An enzyme-encapsulated nanoliposomes based colorimetric immunosensor for the sensitive detection of clothianidin

Clothianidin are significant toxicity toward non-target organisms, underscoring the necessity for a simple and highly sensitive biosensor for on-site detection. Herein, a pH responsive biotin-tagged horseradish peroxidase (HRP)-encapsulated nanoliposome (HRP@liposome) was synthesized and applied to a colorimetric immunosensor as signal amplification generator. In the presence of clothianidin, it competes with coated antigens for binding to biotinylated antibodies, thereby reducing the number of HRP@liposome due to biotin-streptavidin-biotin interactions. Upon addition of substrate solution, the HRP@liposome are lysed, releasing a substantial amount of HRP, which catalyzes the oxidation of substrate. Under optimal conditions, the colorimetric immunosensor exhibited a 50 % inhibition concentration of 4.75 ng mL −1 , with a limit of detection of 0.24 ng mL −1 , and a linear range of 0.24–66.23 ng mL −1 , respectively. The average recoveries were 86.1 %–103.6 % in spiked environmental and food samples. Compared with conventional enzyme-linked immunosorbent assays, the proposed immunosensor demonstrates higher sensitivity. This research provides a promising reference for rapid assessment in environmental health and food safety.