Highly Boosted Microbial Extracellular Electron Transfer by Semiconductor Nanowire Array with Suitable Energy Level

Abstract

Microbial extracellular electron transfer (EET) with high performance and good controllability is always desired in various bioelectric applications. Depending on the redox state, C-type cytochromes located across the outer membranes (OMCs) mediate EET with different behaviors. Here, by incorporating Sn-doped In 2 O 3 nanowire array with flat F-doped In 2 O 3 (FTO), a composite electrode is developed that can highly boost EET by over 60 times at a certain potential of 0.2 V, where normally only limited EET current is observed on a conductive electrode. It is proposed that the underlay FTO with bias 0.2 V promotes EET via OMCs by physical contacting with microbes, while the semiconductor nanowires provide a suitable energy level to facilitate the EET via OMC-flavins cofactor, breaking the stereotype of the certain redox state of OMCs at a given potential. As a synergistic effect, EET via both OMCs and flavins is highly boosted simultaneously to achieve the dual-pathway EET, which could be further amplified by the nanostructured topology of the as-prepared electrode. Moreover, the EET current shows a positive correlation with the nanowire length, showing good controllability. This work provides an applicable method for constructing various highly efficient bioelectric devices.

Three-dimensional hierarchical MoO2/MoC@NC-CC free-standing anode applied in microbial fuel cells

“…Moreover, the longer the nanowires grow on the anode, the higher the current can be achieved. 63 Therefore, the improved hydrophilicity and constructed 3D microstructure of the anode can facilitate the attachment of microorganisms on its surface, and set up an efficient electrical biofilm network, thus forming a high-performance bioanode. 59,64 As can be seen from Fig.…”

Nanomaterials Facilitating Microbial Extracellular Electron Transfer at Interfaces

“…[ 59c ] Similarly, other nanowire structure such as In 2 O 3 have also been explored for electrode modification to facilitate EET at bacteria/electrode interface (Figure 2J,K). [ 67 ]…”

“…[ 102 ] Their ability to exchange electrons with inorganics via transmembrane electron conduits couples intracellular metabolism with extracellular redox transformations. Therefore, various inorganic nanomaterials such as Sn‐doped In 2 O 3 nanowire array, [ 67 ] Fe 3 O 4 , [ 102a ] FeS, [ 102b,c ] FeS 2 , [ 103 ] goethite, [ 104 ] antimony‐doped SnO 2 , [ 105 ] and manganese oxides [ 106 ] have been extensively used to accelerate the bacteria EET. For example, incorporating Fe 3 O 4 nanospheres with macroporous graphene foams and multiwalled carbon nanotubes (MWCNTs) resulted in a higher power output and stronger stability.…”

In Situ Synthesis of Photoactive Polymers on a Living Cell Surface via Bio‐Palladium Catalysis for Modulating Biological Functions

“…Cell surface engineering is an important method for regulating cell functions, such as protecting cells against harsh environments, [1] improving biosynthesis efficiency, [2] and endowing cells with more functionalities. [3] Inspired by this promising method, several functional materials such as metal/semiconductor nanoparticles, [4] polymers, [5] and metalorganic complexes [6] have been explored as coating materials on the cellular surface. To date, considerable research has been focused on cell surface modification by functional polymers owing to the increased availability of secondary interactions and derivation from grafted polymers.…”