A biolayer interferometry-based competitive biosensor for rapid and sensitive detection of saxitoxin

Saxitoxin is a marine neurotoxin, which is commonly found as a paralytic shellfish toxin. It is characterized by strong toxicity, rapid effects and wide distribution with significant public health impacts. The ethical issues and technical defects associated with the currently applied surveillance system for paralytic shellfish toxins are encouraging further studies to develop suitable alternatives. Here, we report a label-free and real-time optical biolayer interferometry competitive biosensor for the detection of saxitoxin using aptamers as specific receptors. The biosensor exhibited a broad detection range from 10 to 2000 ng/mL of saxitoxin (linear range from 100 to 800 ng/mL), with a low detection limit of 0.5 ng/mL. Furthermore, the biosensor showed a high degree of selectivity for saxitoxin, and good reproducibility and stability with real samples. We believe that this novel biosensor offers a promising alternative to traditional analytical methods for the sensitive and rapid (7 min) detection of saxitoxin.