RNA-cleaving deoxyribozyme-linked immunosorbent assay for the ultrasensitive detection of chloramphenicol in milk

•Horseradish peroxidase was substituted by the artificial DNAzyme in ELISA (DLISA).•Ultrasensitive detection demonstrated the feasibility and efficiency of this DLISA.•Antibody and DNA could be quickly and easily functionalized on AuNPs as the probes. In this presented work, an artificial deoxyribozyme was employed as the substitute for horseradish peroxidase (or alkaline phosphatase) in ELISA for generating amplified signals. The feasibility of the proposed deoxyribozyme-based ELISA (DLISA) was demonstrated in the detection of a forbidden veterinary drug, chloramphenicol. And its efficiency was praised since that ultrahigh sensitivity was accomplished with a detection limit of 0.1 ng/L. The wide linear range from 0.000001 μg/mL to 1.0 μg/mL, as well as good recoveries from 86 % to 104 % in whole milk samples showed its excellent practical performances. Besides, the DLISA was worth popularizing due to the easy connection of antibody and DNAzyme through a facile functionalization process of gold nanoparticles. These advantages showed the possibility of DLISA for developing commercial kits, and the utilization of flexible DNA fluorescent probes in DLISA would inspire more work on innovations.