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Interfacing bacteria as biocatalysts with an electrode provides the basis for emerging bioelectrochemical systems that enable sustainable energy interconversion between electrical and chemical energy. Electron transfer rates at the abiotic‐biotic interface are, however, often limited by poor electrical contacts and the intrinsically insulating cell membranes. Herein, we report the first example of an n‐type redox‐active conjugated oligoelectrolyte, namely COE‐NDI, which spontaneously intercalates into cell membranes and mimics the function of endogenous transmembrane electron transport proteins. The incorporation of COE‐NDI into Shewanella oneidensis MR‐1 cells amplifies current uptake from the electrode by 4‐fold, resulting in the enhanced bio‐electroreduction of fumarate to succinate. Moreover, COE‐NDI can serve as a "protein prosthetic" to rescue current uptake in non‐electrogenic knockout mutants. [ABSTRACT FROM AUTHOR]

Back Cover: An n-Type Conjugated Oligoelectrolyte Mimics Transmembrane Electron Transport Proteins for Enhanced Microbial Electrosynthesis (Angew. Keywords: Biocatalysis; Biohybrid; Conjugated Oligoelectrolyte; Energy Conversion; Microbial Electrosynthesis EN Biocatalysis Biohybrid Conjugated Oligoelectrolyte Energy Conversion Microbial Electrosynthesis 1 1 1 08/10/23 20230814 NES 230814 B Microbial electrosynthesis b is a sustainable strategy for electricity-driven chemical production. Biocatalysis, Biohybrid, Conjugated Oligoelectrolyte, Energy Conversion, Microbial Electrosynthesis. [Extracted from the article]

In their Communication (e202305189), Guillermo C. Bazan et al. designed an n-type redox-active conjugated oligoelectrolyte (COE) that intercalates into cell membranes and mimics the function of endogenous transmembrane electron transport proteins. Biocatalysis, Biohybrid, Conjugated Oligoelectrolyte, Energy Conversion, Microbial Electrosynthesis Keywords: Biocatalysis; Biohybrid; Conjugated Oligoelectrolyte; Energy Conversion; Microbial Electrosynthesis EN Biocatalysis Biohybrid Conjugated Oligoelectrolyte Energy Conversion Microbial Electrosynthesis 1 1 1 08/09/23 20230814 NES 230814 B Microbial electrosynthesis b is a sustainable strategy for electricity-driven chemical production. [Extracted from the article]

A membrane-intercalating conjugated oligoelectrolyte (COE), PTTP, was designed and synthesized with the goal of providing red-shifted absorption spectra relative to previously synthesized COE analogs. Specifically, electron-rich and electron-poor subunits were introduced in the conjugated backbone to modulate the band gap. PTTP exhibits maxima of absorption at 507 nm and of emission at 725 nm. PTTP can also efficiently function to generate singlet oxygen in situ (ΦΔ≈20 %) and has appropriate topology and dimensions to interact with lipid membranes. The resulting rapid membrane insertion and sensitizing ability provide PTTP with a highly efficient antibacterial capability under a low light dose (0.6 J cm−2) toward Gram-negative bacteria E. coli, making it a remarkably efficient optically mediated antimicrobial agent. [ABSTRACT FROM AUTHOR]

Highly sensitive and selective mercury detection in aqueous media is urgently needed because mercury poisoning usually results from exposure to water-soluble forms of mercury by inhalation and/or ingesting. An ionic conjugated oligoelectrolye (M1Q) based on 1,4-bis(styryl)benzene was synthesized as a fluorescent mercury(II) probe. The thioacetal moiety and quaternized ammonium group were incorporated for Hg2+ recognition and water solubility. A neutral Hg2+ probe (M1) was also prepared based on the same molecular backbone, and their sensor characteristics were investigated in a mixture of acetonitrile/water and in water. In the presence of Hg2+, the thioacetal group was converted to aldehyde functionality, and the resulting photoluminescence intensity decreased. In water, M1Q successfully demonstrated highly sensitive detection, showing a binding toward Hg2+ that was ~15 times stronger and a signal on/off ratio twice as high, compared to M1 in acetonitrile/water. The thioacetal deprotection by Hg2+ ions was substantially facilitated in water without an organic cosolvent. The limit of detection was measured to be 7 nM with a detection range of 10-180 nM in 100% aqueous medium. [ABSTRACT FROM AUTHOR]

A conjugated oligoelectrolyte (COE), which spontaneously aligns within cell membranes, was shown to completely inhibit H 2 uptake by Geobacter sulfurreducens in microbial electrolysis cells. Coulombic efficiencies that were 490 ± 95%, due to H 2 recycling between the cathode and microorganisms on the anode, were reduced to 86 ± 2% with COE addition. The use of the COE resulted in a 67-fold increase in H 2 gas recovery, and a 4.4-fold increase in acetate removal. Current generation, H 2 recovery and COD removals by Geobacter metallireducens , which cannot use H 2 , were unaffected by COE addition. These results show that this COE is an effective H 2 uptake inhibitor, and that it can enable improved and sustained H 2 gas recovery in this bioelectrochemical system. [ABSTRACT FROM AUTHOR]

