SERS-based microdevices for use as in vitro diagnostic biosensors.

Advances in surface-enhanced Raman scattering (SERS) detection have helped to overcome the limitations of traditional in vitro diagnostic methods, such as fluorescence and chemiluminescence, owing to its high sensitivity and multiplex detection capability. However, for the implementation of SERS detection technology in disease diagnosis, a SERS-based assay platform capable of analyzing clinical samples is essential. Moreover, infectious diseases like COVID-19 require the development of point-of-care (POC) diagnostic technologies that can rapidly and accurately determine infection status. As an effective assay platform, SERS-based bioassays utilize SERS nanotags labeled with protein or DNA receptors on Au or Ag nanoparticles, serving as highly sensitive optical probes. Additionally, a microdevice is necessary as an interface between the target biomolecules and SERS nanotags. This review aims to introduce various microdevices developed for SERS detection, available for POC diagnostics, including LFA strips, microfluidic chips, and microarray chips. Furthermore, the article presents research findings reported in the last 20 years for the SERS-based bioassay of various diseases, such as cancer, cardiovascular diseases, and infectious diseases. Finally, the prospects of SERS bioassays are discussed concerning the integration of SERS-based microdevices and portable Raman readers into POC systems, along with the utilization of artificial intelligence technology.

Advancing COVID-19 Diagnosis: Enhancement in SERS-PCR with 30-nm Au Nanoparticle-Internalized Nanodimpled Substrates.

Real-time polymerase chain reaction (RT-PCR) with fluorescence detection is the gold standard for diagnosing coronavirus disease 2019 (COVID-19) However, the fluorescence detection in RT-PCR requires multiple amplification steps when the initial deoxyribonucleic acid (DNA) concentration is low. Therefore, this study has developed a highly sensitive surface-enhanced Raman scattering-based PCR (SERS-PCR) assay platform using the gold nanoparticle (AuNP)-internalized gold nanodimpled substrate (AuNDS) plasmonic platform. By comparing different sizes of AuNPs, it is observed that using 30 nm AuNPs improves the detection limit by approximately ten times compared to 70 nm AuNPs. Finite-difference time-domain (FDTD) simulations show that multiple hotspots are formed between AuNPs and the cavity surface and between AuNPs when 30 nm AuNPs are internalized in the cavity, generating a strong electric field. With this 30 nm AuNPs-AuNDS SERS platform, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA)-dependent RNA polymerase (RdRp) can be detected in only six amplification cycles, significantly improving over the 25 cycles required for RT-PCR. These findings pave the way for an amplification-free molecular diagnostic system based on SERS.

'Beyond Li-ion technology'-a status review.

Li-ion battery is currently considered to be the most proven technology for energy storage systems when it comes to the overall combination of energy, power, cyclability and cost. However, there are continuous expectations for cost reduction in large-scale applications, especially in electric vehicles and grids, alongside growing concerns over safety, availability of natural resources for lithium, and environmental remediation. Therefore, industry and academia have consequently shifted their focus towards 'beyond Li-ion technologies'. In this respect, other non-Li-based alkali-ion/polyvalent-ion batteries, non-Li-based all solid-state batteries, fluoride-ion/ammonium-ion batteries, redox-flow batteries, sand batteries and hydrogen fuel cells etc. are becoming potential cost-effective alternatives. While there has been notable swift advancement across various materials, chemistries, architectures, and applications in this field, a comprehensive overview encompassing high-energy 'beyond Li-ion' technologies, along with considerations of commercial viability, is currently lacking. Therefore, in this review article, a rationalized approach is adopted to identify notable 'post-Li' candidates. Their pros and cons are comprehensively presented by discussing the fundamental principles in terms of material characteristics, relevant chemistries, and architectural developments that make a good high-energy 'beyond Li' storage system. Furthermore, a concise summary outlining the primary challenges of each system is provided, alongside the potential strategies being implemented to mitigate these issues. Additionally, the extent to which these strategies have positively influenced the performance of these 'post-Li' technologies is discussed.

A facile green synthesis of gold nanoparticles using Canthium parviflorum extract sustainable and energy efficient photocatalytic degradation of organic pollutants for environmental remediation.

