A thermal haptic device was developed to replicate thermal feelings for virtual reality applications.

The worldwide proliferation of COVID-19 poses the urgent need for sterilizable and transparent air filters to inhibit virus transmission while retaining ease of communication. Here, we introduce copper nanowires to fabricate transparent and self-sterilizable air filters. Copper nanowire air filter (CNAF) allowed visible light penetration, thereby can exhibit facial expressions, helpful for better communication. CNAF effectively captured particulate matter (PM) by mechanical and electrostatic filtration mechanisms. The temperature of CNAF could be controlled by Joule-heating up to 100 °C with thermal stability. CNAF successfully inhibited the growth of E. coli because of the oligodynamic effect of copper. With heat sterilization, the antibacterial efficiency against G. anodireducens was greatly improved up to 99.3% within 10 min. CNAF showed high reusability with stable filtration efficiency and thermal antibacterial efficacy after five repeated uses. Our result suggests an alternative form of active antimicrobial air filter in preparation for the current and future pandemic situations.

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In spite of its excellent electrical, mechanical, and low‐cost characteristics, copper nanowire has fatal issues in the oxidation problem and the lack of biological compatibility, which occasionally outweighs its advantages and limits its usage as electronics or biodevice applications. In this study, a novel wet chemical synthesis method is developed for the oxidation‐free Cu–Au core–shell nanowire based on the prepared Cu nanowire with alkylamine‐mediated synthesis and ligand exchange. The synthesized Cu–Au core–shell nanowire exhibits improved electrical stability against thermal oxidation under the harsh environment of 80 °C and 80% relative humidity. Additionally, to substantiate suitability for the biomedical application, the enhanced chemical stability and biocompatibility are investigated by utilizing the artificial perspiration and the cell culture. As a proof‐of‐concept demonstration, high performance wearable electromyogram (EMG), electrocardiogram (ECG) sensors for electrophysiological monitoring with the Cu–Au core–shell nanowire electrode are demonstrated with superior oxidation‐resistance and biocompatibility even after the harsh environment test. The Cu–Au core–shell nanowire can provide promising, cost‐effective electrode materials for various wearable electronics applications.

The patterning of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hydrogels with excellent electrical property and spatial resolution is a challenge for bioelectronic applications. However, most PEDOT:PSS hydrogels are fabricated by conventional manufacturing processes such as photolithography, inkjet printing, and screen printing with complex fabrication steps or low spatial resolution. Moreover, the additives used for fabricating PEDOT:PSS hydrogels are mostly cytotoxic, thus requiring days of detoxification. Here, we developed a previously unexplored ultrafast and biocompatible digital patterning process for PEDOT:PSS hydrogel via phase separation induced by a laser. We enhanced the electrical properties and aqueous stability of PEDOT:PSS by selective laser scanning, which allowed the transformation of PEDOT:PSS into water-stable hydrogels. PEDOT:PSS hydrogels showed high electrical conductivity of 670 S/cm with 6-μm resolution in water. Furthermore, electrochemical properties were maintained even after 6 months in a physiological environment. We further demonstrated stable neural signal recording and stimulation with hydrogel electrodes fabricated by laser.