Label-free biosensor: a novel phage-modified Light Addressable Potentiometric Sensor system for cancer cell monitoring.

Early diagnosis has become the most important factor influencing the cancer's curing efficiency in clinical medicine. Here we present a new way for detection of cancer markers and cancer cells based on phage-modified Light Addressable Potentiometric Sensor (phage-LAPS). Phages were immobilized on the Si(3)N(4) chip surfaces covalently. Using the back-illuminating system, this phage-LAPS is tested to detect human phosphatase of regenerating liver-3 (hPRL-3) in the concentrations of 0.04-400 nM, and the mammary adenocarcinoma cell (MDAMB231) in the concentrations of 0-105 mL. The maximum responding signal is about 10 and 60 microV, respectively. The results demonstrated that the system was more applicable to detection of cancer cell than that of cancer biomarkers. This work might show potential application in clinic assays of cancer and the study of phage-cell interaction.