An Aptasensor Based on Polymer-Gold Nanoparticle Composite Microspheres for the Detection of Malathion Using Surface-Enhanced Raman Spectroscopy

Abstract We present a new format of apta-sensing composite particles for Surface-Enhanced Raman Spectroscopy (SERS) detection of malathion. These apta-sensing microspheres acquire their extraction capability through aptamer-target analyte interaction and Raman signal enhancement for SERS detection of the pesticide. Micron-sized polymer particles were synthesized by precipitation polymerization using methacrylic acid and ethylene glycol dimethacrylate as co-monomers in acetonitrile. Conjugation with colloidal gold nanoparticles (AuNPs) via modification with 2-aminoethanethiol led to polymer-AuNP composites with controlled aggregation of AuNPs onto the polymer surface. The thiolated aptamer targeting malathion was attached to the metal surface by thiol-gold interaction, resulting in polymer-AuNP-aptamer composite microspheres. The new material was characterized using two techniques: scanning electron microscopy imaging and dynamic light scattering measurements. The polymer-AuNP-aptamer particles were incuba...