Immuno-battery: A single use self-powered immunosensor for REASSURED diagnostics

In this work, we present a novel self-powered approach totally independent from any external energy source. We have developed a self-powered paper-based immunosensor that generates energy in the presence of the biomarker in the sample. In particular, the device - which has been labeled as Immuno-Battery - makes use of magnesium as anode and the widely employed HRP-labeled antibody as cathodic catalyst to detect C-reactive protein (CRP) presence in artificial samples. Feasibility of self-powered sensing is proved by submitting the immuno-battery to a resistive load. In this regime, the sensor provides operation voltages above 1.55 V and maximum power densities from 40 to 571 mu W cm-2 that allow for future implementation of an electronic readout circuit. We have demonstrated that sensitivity of the system is not compromised by the self-powered mode operation, as the LOD value delivered by our battery (20 +/- 2 ng mL-1) is compliant with LOD values reported for protein detection in paper-based electrochemical immunoassays with chronoamperometric methods. Moreover, as a case study, a LOD of 269 +/- 39 ng mL-1 is obtained for CRP detection, in accordance with available com-mercial high-sensitivity CRP detection kits. This proof-of-concept opens the path towards the development of digital diagnostic devices in a sustainable and affordable manner.

Automated summary

In this study, a novel self-powered approach for a paper-based immunosensor was developed to generate energy from the biomarker in the sample. The feasibility of self-powered sensing was demonstrated, showing that the system's sensitivity was not compromised and allowing for future implementation of an electronic readout circuit. This proof-of-concept paves the way for the development of sustainable and affordable digital diagnostic devices.