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

0039-9140

We report a microfluidic electrochemical immunosensor forXanthomonas arboricola (XA) determination, based on the covalentlyimmobilization of monoclonal anti-XA antibody (anti-XA) on a previouslyamino functionalized SBA-15 in situ synthesized in the central channel ofa glass-poly(dimethylsiloxane) microfluidic immunosensor. The synthetizedamino-SBA-15 was characterized by N2 adsorption-desorption isotherm,scanning electron microscopy and infrared spectroscopy. XA was detectedby a direct sandwich immunoassay through an alkaline phosphatase (AP)enzyme-labeled anti-XA conjugate. Later, the substrate p-aminophenylphosphate was converted to p-aminophenol by AP. The enzymatic product wasdetected at +100 mV on a sputtered gold electrode. The measured currentwas directly proportional to the level of XA in walnut trees samples. Thelinear range was from 5 x 102 to 1 x 104 CFU mL-1. The detection limitwas 1.5 x 102 CFU mL-1, and the within- and between-assay coefficients ofvariation were below 5 %. Microfluidic immunosensor is a very promisingtool for the early and in situ diagnosis of XA in walnuts avoidingserious economic losses