Search

Electrochemical interfaces are at the core of many important current applications, from corrosion and biophysics to electrocatalytic and battery interfaces. Further understanding in the processes taking place at these interfaces is often linked to better observation techniques. In situ or in operando imaging and characterization of the electrochemical interface helps improve our understanding of structural sequences and kinetics of complex processes. Atomic force microscopy (AFM) offers a unique combination to monitor surface morphology and mechanical properties at micro‐ and nanoscale surfaces and solid–electrolyte interfaces. Two examples are given where the application of AFM during electrochemical processes is clearly useful. Organic inhibitors and their behavior play an important role in corrosion mitigation and the influence of thiol monolayers on dealloying is reported: Zinc films find application for coatings or Zn batteries and an in situ electrodeposition study is shortly described. With the ongoing improvement of computational simulations, the broadening of spatiotemporal scales possible with AFM imaging and its combination with mechanical information points in a prospective future for in operando AFM. [ABSTRACT FROM AUTHOR]

Solvent‐assisted lipid bilayer (SALB) formation is emerged as a versatile approach in forming supported lipid membranes (SLBs) on metal surfaces, interesting platforms for transducing a biological signal to an electrical readout where vesicle rupture is not straightforward. Herein, the effect of the lipid concentration in the organic solvent, a key parameter controlling SALB, is addressed in the low and high concentration limits of 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine lipid on a Au surface. Quartz crystal microbalance with dissipation (QCM‐D) responses are correlated with atomic force microscopy (AFM) topographic and nanomechanical measurements. Upon SALB completion at both concentrations, QCM‐D and AFM topographical characterization suggest the formation of thin, although incomplete, lipid layers at the Au–liquid interface, with frequency and dissipation plateau values departing from well‐established homogeneous SLB responses. Nanomechanical analysis reveals the presence of mostly monolayers at low concentration due to lack of lipid material, while at high concentration excess of lipid material leads to the coexistence of diverse structures. Their formation stems from the SALB formation mechanism, based on lyotropic transformations upon solvent exchange, which differs from customarily vesicle rupture. Such mechanism leads to peculiar two‐step features in approach force curves on SLBs pointing toward a decoupling in bilayer leaflets when supported. [ABSTRACT FROM AUTHOR]

B Electrochemical Interfaces b Fighting the degradation of materials clearly is an important endeavour for reaching a sustainable society. More details can be found in article number 2100470 by Frank Uwe Renner and co-workers. [Extracted from the article]

The interest in nano-sized lipid vesicles in nano-biotechnology relies on their use as mimics for endosomes, exosomes, and nanocarriers for drug delivery. The interactions between nanoscale size lipid vesicles and cell membranes involve spontaneous interbilayer lipid transfer by several mechanisms, such as monomer transfer or hemifusion. Experimental approaches toward monitoring lipid transfer between nanoscale-sized vesicles typically consist of transfer assays by fluorescence microscopy requiring the use of labels or calorimetric measurements, which in turn require a large amount of sample. Here, the capability of a label-free surface-sensitive method, quartz crystal microbalance with dissipation monitoring (QCM-D), was used to monitor lipid transfer kinetics at minimal concentrations and to elucidate how lipid physicochemical properties influence the nature of the transfer mechanism and dictate its dynamics. By studying time-dependent phase transitions obtained from nanoviscosity measurements, the transfer rates (unidirectional or bidirectional) between two vesicle populations consisting of lipids with the same head group and differing alkyl chain length can be estimated. Lipid transfer is asymmetric and unidirectional from shorter-chain lipid donor vesicles to longer-chain lipid acceptor vesicles. The transfer is dramatically reduced when the vesicle populations are incubated at temperatures below the melting of one of the vesicle populations. [ABSTRACT FROM AUTHOR]