Highlights from Faraday Discussion: New horizons in nanoelectrochemistry, Nanjing, China

Abstract

A Faraday Discussions on ‘New horizons in nanoelectrochemistry’ was held from October 14 to October 16, 2024 at Nanjing University, Nanjing, China. The meeting gathered researchers from around the world to explore the challenges and opportunities presented by electrochemistry at the nanoscale, marking a significant step forward in understanding electrochemical processes at the nanoscale. The Faraday Disscussion provided a platform for rigorous discussions and presentations on topics ranging from novel experimental techniques and theoretical advancements, to the latest developments in AI-assisted data processing, reflecting on the rapidly evolving nature of the field. This report provides an overview of the event, including brief summaries of the papers discussed and published.

The Faraday Discussions on ‘New horizons in nanoelectrochemistry’, held at Nanjing University, China, from 14–16 October 2024, brought together leading experts to explore the latest advancements and challenges in the dynamic field of “nanoelectrochemistry”. The nanoelectrochemical technique captures intrinsic transient information at the single-entity level (e.g., single molecules, single nanoparticles and single cells) through confined nano-interfaces. Its ultrasensitive sensing capability enables us to obtain new knowledge of fundamental studies by measuring ultralow currents and interpreting complex signals. This specialized branch of electrochemistry, which deals with processes occurring at the nanoscale, has profound implications for energy utilization, sensing technologies, innovative catalysis, and biological systems.

This meeting, the fourth in a series of Faraday Discussions focused on electrochemistry at the nanoscale, continues to explore this captivating concept. Previous events in the series – Single Entity Electrochemistry (2016, York, UK), Electrochemistry at nano-interfaces (2018, Bath, UK), and Next Generation Nanoelectrochemistry (2020, online) – have been truly inspiring, sparking deep discussions that have shaped our understanding of the challenges and paradigm shifts in the field of nanoscale electrochemistry. This Faraday Discussion is the first to be held in China after the pandemic, and it also marks the first time in 10 years that the event has physically returned to China, bringing the “discussion and debate” format of the conference to young scholars in China. A total of 58 abstracts were received, with 17 selected for oral presentations. The event hosted 88 delegates, including 42 poster presenters, among them 19 PhD students and 8 postdoctoral researchers. Additionally, 25 of the poster presenters also delivered a flash presentation.

The meeting was enriched not only by the vibrant exchange of ideas and cutting-edge research but also by the natural beauty surrounding the venue. The blooming Osmanthus trees on the Nanjing University campus infused the air with their delicate fragrance and adorned the conference setting with graceful blossoms (Fig. 1). This subtle yet enchanting presence enhanced the ambiance, providing a serene and inspiring backdrop that perfectly complemented the spirit of collaboration and discovery. The harmonious blend of scientific discourse and natural beauty created a memorable experience for all participants. Dr Emma Wilson, Director of Publishing, Royal Society of Chemistry, also admired this in her welcome notes (Fig. 2).

Fig. 1 Nanjing University and Conference Room at the Department of Chemistry and Chemical Engineering, hosting the Faraday Discussion.

Fig. 2 Dr Emma Wilson (top left) and Professor Yi-Tao Long (top right) providing the welcome and introduction of the meeting, Professor Lane A. Baker (bottom left) and Professor Andrew G. Ewing (bottom right), giving the Spiers Memorial Lecture and Closing Remarks.

The meeting began with the registration and refreshments held in the lobby of the Nanjing University International Conference Center (NUICC, henceforth). After lunch, the delegates proceeded to the Department of Chemistry and Chemical Engineering at Nanjing University, where all the lecture presentations and the discussions took place. Professor Yi-Tao Long chaired the welcome and introduction, and the conference commenced with an opening address by Professor Yi Cao, International Affairs Office, Nanjing University, and Dr Emma Wilson, Director of Publishing, Royal Society of Chemistry, warmly welcomed delegates and set the stage for the discussions that followed. Regional Publisher, Royal Society of Chemistry, Dr Guanqun Song, outlined the discussion format for the entire meeting.

