QCM immunoassay for recombinant cysteine peptidase: A potential protein biomarker for diagnosis of citrus canker

Autor(es)

Afonso, Andre S. ^{[1, 2]} ; Zanetti, Bianca F. ^[3] ; Santiago, Adelita C. ^[3] ; Henrique-Silva, Flavio ^[3] ; Mattoso, Luiz H. C. ^[2] ; Faria, Ronaldo C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil

^[2] Embrapa Instrumentacao Agr, BR-13560970 Sao Carlos, SP - Brazil

^[3] Univ Fed Sao Carlos, Dept Genet & Evolucao, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Talanta; v. 104, p. 193-197, JAN 30 2013.
• Citações Web of Science: 10

Resumo

Citrus canker is one of the most important agricultural citrus diseases worldwide. It is caused by Xanthomonas citri subsp. citri (Xcc) bacterium that infects leaves and the fruits produce a cysteine peptidase (CPXaC), which makes it a potential target for the development of effective and rapid detection methods for citrus canker. We report here the studies on the development of piezoelectric immunoassay for CPXaC using a polyclonal antibody against CPXaC (anti-CPXaC). Three different strategies for covalent immobilization of anti-CPXaC on gold surfaces were evaluated by monitoring the frequency (Delta f) and energy dissipation (Delta D) variation in real time when 64.5 x 10(-8) mol L-1 CPXaC was added. Anti-CPXaC immobilized with 11-mercaptoundecanoic acid (MUA) showed the best relation between the frequency and dissipation factor variation, and strong values for the kinetic and equilibrium binding constant were obtained. The immunosensor showed a detection limit of 13.0 nmol L-1 with excellent specificity, showing no response for different proteins that include another cysteine peptidase that is used as a target to detect Xylella fastidiosa bacterium, responsible for another important citrus disease. These results provide good perspectives for the use of CPXaC as a new biomarker for citrus canker. (C) 2012 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 11/02259-6 - Desenvolvimento de biossensores para determinação de biomarcadores proteicos visando à aplicação no diagnóstico precoce e monitoramento de câncer
• Beneficiário: Ronaldo Censi Faria
• Linha de fomento: Bolsas no Exterior - Pesquisa