It has been previously reported that the performances of bulk heterojunction polymer solar cells (PSCs) can be improved by incorporation of alcohol/water-soluble conjugated polyelectrolytes as cathode interlayers. Herein, we investigate the effect of three π-conjugated oliogoelectrolytes based on fluorene and carbazole derivatives with quaternary ammonium bromide called 6,6′,6″,6‴,6″″,6″‴-(9 H,9′ H,9″ H-[2,3′:6′,2″-terfluorene]-9,9,9′,9′,9″,9″-hexayl)hexakis( N, N, N-trimethylhexan-1-aminium) bromide ( FFiF), 6,6′,6″,6‴-((9-(6-(trimethylammonio)hexyl)-9 H-carbazole-3,6-diyl)bis(9 H-fluorene-9,9,2-triyl))tetrakis ( N, N, N-trimethylhexan-1-aminium) bromide ( FCiF), and 6,6′,6″,6‴-((9-hexyl-9 H-carbazole-3,6-diyl)bis(9 H-fluorene-9,9,2-triyl))tetrakis( N, N, N-trimethylhexan-1-aminium) bromide ( FCF) as a cathode buffer layer between the active layer and the Al electrode on the photovoltaic properties of conventional type PSCs. The best power conversion efficiency (PCE) of PSCs with the FCF layer is 3.25%, which increases by 24% compared to that of PSCs without any cathode buffer layer (2.62%). The PCE improvement is due to enhancement of the short circuit current, the fill factor, and the open circuit voltage, simultaneously. Interface dipole formation between the active layer and the Al cathode was proposed to explain the improved performances.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of conjugated oligoelectrolytes consisting of fluorene and phenothiazine, 6,6',6″,6‴,6′′′′,6′′′′′-(9H,9′H,9 ′′ H-[2,3′:6′,2′′-terfluorene]-9,9,9′,9′,9′′,9′′-hexayl)hexakis( N,N,N -trimethylhexan-1-aminium)bromide (FFiF),6,6′,6′′,6′′′-((10-(4-(trimethylammonio)butyl)-10H-phenothiazine-3,7-diyl)bis(9H-fluorene-9,9,2-triyl))tetrakis( N,N,N -trimethylhexan-1-aminium)bromide(FPiF) and 6,6',6”,6”'-((10-hexyl-10H-phenothiazine-3,7-diyl)bis(9H-fluorene-9,9,2-triyl))tetrakis( N,N,N -trimethylhexan-1-aminium) bromide (FPF), are utilized as the cathode interfacial layer in conventional-type polymer solar cells based on P3HT and PCBM. Insertion of these interfacial layers between P3HT/PCBM active layer and the metal cathode increases overall power conversion efficiency from 2.76% (reference device) to 2.81%, 3.04%, and 3.37% of devices with FPiF, FFiF, or FPF-coated Al, respectively, primarily due to the reduction of the metal work function through the introduction of conjugated oligoelectrolytes (COEs). This result comes from the difference moiety (i.e., phenothiazine or fluorene) and arrangement of sides chains with quaternary ammonium bromide (QAB) on trimer backbones. The conformation of FFiF is expected to be not exactly in a zigzag arrangement, while the zigzag conformation is expected for the alternated oligomer based on phenothiazine and fluorene (FPiF and FPF). Therefore, the number of accumulated QAB in the side chains of FPiF at the surface of cathode will be smaller than that of FFiF or FPF. The larger amount QAB groups gathering near the cathode layer leads to the bigger in reduction of metal work function. Additionally, FPF coated Al shows the lower work function than that of FFiF coated Al, even though FFiF contains more QAB groups accruing at cathode layer. Thus the device with FPF modified-Al displays the best performances among the devices. [ABSTRACT FROM AUTHOR]

A stilbene-based membrane spanning conjugated oligoelectrolyte 4,4′-bis(4′-N,N-bis(6″-(N,N,N-trimethyl ammonium) hexyl) amino)-styryl) stilbene tetraiodide (DSSN+) has been reported to be able to interact with bacterial cells and enhance their bioelectricity generation in bioelectrochemical devices, although the mechanism remains elusive. The goal of this study was to elucidate the impacts of DSSN+ on extracellular bioactivity and the underlying mechanism. Specifically, extracellular ferrihydrite reduction by Shewanella oneidensis was used to evaluate the influence of cell-DSSN+ interaction. Our results show that DSSN+ enhanced ferrihydrite reduction by S. oneidensis in a growth-dependent manner. The incorporation of DSSN+ into S. oneidensis cell membrane increased the extracellular concentration of redox shuttles, i.e., flavins, and extracellular enzyme activities without significantly decreasing cell viability. The findings suggested that membrane permeabilization is the dominant mechanism for the enhancement of extracellular bioactivity in S. oneidensis by DSSN+. We further demonstrated that the interaction between DSSN+ and S. oneidensis cells enhanced biofilm formation and stability without compromising the overall biofilm activity. Taken together, our results suggest that membrane spanning conjugated oligoelectrolytes, of which DSSN+ is one of many possible molecular structures, may be applied to enhance extracellular bioactivity in bacteria toward more efficient biofilm-based biocatalysis. [ABSTRACT FROM AUTHOR]