A USB-based electrochemical biosensor prototype for point-of-care diagnosis

A portable, USB-based electrochemical biosensor prototype for point-of-care testing (POCT) was designed, fabricated, and tested with a model analyte. The device implements cyclic voltammetry (CV) measurements by means of a portable potentiostat in conjunction with a miniaturized electrochemical cell. The microelectronic circuit consists of a single-supply potentiostat and I/V converter, an analog-to-digital converter (ADC), and a microcontroller unit (MCU); powered and controlled entirely by USB the device is suitable for field testing alongside any portable personal computer (PC). The electrochemical cell contains sixteen test chambers encompassing disposable gold working electrodes fabricated on standard glass slides. The gold working electrodes were patterned using photolithographic techniques while platinum and silver–silver chloride wires served as the counter and reference electrodes, respectively. System performance was evaluated by performing lysozyme detection using surface-bound anti-lysozyme DNA aptamers; the results are comparable to those obtained using a commercial electrochemical system.