Spin-Dependent Extracellular Respiration

Abstract

Biological energy conversion relies on highly efficient electron transfer. The chirality induced spin selectivity (CISS) effect, which couples electron spin to momentum in chiral molecules, is hypothesized to promote this efficiency. While observed in isolated biomolecules, the physiological relevance of CISS during active cellular metabolism remains unknown. Here, we demonstrate that CISS influences extracellular electron transfer in living Geobacter sulfurreducens biofilms. Cultivation on ferromagnetic electrodes yields a significant asymmetry in respiratory current between opposite substrate spin states. Furthermore, in situ magnetization reversal induces reversible changes in respiratory flux. These results provide the first in vivo demonstration that spin selectivity directly impacts respiration. By revealing a quantum feature of extracellular respiration, our findings offer a strategy to exploit the spin degree of freedom in bioelectronics.