Microbial biofilms as living photoconductors due to ultrafast electron transfer in cytochrome OmcS nanowires Jens Neu, Catharine C. Shipps, Matthew J. Guberman-Pfeffer, Cong Shen, Vishok Srikanth, et al. Nature Communications, 2022 Light-induced microbial electron transfer has potential for efficient production of value-added chemicals, biofuels and biodegradable materials owing to diversified metabolic pathways. However, most microbes lack photoactive proteins and require synthetic photosensitizers that suffer from photocorrosion, photodegradation, cytotoxicity, and generation of photoexcited radicals that are harmful to cells, thus severely limiting the catalytic performance. Therefore, there is a pressing need for biocompatible photoconductive materials for efficient electronic interface between microbes and electrodes. Here we show that living biofilms of Geobacter sulfurreducens use nanowires of cytochrome OmcS as intrinsic photoconductors. Photoconductive atomic force microscopy shows up to 100-fold increase in photocurrent in purified individual nanowires. Photocurrents respond rapidly (<100 ms) to the excitation and persist reversibly for hours. Femtosecond transient absorption spectroscopy and quantum dynamics simulations reveal ultrafast (~200 fs) electron transfer between nanowire hemes upon photoexcitation, enhancing carrier density and mobility. Our work reveals a new class of natural photoconductors for whole-cell catalysis.
Protein nanowires with tunable functionality and programmable self-assembly using sequence-controlled synthesis Daniel Mark Shapiro, Gunasheil Mandava, Sibel Ebru Yalcin, Pol Arranz-Gibert, Peter J. Dahl, et al. Nature Communications, 2022 Advances in synthetic biology permit the genetic encoding of synthetic chemistries at monomeric precision, enabling the synthesis of programmable proteins with tunable properties. Bacterial pili serve as an attractive biomaterial for the development of engineered protein materials due to their ability to self-assemble into mechanically robust filaments. However, most biomaterials lack electronic functionality and atomic structures of putative conductive proteins are not known. Here, we engineer high electronic conductivity in pili produced by a genomically-recoded E. coli strain. Incorporation of tryptophan into pili increased conductivity of individual filaments >80-fold. Computationally-guided ordering of the pili into nanostructures increased conductivity 5-fold compared to unordered pili networks. Site-specific conjugation of pili with gold nanoparticles, facilitated by incorporating the nonstandard amino acid propargyloxy-phenylalanine, increased filament conductivity ~170-fold. This work demonstrates the sequence-defined production of highly-conductive protein nanowires and hybrid organic-inorganic biomaterials with genetically-programmable electronic functionalities not accessible in nature or through chemical-based synthesis.
A 300-fold conductivity increase in microbial cytochrome nanowires due to temperature-induced restructuring of hydrogen bonding networks Peter J. Dahl, Sophia M. Yi, Yangqi Gu, Atanu Acharya, Catharine Shipps, et al. Science Advances, 2022 Although proteins are considered as nonconductors that transfer electrons only up to 1 to 2 nanometers via tunneling,Geobacter sulfurreducenstransports respiratory electrons over micrometers, to insoluble acceptors or syntrophic partner cells, via nanowires composed of polymerized cytochrome OmcS. However, the mechanism enabling this long-range conduction is unclear. Here, we demonstrate that individual nanowires exhibit theoretically predicted hopping conductance, at rate (>1010s−1) comparable to synthetic molecular wires, with negligible carrier loss over micrometers. Unexpectedly, nanowires show a 300-fold increase in their intrinsic conductance upon cooling, which vanishes upon deuteration. Computations show that cooling causes a massive rearrangement of hydrogen bonding networks in nanowires. Cooling makes hemes more planar, as revealed by Raman spectroscopy and simulations, and lowers their reduction potential. We find that the protein surrounding the hemes acts as a temperature-sensitive switch that controls charge transport by sensing environmental perturbations. Rational engineering of heme environments could enable systematic tuning of extracellular respiration.
