Handheld Aptasensor for Sandwiched Detection of Chloramphenicol

Abstract

Chloramphenicol(CAP) is an antifungal agent approved for use in aquarium. However, CAP residue imparts serious adverse effect on human health as well as the ecology. Thus, keeping track of CAP in aquatic products and its environmental metabolites are of great importance. Herein, we developed a novel and neat electrochemical aptasensor for the detection of simulated CAP residual in a sandwich fashion. The screen-printed carbon electrode was employed as the sensing platform and electrodeposited with peculiar nanogolds to enhance the electrochemical performance. For the specific recognition of such small target, a pair of chloramphenicol-binding aptamers, the primary Apt1 and the secondary Apt2, were tailored as an artificial single-chained antibody couple, of which the thiolated Apt1 stood on the coated working substrate to capture the analyte, while the biotinylated Apt2 rallied the signal output. In the presence of CAP, Apt1 at the lower place cooperated with the upper Apt2 pinched CAP together. After that, the reporter avidin-conjugated horseradish peroxidase associated atop the mounted biotin labels, resulting in an electrocatalytic amplification. In whole, this modular biosensing construction would set a paradigm not just for practicable checkpoint quarantine or point-of-care testing, but potentially adaptable for technological fusion with “Internet Plus” and “Internet of Things”.