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

TALANTA

卷:104

Article

Afonso, Andre S.^1,3  Zanetti, Bianca F.²  Santiago, Adelita C.²  Henrique-Silva, Flavio²  Mattoso, Luiz H. C.³  Faria, Ronaldo C.¹ 

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

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

[3] EMBRAPA Instrumentacao Agr, BR-13560970 Sao Carlos, SP, Brazil

关键词: Biomarker;    Citrus canker;    Citrus disease;    Cysteine peptidase;    Immunosensor;    QCM;   

DOI  :  10.1016/j.talanta.2012.11.003

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

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