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Microfluidic Nanobiosensor Detection for Botulinum Neurotoxin, Serotypes A and F

Shruthi Srinivasan - Biomedical Engineering Department;
SJSU Khoa Letran - Biomedical Engineering Department, SJSU;
Salim Nasir - Biomedical Engineering Department, SJSU;
Jasmeet Kaur - Biomedical Engineering Department, SJSU;
Imran Meskienyar - Biomedical Engineering Department, SJSU; Cristopher Delgado - Biomedical Engineering Department, SJSU;
Aimee Ramos - Biomedical Engineering Department, SJSU; Jonathan Gomez - Biomedical Engineering Department, SJSU; Ningkun Wang - Department of Chemistry, SJSU;
Kyung Sung - Center for Biologics Evaluation and research;
Johny Lam - Center for Biologics Evaluation and research;
Timothy Duncan - Center for food safety and applied Nutrition, U.S Food and Drug Administration

Dr. Yun Wang

Technical Advisor:

Botulinum neurotoxin (BoNT) is the most potent toxin that can result in muscle paralysis and even death. It is produced by anaerobic spore-forming bacteria that belong to the Clostridium genus. Currently, there are seven identified serotypes of BoNT, serotypes A to G. Serotypes A, B, E, and F can cause human botulism through contaminated foods, wounds, and improper injections for medical/cosmetic reasons. Due to its lethality and ease of dissemination, BoNT has been identified as one of the top bioterrorism agents.

The “gold standard” method of detection is mouse bioassay (MBA). Its main caveats are being time- and labor-consuming and animal cruelty being an issue. Other detection methods such as enzyme-linked immunoassays (ELISA), immunological-PCR assays, and mass-spectrometry (MS)-endopeptidase assays have been developed to supplement the MBA . However, immunoassays cannot provide information on endopeptidase activity which is the key to BoNT toxication, while MS-based assays require expensive instruments and trained personnel.

We developed a novel microfluidic nano-biosensor utilizing luminescent semiconductor nanocrystals, quantum dots (QDs), to detect biologically active BoNT and differentiate BoNT serotypes [5,6]. QDs are tethered to the surface of microfluidic channels through serotype-specific peptides that can be cleaved due to BoNT endopeptidase activity. In the presence of the toxin, the QDs were released from the channels due to the cleavage. The photoluminescence of the QDs was measured to indicate the detection. This biosensor developed offers a low-cost and easy-to-operate rapid method that is capable of detecting biologically active BoNT within an hour.

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