Professor Lane A. Baker from Texas A&M University, USA, set the groundwork with an insightful and illuminating introductory lecture—the Spiers Memorial Lecture (https://doi.org/10.1039/D4FD00159A)—providing a strong foundation for the following discussions. He explored the role of single-entity electrochemistry, reflecting on past achievements in the field and highlighting opportunities for future discoveries built upon existing research.

He pinpointed the challenges of virtual meetings during the pandemic, emphasizing the limitations of being unable to engage in person and the unique benefits of face-to-face interactions.

After the introductory lecture, the first session proceeded and was chaired by Professor Yuanhua Shao from Peking University, China, and Professor Weihua Huang from Wuhan University, China. This session focused on the confinement effects and their role in increasing the probability of electrochemical reactions and identifying the analytes in question. Session 1 began with the commendable work presented by Professor Yi-Lun Ying from Nanjing University, China, about the electrochemical coordination of single molecules by employing K238H mutant aerolysin (https://doi.org/10.1039/D4FD00133H). This work highlights the importance of confined nanopores that promote the formation of coordination bonds between atoms and Au(III) only when they are at the proximal distance. The second talk delivered by Professor Tianyi Xiong from the Institute of Chemistry, CAS, China, featured the role of ion current oscillation in polyelectrolyte-modified micropipettes (https://doi.org/10.1039/D4FD00135D). Their results showed that by applying an extreme bias voltage, the proton-responsive PvimB-modified pipettes displayed considerable current switching behavior at negative voltages, leading to periodic ion current oscillation at constant biases. Following these presentations, an engaging and dynamic discussion unfolded, that allowed scientists and early-career researchers to delve deeper into the details. The discussion was then followed by a delightful refreshment break for delegates to relax, network, and exchange ideas in a more informal setting. With all the restored energy from sumptuous refreshment, the meeting proceeded with another half of the first session.

The second half of Session 1 was chaired by Professor Jun Huang from Forschungszentrum Jülich GmbH, Germany, and Professor Meiqin Zhang from the University of Science and Technology Beijing, China. The first talk was given by Professor Fan Xia from the China University of Geosciences, China. His research points out the critical role of lipid membranes and the influence of their composition on the transport of ions through nanopores/nanochannels (https://doi.org/10.1039/D4FD00149D). They utilized the programmable and versatile properties of DNA nanotechnology, and engineered adjustable DNA nanowire structures on a graphene oxide (GO) membrane surface, resulting in the fabrication of a nanowire-n@GO membrane. His research demonstrated that DNA nanowires of different lengths can effectively modulate the composition of biomimetic membranes, thereby significantly impacting ion transport dynamics. Professor Yueming Zhai from Wuhan University, China, proposed an inspired work to study the denaturation and renaturation of a single protein molecule (ovalbumin) by employing non-sticky SiN_x nanonets (https://doi.org/10.1039/D4FD00117F). These PEG-coated SiN_x nanonets confined the protein molecule for an in-depth analysis of its denaturation upon adding a denaturant, and renaturation upon replacing the denaturant solution. Professor Liang Wang from Chongqing Institute of Green and Intelligent Technology, CAS, China gave the final talk of Session 1. His presentation elaborated on the utility of molecular-sandwich-based DNAzyme catalytic reactions to identify the disease-related antigens in human blood samples using nanopores (https://doi.org/10.1039/D4FD00146J).

Soon after all the presentations of Session 1 ended, an engaging brainstorming discussion commenced, centering on the significance of confinement effects and exploring strategies to further enhance them for insightful analysis of electrochemical reactions at the nanoscale. The discussion was followed by flash poster presentations, hosted by Professor J. Justin Gooding from the University of New South Wales, Australia, which provided a platform for delegates to briefly showcase their research highlights in a 1-minute lightning presentation. The day concluded with an engaging poster session accompanied by a wine reception, offering participants an opportunity to network and exchange ideas in a friendly environment.

Session 2 of the Faraday Discussion began on the second day of the meeting, October 15, 2024. This session was the briefest and hosted by Professor Dongping Zhan from Xiamen University, China, and Professor Wenjun Luo from Nanjing University, China. It centered around the advantages of spectroelectrochemistry, a combination of two amazing techniques: spectroscopy and electrochemistry. Light-activated electrochemical reactions at nanometer-scaled interfaces were also covered in this session.

