A supersensitive silver nanoprobe based aptasensor for low cost detection of malathion residues in water and food samples

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 196; pp. 268 - 273
• Main Authors: Bala, Rajni, Mittal, Sherry, Sharma, Rohit K., Wangoo, Nishima
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05.05.2018
• Subjects: Aptamer; Nanoprobes; Organophosphorus insecticide; Peptide; Silver nanoparticles; Organophosphorus insecticide; Aptamer; Nanoprobes; Peptide; Silver nanoparticles
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2018.02.007

In the present study, we report a highly sensitive, rapid and low cost colorimetric monitoring of malathion (an organophosphate insecticide) employing a basic hexapeptide, malathion specific aptamer (oligonucleotide) and silver nanoparticles (AgNPs) as a nanoprobe. AgNPs are made to interact with the aptamer and peptide to give different optical responses depending upon the presence or absence of malathion. The nanoparticles remain yellow in color in the absence of malathion owing to the binding of aptamer with peptide which otherwise tends to aggregate the particles because of charge based interactions. In the presence of malathion, the agglomeration of the particles occurs which turns the solution orange. Furthermore, the developed aptasensor was successfully applied to detect malathion in various water samples and apple. The detection offered high recoveries in the range of 89–120% with the relative standard deviation within 2.98–4.78%. The proposed methodology exhibited excellent selectivity and a very low limit of detection i.e. 0.5pM was achieved. The developed facile, rapid and low cost silver nanoprobe based on aptamer and peptide proved to be potentially applicable for highly selective and sensitive colorimetric sensing of trace levels of malathion in complex environmental samples. [Display omitted] •A super-sensitive, rapid and low cost nanoprobe validated for malathion employing peptide, oligonucleotide based silver nanoparticles.•In the presence of malathion, the oligonucleotide binds to malathion rendering peptide free resulting agglomeration of the particles.•In absence of malathion, oligonucleotide interacts with peptide and thus, lack of free peptide keeps the particles well dispersed.•Developed aptasensor successfully applied to detect malathion in various spiked water and apple samples.•The proposed methodology exhibited excellent selectivity and a very low limit of detection i.e. 0.5 pM.