Quantitative ciprofloxacin on-site rapid detections using quantum dot microsphere based immunochromatographic test strips.

The ciprofloxacin (CIP) abuse has caused many problems threatening to human health. Here, we design the quantum dot microsphere (QDM) based immunochromatographic quantitative CIP test strip: when the sample under detection contains CIP, the QDM-monoclonal antibody (mAb) probes bound with the CIP and cannot be captured by CIP-bovine serum albumin (BSA) conjugation dispersed on the T lines, reducing the fluorescence intensities. These test strips can provide a low detection limit of 0.05 ng/mL and a wide linear detection range from 0.1 ng/mL to 100 ng/mL in high sensitivity and accuracy as well as good selectivity, reproducibility and stability. Moreover, a smartphone based test strip reader with the size of 85 mm × 48 mm × 44 mm is also fabricated using 3-D printing to automatically and quantitatively detect CIP. The whole process of CIP detection can be finished within 15 min, but only cost ~1 RMB (10 cents).