A comparative evaluation of microarray slides as substrates for the development of protease assay biosensors

The application of commercially available microarray slides as substrates for fluorogenic protease assays has been explored in terms of binding efficiency, stability, and activity. A fluorescent, biotinylated substrate for botulinum neurotoxin A (BoNTA) was attached via self-assembled monolayer of Streptavidin to amine-reactive aldehyde, epoxy, hydrogel, and polymer slides. Nexterion Slide P® was found to have optimal protein binding efficiency and stability of the slides examined. Addition of glycerol to the printing buffer improved spot morphology significantly and polyvinylpyrrolidone provided long-term stability, allowing chips to be stored for up to 1 month with good viability. Detection of a recombinant BoNTA light chain was then carried out at 37°C and a sub-lethal dose was detected in 2 hours.