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Conductometric gas sensors facilitated by photons have been investigated for decades. Light illumination may enhance device attributes including operational temperature, sensing sensitivity and selectivity. This paper aims to provide an overview on the progress of light-activated gas sensors, with a specific focus on sensors based on metal oxides. The material systems that have been studied include pure metal oxides, heterostructures of semiconductor-metal oxides and metal-metal oxides, and metal oxides with dopant. Other reported works on the use of different nanostructures such as one-dimensional and porous nanostructures, study of sensing mechanisms and the interplay between various factors are also summarized. Possible directions for further improvement of sensing properties, through optimizing the size of nanomaterials, film thickness, light intensity and wavelength are discussed. Finally, we point out that the main challenge faced by light-activated gas sensors is their low optical response, and we have analyzed the feasibility of using localized surface plasmon resonance to solve this drawback. This article should offer readers some key and instructive insights into the current and future development of light-activated gas sensors.

Electrokinetic force has been the major choice for driving the translocation of molecules through a nanopore. However, the use of this approach is limited by an uncontrollable translocation speed, resulting in non-uniform conductance signals with low conformational sensitivity, which hinders the accurate discrimination of the molecules. Here, we show the use of inertial-kinetic translocation induced by spinning an in-tube micro-pyramidal silicon nanopore fabricated using photovoltaic electrochemical etch-stop technique for biomolecular sensing. By adjusting the kinetic properties of a funnel-shaped centrifugal force field while maintaining a counter-balanced state of electrophoretic and electroosmotic effect in the nanopore, we achieved regulated translocation of proteins and obtained stable signals of long and adjustable dwell times and high conformational sensitivity. Moreover, we demonstrated instantaneous sensing and discrimination of molecular conformations and longitudinal monitoring of molecular reactions and conformation changes by wirelessly measuring characteristic features in current blockade readouts using the in-tube nanopore device. The authors report a strategy to achieve high S/N ratio signal readout in single molecule sensing by incorporating the inertial forces as a new channel for independently controlling the translocation parameters with high precision.

HighlightsA zero-reflection-induced phase singularity is achieved through precisely controlling the resonance characteristics using two-dimensional nanomaterials.An atomically thin nano-layer having a high absorption coefficient is exploited to enhance the zero-reflection dip, which has led to the subsequent phase singularity and thus a giant lateral position shift.We have improved the detection limit of low molecular weight molecules by more than three orders of magnitude compared to current state-of-art nanomaterial-enhanced plasmonic sensors.Detection of small cancer biomarkers with low molecular weight and a low concentration range has always been challenging yet urgent in many clinical applications such as diagnosing early-stage cancer, monitoring treatment and detecting relapse. Here, a highly enhanced plasmonic biosensor that can overcome this challenge is developed using atomically thin two-dimensional phase change nanomaterial. By precisely engineering the configuration with atomically thin materials, the phase singularity has been successfully achieved with a significantly enhanced lateral position shift effect. Based on our knowledge, it is the first experimental demonstration of a lateral position signal change > 340 μm at a sensing interface from all optical techniques. With this enhanced plasmonic effect, the detection limit has been experimentally demonstrated to be 10–15 mol L−1 for TNF-α cancer marker, which has been found in various human diseases including inflammatory diseases and different kinds of cancer. The as-reported novel integration of atomically thin Ge2Sb2Te5 with plasmonic substrate, which results in a phase singularity and thus a giant lateral position shift, enables the detection of cancer markers with low molecular weight at femtomolar level. These results will definitely hold promising potential in biomedical application and clinical diagnostics.

Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In general, an extremely thin silver (Ag) layer (1, 3, 5 nm) and a 100 nm ZnO film are sequentially deposited on the SiO2/Si substrate by a magnetron sputtering method. The porous nanostructure of ZnO film is formed after thermal annealing contributed by the diffusion of Ag among ZnO crystal grains and the expansion of the ZnO film. Different thicknesses of the Ag layer help the formation of different sizes and quantities of hollows uniformly distributed in the ZnO film, which is demonstrated to hold superior gas sensing abilities than the compact ZnO film. The responses of the different porous ZnO films were also investigated in the ammonia concentration range of 10 to 300 ppm. Experimental results demonstrate that the ZnO/Ag(3 nm) sensor possesses a good electrical resistance variation of 85.74% after exposing the sample to 300 ppm ammonia gas for 310 s. Interestingly, a fast response of 61.18% in 60 s for 300 ppm ammonia gas has been achieved from the ZnO/Ag(5 nm) sensor, which costs only 6 s for the response increase to 10%. Therefore, this controllable, porous, nanostructured ZnO film maintaining a sensitive gas response, fabricated by the physical deposition approach, will be of great interest to the gas-sensing community.

Self‐supervised denoising has emerged as a promising approach for enhancing the quality of medical imaging, particularly in modalities such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and optical microscopy. Traditional supervised methods often require large datasets of paired noisy and clean images, which are challenging to acquire in clinical practice. In contrast, self‐supervised strategies exploit the inherent redundancy and structure within the data itself, enabling effective noise reduction without the need for explicitly labeled training pairs. This Perspective synthesizes recent advances in self‐supervised denoising techniques, outlining their underlying principles, algorithmic innovations, and practical applications across different imaging modalities. In MRI, these methods have been shown to improve contrast and detail resolution, while in CT, they contribute to reducing radiation dose by allowing lower signal acquisitions without compromising image quality. In optical microscopy, self‐supervised denoising facilitates extracting high‐fidelity cellular information from inherently low‐light environments. Furthermore, these techniques have also proven effective in imaging of biomedical materials, such as tissue engineering scaffolds, drug delivery systems, and implants, improving the evaluation of their interactions with biological tissues. Collectively, the integration of these advanced denoising frameworks holds significant promise for improving diagnostic accuracy, streamlining clinical workflows, and ultimately enhancing patient outcomes. Optical microscopy is a fundamental tool of clinical imaging. AI‐driven self‐supervised denoising techniques enhance optical microscopy imaging, enabling high‐resolution long‐term tracking of in vivo and in vitro cells with minimal photodamage. This breakthrough improves clinical tools for molecular tracking, protein interaction studies, and drug efficacy assessment, revolutionizing medical imaging.

Surface plasmon resonance (SPR) biosensor is a powerful tool for studying the kinetics of biomolecular interactions because they offer unique real-time and label-free measurement capabilities with high detection sensitivity. In the past two decades, SPR technology has been successfully commercialized and its performance has continuously been improved with lots of engineering efforts. In this review, we describe the recent advances in SPR technologies. The developments of SPR technologies focusing on detection speed, sensitivity, and portability are discussed in details. The incorporation of imaging techniques into SPR sensing is emphasized. In addition, our SPR imaging biosensors based on the scanning of wavelength by a solid-state tunable wavelength filter are highlighted. Finally, significant advances of the vast developments in nanotechnology-associated SPR sensing for sensitivity enhancements are also reviewed. It is hoped that this review will provide some insights for researchers who are interested in SPR sensing, and help them develop SPR sensors with better sensitivity and higher throughput.

In this paper, we report a simple, rapid, low-cost, biocompatible, and detachable microfluidic chip fabrication method for customized designs based on Parafilm®. Here, Parafilm® works as both a bonding agent and a functional membrane. Its high ultimate tensile stress (3.94 MPa) allows the demonstration of high-performance actuators such as microvalves and micropumps. By laser ablation and the one-step bonding of multiple layers, 3D structured microfluidic chips were successfully fabricated within 2 h. The consumption time of this method (~2 h) was 12 times less than conventional photolithography (~24 h). Moreover, the shear stress of the PMMA–Parafilm®–PMMA specimens (0.24 MPa) was 2.13 times higher than that of the PDMS–PDMS specimens (0.08 MPa), and 0.56 times higher than that of the PDMS–Glass specimens (0.16 MPa), showing better stability and reliability. In this method, multiple easily accessible materials such as polymethylmethacrylate (PMMA), PVC, and glass slides were demonstrated and well-incorporated as our substrates. Practical actuation devices that required high bonding strength including microvalves and micropumps were fabricated by this method with high performance. Moreover, the biocompatibility of the Parafilm®-based microfluidic devices was validated through a seven-day E. coli cultivation. This reported fabrication scheme will provide a versatile platform for biochemical applications and point-of-care diagnostics.

