Highly sensitive detection of salbutamol by ALP-mediated plasmonic ELISA based on controlled growth of AgNPs

Abstract

Salbutamol (SAL), a short-acting β-2 adrenergic receptor agonist, is an undesirable addition to livestock farming and used to improve the growth rates. A direct competitive colorimetric immunoassay for SAL was developed. The alkaline phosphatase (ALP)-mediated controlled growth of the prereduction silver nanoparticles (AgNPs) was used to achieve the highly sensitive, colorimetric detection of SAL through the plasmonic ELISA. Click chemistry reaction was used to synthesize salbutamol biotin label (SAL-Bio) to achieve signal amplification and specific binding with antibody. ALP can efficiently hydrolyze sodium L-ascorbyl-2-phosphate and generate L-ascorbic acid, thereby reducing Ag+ and forming AgNPs. The plasmon resonance absorption signals of AgNPs were enhanced along with a distinct color change. The limit of detection of SAL can be decreased to 26.14 pg/mL. The method offers a good technique for the detection of many small molecular contaminants, such as pesticide residues and veterinary drug residues in food and edible water.