A low-cost smartphone-based electrochemical biosensor for point-of-care diagnostics

This paper describes the development of a smartphone-based electrochemical biosensor module. The module contains a low power potentiostat that interfaces and harvests power from a smartphone through the phone´s audio jack. A prototype with two different potentiostat designs was constructed and used to conduct proof of concept cyclic voltammetry experiments with potassium ferro-/ferricyanide (K₄[Fe(CN)₆] / K₃[Fe(CN)₆]) in a side-by-side comparison with a laboratory grade instrument. Results show that the module functions within the available power budget and that the recovered voltammogram data matches well with the data from an expensive bench top tool. Excluding the loses from supply rectification and regulation, the module consumes either 5.7 mW or 4.3 mW peak power, depending on which of the two discussed potentiostat designs is used. At single quantity pricing, the hardware for the prototype device costs less than $30.