evelopment of a nanostructured immunosensor for early and in situ detection of Xanthomonas arboricola in agricultural food production

MARTIN RINALDI; JHONNY VILLARROEL-ROCHA; J. RABA; DANIEL M.G. REGIART; BERTOLINO, FRANCO A; GERMÁN A. MESSINA; PEDRO ARANDA; KARIM SAPAG; MARTÍN A. FERNÁNDEZ BALDO

TALANTA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 175 p. 535 - 541

0039-9140

We report a microfluidic electrochemical immunosensor for Xanthomonas arboricola (XA) determination,based on the covalently immobilization of monoclonal anti-XA antibody (anti-XA) on a previously aminofunctionalized SBA-15 in situ synthesized in the central channel of a glass-poly(dimethylsiloxane) microfluidicimmunosensor. The synthetized amino-SBA-15 was characterized by N2 adsorption-desorption isotherm,scanning electron microscopy and infrared spectroscopy. XA was detected by a direct sandwich immunoassaythrough an alkaline phosphatase (AP) enzyme-labeled anti-XA conjugate. Later, the substrate p-aminophenylphosphate was converted to p-aminophenol by AP. The enzymatic product was detected at +100 mV on asputtered gold electrode. The measured current was directly proportional to the level of XA in walnut treessamples. The linear range was from 5 × 102 to 1 × 104 CFU mL−1. The detection limit was 1.5 × 102 CFU mL−1,and the within- and between-assay coefficients of variation were below 5%. Microfluidic immunosensor is a verypromising tool for the early and in situ diagnosis of XA in walnuts avoiding serious economic losses.