ElecFeX is a user-friendly toolbox for efficient feature extraction from single-cell electrophysiological recordings.

Characterizing neurons by their electrophysiological phenotypes is essential for understanding the neural basis of behavioral and cognitive functions. Technological developments have enabled the collection of hundreds of neural recordings; this calls for new tools capable of performing feature extraction efficiently. To address the urgent need for a powerful and accessible tool, we developed ElecFeX, an open-source MATLAB-based toolbox that (1) has an intuitive graphical user interface, (2) provides customizable measurements for a wide range of electrophysiological features, (3) processes large-size datasets effortlessly via batch analysis, and (4) yields formatted output for further analysis. We implemented ElecFeX on a diverse set of neural recordings; demonstrated its functionality, versatility, and efficiency in capturing electrical features; and established its significance in distinguishing neuronal subgroups across brain regions and species. ElecFeX is thus presented as a user-friendly toolbox to benefit the neuroscience community by minimizing the time required for extracting features from their electrophysiological datasets.

Plasma-Engineering of Oxygen Vacancies on NiCo2O4 Nanowires with Enhanced Bifunctional Electrocatalytic Performance for Rechargeable Zinc-air Battery.

Designing an efficient, durable, and inexpensive bifunctional electrocatalyst toward oxygen evolution reactions (OER) and oxygen reduction reactions (ORR) remains a significant challenge for the development of rechargeable zinc-air batteries (ZABs). The generation of oxygen vacancies plays a vital role in modifying the surface properties of transition-metal-oxides (TMOs) and thus optimizing their electrocatalytic performances. Herein, a H2/Ar plasma is employed to generate abundant oxygen vacancies at the surfaces of NiCo2O4 nanowires. Compared with the Ar plasma, the H2/Ar plasma generated more oxygen vacancies at the catalyst surface owing to the synergic effect of the Ar-related ions and H-radicals in the plasma. As a result, the NiCo2O4 catalyst treated for 7.5 min in H2/Ar plasma exhibited the best bifunctional electrocatalytic activities and its gap potential between Ej = 10 for OER and E1/2 for ORR is even smaller than that of the noble-metal-based catalyst. In situ electrochemical experiments are also conducted to reveal the proposed mechanisms for the enhanced electrocatalytic performance. The rechargeable ZABs, when equipped with cathodes utilizing the aforementioned catalyst, achieved an outstanding charge-discharge gap, as well as superior cycling stability, outperforming batteries employing noble-metal catalyst counterparts.

Composition and Surface Optical Properties of GaSe:Eu Crystals before and after Heat Treatment.

This work studies the technological preparation conditions, morphology, structural characteristics and elemental composition, and optical and photoluminescent properties of GaSe single crystals and Eu-doped ß-Ga2O3 nanoformations on ε-GaSe:Eu single crystal substrate, obtained by heat treatment at 750-900 °C, with a duration from 30 min to 12 h, in water vapor-enriched atmosphere, of GaSe plates doped with 0.02-3.00 at. % Eu. The defects on the (0001) surface of GaSe:Eu plates serve as nucleation centers of ß-Ga2O3:Eu crystallites. For 0.02 at. % Eu doping, the fundamental absorption edge of GaSe:Eu crystals at room temperature is formed by n = 1 direct excitons, while at 3.00 at. % doping, Eu completely shields the electron-hole bonds. The band gap of nanostructured ß-Ga2O3:Eu layer, determined from diffuse reflectance spectra, depends on the dopant concentration and ranges from 4.64 eV to 4.87 eV, for 3.00 and 0.05 at. % doping, respectively. At 0.02 at. % doping level, the PL spectrum of ε-GaSe:Eu single crystals consists of the n = 1 exciton band, together with the impurity band with a maximum intensity at 800 nm. Fabry-Perrot cavities with a width of 9.3 µm are formed in these single crystals, which determine the interference structure of the impurity PL band. At 1.00-3.00 at. % Eu concentrations, the PL spectra of GaSe:Eu single crystals and ß-Ga2O3:Eu nanowire/nanolamellae layers are determined by electronic transitions of Eu2+ and Eu3+ ions.

3D-printed wound dressing platform for protein administration based on alginate and zinc oxide tetrapods.

Wound treatment requires a plethora of independent properties. Hydration, anti-bacterial properties, oxygenation and patient-specific drug delivery all contribute to the best possible wound healing. Three-dimensional (3D) printing has emerged as a set of techniques to realize individually adapted wound dressings with open porous structure from biomedically optimized materials. To include all the desired properties into the so-called bioinks is still challenging. In this work, a bioink system based on anti-bacterial zinc oxide tetrapods (t-ZnO) and biocompatible sodium alginate is presented. Additive manufacturing of these hydrogels with high t-ZnO content (up to 15 wt.%) could be realized. Additionally, protein adsorption on the t-ZnO particles was evaluated to test their suitability as carriers for active pharmaceutical ingredients (APIs). Open porous and closed cell printed wound dressings were tested for their cell and skin compatibility and anti-bacterial properties. In these categories, the open porous constructs exhibited protruding t-ZnO arms and proved to be anti-bacterial. Dermatological tests on ex vivo skin showed no negative influence of the alginate wound dressing on the skin, making this bioink an ideal carrier and evaluation platform for APIs in wound treatment and healing.

