Advanced Sensor Research最新文献

Urea, a nitrogenous organic compound resulting from protein metabolism, is excreted as a waste product in urine. Elevated blood urea levels are associated with severe health conditions, including chronic kidney disease (CKD) and liver failure. Thus, monitoring urea levels is essential for CKD patients and individuals with metabolic disorders that heighten the risk of CKD. While existing diagnostic technologies offer high sensitivity and specificity, they are often expensive, require skilled operators, involve lengthy processing times, and are typically invasive and discontinuous. To address these challenges, researchers have developed various biosensor systems for rapid and cost-effective urea detection. This review provides a comprehensive overview of recent advancements in urea biosensing technologies, highlighting key challenges and potential solutions in biosensor design. It examines enzymatic and non-enzymatic urea biosensors, focusing on electrochemical detection techniques such as amperometry and potentiometry for enzymatic sensors and cyclic voltammetry for non-enzymatic sensors. Additionally, it explores material innovations, technological advancements, and strategies to enhance sensitivity, selectivity, portability, and stability. The integration of biosensors with IoT for real-time monitoring and their applications in medical diagnostics are also discussed.

In this modern era, wearable biosensors have emerged as a significant innovation in specialized personal healthcare. While smartphones and smartwatches today can easily measure vital signs and mobility, a new generation of wearable technology quickly emerges, allowing users to monitor their health metrics at the molecular level. Wearable electrochemical microneedle biosensors show the capability of detecting analytes and metabolites in interstitial fluid with minimal invasiveness. The use of microneedle sensing technology revolutionises biosensing techniques and opens new avenues for advancing current biosensors. In situ extraction, monitoring, and painless injection become possible through microneedle biosensors. However, there remains a need for improvement in detection accuracy and accessibility. This review begins with a discussion on the introduction and a comprehensive background of microneedle technology. It then explores different types of microneedles and fabrication methods. Various sensing modalities for microneedle biosensors, such as electrical, electrochemical, Raman, and colorimetric methods, are also discussed. Finally, the practical applications of wearable microneedle biosensors in various fields are examined, followed by a comprehensive conclusion and prospects.

In this modern era, wearable biosensors have emerged as a significant innovation in specialized personal healthcare. While smartphones and smartwatches today can easily measure vital signs and mobility, a new generation of wearable technology quickly emerges, allowing users to monitor their health metrics at the molecular level. Wearable electrochemical microneedle biosensors show the capability of detecting analytes and metabolites in interstitial fluid with minimal invasiveness. The use of microneedle sensing technology revolutionises biosensing techniques and opens new avenues for advancing current biosensors. In situ extraction, monitoring, and painless injection become possible through microneedle biosensors. However, there remains a need for improvement in detection accuracy and accessibility. This review begins with a discussion on the introduction and a comprehensive background of microneedle technology. It then explores different types of microneedles and fabrication methods. Various sensing modalities for microneedle biosensors, such as electrical, electrochemical, Raman, and colorimetric methods, are also discussed. Finally, the practical applications of wearable microneedle biosensors in various fields are examined, followed by a comprehensive conclusion and prospects.

Terahertz (THz) technology holds great promise in biomedical imaging, non-destructive testing, biosensing, and telecommunications, but its adoption is limited by weak light–matter interactions and strong dissipative losses in conventional metamaterials. To overcome these limitations, a dual strategy is introduced that combines interdigitated electric split-ring resonators (ID-eSRRs) with the complex-frequency wave (CFW) technique. Electrical gating from 0–200 V tunes the graphene Fermi level from 0.3756 to 0.6505 eV, providing a wide and continuous resonance shift for fingerprint-aligned sensing. The CFW method reconstructs loss-compensated spectra from real-frequency data, generating virtual gain and markedly sharpening resonances. Simulations show that the optimized ID-eSRR achieves a refractive index sensitivity of 196 GHz/RIU for 100 nm analytes, while CFW amplification increases the quality factor from 8.54 to 427.96, a 50.1-fold enhancement. This improvement enables reliable discrimination of DNA variants with refractive index differences as small as $$ at $$. The demonstrated approach provides a generalizable route to simultaneously enhance sensitivity and $$-factor, thereby overcoming the long-standing sensitivity–$$ trade-off and advancing the development of high-performance THz sensors for ultrasensitive biomedical diagnostics.