The first talk of day 2 was given by Professor Frédéric Kanoufi from the Université Paris Cité, CNRS, France. He demonstrated the use of interferometric scattering microscopy (iSCAT), a kind of optical microscopy based on the refractive index to monitor the electrochemistry at single MoS₂ petal-like sub-microparticles. This work introduced a high-sensitivity imaging technique to identify the oxygen reduction reaction at single-particle resolution (https://doi.org/10.1039/D4FD00132J). The next speaker of this session was Professor Caleb M. Hill from the University of Wyoming, USA, who joined the session online. He presented the advantages of scanning electrochemical cell microscopy (SECCM) to control and identify the electrochemical nucleation and growth kinetics of silver nanoparticles on carbon and indium tin oxide (ITO) electrodes (https://doi.org/10.1039/D4FD00131A). Professor Hill emphasized the appropriateness of time-dependent kinetic models instead of quasi-equilibrium kinetic models, to evaluate important chemical properties. The final presentation of this session was given by Professor Kaoru Hiramoto from Tohoku University, Japan. Her research figured out the use of electrochemiluminescence microscopy to monitor the effects of peptide interactions with planar lipid membranes, advantageous for designing antibiotics (https://doi.org/10.1039/D4FD00137K). Session 2 was concluded with a thought-provoking discussion with an exchange of ingenious ideas. Afterward, sumptuous refreshment was served to delegates to keep them energized and focused for the upcoming Session 3, the longest one.

With the revitalizing energy from the refreshments, the third session commenced with renewed enthusiasm. The research presented under Session 3 focused on a family of techniques that use specialized probes to investigate electrochemical processes at surfaces with high spatial resolution. The first half of this session was led by Professor Zhifeng Ding from the University of Western Ontario, Canada.

The first presentation of this session was delivered by Professor Mei Shen from the University of Illinois Urbana-Champaign, USA. She proposed an enzyme-modified platinum nanoelectrode for the detection of glutamate, the smaller size of this nanoelectrode favors the safer in vivo detection with minimal damage to the cell membrane (https://doi.org/10.1039/D4FD00138A). The second talk was presented by Professor Dechen Jiang from Nanjing University, China, about the implementation of scanning electrochemical cell microscopy (SECCM) with local electrochemical impedance spectroscopy (LEIS) using a preamplifier to achieve an image of LEIS at the indium tin oxide/gold (ITO/Au) electrode with a spatial resolution of 180 nm (https://doi.org/10.1039/D4FD00122B). The next presentation was also about the SECCM technique, presented by Dr Lachlan F. Gaudin from Monash University, Australia. His study unveiled the misinterpretation of some parameters and datasets obtained from SECCM and proposed ways to resolve the issues and make the most of this technique (https://doi.org/10.1039/D4FD00115J). This segment of Session 3 came to a halt for an intellectually enriched discussion that was followed by another sumptuous feast for the delegates. The Lecture Hall of the Chemistry Department was elegantly arranged, providing a welcoming and comfortable space for delegates to relax, network, and enjoy their meals in a pleasant atmosphere. During lunch, experts and early-career researchers engaged in informal discussions, fostering knowledge exchange in a relaxed setting.

After lunch, the session was resumed and chaired by Professor John J. Kasianowicz from the University of South Florida, USA, and Professor Ping Yu from the Institute of Chemistry, CAS, China. The session commenced with a talk by Professor Yasufumi Takahashi from Nagoya University, Japan. His research employed scanning ion conductance microscopy (SICM), to monitor a cell’s surface change with the help of a glass nanopipette as a probe. They monitored the anti-tumor effect of plasma-activated Ringer’s lactate solution (https://doi.org/10.1039/D4FD00116H). His research allowed them to differentiate between normal and cancer cells by visualizing cell surfaces. The next speech was delivered by Dr Giada Caniglia from Ulm University, Germany. Her research manifested the potential of platinum-black (Pt-B) micro- and sub-micro-sized sensors for the detection and quantification of hydrogen (H₂) in solution (https://doi.org/10.1039/D4FD00136B). The final presentation of this session was by Professor Liang Liu from CNRS, LCPME, France. His research figured out the theoretical analysis of charge-induced deformation of scanning electrolytes before they come into contact with a sample (https://doi.org/10.1039/D4FD00147H).

