ACS Sensors最新文献

Self-powered sensors based on triboelectric nanogenerators (TENG) possess advantages such as lightweight, small size, and low cost. However, the trade-off among response time, sensitivity, and wear resistance of the triboelectric layer in such sensors remains unresolved. In this paper, a hydrophobic triboelectric layer was prepared using polydimethylsiloxane (PDMS) doped with polytetrafluoroethylene (PTFE), generating triboelectric signals through the contact and separation of the triboelectric layer with water. Compared to the traditional solid–solid triboelectric charging method in self-powered sensors, this sensor primarily relies on solid–liquid triboelectric charging, effectively avoiding the wear issues caused by traditional solid–solid triboelectric charging. Simultaneously, thanks to the solid–liquid contact mode, the response time of the self-powered sensor is significantly improved, and it maintains high sensitivity under extremely small trigger forces. Finally, this paper demonstrates the application of this self-powered sensor in scenarios such as detecting human joint movements, mechanical finger states, and robotic hand grasping states, showing its promising application prospects in the field of intelligent monitoring.

Metal-oxide-based gas sensors have attracted considerable interest due to their low cost, high sensitivity, quick response, and ease of miniaturization and integration. Unfortunately, metal oxides are susceptible to the interference of moisture, which brings about hydroxyl poisoning of the sensing layer and decrement in baseline resistance and sensor performance. In this study, WO₃ films were modified with a porous amorphous carbon layer. The as-loaded amorphous carbon layer improves simultaneously the adsorption capacity of WO₃ and hydrophobicity of the surface, which endows the composite films with not only surpassing NO₂ sensitivity at the parts per billion level but also enhanced immunity to humidity. The incorporation of amorphous carbon with metal oxides is expected to be a general route for the fabrication of high performance, antihumidity gas sensors.

Rapid identification of microparticles in liquid is an important problem in environmental and biomedical applications such as microplastic detection in water sources and physiological fluids. Existing spectroscopic techniques are usually slow and not compatible with flow-through systems. Here we analyze single microparticles in the 10–24 μm range using a combination of two electronic sensors in the same microfluidic system: a microwave capacitive sensor and a resistive pulse sensor. Together, this integrated sensor system yields an electrical signature of the analyte particles for their differentiation. To simplify data analysis, 3D electrode arrangements were used instead of planar electrodes so that the generated signal is unaffected by the height of the particle in the microfluidic channel. With this platform, we were able to distinguish between polystyrene (PS) and polyethylene (PE) microparticles. We showcase the sensitivity and speed of this technique and discuss the implications for the future application of microwave cytometry technology in the environmental and biomedical fields.

Understanding the origin and behavior of nonspecific interactions is essential for advancing biosensing technologies. In this study, we investigate nonspecific interactions between a functionalized single nanoparticle (NP) and a sensor surface. The NP, tethered by a single DNA molecule, exhibits flexible motion that allows it to interact with the surface. Using surface plasmon resonance microscopy (SPRM) with nanometer precision, we tracked the motion dynamics of the NP and revealed that nonspecific binding leads to repeated transient trapping at the surface. The NP shows a preference for interacting with a particular site, indicating site-preferred nonspecific interactions. This behavior mimics specific binding events, emphasizing the need to mitigate such effects in biosensors. By systematically varying NP size, ionic strength, solution viscosity, blocking agents, and applying external forces, we identified external force as the most effective factor in reducing such nonspecific interactions. We hope these insights can provide strategies for designing next-generation single-NP and single-molecule biosensors with minimal nonspecific signals, thereby enhancing detection reliability.

Iontronic pressure sensors (IPSs) are emerging as promising candidates for integration into wearable electronics and healthcare monitoring systems due to their high sensitivity and low power consumption. However, achieving high sensitivity across a broad linear pressure range remains a significant challenge. This study presents a novel IPS device with an asymmetric sandwich structure, which includes a three-dimensional electrode made of nickel manganese oxide/carbon nanotubes (NMO/CNT) and an embedded iron needles ionic dielectric layer. The proposed device demonstrates exceptional linearity over 1700 kPa, with a sensitivity exceeding 7700 kPa^–1. It exhibits rapid response and recovery times in the millisecond range and maintains a consistent capacitive response over 15,000 loading–unloading cycles. Moreover, the device enables noncontact sensing in response to magnetic field variations, broadening its potential applications. The innovative IPS design effectively balances high sensitivity and a wide linear pressure range, rendering it suitable for various applications such as nonverbal communication aids and healthcare monitoring systems.

The COVID-19 pandemic has highlighted the critical need for scalable, rapid, and cost-effective diagnostic solutions, especially in resource-limited settings. In this study, we developed a sustainable magnetic electrochemical biosensor for the mass testing of SARS-CoV-2, emphasizing affordability, environmental impact reduction, and clinical applicability. By leveraging recycled materials from spent batteries and plastics, we achieved a circular economy-based fabrication process with a recyclability rate of 98.5%. The biosensor employs MnFe₂O₄ nanoparticles functionalized with anti-SARS-CoV-2 antibodies, integrated into a 3D-printed electrochemical device for decentralized testing. Advanced characterization confirmed the biosensor’s robust performance, including high sensitivity (LOD: 3.46 pg mL^–1) and specificity, with results demonstrating a 95% correlation to RT-PCR gold standard testing. The cost of materials used per biosensor test is only USD 0.2, making it highly affordable and suitable for large-scale production using additive manufacturing. Key features include simple preparation, rapid response, and reusability, making it ideal for point-of-care diagnostics. Beyond COVID-19, this platform’s modularity allows for adaptation to other viral diseases, offering a versatile solution to global diagnostic challenges. This work highlights the potential of integrating electrochemical sensing with sustainable practices to address healthcare inequities and reduce environmental impact.