Development of Quantum Dot-based Nanobiosensors against Citrus Tristeza Virus (CTV)

• Main Authors: Mohammad Reza SAFARNEJAD, Fatemeh SAMIEE, Meisam TABATABIE, Afshin MOHSENIFAR
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2017-06-01
• Series: Sensors & Transducers
• Subjects: Biosensor; Citrus Tristeza; FRET; Quantum dot
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/june_2017/Vol_213/P_RP_0227.pdf
• ISSN: 2306-8515; 1726-5479

Citrus tristeza is one of the most important diseases of citrus in the world. To avoid the destructive effect of the disease, early detection of infected plants is crucial. Therefore, simple and sensitive diagnosis tools are decisive. The main objective of the present study was developing nanobiosensors for detection of citrus tristeza based on the florescence emission of cadmium telluride quantum dots (CdTe-QDs). To achieve that, CdTe-QD particles were initially synthesized and effectively conjugated to CTV coat protein (CTV-CP) corresponding antibody. In a parallel reaction, rhodamine dye molecules were attached to the purified recombinant CTV-CP. Two independent approaches were explored for detection of the infected plants. First, in a fluorescence resonance energy transfer (FRET) based assay, the quenching ability of rhodamine molecules was applied for altering the QDs light emission. More specifically, donor- acceptor complexes (Ab-QD+CP-Rd) were created based on the affinity of antibody- antigen molecules. The resulting assembly brought Ab-QD (the donor) and the Rd-CP (the acceptor) into a close proximity and resulted in a substantial decrease in the intensity of QD light emission. Addition of free antigen into the solution resulted in the replacement of CP-Rd with free CP and a subsequent increase in the emission of QDs. In the second approach, a non-FRET based assay was performed through the addition of free antigen to the Ab-QD solution, which led to the aggregation of the Ab-QD conjugates and consequently a significant increase in the light intensity emission of the QD. To the best of our knowledge, this is the first time that the non-FRET based assay developed herein is being reported.