A Tutorial for Scanning Electrochemical Cell Microscopy (SECCM) Measurements: Step-by-Step Instructions, Visual Resources, and Guidance for First Experiments

ACS Measurement Science Au · 2025-03-27 · 9 citations

Scanning electrochemical cell microscopy (SECCM) produces nanoscale-resolution electrochemical maps of electrode surfaces using the meniscus at the tip of an electrolyte-filled nanopipette as a mobile electrochemical cell. While the use and range of applications of SECCM have grown rapidly since its introduction, the pathway to performing SECCM measurements can be daunting to those without direct access to expert users. This work fills this expertise gap by providing a step-by-step guide to performing one's first SECCM experiments, including troubleshooting strategies, videos/images, suggested parameters and experimental systems, and representative data (of both successful experiments and common problems). No background in SECCM is assumed and fundamentals are clearly explained at each stage with a rationale for the experimental steps provided. This work provides an entry point for the uninitiated to understand and use this powerful nanoscale electrochemical characterization technique.

A Look inside a Flexible Open-Source Scanning Electrochemical Probe Microscope

ACS electrochemistry. · 2025-12-04 · 2 citations

The instrument makes use of a field programmable gate array (FPGA)-based data acquisition card, and this contribution further illustrates the benefits of adopting FPGA architecture generally in electrochemical instrumentation. We describe the software and hardware for the instrument, using examples from the literature to illustrate how common SEPM operation modes and hyphenated techniques are readily implemented. Additionally, to demonstrate the application of custom-developed scanning protocols, we briefly present some further experimental examples. This Tutorial seeks to serve the needs of expert users of SEPMs and encourage new entrants alike. To this end, to encourage those who are interested in either setting up their own instruments or making optimal use of commercially available instruments, we also briefly include some more basic and general information on SEPM techniques and uses, to put the more advanced work and instrumental aspects in context.

Critical Role of Molecular Adsorption on Electrocatalysis at Single Nanoparticles

Analytical Chemistry · 2025-02-14 · 5 citations

We report a mechanistic study of the electrocatalytic response of single Pt nanoparticles (NPs) on a carbon ultramicroelectrode (UME) in a hydrazine (N2H4) solution. Using a NP collision approach, our study shows their catalytic response is characterized by a sharp, <50 μs-long current spike followed by a steady step-current signal. Our results suggest that the current spike is due to the quick oxidation of N2H4 molecules preadsorbed onto the NP surface, while the step current reflects the continuous catalytic oxidation of protonated hydrazine (N2H5+), which goes through a deprotonation and adsorption step on Pt. Since each N2H5+ molecule releases five H+ upon complete oxidation, a drastic decrease in local pH can be expected in the vicinity of the NP. This pH shift in turn limits the rate of adsorption and the steady-state oxidation current one can observe from each colliding particle. Our study reveals the key importance of molecular adsorption and the changing local chemical environment (e.g., pH) to the observed catalytic response of single NPs and highlights that steady-state currents in their measurement may be chemically or mass-transport limited.

Electric Potential-Driven Acid/Base Chemistry: Kinetics of Electrochemical Interfacial Proton Transfer and Transport

The Journal of Physical Chemistry C · 2024-04-22 · 4 citations

Proton transfer at solid/liquid interfaces is a fundamental step in many complex biological and electrocatalytic processes. Previous model studies using electrodes modified with self-assembled monolayers (SAMs) of carboxylic acid-terminated alkanethiols have demonstrated that interfacial proton transfer is controlled by the local electrochemical microenvironment. The thermodynamic driving force for electrochemically driven protonation/deprotonation of acid/base SAMs is governed by a combination of the electric potential at the SAM/solvent interface, the pKa of the acid group, and the solution pH. Here, we develop a kinetic model to describe electric potential-driven protonation/deprotonation as a two-step process. This comprises a reversible proton transfer step at the SAM/electrolyte interface (i.e., (de)protonation) and a proton transport step describing the motion of protons as they traverse the diffuse electrical double layer to and from the solution bulk. The kinetics of the transport step are investigated using finite element simulations, providing numerical estimates for the transport rate constants under combined diffusional and migrational transport modes. Using the dependence of these rate constants on the electric potential at the SAM/electrolyte interface, we define situations where the overall rate expression is limited by either (de)protonation, proton transport, or a combination of both. From this analysis, we determine a lower limit for the acid group pKa of ≈3, above which proton transfer at the plane of acid dissociation is generally the rate-determining step. The electric potential-driven proton transfer/transport kinetic model developed herein provides a general approach to treat electric potential-driven coupled ion transfer and transport phenomena, with potential applications including proton-coupled electron transfer processes, ion intercalation in alkali metal batteries, and ion transport across biological membranes.

