A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells

TL;DR

This paper presents a microfluidic biophotovoltaic device using cyanobacterial cells that achieves high power density without mediators, leveraging miniaturized geometry and a novel fabrication approach.

Contribution

Developed a membrane-free, mediator-free microfluidic biophotovoltaic platform with high power density using a soft-lithography fabrication method.

Findings

Power densities above 100 mW/m2 under white light.

Mediator-free operation enabled by cell-electrode proximity.

Microfluidic design enhances power output.

Abstract

Biophotovoltaics has emerged as a promising technology for generating renewable energy since it relies on living organisms as inexpensive, self-repairing and readily available catalysts to produce electricity from an abundant resource - sunlight. The efficiency of biophotovoltaic cells, however, has remained significantly lower than that achievable through synthetic materials. Here, we devise a platform to harness the large power densities afforded by miniaturised geometries. To this effect, we have developed a soft-lithography approach for the fabrication of microfluidic biophotovoltaic devices that do not require membranes or mediators. Synechocystis sp. PCC 6803 cells were injected and allowed to settle on the anode, permitting the physical proximity between cells and electrode required for mediator-free operation. We demonstrate power densities of above 100 mW/m2 for a chlorophyll concentration of 100 {\mu}M under white light, a high value for biophotovoltaic devices without extrinsic supply of additional energy.