Team:UC Davis/Potentiostat Design

Our biosensor required a potentiostat. A potentiostat is an instrument capable of maintaining a voltage bias between electrodes.

The bias encourages diffusion but more importantly the transfer of electrons which are recorded, and ultimately related to the species present in solution. We were faced with the decision to buy or build.

Unfortunately, there weren't any entry-level potentiostats that met our requirements, and commcercial potentiostats are in the thousands of dollars. We needed a cheaper solution if we wanted our device to be consumer friendly. We researched the literature for potentiostat circuits and were presented with the CheapStat.

The CheapStat is a budget friendly device developed at UC Santa Barbara several years ago. We aspired to build this circuit and modify the software for our purposes, however, the microcontroller on the CheapStat was controlled predominantly in machine level code. The learning curve seemed unreasonable considering our deadline, so we had to find another solution.

We were ultimately forced to build our own. With a clean slate, we wanted to create a device that would fulfill our needs, but also be welcomed by the iGEM community. We aimed to match the performance of the CheapStat, but also improve in three ways: increase the effective range of the instrument, decrease the cost of the circuit, and convert to an arduino-friendly microcontroller. In this capacity, we have succeeded.

We modeled our circuit after the CheapStat, eventually including more than 30 components. We went on to create five iterative prototypes. The schematic and board files for the various prototypes are all available here. To read more about our inspiration and circuit design, click here.