A microfluidic sensor of Botulinum neurotoxin type a utilizing SNAP-25 incorporated responsive hydrogel

Clostridium Botulinum neurotoxins (BoNTs) are the most lethal bacterial toxins known to humankind in nature. They present grave bioterrorism concern, especially within food supplies. The current pharmacotoxicological mouse bioassay accepted for detection of BoNT in food is laborious and expensive, lacks specificity, or may cause false alarm. It is highly desired to develop a rapid and sensitive on-site toxin-screening vehicle for the detection of BoNT. We developed a prototype microfluidics-based BoNT sensor based on our newly synthesized photo-patternable hydrogel, which was polymerized with a modified peptide containing crosslinker incorporating the synaptosome-associated protein SNAP-25 peptide specifically responsive to serotype A of BoNT, or BoNT/A. The cleavage caused by BoNT/A provided an easily observable change in the hydrogel patterns. Hydrogel structures were photo-patterned in a microfluidic channel. These hydrogels were compromised and cleaved in 100 mg/ml of trypsin after 4 hours, and in a solution containing the light chain (LC) of BoNT/A (concentration: 45 μg/mL) in 38 hours. In the control experiments, the same hydrogels were intact in Hepes buffer (30mM).