Development of novel portable and reusable fiber optical chemiluminescent biosensor and its application for sensitive detection of microcystin-LR

A novel portable fiber optical chemiluminescent biosensor (FOCB) system was successfully constructed using fiber optic bio-probe as biorecognition element as well as transducer and a Si-based photodiode detector (PD-3000). The compact design of FOCB with free magnetic beads and photomultiplier allows it to be portable and suitable for on-site and automatic detection of targets, as well as to be cost-effective and small sample volume (only 40.0 µL). The sensitivity of 5 fW could be obtained for the FOCB due to the high performance of PD-3000 and no background light signal. Next, the FOCB was applied for the CL-based detection of microcystin-LR (MC-LR) in water using hapten-carrier protein conjugates modified fiber optic bio-probe as biorecognition element. Based on indirect competitive sandwich-like CL immunoassay principle, the highly sensitive detection of MC-LR was achieved using FOCB system. Under optimal conditions, the limit of detection for MC-LR is 0.03 µg/L, which is comparable with that of most reported MC-LR immunoassay methods. The robustness of the hapten-carrier protein-modified biosensor surface allowed multiple MC-LR immunoassays without any significant loss of performance, which ensured accurate and cost-effective detection results. The proposed strategy demonstrated good recovery, precision, and accuracy through the evaluation of the spiked water samples. The FOCB system can be readily extended toward the on-site real-time sensitive detection of other targets in the field of environment, food, and medical diagnosis.