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A flexible microneedle patch that can transdermally deliver liquid-phase therapeutics would enable direct use of existing, approved drugs and vaccines, which are mostly in liquid form, without the need for additional drug solidification, efficacy verification, and subsequent approval. Specialized dissolving or coated microneedle patches that deliver reformulated, solidified therapeutics have made considerable advances; however, microneedles that can deliver liquid drugs and vaccines still remain elusive because of technical limitations. Here, we present a snake fang–inspired microneedle patch that can administer existing liquid formulations to patients in an ultrafast manner (<15 s). Rear-fanged snakes have an intriguing molar with a groove on the surface, which enables rapid and efficient infusion of venom or saliva into prey. Liquid delivery is based on surface tension and capillary action. The microneedle patch uses multiple open groove architectures that emulate the grooved fangs of rear-fanged snakes: Similar to snake fangs, the microneedles can rapidly and efficiently deliver diverse liquid-phase drugs and vaccines in seconds under capillary action with only gentle thumb pressure, without requiring a complex pumping system. Hydrodynamic simulations show that the snake fang–inspired open groove architectures enable rapid capillary force–driven delivery of liquid formulations with varied surface tensions and viscosities. We demonstrate that administration of ovalbumin and influenza virus with the snake fang–inspired microneedle patch induces robust antibody production and protective immune response in guinea pigs and mice.

Diffusiophoresis (DP) is described as typically being divided into chemiphoresis (CP) and electrophoresis (EP), and the related theory is well-established. However, not only the individual effect of CP and EP but also the size dependency on the resulting DP of colloidal particles has not yet been comprehensively demonstrated in an experimental manner. In this paper, we present a dynamic transport control mechanism for colloidal particles by developing a micro-/nanofluidic DP platform (MNDP). We demonstrate that the MNDP can generate transient and/or steady-state concentration gradients, making it possible to control the direction and rate of transport of colloidal particles through the individual manipulation of CP and EP by simply and rapidly switching solutions. In addition, the MNDP allows the size-dependent separation as well as fractionation of submicron particles through the individual manipulation of CP and EP, thus empirically validating the classic theoretical model for DP under the influence of electrical double layer (EDL) thickness. Furthermore, we provide theoretical analysis and simulation results that will enable the development of a versatile separation and/or fractionation technique for various colloidal particles, including biosamples, according to their size or electrical feature.

Liquid foam consists of liquid film networks. The films can be thinned to the nanoscale via evaporation and have potential in bottom-up material structuring applications. However, their use has been limited due to their dynamic fluidity, complex topological changes, and physical characteristics of the closed system. Here, we present a simple and versatile microfluidic approach for controlling two-dimensional liquid foam, designing not only evaporative microholes for directed drainage to generate desired film networks without topological changes for the first time, but also microposts to pin the generated films at set positions. Patterning materials in liquid is achievable using the thin films as nanoscale molds, which has additional potential through repeatable patterning on a substrate and combination with a lithographic technique. By enabling direct-writable multi-integrated patterning of various heterogeneous materials in two-dimensional or three-dimensional networked nanostructures, this technique provides novel means of nanofabrication superior to both lithographic and bottom-up state-of-the-art techniques.

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Objectives: Irritability is a transdiagnostic symptom in developmental psychopathology, conceptualized as a low threshold for frustration and increased proneness to anger. While central to emotion regulation, there is a vital need for empirical studies to explore the relationship between irritability and underlying physiological mechanisms of cardiovascular arousal. Methods:We examined the relationship between irritability and cardiovascular arousal (i.e., heart rate [HR] and heart rate variability [HRV]) in a transdiagnostic sample of 51 youth (M = 12.63 years, SD = 2.25; 62.7% male). Data was collected using the Empatica E4 during a laboratory stop-signal task. In addition, the impact of motion activity, age, medication, and sleep on cardiovascular responses was explored.Results: Main findings showed that irritability was associated with increased HR and decreased HRV during task performance. Conclusions:Findings support the role of peripheral physiological dysregulation in youth with emotion regulation problems and suggest the potential use of available wearable consumer electronics as an objective measure of irritability and physiological arousal in a transdiagnostic sample of youth.

Diffusioosmosis (DO) results from ion transport near charged surfaces in the presence of electrolyte gradients and is critical in nanofluidic systems. However, DO has not yet been comprehensively studied because nanofabrication materials have limitations of low throughput and difficult quantification. Herein, we describe a self-assembled particle membrane (SAPM)-integrated microfluidic platform that can modulate the material properties (e.g., zeta-potential) and transport flux of nanopores. We quantify the effect of the zeta-potential on DO by measuring the electrical signals across three different nanopores/nanochannels of the SAPM. We then empirically quantify the effects of the temperature and ionic strength of the electrolytes on DO and reveal a nonlinear relationship with DO-driven ion transport; the ionic strengths govern the DO-or diffusion-effective ion transport phenomena. Finally, we demonstrate DO-driven electric power generation with enhanced performance as a potential application under optimized experimental conditions.