Hybrid Aeromaterials for Enhanced and Rapid Volumetric Photothermal Response.

Conversion of light into heat is essential for a broad range of technologies such as solar thermal heating, catalysis and desalination. Three-dimensional (3D) carbon nanomaterial-based aerogels have been shown to hold great promise as photothermal transducer materials. However, until now, their light-to-heat conversion is limited by near-surface absorption, resulting in a strong heat localization only at the illuminated surface region, while most of the aerogel volume remains unused. We present a fabrication concept for highly porous (>99.9%) photothermal hybrid aeromaterials, which enable an ultrarapid and volumetric photothermal response with an enhancement by a factor of around 2.5 compared to the pristine variant. The hybrid aeromaterial is based on strongly light-scattering framework structures composed of interconnected hollow silicon dioxide (SiO2) microtubes, which are functionalized with extremely low amounts (in order of a few µg cm-3) of reduced graphene oxide (rGO) nanosheets, acting as photothermal agents. Tailoring the density of rGO within the framework structure enables us to control both light scattering and light absorption and thus the volumetric photothermal response. We further show that by rapid and repeatable gas activation, these transducer materials expand the field of photothermal applications, like untethered light-powered and light-controlled microfluidic pumps and soft pneumatic actuators.

Modulation of SK Channels via Calcium Buffering Tunes Intrinsic Excitability of Parvalbumin Interneurons in Neuropathic Pain: A Computational and Experimental Investigation.

Parvalbumin-expressing interneurons (PVINs) play a crucial role within the dorsal horn of the spinal cord by preventing touch inputs from activating pain circuits. In both male and female mice, nerve injury decreases PVINs' output via mechanisms that are not fully understood. In this study, we show that PVINs from nerve-injured male mice change their firing pattern from tonic to adaptive. To examine the ionic mechanisms responsible for this decreased output, we used a reparametrized Hodgkin-Huxley type model of PVINs, which predicted (1) the firing pattern transition is because of an increased contribution of small conductance calcium-activated potassium (SK) channels, enabled by (2) impairment in intracellular calcium buffering systems. Analyzing the dynamics of the Hodgkin-Huxley type model further demonstrated that a generalized Hopf bifurcation differentiates the two types of state transitions observed in the transient firing of PVINs. Importantly, this predicted mechanism holds true when we embed the PVIN model within the neuronal circuit model of the spinal dorsal horn. To experimentally validate this hypothesized mechanism, we used pharmacological modulators of SK channels and demonstrated that (1) tonic firing PVINs from naive male mice become adaptive when exposed to an SK channel activator, and (2) adapting PVINs from nerve-injured male mice return to tonic firing on SK channel blockade. Our work provides important insights into the cellular mechanism underlying the decreased output of PVINs in the spinal dorsal horn after nerve injury and highlights potential pharmacological targets for new and effective treatment approaches to neuropathic pain.SIGNIFICANCE STATEMENT Parvalbumin-expressing interneurons (PVINs) exert crucial inhibitory control over Aß fiber-mediated nociceptive pathways at the spinal dorsal horn. The loss of their inhibitory tone leads to neuropathic symptoms, such as mechanical allodynia, via mechanisms that are not fully understood. This study identifies the reduced intrinsic excitability of PVINs as a potential cause for their decreased inhibitory output in nerve-injured condition. Combining computational and experimental approaches, we predict a calcium-dependent mechanism that modulates PVINs' electrical activity following nerve injury: a depletion of cytosolic calcium buffer allows for the rapid accumulation of intracellular calcium through the active membranes, which in turn potentiates SK channels and impedes spike generation. Our results therefore pinpoint SK channels as potential therapeutic targets for treating neuropathic symptoms.

Tetrapodal ZnO-Based Composite Stents for Minimally Invasive Glaucoma Surgery.

The glaucoma burden increases continuously and is estimated to affect more than 100 million people by 2040. As there is currently no cure to restore the optic nerve damage caused by glaucoma, the only controllable parameter is the intraocular pressure (IOP). In recent years, minimally invasive glaucoma surgery (MIGS) has emerged as an alternative to traditional treatments. It uses micro-sized drainage stents that are inserted through a small incision, minimizing the trauma to the tissue and reducing surgical and postoperative recovery time. However, a major challenge for MIGS devices is foreign body reaction and fibrosis, which can lead to a complete failure of the device. In this work, the antifibrotic potential of tetrapodal ZnO (t-ZnO) microparticles used as an additive is elucidated by using rat embryonic fibroblasts as a model. A simple, direct solvent-free process for the fabrication of stents with an outer diameter of 200-400 µm is presented, in which a high amount of t-ZnO particles (45-75 wt %) is mixed into polydimethylsiloxane (PDMS) and a highly viscous polymer/particle mixture is extruded. The fabricated stents possess increased elastic modulus compared to pure PDMS while remaining flexible to adapt to the curvature of an eye. In vitro experiments showed that the fibroblast cell viability was inhibited to 43 ± 3% when stents with 75 wt % t-ZnO were used. The results indicate that cell inhibiting properties can be attributed to an increased amount of protruding t-ZnO particles on the stent surface, leading to an increase in local contacts with cells and a disruption of the cell membrane. As a secondary mechanism, the released Zn ions could also contribute to the cell-inhibiting properties in the close vicinity of the stent surface. Overall, the fabrication method and the antifibrotic and mechanical properties of developed stents make them promising for application in MIGS.

