fluorescence based sensors because of its easy measurement and low detection limit. Herein we report a nonconjugated polyelectrolyte as efficient fluorescent quencher and its application for the quantitation in serum of an acute phase reactant, C-reactive protein (CRP).
%U http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/841857/