Multimodal nanoparticle analysis enabled by a polymer electrolyte nanopore combined with nanoimpact electrochemistry

Faraday Discussions · 2024-07-22 · 3 citations

Nanopores are emerging as a powerful tool for the analysis and characterization of nanoparticles at the single entity level. Here, we report that a PEG-based polymer electrolyte present inside the nanopore enables the enhanced detection of nanoparticles at low ionic strength. We develop a numerical model that recapitulates the electrical response of the glass nanopore system, revealing the response to be sensitive to the position of the polymer electrolyte interface. As proof of concept, we demonstrate the multimodal analysis of a nanoparticle sample by coupling the polymer electrolyte nanopore sensor with nanoimpact electrochemistry. This combination of techniques could deliver the multiparametric analysis of nanoparticle systems complementing electrochemical reactivity data provided by nanoimpact electrochemistry with information on size, shape and surface charge provided by nanopore measurements.

Next‐Generation Nanopore Sensors Based on Conductive Pulse Sensing for Enhanced Detection of Nanoparticles (Small 4/2024)

Small · 2024-01-01

Nanopore Sensors In article number 2305186, Martin Andrew Edwards, Pietro Strobbia, Devleena Samanta, Christoph Wälti, Paolo Actis, and co-workers demonstrate the wide applicability of the method by characterizing metallic nanospheres of varied sizes, plasmonic nanostars with various degrees of branching, and protein-based spherical nucleic acids with different oligonucleotide loadings. The artwork represents an artistic interpretation of a nanopore systems augmented by a polymer electrolyte that enables the analytical characterization of heterogenous nanoparticle mixtures.

MSR24 Large Language Models for Data Extraction in a Targeted Review: A Case Study

Value in Health · 2024-12-01

38 Compassionate leadership within pharmacy teams

2024-05-31

<h3>Introduction</h3> As a profession, pharmacy comprises of multiple workplace settings but also of a wide range of individuals, all with varying levels of personal, professional, and educational experience. The nature of the roles within pharmacy also requires individuals to work autonomously and within often diverse and multi-disciplinary teams, and so it is important for pharmacy staff to understand the principles and behaviours of compassionate leadership in their day-to-day work. Dependent on their role, staff may find themselves in patient-facing settings or scenarios and could be responsible and required to display the compassionate leadership principles (attending, understanding, empathising, and helping), and education is vital to support this. Compassionate leaders learn from the lived experience of others, engaging in topics relating to equality, diversity, and inclusion to help inform their practice, creating an environment of no intimidation or victimisation, and where respecting, supporting, listening, and belonging becomes routine. <h3>Aims and objectives of the research project or activity</h3> It is hoped that providing education and examples of compassionate leadership will enable all staff to be more aware of their ability to display such principles, leading to a more inclusive, understanding, and enabled pharmacy workforce. Compassionate leadership principles extend much beyond the remit of the pharmacy workforce, and displaying these principles in practice may potentially influence those outside of the profession to reflect on their practice too. By creating a more compassionate workforce, we could be making small steps to ensuring a more sustainable, productive, and positive health and social care environment to be a part of. Given the ongoing impact of burnout on health and social care workers, it is important to address how principles of compassionate leadership can support those who are struggling, and may reduce the risk of colleagues leaving roles within such sectors. <h3>Method or approach</h3> In order to fulfil assessment criteria for a module titled ‘Compassionate Leadership in Practice’ as part of the MSc in Professional Practice in Health with Wrexham University, students were asked to produce a resource to introduce a new member of staff to the culture of compassionate leadership that is core to practice in their area of work. Students were also asked to provide a short rationale for the format used and how it will be utilised within their chosen area. As described above, the various roles within pharmacy also requires individuals to work autonomously and within often diverse and multi-disciplinary teams, and so it is important for pharmacy staff to understand and display the principles of compassionate leadership in their day-to-day work. GJ chose to create an audio-visual resource to be used as a potential eLearning resource. This was created on Canva with a professional audio, ensuring a high-quality and engaging piece of work to begin embedding the principles of compassionate leadership within pharmacy teams. GJ also suggested that this could be implemented as a mandatory resource to be completed by all staff. The resource should also be available in Welsh, along with descriptive text for staff living with any hearing or visual impairments. This resource will be available and accessible to all members of the pharmacy workforce, regardless of any disabilities that they are living with, demonstrating our commitment to increase inclusion and diversity within the workplace. <h3>Findings</h3> The resource has not been assessed yet; however, it has received great acclaim and feedback from colleagues. GJ is currently engaging with JC, ML and VG to understand how best to assess the potential impact of this work, and findings will be available in time for March 2024. <h3>Key messages</h3> Providing education and examples of compassionate leadership will enable all staff to be more aware of their personal ability to display such principles, leading to a more inclusive, understanding, and enabled pharmacy workforce. Compassionate leadership principles extend much beyond the remit of the pharmacy, and by embodying and leading such principles in practice may potentially influence others to reflect on their practice too. The benefits of developing a more compassionate workforce are wide-ranging; from improving employee engagement and retention and boosting productivity, to lowering heart rate, blood pressure and strengthening the immune system. By creating a more compassionate workforce, we could be making small steps to ensuring a more sustainable, productive, and positive health and social care environments to work within.