A stimulating discussion of this sub-session was followed by a refreshment break, before the final segment of Session 3 continued. The chairs of this session were Professor Jingyuan Chen from the University of Fukui, Japan, and Professor Yige Zhou from Hunan University, China. The session began with the talk of Professor Kim McKelvey from Victoria University of Wellington, New Zealand. His research proposed a novel scanning probe technique for delivering a gas-phase reactant to the surface of an electrocatalyst via a self-replenishing bubble fabricated at the tip of the scanning probe. The results of this study suggest a complicated interaction between carbon dioxide reduction and hydrogen evolution, controlled by the probe–electrode distance and the potential of the gold ultramicroelectrode (https://doi.org/10.1039/D4FD00124A). Professor Hang Ren delivered the final speech of this session from the University of Texas at Austin, USA. This qualitative research figured out the critical role of the voltage bias between the dual-pore nanopipette in controlling the local droplet cell environment in scanning electrochemical cell microscopy (https://doi.org/10.1039/D4FD00080C). The session concluded with a stimulating discussion, addressing the challenges faced in scanning electrochemical probe microscopy and emphasizing strategies for enhancing probe performance.

Day 2 of the Faraday’s Discussion was marked by an energetic atmosphere, featuring 11 presentations organized across three sub-sessions, interspersed with refreshments and lunch breaks. After a full day of engaging discussions, delegates were welcomed to a pre-dinner reception at the Nanjing Qixia Mountain Resort, where a beautifully arranged seating area provided a relaxed setting for continued networking. During the formal dinner, Professor Andrew Mount from the University of Edinburgh shared a reflective and warmly told history of the Faraday Community and Faraday Discussions, weaving together tradition, memory, and scientific spirit. He then commenced the “Faraday Community for Physical Chemistry Loving Cup Ceremony”, a cherished ritual of the Faraday Discussions (Fig. 3). The ceremony, rich in tradition, offered a meaningful moment of connection among delegates.

Fig. 3 The “Faraday Community for Physical Chemistry Loving Cup Ceremony” and Conference Dinner.

The fourth and last session of this Faraday Discussion continued on day 3, chaired by Professor Hua Cui from the University of Science and Technology of China, China, and Professor Wei Wang from Nanjing University, China. The first sub-session of the meeting was begun by Professor Paolo Actis from the University of Leeds, UK. His research manifested the multimodal analysis of a nanoparticle sample by combining the polymer electrolyte nanopore sensor with nanoimpact electrochemistry (https://doi.org/10.1039/D4FD00143E). Professor Kaiyu X. Fu from the University of Notre Dame, USA, gave the next speech. His presentation introduced Nafion as a coating material to overcome weak signals and biofouling issues. He presented the use of a gold nanoporous electrode that was coated with Nafion. The Nafion passes through the nanoporous structure leaving sufficient space for the immobilized aptamers to bind and detect the target analyte (https://doi.org/10.1039/D4FD00144C).

The meeting continued with the second last presentation of the first half of Session 4. The speech was delivered by Professor J. Justin Gooding from The University of New South Wales, Australia. His research figured out the role of electric potential and laser excitation in modulating electrochemical fluorescence, indicating the syncing between photochemical and electrochemical reactions. He also mentioned that different internal structures of dyes exhibit different extents of electrochemical fluorescence (https://doi.org/10.1039/D4FD00111G). The final report of this session was presented online by Professor Zuzanna S. Siwy from the University of California, Irvine, USA. Her research deals with a very important quality of charged nanopores, which is ion-selectivity. She explained that the conductance of nanopores is independent of the pore length due to the ion concentration polarization effect. Moreover, Professor Siwy mentioned how voltage regulates ion selectivity in nanopores of varying lengths and described the conditions under which charged nanopores exhibit lower current conduction compared to uncharged nanopores with identical geometries (https://doi.org/10.1039/D4FD00148F).

