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

MATÍAS REGIART; MARTÍN RINALDI TOSI; PEDRO R. ARANDA; FRANCO A. BERTOLINO; JHONNY VILLARROEL-ROCHA; KARIM SAPAG; GERMÁN A. MESSINA; JULIO RABA; 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 amino functionalized SBA-15 in situ synthesized in the central channel of a glass-poly(dimethylsiloxane) microfluidic immunosensor. 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 immunoassay through an alkaline phosphatase (AP) enzyme-labeled anti-XA conjugate. Later, the substrate p-aminophenyl phosphate was converted to p-aminophenol by AP. The enzymatic product was detected at +100 mV on a sputtered gold electrode. The measured current was directly proportional to the level of XA in walnut trees samples. The linear range was from 5 x 102 to 1 x 104 CFU mL-1. The detection limit was 1.5 x 102 CFU mL-1, and the within- and between-assay coefficients of variation were below 5 %. Microfluidic immunosensor is a very promising tool for the early and in situ diagnosis of XA in walnuts avoiding serious economic losses.