To realize continuously and stably work in a “moist/hot environment”, flexible electronics with excellent humid resistance, anti-swelling, and detection sensitivity are demanding. Herein, a solvent-resistant and temperature-ultrasensitive hydrogel sensor was prepared by combining MXene and quaternized chitosan (QCS) with the binary polymer chain. The strong electrostatic interaction between the QCS chain and the poly(acrylic acid) (PAA) network endows the hydrogel stability against solvent erosion, high temperature, and high humidity. The strong dynamic interaction between MXene and polymer matrix significantly improves the mechanical properties and sensing (strain and temperature) sensitivity of the hydrogel. The hydrogel strain sensor exhibits a high gauge factor (5.53), temperature/humidity tolerance (equilibrium swelling ratio of 2.5% at 80 °C), and excellent cycle stability, which could achieve a remote and accurate perception of complex human motion and environment fluctuation under aquatic conditions. Moreover, the hydrogel sensor exhibits impressive thermal response sensitivity (−3.183%/°C), ultra-short response time (< 2.53 s), and a low detection limit (< 0.5 °C) in a wide temperature range, which is applied as an indicator of the body surface and ambient temperature. In short, this study broadens the application scenarios of hydrogels in persistent extreme thermal and wet environments.

The anti-tumor effect of therapeutic carbon monoxide (CO) has been considered concerning the electron transport chain on the inner mitochondrial membrane. Herein, a tumor microenvironment and photo-responsive CO nanoplatform Ca-Flav nanoparticles (NPs) were constructed through biomineralizing acryloyl-modified flavonol, which could release CO both in normoxia and hypoxia conditions upon irradiation at tumor lesion. The in vitro experiments demonstrated that the endoplasmic reticulum stress-related signal pathways could be activated through oxidative stress caused by CO mediated mitochondrial biogenesis and calcium ion turbulence induced by Ca₃(PO₄)₂ acidolysis, resulting in mitochondrial dysfunction and cell apoptosis. In addition, the Ca-Flav NPs exhibited excellent biocompatibility and tumor inhibition effect in vivo. This work provides new insight into the potential characteristics of CO, paving a new way to engineer more efficient treatment based on CO.

With the widespread prevailing of flexible electronics in human–machine interfaces, health monitor, and human motion detection, ultrasoft flexible sensors are urgently desired with critical demands in conformality. Herein, a temperature-sensitive ionogel with near-infrared (NIR)-light controlled adhesion is prepared by electrostatic interaction of poly(diallyl dimethylammonium chloride) (PDDA) and acrylic acid, as well as the incorporation of the conductive polydopamine modified polypyrrole nanoparticles (PPy-PDA NPs). The PPy-PDA NPs could weaken the tough interaction between polymer chains and depress the Young’s modulus of the ionogel, thus promoting the ionogel ultrasoft (34 kPa) and highly stretchable (1,013%) performance to tensile deformations. In addition, the high photothermal conversion capacity of PPy-PDA NPs ensured the ionogel excellent NIR-light controlled adhesion and temperature sensitivity, which facilitated the ionogel on-demand removal and promised a reliable thermal sensor. Moreover, the resulted ultrasoft flexible sensor exhibited high sensitivity and stability to both strain and pressure in a broad range of deformations, enabling a precise monitoring on various human motions and physiological activities. The temperature-sensitive, ultrasoft, and controlled adhesive capabilities prompted great potential of the flexible ionogel in medical diagnosis and wearable electronics.

As significant biocatalysts, natural enzymes have exhibited a vast range of applications in biocatalytic reactions. However, the “always-on” natural enzyme activity is not beneficial for the regulation of catalytic processes, which limits their bio-applications. Recently, it has been extensively reported that various organic artificial enzymes exhibit prominent absorption and controlled activity under illumination, which not only creates a series of light-responsive catalytic platforms but also plays a key role in biosensing and biomedical research. To provide novel ideas for the design of artificial enzymes, we conduct this review to highlight the recent progress of light-responsive organic artificial enzymes (LOA-Enz). The specific photoresponse mechanism and various bio-applications of LOA-Enz are also presented in detail. Furthermore, the remaining challenges and future perspectives in this field are discussed.

Hydrogel is a potential matrix material of electronic-skins (E-skins) because of its excellent ductility, tunability, and biocompatibility. However, hydrogel-based E-Skins will inevitably lose their sensing performance in practical applications for water loss, physical damage, and ambient interferences. It remains a challenge to manufacture highly durable gel-based E-skins. Herein, an E-Skin is fabricated by introducing ionic liquids (ILs) into MXene-composited binary polymer network. The obtained ionic gel shows excellent mechanical properties, strong adhesion, and superior tolerance to harsh environments. The E-skin exhibits high sensitivity to both strain and pressure in a wide range of deformations, which enables a monitoring function for various human motions and physiological activities. Importantly, the E-skin shows consistent electrical response after being stored in the open air for 30 days and can be quickly healed by irradiation with 808 nm near-infrared light, originating from the photo-thermal effect induced self-healing acceleration. It is noteworthy that the E-skin also reveals a highly sensitive perception of temperature and near-infrared light, displaying the promising potential applications in the multifunctional flexible sensor.

