Wearable Biodevices Based on Two-Dimensional Materials: From Flexible Sensors to Smart Integrated Systems

Flexible and wearable electrochemical sensors for health and safety monitoring

Environmental safety monitoring is a crucial process that involves continuous and systematic observation and analysis of various pollutants in the environment to ensure its quality and safety. This monitoring encompasses a wide range of areas, including physical indicator monitoring (pertaining to parameters such as temperature, humidity, and wind speed), chemical indicator monitoring (focused on detecting harmful substances in environmental media such as air, water, and soil), and ecosystem monitoring (including biodiversity assessments and judgments on the health status of ecosystems). This review delves deeply into the significant advancements achieved in the field of flexible and wearable electrochemical sensors (FWESs) over the past fifteen years (from 2010 to 2024). It emphasizes the broad application of these sensors in health and environmental safety monitoring, with health monitoring primarily focusing on exhaled breath and sweat, and environmental monitoring covering temperature, humidity, and pollutants in air and water. By seamlessly integrating electrochemical principles, advanced sensor manufacturing technologies, and sensor functionalization, FWESs have opened up new avenues for non-invasive real-time monitoring of human health and environmental safety. This review highlights key developments in sensor structures, including flexible substrates, printed electrodes, and active materials. It also underscores the remarkable progress made in healthcare and environmental monitoring through the utilization of FWES. Despite these promising advancements, this emerging field still faces numerous challenges, such as improving sensor accuracy, enhancing durability, and reducing costs. The review concludes by discussing the future directions in this field, including ongoing research efforts aimed at overcoming these challenges and expanding the applications of FWESs in various sectors.

Trace Detection of Nitrogen Dioxide via Porous Tin Dioxide Nanopods with High Specific Surface Area and Enhanced Charge Transfer

Nitrogen oxides, particularly nitrogen dioxide (NO2), contribute significantly to environmental pollution and pose serious risks to public health. Therefore, detecting even low concentrations of NO2 is significant for effective environmental monitoring and public health protection. Existing NO2 gas sensors, however, have limitations such as low sensitivity, insufficient selectivity, and slow response and recovery times. In this work, we synthesized tin-based metal-organic framework nanorods using phthalic acid as the ligand and subsequently fabricated porous tin dioxide (SnO2) nanopods through high-temperature calcination. The resulting SnO2 nanopods feature one-dimensional rod-like SnO2 frameworks filled with plenty of SnO2 nanoparticles. This micronanostructure exhibits a large specific surface area (299.8 m2/g) and a large pore size (30.8 nm), which facilitates the adsorption, diffusion, and surface reactions of NO2. The sensors demonstrate excellent performance in detecting NO2, with a response value of 64 to 1 part per million (ppm) NO2 at a working temperature of 250 °C, a response time of 15 s, and a recovery time of 20 s. Moreover, the SnO2 nanopod sensors show a wide detection range from 10 parts per billion to 100 ppm, good repeatability, long-term stability, and reliable NO2 detection at low concentrations even under high humidity conditions (90% relative humidity).

Gestational Exposure to Black Phosphorus Nanoparticles Induces Placental Trophoblast Dysfunction by Triggering Reactive Oxygen Species-Regulated Mitophagy

As a type of two-dimensional nanomaterial, black phosphorus (BP) has attracted considerable interest for applications in various fields. Despite its advantages, including biodegradability and biocompatibility, recent studies have shown that BP exhibits cytotoxicity in different types of cells. However, no studies have investigated the effects of BP exposure during pregnancy. Herein, we first investigated the effect of gestational exposure to BP nanoparticles (BPNPs) in a mouse model. Our findings indicated that BPNPs exposure restricted fetal growth and hindered placental development. In HTR8/SVneo trophoblast cells, BPNPs inhibited cell proliferation, migration, and invasion and caused apoptosis in a dose-dependent manner. Furthermore, BPNPs induced intracellular reactive oxygen species (ROS) overproduction and extensive mitochondrial damage. We further demonstrated that BPNPs promoted mitophagy via the PINK1/Parkin signaling pathway. Parkin siRNA knockdown rescued BPNPs-induced trophoblast dysfunction, while ROS inhibition attenuated BPNPs-induced cytotoxicity by reducing mitochondrial damage. Finally, treatment with mdivi-1, a mitophagy inhibitor, mitigated mitochondrial membrane potential reduction, excessive mtROS production, and the resulting trophoblast dysfunction. In vivo model investigation indicated that the application of mdivi-1 ameliorated embryonic resorption and fetal growth by alleviating placental damage. In summary, gestational exposure to BPNPs impairs fetal growth by inducing placental trophoblast dysfunction through ROS-regulated, PINK1/Parkin-dependent mitophagy.