Next‐Generation Nanopore Sensors Based on Conductive Pulse Sensing for Enhanced Detection of Nanoparticles

Small · 2023-08-30 · 26 citations

Nanopore sensing has been successfully used to characterize biological molecules with single-molecule resolution based on the resistive pulse sensing approach. However, its use in nanoparticle characterization has been constrained by the need to tailor the nanopore aperture size to the size of the analyte, precluding the analysis of heterogeneous samples. Additionally, nanopore sensors often require the use of high salt concentrations to improve the signal-to-noise ratio, which further limits their ability to study a wide range of nanoparticles that are unstable at high ionic strength. Here, a new paradigm in nanopore research that takes advantage of a polymer electrolyte system to comprise a conductive pulse sensing approach is presented. A finite element model is developed to explain the conductive pulse signals observed and compare these results with experiments. This system enables the analytical characterization of heterogeneous nanoparticle mixtures at low ionic strength . Furthermore, the wide applicability of the method is demonstrated by characterizing metallic nanospheres of varied sizes, plasmonic nanostars with various degrees of branching, and protein-based spherical nucleic acids with different oligonucleotide loadings. This system will complement the toolbox of nanomaterials characterization techniques to enable real-time optimization workflow for engineering a wide range of nanomaterials.

Mechanistic Study of the Conductance and Enhanced Single-Molecule Detection in a Polymer–Electrolyte Nanopore

ACS Nanoscience Au · 2023-01-10 · 27 citations

Solid-state nanopores have been widely employed in the detection of biomolecules, but low signal-to-noise ratios still represent a major obstacle in the discrimination of nucleic acid and protein sequences substantially smaller than the nanopore diameter. The addition of 50% poly(ethylene) glycol (PEG) to the external solution is a simple way to enhance the detection of such biomolecules. Here, we demonstrate with finite-element modeling and experiments that the addition of PEG to the external solution introduces a strong imbalance in the transport properties of cations and anions, drastically affecting the current response of the nanopore. We further show that the strong asymmetric current response is due to a polarity-dependent ion distribution and transport at the nanopipette tip region, leading to either ion depletion or enrichment for few tens of nanometers across its aperture. We provide evidence that a combination of the decreased/increased diffusion coefficients of cations/anions in the bath outside the nanopore and the interaction between a translocating molecule and the nanopore-bath interface is responsible for the increase in the translocation signals. We expect this new mechanism to contribute to further developments in nanopore sensing by suggesting that tuning the diffusion coefficients of ions could enhance the sensitivity of the system.