Spinal processing of cold information by Kcnip2 neurons.

Spinal cord circuits that process cold inputs from the periphery are poorly understood. In this issue of Neuron, Albisetti et al.1 identify a subset of inhibitory interneurons essential to this function.

Development of Polythiourethane/ZnO-Based Anti-Fouling Materials and Evaluation of the Adhesion of Staphylococcus aureus and Candida glabrata Using Single-Cell Force Spectroscopy.

The attachment of bacteria and other microbes to natural and artificial surfaces leads to the development of biofilms, which can further cause nosocomial infections. Thus, an important field of research is the development of new materials capable of preventing the initial adhesion of pathogenic microorganisms. In this work, novel polymer/particle composite materials, based on a polythiourethane (PTU) matrix and either spherical (s-ZnO) or tetrapodal (t-ZnO) shaped ZnO fillers, were developed and characterized with respect to their mechanical, chemical and surface properties. To then evaluate their potential as anti-fouling surfaces, the adhesion of two different pathogenic microorganism species, Staphylococcus aureus and Candida glabrata, was studied using atomic force microscopy (AFM). Our results show that the adhesion of both S. aureus and C. glabrata to PTU and PTU/ZnO is decreased compared to a model surface polydimethylsiloxane (PDMS). It was furthermore found that the amount of both s-ZnO and t-ZnO filler had a direct influence on the adhesion of S. aureus, as increasing amounts of ZnO particles resulted in reduced adhesion of the cells. For both microorganisms, material composites with 5 wt.% of t-ZnO particles showed the greatest potential for anti-fouling with significantly decreased adhesion of cells. Altogether, both pathogens exhibit a reduced capacity to adhere to the newly developed nanomaterials used in this study, thus showing their potential for bio-medical applications.

Polydimethylsiloxane Microdomains Formation at the Polythiourethane/Air Interface and Its Influence on Barnacle Release.

In this study, polydimethylsiloxane (PDMS)/polythiourethane (PTU) composite reinforced with tetrapodal shaped micro-nano ZnO particles (t-ZnO) was successfully produced by a versatile, industrially applicable polymer blending process. On the surface of this composite, PDMS is distributed in the form of microdomains embedded in a PTU matrix. The composite inherited not only good mechanical properties originating from PTU but also promising fouling-release (FR) properties due to the presence of PDMS on the surface. It was shown that the preferential segregation of PDMS domains at the polymer/air interface could be attributed to the difference in the surface free energy of PDMS and PTU. The PDMS microdomains at the PTU/air interface significantly reduced the barnacle adhesion strength on the composite. Both the pseudo- and natural barnacle adhesion strength on the composite was approximately 0.1 MPa, similar to that on pure PDMS. The pseudo-barnacle adhesion on reference surfaces AlMg3 and PTU reached approximately 4 and 6 MPa, respectively. Natural barnacles could not be removed intact from AlMg3 and PTU surfaces without breaking the shell, indicating that the adhesion strength was higher than the mechanical strength of a barnacle shell (approximately 0.4 MPa). The integrity of PDMS microdomains was maintained after 12 months of immersion in seawater and barnacle removal. No surface deteriorations were found. In short, the composite showed excellent potential as a long-term stable FR coating for marine applications.

Development and Characterization of Mechanically Durable Silicone-Polythiourethane Composites Modified with Tetrapodal Shaped ZnO Particles for the Potential Application as Fouling-Release Coating in the Marine Sector.

Ecological considerations strongly necessitate the development of environmentally friendly antifouling paints. A promising alternative to biocide containing antifouling paints are fouling-release coatings, which are non-toxic and designed to prevent permanent attachment of marine organisms to the surface, due to their low surface energy. However, these coatings suffer from insufficient mechanical properties, which make them unsuitable for mechanically stressed surfaces e.g., on ship hulls. To overcome those obstacles, polydimethylsiloxane (PDMS)-polythiourethane (PTU) composites modified with tetrapodal shaped micro-nano ZnO particles (t-ZnO) were produced and characterized by evaluating the surface energy, mechanical properties, and fouling-release performance. Among all variations, PTU/1 wt.% PDMS composites with 1 wt.% t-ZnO particles possess superior properties for applications as fouling-release coatings for maritime purposes.