Smartphone-based portable biosensing system using impedance measurement with printed electrodes for 2，4，6-trinitrotoluene (TNT) detection.

Rapid， sensitive， selective and portable detection of 2，4，6-trinitrotoluene (TNT) is in high demand for public safety and environmental monitoring. In this study， we reported a smartphone-based system using impedance monitoring for TNT detection. The screen-printed electrodes modified with TNT-specific peptides were used as disposable a biosensor to produce impedance responses to TNT. The responses could be monitored by a hand-held device and send out to smartphone through Bluetooth. Then， the smartphone was used to display TNT responses in real time and report concentration finally. In the measurement， the system was demonstrated to detect TNT at concentration as low as 10(-6) M and distinguish TNT versus different chemicals in high specificity. Thus， the smartphone-based biosensing platform provided a convenient and efficient approach to design portable instruments for chemical detections such as TNT recognition.