Enhancing Extracellular Electron Transfer of Geobacter sulfurreducens in Bioelectrochemical Systems Using N-Doped Fe₃O₄@Carbon Dots

Abstract

A nanomaterial−living cell biohybrid system is an efficient energy conversion method due to enhanced interactions between inorganic materials and bacteria. However, inefficient electron transfer at the interface of the biohybrid remains as a limiting factor. Herein, an inorganic−biologic hybrid was proposed by combining a typical electroactive bacterium, Geobacter sulfurreducens, and a highly conductive N-doped Fe 3 O 4 with a carbon dot shell (Fe 3 O 4 @CD) to boost energy conversion in bioelectrochemical systems (including microbial electrolytic cells and electro-methanogenesis). One-potsynthesized Fe 3 O 4 @CDs enhanced extracellular electron transfer in the biohybrid system by forming an interaction network with conductive proteins inside and outside G. sulfurreducens. In the microbial electrolytic cell, the maximum current of Fe 3 O 4 @CDs-fed cells was 6.37 times higher than that of the control group without nanoparticle addition. This enhanced performance was accompanied with higher bioactivity, higher cellular adhesion, and lower biofilm resistance. The G. sulfurreducens−Fe 3 O 4 @CDs biohybrids supplemented during electro-methanogenesis remained stable on anodes, which promoted microbial syntrophy. The metabolic methanogenesis pathways are strongly related to the electron transfer ability of G. sulfurreducens, which demonstrates a new strategy to promote extracellular electron transfer through the constructed biohybrid system.

Microbial electrosynthesis: carbonaceous electrode materials for CO2 conversion

“…90 This cathode demonstrated more efficacy, and the superior functionality was accompanied by increased bioactivity, cellular adherence, and moderate biofilm resistance. 90 CDs promote the improved metabolism of S. oneidensis MR-1 due to the increase in intracellular electron generation, ATP level, active extracellular secretions, transmembrane, and EET. 89…”

“…The zeta potential of the CDs was observed to be substantially connected with the effectiveness of bioelectricity generation. Recently, an inorganic-biologic hybrid was investigated to improve energy conversion in MES by merging a typical electroactive bacterium, Geobacter sulfurreducens, and a highly conductive N-doped Fe3O4 with a CDs shell 90 . This cathode demonstrated more efficacy, and the superior functionality was accompanied by increased bioactivity, cellular adherence, and moderate biofilm resistance 90 .…”

“…Recently, an inorganic-biologic hybrid was investigated to improve energy conversion in MES by merging a typical electroactive bacterium, Geobacter sulfurreducens, and a highly conductive N-doped Fe3O4 with a CDs shell 90 . This cathode demonstrated more efficacy, and the superior functionality was accompanied by increased bioactivity, cellular adherence, and moderate biofilm resistance 90 . CDs promote the improved metabolism of S. oneidensis MR-1 due to the increase in intracellular electron generation, ATP level, active extracellular secretions, transmembrane and EET 89 .…”

A universal strategy for green and in situ synthesis of carbon dot-based pickling solution

“…Meanwhile, the peak at 1712 cm −1 attributed to CvO stretching vibrations was observed, 40,41 indicating that there are various oxygen-containing functional groups on the surfaces of all the CDs. In addition, an obvious absorption peak at 1580 cm −1 is caused by aromatic CvC skeletal vibration, 42,43 demonstrating that in the acid oxidation process, saccharides are dehydrated to form CvC serving as the elementary unit of CDs. 32 This finding corresponds to the results drawn from TEM and Raman spectroscopy.…”

Naproxen release from carbon dot coated magnetite nanohybrid as versatile theranostics for HeLa cancer cells

“…Nevertheless, most of the hybrid materials are reported without any details on how they carry drugs to the target site, and are prepared via complicated processes along with the costly design. Some studies have reported the combination of CDs and Fe 3 O 4 nanohybrids, which exhibit superior and multi-functional features on detecting particular compounds such as doxycycline, 45 Geobacter sulfurreducens , 46 bacteria, 47 and metals. 47,48 However, integrative studies on the evaluation of naproxen release from the nanohybrid and its potential delivery have not been reported yet.…”