Abstract Supported lipid bilayers are key platforms for measuring membrane-implicated drug interactions, disease mechanisms, and biological processes. Bacterial model membranes are a particularly high-value target but present unique fabrication challenges due to the high intrinsic curvature of their constituent lipids, notably phosphatidylethanolamine (PE). Here, we report a fundamental role for headgroup chemistry in stabilizing lipids with high intrinsic curvature on flat solid surfaces and predictive guidelines for tuning the preparative lipid concentration depending on surface chemistry. Building on recent developments in solvent-exchange techniques, we fully automate the production of bilayers comprised of a biologically relevant ratio of PE and the anionic lipid phosphatidylglycerol (PG). Neutron reflectometry measurements are performed to compare the structure of these membranes with that of bilayers containing phosphatidylcholine, the benchmark lipid for supported lipid bilayers. Bilayers are characterized in terms of both completeness and bilayer-substrate distance, which is indicative of adsorption strength, on neutral oxide, acidic, and basic surfaces. Despite their high intrinsic curvature, bacterial model membranes are found to interact strongly with all surfaces. We attribute this surprising observation to hydrogen bonding with substrate surface moieties. These observations lead to a unified predictive model of the physicochemical forces of bilayer adhesion to solid surfaces, enabling a future of high-throughput production of custom bilayers for complex assays and drug discovery.
Abstract Lyocell fibers are prone to fibrillation under wet mechanical action, which limits their durability and further processing. In this study, three multifunctional cross-linkers with different molecular structures, including two aziridine-based cross-linkers (N1 and N3) and one isocyanate-based cross-linker (N2), were investigated for antifibrillation finishing of Lyocell fibers, yarns, and fabrics. The optimized conditions were 8% o.w.f. N1 at pH 9 and 60 °C, 6% o.w.f. N2 at pH 10 and 60 °C, and 6% o.w.f. N3 at pH 9 and 80 °C, with a treatment time of 4 h. Under these conditions, the dissolution time of cross-linked fibers in 70% ZnCl2 increased to approximately 70 min, approaching that of commercial A100. The whiteness values of N1-, N2-, and N3-treated Lyocell were 75.24, 74.08, and 72.72, respectively, while bursting strengths remained at 366.1–373.6 N. Cross-linking reduced water retention but maintained water absorption at approximately 6 g g–1. Reactive-dye exhaustion, fixation, color strength, levelness, and color fastness were also largely preserved. These results demonstrate that intermolecular cross-linking effectively suppresses Lyocell fibrillation while maintaining key physical and dyeing properties.
Abstract Transparent conductive films (TCFs) have attracted extensive attention due to their broad applications in optoelectronic devices. However, the Volmer–Weber growth mode of ultrathin metal films generally results in poor film continuity, introducing an inherent tradeoff between sheet resistance and optical transmittance, which fundamentally constrains the overall optoelectronic performance of TCFs. To overcome this limitation, we introduced an ultrathin Cu seed layer to regulate the growth behavior of Au films, subsequently fabricating an ITO/Cu/Au/ITO multilayer transparent conductive film. The optimized multilayer film achieved a low sheet resistance of 8.47 ± 0.33 Ω/sq, a high visible transmittance of 89.1%, and a figure of merit (FoM) of 37.23 × 10–3 Ω–1, yielding roughly 1.7-fold enhancement in FoM over the control Cu/Au/ITO sample annealed at 450 °C. Scanning electron microscopy (SEM) observations revealed that the introduction of the ultrathin Cu seed layer effectively reduced the continuity threshold of the Au film, substantially enhancing the uniformity and continuity of the metallic layer, which facilitates a stable conductive network. Atomic force microscopy (AFM) and X-ray diffraction (XRD) analyses further demonstrated that post-annealing treatment promoted grain growth and enhanced the crystallinity of the multilayer films. These findings indicate that Cu seed layer and multilayer optimization provide an effective strategy for regulating the growth of ultrathin Au films and concurrently enhancing both the electrical and optical properties of TCFs.
Abstract Tafel analysis is a cornerstone of electrocatalyst research, providing mechanistic and kinetic information from current–potential measurements. However, its application has largely been restricted to macroscopic electrochemical measurements, limiting its use for heterogeneous electrode surfaces. Scanning electrochemical cell microscopy (SECCM) offers the spatial resolution necessary to perform local Tafel analysis, but its compatibility with the experimental conditions typically employed for reliable, high-throughput SECCM measurements has not been systematically explored. Here, the acidic hydrogen evolution reaction (HER) on polycrystalline platinum and gold is used as a model system to establish practical guidelines for performing Tafel analysis by SECCM. By systematically examining the effects of probe size, voltammetric scan rate, and electrochemical surface conditioning, it is shown that individual (i.e., spatially resolved) Tafel analyses can be completed in a matter of seconds, irrespective of probe size, provided sufficiently slow voltammetric scan rates and appropriate electrochemical preconditioning are employed. The resulting methodology is demonstrated through high-throughput SECCM mapping of the HER on polycrystalline gold over a 180 × 180 μm2 area containing over 2000 individual measurements. The measured Tafel slope and exchange current densities are consistent with established macroscopic behavior while providing direct, spatially resolved access to individual crystallographic facets. This methodology extends conventional macroscopic Tafel analysis to heterogeneous electrode surfaces, enabling high-throughput mapping of local Tafel parameters.
Abstract Obesity, as a global public health crisis, is fundamentally linked to the pathological expansion and dysfunction of white fat. White adipose tissue (WAT) browning, which activates UCP1-mediated mitochondrial thermogenesis, has emerged as a promising therapeutic target for obesity and related metabolic diseases. In this study, we developed polydopamine–polyethylene glycol (PDA–PEG) nanozymes that integrate the photothermal-tunable multienzyme activities of PDA with the stealth properties of PEG. Furthermore, the PDA–PEG nanozymes were engineered in combination with near-infrared (NIR) irradiation to induce browning of white adipocytes. Our experimental results demonstrated that PDA–PEG nanozymes showed temperature-dependent SOD- and CAT-like activities, as well as excellent photothermal properties. The combination of the PDA–PEG nanozymes and NIR markedly promoted white adipocyte browning, as indicated by morphological remodeling of lipid droplets, decreased lipid storage, increased mitochondrial levels, and upregulation of thermogenic genes, including Pparg, Sirt1, Cidea, and Ucp1. Notably, this combined treatment effectively reversed mitochondrial structural impairment and significantly increased the mitochondrial population with a well-defined and intact ultrastructure. Further mechanistic studies showed that by scavenging excess reactive oxygen species (ROS) in white adipocytes, the PDA–PEG nanozymes with NIR alleviated AMPK suppression, thus enhancing its phosphorylation and upregulating PGC-1α to coordinate mitochondrial biogenesis and UCP1 expression, ultimately driving the browning. This work presents a photothermal-enzymatic synergistic strategy to promote white adipocyte browning, thereby offering a promising therapeutic approach against obesity and related metabolic disorders.