Roadmap on emerging concepts in the physical biology of bacterial biofilms: From surface sensing to community formation Gerard C L Wong, Jyot D Antani, Pushkar P Lele, Jing Chen, Beiyan Nan, et al. Physical Biology, 2021 Bacterial biofilms are communities of bacteria that exist as aggregates that can adhere to surfaces or be free-standing. This complex, social mode of cellular organization is fundamental to the physiology of microbes and often exhibits surprising behavior. Bacterial biofilms are more than the sum of their parts: single-cell behavior has a complex relation to collective community behavior, in a manner perhaps cognate to the complex relation between atomic physics and condensed matter physics. Biofilm microbiology is a relatively young field by biology standards, but it has already attracted intense attention from physicists. Sometimes, this attention takes the form of seeing biofilms as inspiration for new physics. In this roadmap, we highlight the work of those who have taken the opposite strategy: we highlight the work of physicists and physical scientists who use physics to engage fundamental concepts in bacterial biofilm microbiology, including adhesion, sensing, motility, signaling, memory, energy flow, community formation and cooperativity. These contributions are juxtaposed with microbiologists who have made recent important discoveries on bacterial biofilms using state-of-the-art physical methods. The contributions to this roadmap exemplify how well physics and biology can be combined to achieve a new synthesis, rather than just a division of labor.
Ultrafast surface plasmon pulses and their limitations using prism coupling excitation Optics Infobase Conference Papers, 2008
Ultrafast surface plasmon pulses and their limitations using prism coupling excitation Optics Infobase Conference Papers, 2008
RECENT SCHOLAR PUBLICATIONS
Systems and methods for forming biological nanowires and applications thereof N MALVANKAR, SE Yalcin US Patent 12,612,434 , 2026 2026 Citations: 6
Compositions and methods for making and using protein nanowires with tunable functionality F Isaacs, N MALVANKAR, DM Shapiro, SE Yalcin, G Mandava US Patent App. 18/833,335 , 2025 2025
A widespread and ancient bacterial machinery assembles cytochrome OmcS nanowires essential for extracellular electron transfer C Shen, AI Salazar-Morales, W Jung, J Erwin, Y Gu, A Coelho, K Gupta, ... Cell chemical biology 32 (2), 239-254. e7 , 2025 2025 Citations: 10
A widespread porin-cytochrome complex Om (abc) B kickstarts microbial respiration and nanowire formation J Erwin, C Shen, V Saldivar, AS Morales, V Pentalic, F Samatey, P Dahl, ... 2024 Citations: 1
Microbial biofilms as living photoconductors due to ultrafast electron transfer in cytochrome OmcS nanowires J Neu, CC Shipps, MJ Guberman-Pfeffer, C Shen, V Srikanth, JA Spies, ... Nature Communications 13 (1), 5150 , 2022 2022 Citations: 70
A 300-fold conductivity increase in microbial cytochrome nanowires due to temperature-induced restructuring of hydrogen bonding networks PJ Dahl, SM Yi, Y Gu, A Acharya, C Shipps, J Neu, JP O’Brien, ... Science advances 8 (19), eabm7193 , 2022 2022 Citations: 87
Protein nanowires with tunable functionality and programmable self-assembly using sequence-controlled synthesis DM Shapiro, G Mandava, SE Yalcin, P Arranz-Gibert, PJ Dahl, C Shipps, ... Nature communications 13 (1), 829 , 2022 2022 Citations: 86
Structure of Geobacter pili reveals secretory rather than nanowire behaviour Y Gu, V Srikanth, AI Salazar-Morales, R Jain, JP O’Brien, SM Yi, RK Soni, ... Nature 597 (7876), 430-434 , 2021 2021 Citations: 219