Advancements in Wearable and Implantable BioMEMS Devices: Transforming Healthcare Through Technology

Wearable and implantable BioMEMSs (biomedical microelectromechanical systems) have transformed modern healthcare by enabling continuous, personalized, and minimally invasive monitoring, diagnostics, and therapy. Wearable BioMEMSs have advanced rapidly, encompassing a diverse range of biosensors, bioelectronic systems, drug delivery platforms, and motion tracking technologies. These devices enable non-invasive, real-time monitoring of biochemical, electrophysiological, and biomechanical signals, offering personalized and proactive healthcare solutions. In parallel, implantable BioMEMS have significantly enhanced long-term diagnostics, targeted drug delivery, and neurostimulation. From continuous glucose and intraocular pressure monitoring to programmable drug delivery and bioelectric implants for neuromodulation, these devices are improving precision treatment by continuous monitoring and localized therapy. This review explores the materials and technologies driving advancements in wearable and implantable BioMEMSs, focusing on their impact on chronic disease management, cardiology, respiratory care, and glaucoma treatment. We also highlight their integration with artificial intelligence (AI) and the Internet of Things (IoT), paving the way for smarter, data-driven healthcare solutions. Despite their potential, BioMEMSs face challenges such as regulatory complexities, global standardization, and societal determinants. Looking ahead, we explore emerging directions like multifunctional systems, biodegradable power sources, and next-generation point-of-care diagnostics. Collectively, these advancements position BioMEMS as pivotal enablers of future patient-centric healthcare systems.

Biomass Cellulose-Derived Carbon Aerogel Supported Magnetite-Copper Bimetallic Heterogeneous Fenton-like Catalyst Towards the Boosting Redox Cycle of ≡Fe(III)/≡Fe(II)

To degrade high-concentration and toxic organic effluents, we developed Fe-Cu active sites loaded on biomass-source carbon aerogel (CA) to produce a low-cost and high-efficiency magnetic Fenton-like catalyst for the catalytic oxidative decomposition of organic pollutants. It exhibits excellent performance in catalytic Fenton-like reactions for RhB removal at an ultrahigh initial concentration of up to 1000 ppm. To be specific, Fe3O4 and Cu nanoparticles are generated in situ on a mesoporous CA support, denoted as an Fe3O4-Cu/CA catalyst. Experimentally, factors including initial dye concentration, catalyst dosage, H2O2 dosage, pH, and temperature, which significantly influence the oxidative degradation rate of RhB, are carefully studied. The RhB (1000 ppm) degradation ratio reaches 93.7% within 60 min under low catalyst and H2O2 dosage. The catalyst also shows slight metal leaching (almost 1.4% of total Fe and 4.0% of total Cu leached after a complete degradation of 25 μmol RhB under conditions of 15 mg catalyst dosage, 20 mL RhB solution (600 ppm), and 200 μL 30 wt% H2O2 dosage, at pH of 2.5, at 40 °C), good catalytic activity for degrading organic pollutants, excellent reusability, and good catalytic stability (the degradation ratio is nearly 82.95% in the 8th cycle reaction). The synergistic effect between Fe and Cu species plays a vital role in promoting the redox cycle of Fe(III)/Fe(II) and enhancing the generation of ·OH. It is suitable for ultrahigh-concentration organic pollutant degradation in practical wastewater treatment applications.

Integration of Bio-Enzyme-Treated Super-Wood and AIE-Based Nonwoven Fabric for Efficient Evaporating the Wastewater with High Concentration of Ammonia Nitrogen

The treatment of ammonia nitrogen wastewater (ANW) has garnered significant attention due to the ecology, and even biology is under increasing threat from over discharge ANW. Conventional ANW treatment methods often encounter challenges such as complex processes, high costs and secondary pollution. Considerable progress has been made in employing solar-induced evaporators for wastewater treatment. However, there remain notable barriers to transitioning from fundamental research to practical applications, including insufficient evaporation rates and inadequate resistance to biofouling. Herein, we propose a novel evaporator, which comprises a bio-enzyme-treated wood aerogel that serves as water pumping and storage layer, a cost-effective multi-walled carbon nanotubes coated hydrophobic/hydrophilic fibrous nonwoven mat functioning as photothermal evaporation layer, and aggregation-induced emission (AIE) molecules incorporated as anti-biofouling agent. The resultant bioinspired evaporator demonstrates a high evaporation rate of 12.83 kg m-2 h-1 when treating simulated ANW containing 30 wt% NH4Cl under 1.0 sun of illumination. AIE-doped evaporator exhibits remarkable photodynamic antibacterial activity against mildew and bacteria, ensuring outstanding resistance to biofouling over extended periods of wastewater treatment. When enhanced by natural wind under 1.0 sun irradiation, the evaporator achieves an impressive evaporation rate exceeding 20 kg m-2 h-1. This advancement represents a promising and viable approach for the effective removal of ammonia nitrogen wastewater.