摘要

The authors describe an electrochemiluminescence (ECL) based aptasensor for the pesticide aldicarb. The method is based on effective ECL energy transfer that occurs between the ruthenium(II) bipyridyl complex [referred to as Ru(bpy)(3) (2+)] and gold nanoparticles (AuNPs). More specifically, multiwalled carbon nanotubes were modified with dendritic poly(L-arginine) labeled with Ru(bpy)(3) (2+), and the aptamers were taggedd with AuNPs. In the absence of aldicarb, the ECL emitted by Ru(bpy)(3) (2+) is enhanced by AuNPs under peak wavelength at at a wavelength of 610 nm. In the presence of aldicarb, the capture and competitive binding of aldicarb to the DNA aptamers causes their separation from the DPA6/Ru(bpy)(3) (2+)/MWCNT. As a result, ECL intensity decreases linearly with increasing aldicarb concentrations in the range between 40 pM and 4 nM, with a detection limit of 9.6 pM. This aptamer switch is highly sensitive, selective and inexpensive. Conceivably, it can be adapted to formats for the determination of other pesticide residues by using different DNA aptamers.