Organic dye and nitrophenol pollution from textiles and other industries present a substantial risk to people and aquatic life. One of the most essential remediation techniques is photocatalysis, which uses the strength of visible light to decolorize water. The present study reports Canthium Parviflorum (CNP) leaf extract utilization as an effective bio-reductant for green synthesis of Au NPs. A simple, eco-friendly process with low reaction time and temperature was adopted to synthesize CNP extract-mediated Au-NPs (CNP-AuNPs). The prepared AuNPs characterization involving X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron microscopy (XPS) surface area analysis, ultraviolet-visible spectroscopy (UV-Vis). XRD results showed that the cubic-structured AuNPs had a crystallite size of 14.12 nm. Assessment of organic dyes performance in degrading brilliant green (BTG) and amido black 10B (AMB) under visible light irradiation highlights an impressive 83.25% and 86% degradation efficiency within 120 min, accompanied by a kinetic rate constant dyes was found to be 0.0828 min⁻1, BTG, and 0.0123 min⁻1, Furthermore, the reduction of 4-nitrophenol by NaBH4 using CNP-AuNPs as a catalyst demonstrated good catalytic performance and rapid degradation at 89.4%. and rate constant 0.099 min-1 followed pseudo-first-order. The LC-MS analysis identified various intermediates during the degradation of the CR dye. Radical trapping experiments suggest that photogenerated free electrons and hydroxyl radicals are crucial for degrading the amido black 10B dye The AuNPs influenced the significant factors responsible for the photocatalytic activity, such as the increase in range of absorbance, increased e- and h+ pair separation, improvement in the charge transfer process, and active site formation, which significantly enhanced the process of degradation. We found that the CNP-AuNPs could effectively remove dyes and nitrophenol from industrial wastewater.

Fully printed non-contact touch sensors based on GCN/PDMS composites: enabling over-the-bottom detection, 3D recognition, and wireless transmission.

The rapid advancement in intelligent bionics has elevated electronic skin to a pivotal component in bionic robots, enabling swift responses to diverse external stimuli. Combining wearable touch sensors with IoT technology lays the groundwork for achieving the versatile functionality of electronic skin. However, most current touch sensors rely on capacitive layer deformations induced by pressure, leading to changes in capacitance values. Unfortunately, sensors of this kind often face limitations in practical applications due to their uniform sensing capabilities. This study presents a novel approach by incorporating graphitic carbon nitride (GCN) into polydimethylsiloxane (PDMS) at a low concentration. Surprisingly, this blend of materials with higher dielectric constants yields composite films with lower dielectric constants, contrary to expectations. Unlike traditional capacitive sensors, our non-contact touch sensors exploit electric field interference between the object and the sensor's edge, with enhanced effects from the low dielectric constant GCN/PDMS film. Consequently, we have fabricated touch sensor grids using an array configuration of dispensing printing techniques, facilitating fast response and ultra-low-limit contact detection with finger-to-device distances ranging from 5 to 100 mm. These sensors exhibit excellent resolution in recognizing 3D object shapes and accurately detecting positional motion. Moreover, they enable real-time monitoring of array data with signal transmission over a 4G network. In summary, our proposed approach for fabricating low dielectric constant thin films, as employed in non-contact touch sensors, opens new avenues for advancing electronic skin technology.

We've created 3D recognition sensing arrays using a printed method, enabling remote data transmission. We've identified an intriguing interfacial effect in GCN/PDMS doping, opening new possibilities in smart skin technology.

Recent advances in point-of-care testing of COVID-19.

Advances in microfluidic device miniaturization and system integration contribute to the development of portable, handheld, and smartphone-compatible devices. These advancements in diagnostics have the potential to revolutionize the approach to detect and respond to future pandemics. Accordingly, herein, recent advances in point-of-care testing (POCT) of coronavirus disease 2019 (COVID-19) using various microdevices, including lateral flow assay strips, vertical flow assay strips, microfluidic channels, and paper-based microfluidic devices, are reviewed. However, visual determination of the diagnostic results using only microdevices leads to many false-negative results due to the limited detection sensitivities of these devices. Several POCT systems comprising microdevices integrated with portable optical readers have been developed to address this issue. Since the outbreak of COVID-19, effective POCT strategies for COVID-19 based on optical detection methods have been established. They can be categorized into fluorescence, surface-enhanced Raman scattering, surface plasmon resonance spectroscopy, and wearable sensing. We introduced next-generation pandemic sensing methods incorporating artificial intelligence that can be used to meet global health needs in the future. Additionally, we have discussed appropriate responses of various testing devices to emerging infectious diseases and prospective preventive measures for the post-pandemic era. We believe that this review will be helpful for preparing for future infectious disease outbreaks.

Advanced protein nanobiosensors to in-situ detect hazardous material in the environment.