Centrifugal microfluidic or lab-on-a-disc platforms have many advantages over other microfluidic systems. These advantages include a minimal amount of instrumentation, the efficient removal of any disturbing bubbles or residual volumes, and inherently available density-based sample transportation and separation. Centrifugal microfluidic devices applied to biomedical analysis and point-of-care diagnostics have been extensively promoted recently. This paper presents an up-to-date overview of these devices. The development of biomedical centrifugal microfluidic platforms essentially covers two categories: (i) unit operations that perform specific functionalities, and (ii) systems that aim to address certain biomedical applications. With the aim to provide a comprehensive representation of current development in this field, this review summarizes progress in both categories. The advanced unit operations implemented for biological processing include mixing, valving, switching, metering and sequential loading. Depending on the type of sample to be used in the system, biomedical applications are classified into four groups: nucleic acid analysis, blood analysis, immunoassays, and other biomedical applications. Our overview of advanced unit operations also includes the basic concepts and mechanisms involved in centrifugal microfluidics, while on the other hand an outline on reported applications clarifies how an assembly of unit operations enables efficient implementation of various types of complex assays. Lastly, challenges and potential for future development of biomedical centrifugal microfluidic devices are discussed.

Graphene is emerging as an ideal material for new-generation optoelectronic devices. In this paper, a novel graphene metasurface-based electrically switchable and tunable infrared light modulator has been proposed and theoretically studied. The functional modulator comprises a monolayer graphene sheet sandwiched in a Fabry–Perot (FP) like nanostructure consisting of a metal reflector, a dielectric spacer, and an ellipse patterned anisotropy antenna layer. As a result of the photon localization effect of the guided-mode resonance (GMR) in the FP structure, the graphene electroabsorption can be significantly enhanced to enable a high-performance light modulator. By fine-tuning the Fermi energy ( ) of graphene via controlling its bias-gate voltage, the proposed modulator can switch between a perfect absorber and a reflective polarization converter of high conversion efficiency (i.e., >90%) at 1550 nm. The conversion mechanism and the geometric dependences of the infrared light modulator have been investigated. We further demonstrated the tunability of the highly-efficient polarization converter over a broad spectrum by adjusting the real dispersion of . Our design concept provides an effective strategy for customizing novel optoelectronic devices by combining an electrically-tunable 2D material with a functional metasurface.

Surface plasmonic resonance (SPR) has been a corner stone for approaching single molecular detection due to its high-sensitivity capability and simple detection mechanism, and has brought major advancements in biomedicine and life science technology. Over decades, the successful integration of SPR with versatile techniques has been demonstrated. However, several crucial limitations have hindered this technique for practical applications, such as long detection time and low overall sensitivity. This review aims to provide a comprehensive summary of existing approaches in enhancing the performance of SPR sensors based on “passive” and “active” methods. Firstly, passive enhancement is discussed from a material aspect, including signal amplification tags and modifications of conventional substrates. Then, the focus is on the most popular active enhancement methods including electrokinetic, optical, magnetic, and acoustic manipulations that are summarized with highlights on their advantageous features and ability to concentrate target molecules at the detection sites. Lastly, prospects and future development directions for developing SPR sensing towards a more practical, single molecular detection technique in the next generation are discussed. This review hopes to inspire researchers’ interests in developing SPR-related technology with more innovative and influential ideas.