Interaction and surface binding characteristics of staphylococcal protein A (SpA) and an anti-Escherichia coli immunoglobulin G (IgG) were studied using the Raman spectroscopy. The tyrosine amino acid residues present in the α-helix structure of SpA were found to be involved in interaction with IgG. In bulk interaction condition the native structure of proteins was almost preserved where interaction-related changes were observed in the overall secondary structure (α-helix) of SpA. In the adsorbed state, the protein structure was largely modified, which allowed the identification of tyrosine amino acids involved in SpA and IgG interaction. This study constitutes a direct Raman spectroscopic investigation of SpA and IgG (receptor-antibody) interaction mechanism in the goal of a future biosensor application for detection of pathogenic microorganisms.
A simple electrochemical procedure was used for the synthesis of a polythiophene containingpara-benzenesulfonyl chloride groups. The obtained polymer was shown to be very reactive and directly able to covalently bind nucleophile biomolecules. Protein A and a specific antibody were then successively immobilized on the conductive polymer through a covalent bonding of Protein A with the as-prepared linker for bacteria trapping purpose. All reactions were controlled in situ by cyclic voltammetry, quartz crystal microbalance and Raman spectroscopy. The results were compared to those previously obtained on gold surface modified with the same chemical linker. The conductive polymer led to a very high rate of antibody recognition compared to the gold surface and to literature, probably due to a large available surface obtained after polymerization. One example of pathogenic bacteria “Salmonella enterica paratyphi” detection was successfully tested on the substrates. The presented results are promising for the future design of simple and inexpensive immunocapture-based sensors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.