Roadmap on emerging concepts in the physical biology of bacterial biofilms: from surface sensing to community formation GCL Wong, JD Antani, PP Lele, J Chen, B Nan, MJ Kühn, A Persat, JL Bru, ... Physical biology 18 (5), 051501 , 2021 2021 Citations: 100
The blind men and the filament: understanding structures and functions of microbial nanowires SE Yalcin, NS Malvankar Current opinion in chemical biology 59, 193-201 , 2020 2020 Citations: 112
Electric field stimulates production of highly conductive microbial OmcZ nanowires SE Yalcin, JP O’Brien, Y Gu, K Reiss, SM Yi, R Jain, V Srikanth, PJ Dahl, ... Nature chemical biology 16 (10), 1136-1142 , 2020 2020 Citations: 222
Direct observation of anisotropic growth of water films on minerals driven by defects and surface tension SE Yalcin, BA Legg, M Yeşilbaş, NS Malvankar, JF Boily Science advances 6 (30), eaaz9708 , 2020 2020 Citations: 55
Probing the Role of Metal Coordination and pH in Assembly and Function of Cytochrome Nanowires V Srikanth, Y Gu, JP O'Brien, R Jain, SE Yalcin, SM Yi, FA Samatey, ... Biophysical Journal 118 (3), 335a-336a , 2020 2020
Structure of microbial nanowires reveals stacked hemes that transport electrons over micrometers F Wang, Y Gu, JP O’Brien, SM Yi, SE Yalcin, V Srikanth, C Shen, D Vu, ... Cell 177 (2), 361-369. e10 , 2019 2019 Citations: 638
Mechanism of metal-like conductivity in bacterial protein nanowires S Yi, Y Gu, J Neu, JP O'brien, SE Yalcin, D Vu, W Huynh, V Batista, ... APS March Meeting Abstracts 2019, F65. 010 , 2019 2019
Conformation-induced conductivity switching in bacterial protein nanowires SE Yalcin, JP O'brien, A Acharya, Y Gu, P Dahl, S Yi, W Huynh, ... APS March Meeting Abstracts 2019, Y64. 005 , 2019 2019 Citations: 1
Towards a molecular-level understanding of metal-like conductivity in bacterial protein nanowires P Dahl, A Acharya, SE Yalcin, S Yi, JP O'brien, V Batista, N Malvankar APS March Meeting Abstracts 2019, C31. 007 , 2019 2019
Structural Basis for Metallic Conductivity in Bacterial Pili Protein Filaments SE Yalcin, P O'Brien, W Huynh, Y Gu, T Varga, N Malvankar APS March Meeting Abstracts 2018, C51. 005 , 2018 2018
Femtosecond Dynamics of Nanoscale Molecular Heterogeneity JM Atkin, B Pollard, B Metzger, PM Sass, SE Yalcin, AS Lea, PE Teichen, ... International Conference on Ultrafast Phenomena, UW1A. 3 , 2016 2016
Photoluminescence imaging of solitary dopant sites in covalently doped single-wall carbon nanotubes HHSD Nicolai F. Hartmann, Sibel Ebru Yalcin, Lyudmyla Adamska, Erik H Haroz ... Nanoscale , 2015 2015 Citations: 85
MOST CITED SCHOLAR PUBLICATIONS
Phase-engineered low-resistance contacts for ultrathin MoS 2 transistors R Kappera, D Voiry, SE Yalcin, B Branch, G Gupta, AD Mohite, ... Nature materials 13 (12), 1128-1134 , 2014 2014 Citations: 2207
Structure of microbial nanowires reveals stacked hemes that transport electrons over micrometers F Wang, Y Gu, JP O’Brien, SM Yi, SE Yalcin, V Srikanth, C Shen, D Vu, ... Cell 177 (2), 361-369. e10 , 2019 2019 Citations: 638
Visualization of charge propagation along individual pili proteins using ambient electrostatic force microscopy NS Malvankar, SE Yalcin, MT Tuominen, DR Lovley Nature nanotechnology 9 (12), 1012-1017 , 2014 2014 Citations: 261
Metallic 1T phase source/drain electrodes for field effect transistors from chemical vapor deposited MoS2 R Kappera, D Voiry, SE Yalcin, W Jen, M Acerce, S Torrel, B Branch, S Lei, ... Apl Materials 2 (9) , 2014 2014 Citations: 246
