Advanced Sensor Research最新文献

Coupling surface plasmon resonance (SPR) sensing with electrochemistry (EC) is a promising analytical strategy to obtain information about interfacial phenomena in heterogeneous reactions. Typical EC-SPR sensors utilize a metal film both as the plasmonic material and as the working electrode. In this configuration, the eigenmodulation of the plasmonic properties of the metal film under applied potential results in a background signal, which hampers the unambiguous interpretation of the sensor response due to redox reactions. Here, a new strategy is presented to overcome this disadvantage by using a van der Waals heterostructure (vdW-HS) as the working electrode. The vdW-HS comprises of a graphene / hexagonal boron nitride (hBN) stack on a gold film of a standard SPR sensor. It is shown here that the background signal is completely suppressed enabling the unambiguous analysis of SPR sensor response due to electrochemical reactions. It is further observed that the potential dependent plasmonic signals are not just a reproduction of the electrochemical current and subtle differences can be traced back to the diffusive nature of the redox active species. Finally, it is demonstrated that EC-SPR can be used as a complementary method to distinguish if the electrochemical response is mainly surface-bound or due to diffusion.

Reliable detection of hydrogen (H₂) leakage at low temperatures (e.g., < 273 K) is highly desired in those critical environments that may cause failure in detection, which needs further development. Herein, H₂ sensing that can work at ≈190–388 K temperature range has been developed by integrating palladium and zinc nanowires enwrapped with nanosheets (PdZn NWs) as the sensing materials, which have been prepared via combined anodic aluminum oxide (AAO) template-confined electrodeposition and surface engineering. Typically, as-synthesized PdZn NWs with a diameter of ≈50 nm present rough surfaces, along which abundant pores and fractures have been observed. Beneficially, the PdZn NWs show a lower critical temperature (≈190 K) of the “reverse sensing behavior” than that of pure Pd NWs (287 K), indicating the PdZn NWs are able to work at ≈190–388 K temperature range. Theoretically, such stable H₂ sensing can be attributed to the rough surfaces and chemical composition of PdZn NWs, which facilitates H atoms diffusion and accommodates the expansion of PdHx intermediates. The surface engineering of PdZn NWs may contribute to stable H₂ sensing at low temperatures, which can be applied to other gas-sensing materials working at low temperatures.

Sensors play a crucial role in enhancing the quality of life, ensuring safety, and facilitating technological advancements. Over the past decade, 2D layered materials have been added as new sensing element in addition to existing materials such as metal oxides, semiconductors, metals, and polymers. 2D Layered materials are typically characterized by their single or few-layer thickness and offer a high surface-to-volume ratio, exceptional mechanical strength, and unique electronic attributes. These properties make them ideal candidates for a variety of sensing applications. This review article focused on utilizing 2D layered materials in triboelectric nanogenerators (TENGs) for different sensing applications. The best part of TENG-based sensing is that it is self-powered, so no external power supply is required. The initial part of the review focused on the importance of the 2D layered materials and their innovative integration methods in TENGs. Further, this review discusses various sensing applications, including humidity, touch, force, temperature, and gas sensing, highlighting the impact of 2D layered materials in enhancing the sensitivity and selectivity of TENG sensors. The last part of the review discusses the challenges and prospects of TENG-based self-powered sensors.

Chronic kidney disease (CKD) has asymptomatic early stages, whereby early detection is crucial to prevent its complications and progression. Creatinine and cystatin C (cysC) assays are known for assessing kidney function but there are limited point-of-care diagnostics which are rapid, precise, and easy to use. Here, high resistivity silicon conductometric sensors for detection of creatinine and cysC with a 10 min sample incubation is introduced. The sensors provide resistance-based signals that can be quantified and measured wirelessly. The sensors successfully detect creatinine and cysC in both phosphate buffer saline (PBS) and artificial saliva in the nanomolar range, being able to distinguish their critical concentrations at 8.8 and 20 nm, respectively, for diagnosis of early stage of CKD. The detection limit for both creatinine and cysC is determined as 0.01 nm which is more than 500× and 1000× times lower than critical concentrations for the two biomarkers, respectively. Finally, these sensors are incorporated into a battery-free, miniaturized electronic device for wireless biomarker detection as a proof-of-concept demonstration of a point-of-care tool for assessing kidney functionality.

