Inward-to-outward assembly of amine-functionalized carbon dots and polydopamine to Shewanella oneidensis MR-1 for high-efficiency, microbial-photoreduction of Cr(VI)

Feasibility of nanomaterials to support electroactive microbes in nanobiohybrids

“…Recent studies demonstrated that direct contact with Fe 3 O 4 NPs led to the formation of augmented the EPS in biofilms, thereby propagating long-distance electron transfer across larger scales (Wang et al, 2018). Likewise, our group previously reported a higher production (increased by 0.7 times versus wild strain) of flavins in nanobiohybrids comprised of S. oneidensis MR-1, NH 2 -doped CDs carbon dots, and polydopamine (Li et al, 2022). The increased flavin production enhanced shuttling of inwardto-outward delivery of electrons in the nanobiohybrid.…”

“…For instance, a previous investigation demonstrated that up-regulation of c-Cyts (e.g., OmcJ, PgcA, and OmcK) and pili-relating PilA in G. sulfurreducens was stimulated by direct contact with (semi)conductive NMs (Fe 3 O 4 , Fe 2 O 3 and TiO 2 NPs) (Dong et al, 2020a). Similarly, recent studies examining engineered nanobiohybrids confirmed a more than 3-fold up-regulation of c-Cyts in a system of S. oneidensis MR-1 cells that were configured with NH 2doped CDs (Li et al, 2022;Yang et al, 2020). The increased production of c-Cyts with the addition of (semi)conductive NMs manifested a positive response for electron-transporting cellular components to the foreign stimuli of (semi)conductive NMs.…”

“…This is accomplished by introducing engineered conductive NMs (such as Pd, Au, and CNTs, as well as conductive oligomers such as DSSN+) into a wild EAB cell through conductive NMs-intercalation (Zhang et al, 2018). Owing to these conductive NM-anchors, an efficient pathway for electron transport is thereafter established across the periplasmic space that was originally nonconductive due to the lack of essential conductive c-Cyts (Apetrei et al, 2019;Li et al, 2022;Sun et al, 2010;Wu et al, 2011). The intercalation techniques consist of microbial mineralization and intracellular internalization for in-situ assembly of conductive NMs at the intracellular periplasmic outer-space membrane junction sites (Chen et al, 2022).…”