ACS Sensors最新文献

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.

How to modulate the molecular structure to finely manipulate the sensing performance is of great significance for propelling the oriented design of the optical sensing probe. Here, by taking the optical detection toward amphetamine (AMP) as a model, a structural regulation strategy for the D-π-A probe was proposed to manipulate the reaction activity and optical response. The optimal probe was screened out from a series of D-π-A molecules with an electrophilic site owing to its faster response and more remarkable emission shift, as well as the desirable specificity. In particular, it was found that the probe reactivity induced two trade-off effects. First, it is kinetically expressed by the reaction time that greatly affects the sensitivity (emission shift), and second, it thermodynamically determines the specificity. Upon fine modulation, the optimal probe in the solid state integrated in a portable sensing chip was demonstrated with fast and visualized analysis for AMP in complicated scenarios. Overall, the proposed structure–performance correlation and the mediation on the trade-off effect would provide an in-depth insight for the oriented design of an optical sensor with a desirable sensing performance.

Highly sensitive, selective, and compact hydrogen (H₂) sensors for safety and process monitoring are needed due to the growing adoption of H₂ as a clean energy carrier. Current resonant frequency-based H₂ sensors face a critical challenge in simultaneously achieving high sensitivity, low operating frequency, and miniaturization while maintaining a high figure of merit (FOM). This study addresses these challenges by introducing a novel piezoelectric micro diagram (PMD) H₂ sensor that achieves an unprecedented FOM exceeding 10⁴. The sensor uniquely integrates a PMD resonator with a palladium (Pd) sensing layer, operating on a stress-based mechanism distinct from traditional mass-loading principles. Despite a low operating frequency of 150 kHz, the sensor demonstrates a remarkable sensitivity of 18.5 kHz/% H₂. Comprehensive characterization also reveals a minimal cross-sensitivity to humidity and common gases and a compact form factor (600 μm lateral length) suitable for IC integration. The sensor’s performance was systematically evaluated across various Pd thicknesses (40–125 nm) and piezoelectric stack covering ratios (50% and 70%), revealing a trade-off between sensitivity and response time. This PMD H₂ sensor represents a significant advancement in resonant frequency-based H₂ sensing, offering superior sensitivity, compact size, and robust performance for diverse applications in H₂ detection and monitoring.

Surface-enhanced Raman scattering (SERS) offers significant advantages for single-molecule detection. However, stochastic molecular motion makes it challenging to consistently capture signals from single-molecule binding events, particularly in complex environments. Herein, we propose a novel SERS system via the pore nanoconfinement effect of covalent organic frameworks (COFs) to achieve reliable single-molecule detection. The self-assembled COF thin films on SERS metal substrates (Au/Ag) create a nanogap of 3 nm, allowing electric field enhancement. By precise tuning of the COF shell thickness, a molecular-scale pore volume is formed, effectively trapping individual molecules from molecular aggregates. Furthermore, the strong intermolecular forces within the COF pores significantly enhance the residence time of individual molecules, thereby increasing the probability of detecting single-molecule binding events. This innovative approach ensures consistent and reliable SERS single-molecule detection in complex mixtures, paving the way for advanced applications in biochemical sensing and diagnostics.