The volatile aroma released from agricultural products is closely related to the health status and quality of their growth, thus endowing the related detection with great significance. For example, the dynamic variation of the volatile chemical composition of a banana during the growth process can reflect its ripeness. Also important for quality monitoring and storage is to precisely and swiftly identify volatile compounds produced by mildew in rice and wheat. In this endeavor, the current detection technologies such as gas chromatography-mass spectrometry method (GC-MS)  cannot meet the pressing needs of smart agriculture in terms of real-time monitoring, cost-effectiveness, sensitivity, and detection speed, thereby necessitating alternative strategies to simultaneously satisfy these requirements. Aiming to provide an overall development trend in this field, this paper summarizes the existing detection technologies including GC-MS, E-nose, and sensory analysis with their respective shortcomings and challenges, and then proposes the application prospects. This work can effectively enrich the reliable monitoring methods for volatile agricultural fragrance while promoting the long-run development of smart agriculture.

To develop a field applicable hazardous molecular detection system, highly sensitive and multiplex detection capability is required for practical utilization. Here, a paper-based 3D spiky needle-clustered gold grown on silver (Ag@Au) plasmonic nanoarchitecture (3D-SNCP) is fabricated through whole solution process. The developed substrate is investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) to find out morphological development mechanism. Also, finite-domain time difference (FDTD) simulation is conducted for the observation of electromagnetic field (E-field) distribution. After surface-enhanced Raman scattering (SERS) characterization, the 3D-SNCP is utilized for ultra-sensitive and multiplex hazardous molecular detection, such as bipyridine pesticides including paraquat (PQ), diquat (DQ), and difenzoquat (DIF). Then, each of pesticide molecular Raman signals are trained by a machine learning technique of multinomial logistic regression (MLR), followed by multiplex classificationf of blank, PQ, DQ, DIF, and four mixture types of each pesticide, spiked in real agricultural matrix. The developed 3D-SNCP substrate combined with the machine learning method successfully verifies the multiple pesticides and it is expected to be applied for various hazardous molecular detection in much complicated matrix environments.

Developing progressive photoelectrochemical (PEC) techniques holds great potential for advancing analytical sensitivity in clinical. However, the low transport and separation of charge carrier efficiency and deficient active sites block efficient and durable PEC analytical performance features. And herein a piezo-assisted PEC sensing platform for glutathione (GSH) detection are successfully prepared based on S vacancies rich CdS (S_v-CdS) nanowires. The collaboration of piezoelectric polarization and S vacancies engineering contributed to the boosted PEC performance by accelerating the spatial separation of photogenerated charges and providing abundant active sites. Moreover, the charge transfer efficiency further promoted with the introduction of GSH acted a hole scavenge that effectively suppresses the electron-hole recombination, giving rise to an amplified photocurrent. As a demonstration, the proposed method presents an outstanding analytical performance toward GSH. Consequently, this work provides an inspirable and convenient route for designing high-efficiency photoelectrode in PEC sensing in virtue of judicious structural, and defect engineering, and the exploring of an external-field-coupling-enhanced PEC platform.

Detection of liquid viscosity is important from chemical engineering to daily safety. To match the emergence of internet of things, precise and fast viscosity determination is attracting intention in the society. However, most miniature viscometers face limitations such as high operation frequency, moving component, and non-linear sensing, etc. Herein, a flexible viscometer is developed via coupling the electromagnetic induction with inherent oscillation of a magnetized oscillator. The mechanism allows vibration of the oscillator to be electrically reflected using damping signals. By analyzing the damping factor from viscosity-dependent voltage profiles, viscosity of an unknown liquid can be accurately obtained. Furthermore, the 3D structures is developed with a dual-template method, which enables convenient and high-throughput preparations of devices with complex 3D structures. Via optimizing the structural and physical parameters, the “sphere” oscillator enables a linear relationship between the damping factor and the square root of viscosity for quantitative sensing in range of 0.01809–24.7 mPa s. The principle of electromagnetic induction renders the viscometer with superiorities of low operating frequency, remote sensing, self-powered and chemical stability. It is expected that the methodology and damping dominant mechanism will serve as a promising platform for cost-effective, portable and convenient viscosity detection for applications in diverse fluids.

Magneto-plasmonic particles, comprising gold and iron oxide, exhibit substantial potential for biosensing applications due to their distinct properties. Gold nanoparticles (AuNPs) provide plasmonic features, while iron oxide composites, responsive to an external magnetic field, significantly reduce detection time compared to passive diffusion. This study explores core@satellite magneto-plasmonic particles (CSMPs), featuring magnetic nanoparticle clusters and numerous satellite-like AuNPs, to amplify the optical response on a nanostructured gold surface. Using a sandwich scheme, target analytes are detected as hybrid nanoparticles bind to the pre-immobilized target on the AuNPs surface, inducing changes in the immunosensor's extinction spectrum. Application of an external magnetic field notably enhances biosensor response and sensitivity, reducing assay time from hours to minutes. Leveraging the properties of CSMPs, the immunosensor detects specific immune protein at low concentrations within minutes. CSMPs hold considerable promise for precise and sensitive analyte detection, offering potential applications in rapid testing and mass screening.