Electric field stimulates production of highly conductive microbial OmcZ nanowires SE Yalcin, JP O’Brien, Y Gu, K Reiss, SM Yi, R Jain, V Srikanth, PJ Dahl, ... Nature chemical biology 16 (10), 1136-1142 , 2020 2020 Citations: 222
Structure of Geobacter pili reveals secretory rather than nanowire behaviour Y Gu, V Srikanth, AI Salazar-Morales, R Jain, JP O’Brien, SM Yi, RK Soni, ... Nature 597 (7876), 430-434 , 2021 2021 Citations: 219
Electronic structure and chemical nature of oxygen dopant states in carbon nanotubes X Ma, L Adamska, H Yamaguchi, SE Yalcin, S Tretiak, SK Doorn, H Htoon ACS nano 8 (10), 10782-10789 , 2014 2014 Citations: 193
Block-copolymer-based plasmonic nanostructures PA Mistark, S Park, SE Yalcin, DH Lee, O Yavuzcetin, MT Tuominen, ... ACS nano 3 (12), 3987-3992 , 2009 2009 Citations: 142
The blind men and the filament: understanding structures and functions of microbial nanowires SE Yalcin, NS Malvankar Current opinion in chemical biology 59, 193-201 , 2020 2020 Citations: 112
Roadmap on emerging concepts in the physical biology of bacterial biofilms: from surface sensing to community formation GCL Wong, JD Antani, PP Lele, J Chen, B Nan, MJ Kühn, A Persat, JL Bru, ... Physical biology 18 (5), 051501 , 2021 2021 Citations: 100
A 300-fold conductivity increase in microbial cytochrome nanowires due to temperature-induced restructuring of hydrogen bonding networks PJ Dahl, SM Yi, Y Gu, A Acharya, C Shipps, J Neu, JP O’Brien, ... Science advances 8 (19), eabm7193 , 2022 2022 Citations: 87
Protein nanowires with tunable functionality and programmable self-assembly using sequence-controlled synthesis DM Shapiro, G Mandava, SE Yalcin, P Arranz-Gibert, PJ Dahl, C Shipps, ... Nature communications 13 (1), 829 , 2022 2022 Citations: 86
Photoluminescence imaging of solitary dopant sites in covalently doped single-wall carbon nanotubes HHSD Nicolai F. Hartmann, Sibel Ebru Yalcin, Lyudmyla Adamska, Erik H Haroz ... Nanoscale , 2015 2015 Citations: 85
Microbial biofilms as living photoconductors due to ultrafast electron transfer in cytochrome OmcS nanowires J Neu, CC Shipps, MJ Guberman-Pfeffer, C Shen, V Srikanth, JA Spies, ... Nature Communications 13 (1), 5150 , 2022 2022 Citations: 70
Bench-top aqueous two-phase extraction of isolated individual single-walled carbon nanotubes NK Subbaiyan, ANG Parra-Vasquez, S Cambré, MAS Cordoba, SE Yalcin, ... Nano research 8 (5), 1755-1769 , 2015 2015 Citations: 58
Direct observation of anisotropic growth of water films on minerals driven by defects and surface tension SE Yalcin, BA Legg, M Yeşilbaş, NS Malvankar, JF Boily Science advances 6 (30), eaaz9708 , 2020 2020 Citations: 55
Spectral properties of multiply charged semiconductor quantum dots SE Yalcin, JA Labastide, DL Sowle, MD Barnes Nano letters 11 (10), 4425-4430 , 2011 2011 Citations: 55
Direct imaging of charge transport in progressively reduced graphene oxide using electrostatic force microscopy SE Yalcin, C Galande, R Kappera, H Yamaguchi, U Martinez, ... ACS nano 9 (3), 2981-2988 , 2015 2015 Citations: 42
Electrostatic force microscopy and spectral studies of electron attachment to single quantum dots on indium tin oxide substrates SE Yalcin, B Yang, JA Labastide, MD Barnes The Journal of Physical Chemistry C 116 (29), 15847-15853 , 2012 2012 Citations: 35
Spectral bandwidth and phase effects of resonantly excited ultrafast surface plasmon pulses SE Yalcin, Y Wang, M Achermann Applied Physics Letters 93 (10) , 2008 2008 Citations: 17