Metal halide perovskites (MHPs) have been proven to have excellent direct X-ray detection properties due to their high carrier lifetime product, strong X-ray absorption ability, a low electron-hole pair creation energy, and excellent charge transport properties. Millimeter-thickness polycrystalline MHPs (MPMHPs) can effectively utilize X-rays and have detection performance comparable to single-crystal MHP, and it is less difficult to synthesize. In this paper, we review the direct X-ray detectors and imagers based on MPMHPs. The basic knowledge of X-ray and direct X-ray detectors is introduced. This review focuses on describing in synthesis methods of MPMHPs and their X-ray detection performance. Furthermore, we summarize the X-ray imaging scheme and imaging application results of MPMHPs. Finally, we discuss future optimization methods in material synthesis, device optimization, and imaging applications. We hope that this review will help readers understand the basics of MPMHPs, improve detection performance, and boost imaging applications.

This study investigates how the emission mechanism (fluorescence, phosphorescence, or thermally activated delayed fluorescence, TADF) of a luminescence-quenching chemical sensor influences the sensitivity of explosives detection. Steady-state and time-resolved photoluminescence measurements were used to evaluate the quenching kinetics of representative emitters in the presence of 2,4-dinitrotoluene (DNT), a model nitroaromatic explosive. Linear Stern-Volmer behavior was observed for the fluorescent and phosphorescent emitters, whereas the TADF compound exhibited a pronounced downward deviation in steady-state measurements, arising from the simultaneous but distinct quenching of singlet and triplet exciton populations. To describe this behavior, we derived a modified Stern–Volmer formalism comprising separate relationships for the prompt and delayed fluorescence. The quenching dynamics of the TADF system were found to be strongly dependent on the intrinsic parameters $$, k_Stot and k_Ttot, with the singlet and triplet populations being quenched with different efficiencies. These insights highlight the potential of TADF luminophores to act as sensitive photoinduced electron transfer-based explosives sensors.

A high-performance capacitive sensor is presented for the determination of hydroquinone (HQ) based on n-type indium phosphide (n-InP) electrodes with an electrochemically deposited polyphosphazene (PPP) coating. The integration of PPP with InP electrodes offers a previously unexplored approach to chemical sensing. The polymer film is deposited evenly and well examined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS), which confirms the formation of a chemically stable and passivating interface. Capacitance–voltage (C–V) measurements in phosphate-buffered saline (PBS) reveal a linear detection range of 1–100 µm and a limit of detection (LOD) of 0.73 µm (n = 3), highlighting the sensitivity of the sensor. Selectivity tests indicate minimal interferences from structurally related phenolic substances such as catechol and phenol, corroborating the very high selectivity toward HQ. This capacitive sensing platform offers a promising approach for the rapid, sensitive, and selective detection of these hazardous chemicals, with vast potential for use in environmental monitoring and analytical fields.

Research in the domain of wearable electronics is observing a paradigm shift. Nowadays, most researchers are focusing on developing a unique wearable sensor solution for the early prognosis of several life-threatening diseases. Not only is prognosis important, but gaining a deeper insight into the underlying causality with the aid of sensors is also becoming popular. Among the various diseases, challenges related to respiratory disorders are potentially increasing worldwide. Accordingly, a lot of research is now being conducted to appropriately understand the various facets using such sensors. Therefore, in this review, the potential of polymer nanocomposite-based respiratory sensors has been examined. Representative examples of developing such sensors are discussed. The various mechanistic approaches that control the detection mechanism in such sensors are explored. Further, this review also discusses important factors such as cross-interference of signals and their impact on the final results. The futuristic self-powered respiratory sensors, with emphasis on triboelectric nanogenerators (TENG) and moisture electric generators (MEG), are discussed. All the sections are supported through examples from the literature. As a future outlook, the potential contributions of artificial intelligence (AI) and material improvisation to the growth and development of this field have also been discussed.

Non-Enzymatic Electrochemical Glucose Sensor

In the Research Article (DOI: 10.1002/adsr.202500069), Rahul Panat, Suhas Jejurikar, and co-workers demonstrate effective detection of glucose molecules using a carbon paper electrode modified by a stack of MWCNTs and NiO. Various characterization techniques show that the unique combination of materials in the stack enhances the electrocatalytic activity of the electrode, leading to the observed effects. This approach leads to enhanced non-enzymatic sensors for biomolecule detection.