After an engaging discussion and a refreshment break, the last sub-session of the last day of the meeting resumed, chaired by Professor Koichi Aoki from the University of Fukui, Japan, and Professor Fei Li from Xi’an Jiaotong University, China. The meeting began with the presentation of Professor Andrew R. Mount from the University of Edinburgh, UK. He explained that for increased electrochemical analysis in flow systems, his lab designed and characterized a micropore nanoband electrode (MNE) array designed for flow-through detection. The accuracy of this device was justified by the similarity in experimental and simulated results along with the enhanced detection of redox entities traversing through the pores (https://doi.org/10.1039/D4FD00125G). The second speaker of this session was Professor Jin Lu from the National Center for Nanoscience and Technology, China. His research proposes a unique way for single-molecule electrochemical imaging to investigate the electrocatalytic mechanism. He used the fluorescent molecule ATTO647N at extremely low concentrations as a substrate and validated its catalytic reduction into a nonfluorescent form in the presence of the mediator phenazine methosulfate (PMS), through imaging and quantification of fluorescent molecules. He found the shifts in the catalytic reduction potential of ATTO647N at different concentrations of the mediator (https://doi.org/10.1039/D4FD00126E). The final presentation of this session was given by Dr Ziwen Zhao from Uppsala University, Sweden. He proposed an advanced algorithm for the detection of steps in single-entity electrochemistry. He compared discrete wavelet transform (DWT) and convolutional neural network (CNN) and found that DWT served well for low-noise data containing steps with simple shapes, however, noisy data containing signals with more complex shapes was well defined by CNN (https://doi.org/10.1039/D4FD00130C). The last session was followed by a lively discussion.

The meeting was closed with the “Concluding Remarks” by Professor Andrew G. Ewing from the University of Gothenburg, Sweden, in the chairmanship of Professor Yi-Tao Long from Nanjing University, China. He delivered a captivating lecture on the current advancements and future prospects of nanoelectrochemistry across a wide range of applications. He emphasized the importance of applying this sensitive and versatile technique in diverse domains. Furthermore, he highlighted the crucial role of artificial intelligence in enhancing and optimizing its potential (https://doi.org/10.1039/D4FD00183D).

The posters presented by the delegates were all outstanding on their own but the 7 most commendable and extraordinary posters were chosen by experts and the organizers (Fig. 4). The names of the winners are Lingjie Zhang from Texas A&M University, Yunong Wang from Texas A&M University, Chuchu Xu from Xiamen University, Lachlan F. Gaudin from Monash University, Haihan He from the Southern University of Science and Technology, Zhifeng Ding from the University of Western Ontario, and Hui Ma from Nanjing University and Zhejiang Sci-Tech University.

Fig. 4 Poster Prize Ceremony.

This Faraday Discussion on New horizons in nanoelectrochemistry served as a perfect embodiment of an exemplary scientific gathering. The fragrant bloom of Osmanthus filled the air, transforming each walk from the hotel to the lecture hall into a truly memorable experience. The conference showcased recent advancements in nanoscale imaging, electrochemical interfaces, and single-entity analysis, and paved the stage for future research directions and applications. Throughout the discussions, participants underscored the need for innovative techniques and interdisciplinary collaboration, to address the challenges of nanoelectrochemistry.

The vibrant exchange of ideas during the sessions reflected the collaborative and intellectually stimulating environment that defines Faraday Discussions, ensuring that nanoelectrochemistry remains at the forefront of scientific innovation. Coffee and lunch breaks were also full of untiring exchanges of thought on a lighter note. Overall, the meeting provided an exceptional platform for exploring the essence of nanoelectrochemistry. Delegates from around the world, along with numerous Chinese professors, participated in the event. By adopting this unique format, the conference fostered an atmosphere of lively discussion, enriching the scientific community and inspiring Chinese scholars to engage more actively in global dialogues.

Conflicts of interest

There are no conflicts to declare.

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