In-situ monitoring of decane-in-water emulsion during microwave irradiation

Microwave (MW)-assisted de-emulsification has been attractive in processes of petroleum production and refining. However, the mechanism and optimal operation remain poorly understood. In this study, the behaviour of decane-in-water emulsion under MW irradiation was monitored in-situ through a size measurement system equipped with the reactor and surface tension profiles. The results indicated that the bubble was formed around the oil droplet during MW irradiation. The MW-induced bubbles can enhance de-emulsification in a similar mechanism as the flotation column. The efficiency of MW de-emulsification depends on emulsion content and MW power. Although a higher MW power is more effective, boiling caused by excessive energy must be considered due to the higher local heating. As a result, moderate power is more desirable. For the decane-in-water emulsions in this study, the optimal condition was determined to be around 500 W.     

Flexible Nanoarchitectonics for Biosensing and Physiological Monitoring Applications

Flexible and implantable electronics hold tremendous promises for advanced healthcare applications, especially for physiological neural recording and modulations. Key requirements in neural interfaces include miniature dimensions for spatial physiological mapping and low impedance for recognizing small biopotential signals. Herein, a bottom-up mesoporous formation technique and a top-down microlithography process are integrated to create flexible and low-impedance mesoporous gold (Au) electrodes for biosensing and bioimplant applications. The mesoporous architectures developed on a thin and soft polymeric substrate provide excellent mechanical flexibility and stable electrical characteristics capable of sustaining multiple bending cycles. The large surface areas formed within the mesoporous network allow for high current density transfer in standard electrolytes, highly suitable for biological sensing applications as demonstrated in glucose sensors with an excellent detection limit of 1.95 µm and high sensitivity of 6.1 mA cm⁻² µM⁻¹, which is approximately six times higher than that of benchmarking flat/non-porous films. The low impedance of less than 1 kΩ at 1 kHz in the as-synthesized mesoporous electrodes, along with their mechanical flexibility and durability, offer peripheral nerve recording functionalities that are successfully demonstrated in vivo. These features highlight the new possibilities of our novel flexible nanoarchitectonics for neuronal recording and modulation applications.     

Design of Stimuli-Responsive Peptides and Proteins

Stimuli-responsive peptides and proteins are an exciting class of smart biomaterials for various applications and have received significant attention over the past decades. A wide variety of stimuli such as temperature, pH, ions, enzymes, magnetic field, redox, etc., are explored. This article provides a review of five intensively studied types of stimuli-responsive peptides and proteins, their design principles and applications, including temperature-, pH-, light-, metal ion-, and enzyme-responsive with an emphasis on the key design concepts and switch function. Moreover, typical examples of their applications are discussed to provide a better understanding of the design concept and underlying methodology. This review will facilitate and inspire future innovation toward new peptide- and protein-based materials and their diverse applications.     

Engineering Route for Stretchable, 3D Microarchitectures of Wide Bandgap Semiconductors for Biomedical Applications

Wide bandgap (WBG) semiconductors have attracted significant research interest for the development of a broad range of flexible electronic applications, including wearable sensors, soft logical circuits, and long-term implanted neuromodulators. Conventionally, these materials are grown on standard silicon substrates, and then transferred onto soft polymers using mechanical stamping processes. This technique can retain the excellent electrical properties of wide bandgap materials after transfer and enables flexibility; however, most devices are constrained by 2D configurations that exhibit limited mechanical stretchability and morphologies compared with 3D biological systems. Herein, a stamping-free micromachining process is presented to realize, for the first time, 3D flexible and stretchable wide bandgap electronics. The approach applies photolithography on both sides of free-standing nanomembranes, which enables the formation of flexible architectures directly on standard silicon wafers to tailor the optical transparency and mechanical properties of the material. Subsequent detachment of the flexible devices from the support substrate and controlled mechanical buckling transforms the 2D precursors of wide band gap semiconductors into complex 3D mesoscale structures. The ability to fabricate wide band gap materials with 3D architectures that offer device-level stretchability combined with their multi-modal sensing capability will greatly facilitate the establishment of advanced 3D bio-electronics interfaces.