Determining hazardous substances in the environment is vital to maintaining the safety and health of all components of society, including the ecosystem and humans. Recently, protein-based nanobiosensors have emerged as effective tools for monitoring potentially hazardous substances in situ. Nanobiosensor detection mode is a combination of particular plasmonic nanomaterials (e.g., nanoparticles, nanotubes, quantum dots, etc.), and specific bioreceptors (e.g., aptamers, antibodies, DNA, etc.), which has the benefits of high selectivity, sensitivity, and compatibility with biological systems. The role of these nanobiosensors in identifying dangerous substances (e.g., heavy metals, organic pollutants, pathogens, toxins, etc.) is discussed along with different detection mechanisms and various transduction methods (e.g., electrical, optical, mechanical, electrochemical, etc.). In addition, topics discussed include the design and construction of these sensors, the selection of proteins, the integration of nanoparticles, and their development processes. A discussion of the challenges and prospects of this technology is also included. As a result, protein nanobiosensors are introduced as a powerful tool for monitoring and improving environmental quality and community safety.

Effective removal of perfluorooctanoic acid from water using PVA@UiO-66-NH2/GO composite materials via adsorption.

This study introduces an innovative approach using highly efficient nanocomposite materials to effectively remove PFAS from water, demonstrating remarkable adsorption capabilities. The nanocomposite was synthesized by integrating a zirconium-based metal-organic framework (MOF) called UiO-66 with graphene oxide (GO) within a polyvinyl alcohol (PVA) matrix. The resulting PVA@UiO-66/GO material features flower-like UiO-66 MOF crystals embedded in the PVA and GO matrix. Various kinetic models were applied to determine the rate constants and adsorption capacities, with the Langmuir isotherm indicating an adsorption capacity of 9.904 mg/g. Thermodynamic analysis confirmed the process's spontaneity and exothermic nature. The UiO-66-NH2/GO/PVA composite also demonstrated high reusability, maintaining substantial PFOA removal efficiency across multiple cycles, with optimal reduction occurring at approximately pH 5. Overall, the PVA@UiO-66/GO composites offer an effective, sustainable, and environmentally friendly solution for PFAS removal in water purification.

Efficient synthesis of 3D ZnO nanostructures on ITO surfaces for enhanced photoelectrochemical water splitting.

New photoactive materials with uniform and well-defined morphologies were developed for efficient and sustainable photoelectrochemical (PEC) water splitting and hydrogen production. The investigation is focused on hydrothermal deposition of zinc oxide (ZnO) onto indium tin oxide (ITO) conductive surfaces and optimization of hydrothermal temperature for growing uniform sized 3D ZnO morphologies. Fine-tuning of hydrothermal temperature enhanced the scalability, efficiency, and performance of ZnO-decorated ITO electrodes used in PEC water splitting. Under UV light irradiation and using eco-friendly low-cost hydrothermal process in the presence of stable ZnO offered uniform 3D ZnO, which exhibited a high photocurrent of 0.6 mA/cm2 having stability up to 5 h under light-on and light-off conditions. The impact of hydrothermal temperature on the morphological properties of the deposited ZnO and its subsequent performance in PEC water splitting was investigated. The work contributes to advancement of scalable and efficient fabrication technique for developing energy converting photoactive materials.

Highly Uniform Self-Assembly of Gold Nanoparticles by Butanol-Induced Dehydration and Its SERS Applications in SARS-CoV-2 Detection.

We report the development of a reproducible and highly sensitive surface-enhanced Raman scattering (SERS) substrate using a butanol-induced self-assembly of gold nanoparticles (AuNPs) and its application as a rapid diagnostic platform for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The butanol-induced self-assembly process was used to generate a uniform assembly of AuNPs, with multiple hotspots, to achieve high reproducibility. When an aqueous droplet containing AuNPs and target DNAs was dropped onto a butanol droplet, butanol-induced dehydration occurred, enriching the target DNAs around the AuNPs and increasing the loading density of the DNAs on the AuNP surface. The SERS substrate was evaluated by using Raman spectroscopy, which showed strong electromagnetic enhancement of the Raman signals. The substrate was then tested for the detection of SARS-CoV-2 using SERS, and a very low limit of detection (LoD) of 3.1 × 10-15 M was obtained. This provides sufficient sensitivity for the SARS-CoV-2 screening assay, and the diagnostic time is significantly reduced as no thermocycling steps are required. This study demonstrates a method for the butanol-induced self-assembly of AuNPs and its application as a highly sensitive and reproducible SERS substrate for the rapid detection of SARS-CoV-2. The results suggest the potential of this approach for developing rapid diagnostic platforms for other biomolecules and infectious diseases.