Paper-based antibiotic sensor (PAS) relying on colorimetric indirect competitive enzyme-linked immunosorbent assay for quantitative tetracycline and chloramphenicol detection

Antibiotics such as tetracycline (TET) and chloramphenicol (CAP) are widely used, but their abuse leads to antibiotic residue which is harmful to human health. To obtain sensitive and accurate TET and CAP detections, we design the paper-based antibiotic sensor (PAS) relying on the colorimetric indirect competitive ELISA. PAS can be simply fabricated only via wax printing and surface modification, making the cost of single detection rather cheap as ∼0.15 US dollar; and additionally, it can be fabricated and conserved in good stability. Moreover, the PAS supporting smartphone application with the functions of image recording, correction and analysis is also designed for quantitative antibiotic detections. Using a series of standard solutions, it is proved that the PAS could reach the extremely low limits of detection as 0.5 ng/mL and 0.05 ng/mL as well as the wide effective linear detecting ranges as 1∼103 ng/mL and 0.1∼100 ng/mL in the TET and CAP detections, respectively. Moreover, using milk and fish samples, it was also verified that the PAS could quantify the TET and CAP concentrations accurately even in the practical applications.