HOME-Stat: a handheld potentiostat with open-access mobile-interface and extended measurement ranges

Rapid advances in the development of novel materials coupled with the enhanced understanding of molecular interactions are leading to interesting electrochemical biosensor technologies with potential for commercialization. Reliable handheld potentiostats are the key requirements for transformation of these technologies from laboratories to point-of-care applications. Towards this end, we have developed HOME-Stat which is a handheld, open source, battery powered, smartphone integrated system with extended voltage application and current measurement range. The voltage generator circuit has been upgraded to accommodate a flexible voltage range upto ± 4V with a maximum current measuring capability of ± 5 mA which is a significant improvement compared to the existing wireless potentiostats at a nominal cost of 71 USD. This feature enhances the applicability of the device ranging from interface with a wide category of electrochemical biosensors for PoC testing to laboratory based electrochemical analysis in resource limited educational institutions. User selectable switches have been incorporated in the hardware to select the voltage sweep range and the protocol instead of smartphone based control. This reduces the power consumption of Bluetooth enabled smartphone based control. Presently HOME-Stat is capable of performing routine cyclic voltammetry (CV) and chronoamperometry analysis. It can also estimate the sensitivity of a sensor from CV graphs. Further, the sensitivity information which is displayed in the smartphone can be transmitted with the WiFi facility to the stakeholders. We also suggest design modifications required for incorporating more protocols.