Cisplatin (CDDP)-based chemotherapy is substantially limited in the clinic due to its high postoperative recurrence rate. Synergy therapy has been proven as a potent approach to minimize recurrence and achieve enhanced treatment effects. Herein, chemotherapy drug CDDP is assembled with the photothermal-Fenton agent of bovine serum albumin (BSA) stabilized gallic acid-functionalized iron nanoparticles (GA-Fe NPs) to achieve chemo/chemodynamic synergistic cascade oncotherapy. The Pt-GA-Fe NPs can be utilized to generate H₂O₂ via the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) in the tumor microenvironment (TME), which would then greatly boost H₂O₂-depending chemodynamic therapy (CDT). The generated cytotoxic reactive oxygen species (hydroxyl radicals, ·OH) and the depletion of glutathione (GSH) would further promote CDDP-induced DNA damage. Moreover, benefiting from the absorption in the near-infrared (NIR) region, Pt-GA-Fe NPs exhibit excellent photothermal conversion efficiency (η = 45.5%) and allow photoacoustic imaging (PAI) guided photothermal therapy (PTT). In vitro and in vivo experiments show that synergy therapy can effectively kill cancer cells and successfully cure cancer without systemic toxicity. The work highlights a new type of therapeutic agent based on CDDP with the ability of H₂O₂ self-generation, thermal responsiveness, and enhanced CDT effects for applications in cancer therapy.

A highly active and stable oxygen evolution reaction (OER) electrocatalyst is critical for hydrogen production from water splitting. Herein, three-dimensional Ni₃S₂@graphene@Co₉₂S₈ (Ni₃S₂@G@Co₉S₈), a sandwich-structured OER electrocatalyst, was grown in situ on nickel foam; it afforded an enhanced catalytic performance when highly conductive graphene is introduced as an intermediary for enhancing the electron transfer rate and stability. Serving as a free-standing electrocatalytic electrode, Ni₃S₂@G@Co₉S₈ presents excellent electrocatalytic activities for OER: A low onset overpotential (2 mA·cm^-2 at 174 mV), large anode current density (10 mA·cm^-2 at an overpotential of 210 mV), low Tafel slope (66 mV·dec^-1), and predominant durability of over 96 h (releasing a current density of ~14 mA·cm^-2 with a low and constant overpotential of 215 mV) in a 1 M KOH solution. This work provides a promising, cost-efficient electrocatalyst and sheds new light on improving the electrochemical performance of composites through enhancing the electron transfer rate and stability by introducing graphene as an intermediary.

Current research on vanadium oxides in lithium ion batteries (LIBs) considers them as cathode materials, whereas they are rarely studied for use as anodes in LIBs because of their low electrical conductivity and rapid capacity fading. In this work, hydrogenated vanadium oxide nanoneedles were prepared and incorporated into freeze-dried graphene foam. The hydrogenated vanadium oxides show greatly improved charge-transfer kinetics, which lead to excellent electrochemical properties. When tested as anode materials (0.005–3.0 V vs. Li/Li⁺) in LIBs, the sample activated at 600 ℃ exhibits high specific capacity (~941 mA·h·g^-1 at 100 mA·g^-1) and high-rate capability (~504 mA·h·g^-1 at 5 A·g^-1), as well as excellent cycling performance (~285 mA·h·g^-1 in the 1, 000^th cycle at 5 A·g^-1). These results demonstrate the promising application of vanadium oxides as anodes in LIBs.

In this work, single- and double-shelled NiCo₂O₄ hollow spheres have been synthesized in situ by a one-pot solvothermal method assisted by xylose, followed by heat treatment. Employed as supercapacitor electrode materials, the double-shelled NiCo₂O₄ hollow spheres exhibit a remarkable specific capacitance (1, 204.4 F·g^-1 at a current density of 2.0 A·g^-1) and excellent cycling stability (103.6% retention after 10, 000 cycles at a current density of 10 A·g^-1). Such outstanding electrochemical performance can be attributed to their unique internal morphology, which provides a higher surface area with a larger number of active sites available to interact with the electrolyte. The versatility of this method was demonstrated by applying it to other binary metal oxide materials, such as ZnCo₂O₄, ZnMn₂O₄, and CoMn₂O₄. The present study thus illustrates a simple and general strategy for the preparation of binary transition metal oxide hollow spheres with a controllable number of shells. This approach shows great promise for the development of next-generation high-performance electrochemical materials.

Therapeutic nanoparticles (NPs) based on the donor-acceptor-donor structured small organic molecule diketopyrrolopyrrole (SDPP) were prepared using a simple reprecipitation approach. These near-infrared radiation-absorbing NPs have high photothermal conversion efficiency and are able to selectively target cancer tissues through the enhanced permeability and retention effect. Benefiting from these advantages, SDPP NPs can serve as an excellent therapeutic agent for highly efficient and noninvasive photoacoustic imaging-guided photothermal therapy. Experiments using mouse tumor models showed that the SDPP NPs exhibited exceptional tumor ablation ability under laser irradiation (660 nm, 1.0 W·cm^-2), even at a low dose (0.16 mg·kg^-1).