Conductive hydrogels have drawn significant attention in the field of stretchable/wearable sensors due to their intrinsic stretchability, tunable conductivity, biocompatibility, multistimuli sensitivity, and self-healing ability. Recent advancements in hydrogel- and organohydrogel-based sensors, including a novel sensing mechanism, outstanding performance, and broad application scenarios, suggest the great potential of hydrogels for stretchable electronics. However, a systematic summary of hydrogel- and organohydrogel-based sensors in terms of their working principles, unique properties, and promising applications is still lacking. In this spotlight, we present recent advances in hydrogel- and organohydrogel-based stretchable sensors with four main sections: improved stability of hydrogels, fabrication and characterization of organohydrogel, working principles, and performance of different types of sensors. We particularly highlight our recent work on ultrastretchable and high-performance strain, temperature, humidity, and gas sensors based on polyacrylamide/carrageenan double network hydrogel and ethylene glycol/glycerol modified organohydrogels obtained via a facile solvent displacement strategy. The organohydrogels display higher stability (drying and freezing tolerances) and sensing performances than corresponding hydrogels. The sensing mechanisms, key factors influencing the performance, and application prospects of these sensors are revealed. Especially, we find that the hindering effect of polymer networks on the ionic transport is one of the key mechanisms applicable for all four of these kinds of sensors.

Porous hollow carbon spheres (PHCS) decorated with MoSe2 nanosheets (MoSe2@ PHCS) are synthesized via a three-step process. Uniform and conformal MoSe2 nanosheets are firmly attached to PHCS according to the characterization of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. Enhanced electrochemical performance of MoSe2@PHCS is investigated in lithium-ion and sodium-ion storage. The MoSe2@PHCS deliver a reversible lithium storage capacity of 681 mA h g(-1) for 100 discharge/charge cycles. In Na-ion batteries, it manifests a reversible sodium capacity of 580 mA h g(-1) after 100 cycles. Three synergic effects can be attributed to the enhanced electrochemical performance of MoSe2@PHCS: (1) both the sheet structure of the MoSe2 and the mechanically robust carbon sphere supporter can accommodate stress from cycling; (2) the porous hollow carbon spheres matrix in the MoSe2@PHCS offers a beneficial conductivity environment; (3) uniform and conformal MoSe2 nanosheets attachment shortens the electronic lithium-ion and sodium-ion pathway during cycling. The MoSe2@PHCS have a great potential as an anode for lithium and sodium batteries.

The development of high-performance recyclable polymers represents a circular plastics economy to address the urgent issues of plastic sustainability. Herein, we design a series of biobased seven-membered-ring esters containing aromatic and aliphatic moieties. Ring-opening polymerization studies showed that they readily polymerize with excellent activity (TOF up to 2.1 × 105 h–1) at room temperature and produce polymers with high molecular weight (M n up to 438 kg/mol). The variety of functionalities allows us to investigate the substitution effect on polymerizability/recyclability of monomers and properties of polymers (such as T gs from −1 to 79 °C). Remarkably, a stereocomplexed P­(M2) exhibited significantly increased T m and crystallization rate. More importantly, product P­(M)­s were capable of depolymerizing into their monomers in solution or bulk with high efficiency, thus establishing their circular life cycle.

Rapid bacterial identification (ID) and antibiotic susceptibility testing (AST) are in great demand due to the rise of drug-resistant bacteria. Conventional culture-based AST methods suffer from a long turnaround time. By necessity, physicians often have to treat patients empirically with antibiotics, which has led to an inappropriate use of antibiotics, an elevated mortality rate and healthcare costs, and antibiotic resistance. Recent advances in miniaturization and automation provide promising solutions for rapid bacterial ID/AST profiling, which will potentially make a significant impact in the clinical management of infectious diseases and antibiotic stewardship in the coming years. In this review, we summarize and analyze representative emerging micro- and nanotechnologies, as well as automated systems for bacterial ID/AST, including both phenotypic (e.g., microfluidic-based bacterial culture, and digital imaging of single cells) and molecular (e.g., multiplex PCR, hybridization probes, nanoparticles, synthetic biology tools, mass spectrometry, and sequencing technologies) methods. We also discuss representative point-of-care (POC) systems that integrate sample processing, fluid handling, and detection for rapid bacterial ID/AST. Finally, we highlight major remaining challenges and discuss potential future endeavors toward improving clinical outcomes with rapid bacterial ID/AST technologies.

Presently, considerable attention has been paid to the Fe-based dichalcogenides as anode materials for sodium ion batteries (SIBs) due to their abundant resources, chemical stability, and high theoretical capacity. In this paper, we make nanooctahedra particles assembled FeSe2 microspheres embedded into sulfur-doped reduced graphene oxide sheets through a one-step hydrothermal reduction route, in which the reduction of graphene oxide, the doping of sulfur atoms, and the preparation of FeSe2/sulfur-doped reduced graphene oxide (FeSe2/SG) composites are realized at the same time. When serving as anodes for SIBs, the FeSe2/SG electrode can display superior electrochemical performances with a large reversible capacity of 447.5 mA h g(-1) at 0.5 A g(-1) and an excellent rate capability of 383.3 and 277.5 mA h g(-1) at the current density of 2.0 and 5.0 A g(-1), which could be attributed to the introduction of sulfur atoms into the reduced graphene oxide structure and the synergistic effect between microsphere-like FeSe2 particles and sulfur-doped reduced graphene oxide sheets.