Rapid capture and SERS detection of triclosan using a silver nanoparticle core - protein satellite substrate

Biosensor Technologies for Water Quality: Detection of Emerging Contaminants and Pathogens

This review explores the development, technological foundations, and applications of biosensor technologies across various fields, such as medicine for disease diagnosis and monitoring, and the food industry. However, the primary focus is on their use in detecting contaminants and pathogens, as well as in environmental monitoring for water quality assessment. The review classifies different types of biosensors based on their bioreceptor and transducer, highlighting how they are specifically designed for the detection of emerging contaminants (ECs) and pathogens in water. Key innovations in this technology are critically examined, including advanced techniques such as systematic evolution of ligands by exponential enrichment (SELEX), molecularly imprinted polymers (MIPs), and self-assembled monolayers (SAMs), which enable the fabrication of sensors with improved sensitivity and selectivity. Additionally, the integration of microfluidic systems into biosensors is analyzed, demonstrating significant enhancements in performance and detection speed. Through these advancements, this work emphasizes the fundamental role of biosensors as key tools for safeguarding public health and preserving environmental integrity.

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.

Potential of a deep eutectic solvent in silver nanoparticle fabrication for antibiotic residue detection

Deep eutectic solvents (DESs) have recently emerged as an alternative solvent for nanoparticle synthesis. There have been numerous advancements in the fabrication of silver nanoparticles (Ag NPs), but the potential of DESs in Ag NP synthesis was neither considered nor studied carefully. In this study, we present a novel strategy to fabricate Ag NPs in a DES (Ag NPs-DES). The DES composed of ᴅ-glucose, urea, and glycerol does not contain any anions to precipitate with Ag+ cations. Our Ag NPs-DES sample is used in a surface-enhanced Raman scattering (SERS) sensor. The two analytes for SERS quantitation are nitrofurantoin (NFT) and sulfadiazine (SDZ) whose residues can be traced down to 10-8 M. The highest enhancement factors (EFs) are competitive at 6.29 × 107 and 1.69 × 107 for NFT and SDZ, respectively. Besides, the linearity coefficients are extremely close to 1 in the range of 10-8 to 10-3 M of concentration, and the SERS substrate shows remarkable uniformity along with great selectivity. This powerful SERS performance indicates that DESs have tremendous potential in the synthesis of nanomaterials for biosensor substrate construction.

Bimetallic nanozyme triple-emission fluorescence intelligent sensing platform-integrated molecular imprinting for ultrasensitive visual detection of triclosan

Triclosan (TCS) is an endocrine disruptor, which has been widely used in daily chemicals, resulting in the potential risk to the ecosystem and human health. Herein, a smartphone-integrated bimetallic nanozyme triple-emission fluorescence capillary imprinted sensing system was developed for ultrasensitive and intelligent visual microanalysis of TCS. Carbon dots (CDs) and bimetallic organic framework (MOF-(Fe/Co)-NH2) were used as fluorescence sources to synthesize nanozyme fluorescence molecularly imprinted polymer (MOF-(Fe/Co)-NH2@CDs@NMIP), which oxidized o-phenylenediamine to 2,3-diaminophenazine (OPDox), resulting in the derivation of a new fluorescence peak at 556 nm. In the existence of TCS, the fluorescence of MOF-(Fe/Co)-NH2 at 450 nm was restored, the fluorescence of OPDox at 556 nm was suppressed, and the CDs fluorescence of at 686 nm remained constant. The color of triple-emission fluorescence imprinted sensor varied from yellow to pink to purple to blue. The response efficiency (F450/F556/F686) of this sensing platform based on the capillary waveguide effect demonstrated a significant linear relationship toward the concentration of TCS ranged from 1.0 × 10-12 to 1.5 × 10-10 M with the LOD of 8.0 × 10-13 M. Compared with dual-emission capillary fluorescence sensor, this sensing system has higher sensitivity and richer visual color. Combined with the smartphone-integrated portable sensing platform, the color of fluorescence was transformed into an RGB value to calculate TCS concentration with the LOD of 9.6 × 10-13 M, providing a novel method for intelligent visual microanalysis (18 μL/time) of environmental pollutants.

Subppb level monitoring and UV degradation of triclosan pollutants using ZnO multipod and Ag nanocomposites

A unique nanomaterial platform was developed for trace detection and efficient degradation of triclosan (TCS). A facile spectroscopic technique for surface-enhanced Raman scattering (SERS)-supported identification and ultraviolet (UV) degradation of TCS using a SERS template based on silver spherical nanoparticle (AgNP)-modified ZnO multipods (ZnO@Ag) is reported. Core-shell composite materials of ZnO multipods with a dimension of around 3 μm and AgNPs with an average diameter of ∼27 nm was designed not only as a substrate for TCS degradation up to ∼92% upon UV irradiation (λ = 365 mm, 300 μW/cm²) but also as a monitoring platform sensitive to TCS at a detection limit as low as 10^-9 M (≈0.3 ppb). Herein, the first investigation into ZnO@Ag bimetallic composites is established for both the SERS-based detection and UV-assisted degradation of environmental TCS pollutants. The calibration curve was estimated to be linear at R² > 0.97. The validated technology was successfully used to determine the antibacterial agent and TCS in distilled or river water. The advantages of the ZnO@Ag template are highlighted over conventional detection and excellent degradation.

Study of microplastics as sorbents for rapid detection of multiple antibiotics in water based on SERS technology

Online monitoring of antibiotics in the environment attracts more and more attention. Surface-enhanced Raman scattering (SERS) is a promising technique for the detection of trace amounts of antibiotics in the environment, which is fast, non-invasive and sensitive. To investigate the enrichment of trace amounts of antibiotics in water, polyethylene microplastics (PE MPs) were prepared as sorbents to simply concentrate enrofloxacin, ciprofloxacin hydrochloride monohydrate and triclosan in water, followed by the SERS measurement of antibiotics extract washed from MPs on an AgNPs@Si SERS substrate. Limit of detection of Rhodamine 6G is 2.1 × 10^-12 M achieved from the AgNPs@Si SERS, indicating a high enhancement. The detection results show that SERS peaks of the antibiotics could be observed from the spectra of the extracts eluted from MPs, indicating MPs could adsorb and desorb antibiotics from water. Besides, for enrofloxacin and triclosan, the intensity of SERS measured from the MPs extracts are higher than that of directly from the spiked water, demonstrating the proposed method could lower the detectable concentration of hydrophobic antibiotics in water. Moreover, the proposed MPs sorbents combined with SERS method was applied to detect the antibiotics in real river water, with minimal detection of 10^-10 M, 10^-8 M, and 10^-8 M achieved for enrofloxacin, ciprofloxacin hydrochloride monohydrate and triclosan, respectively. The proposed method provides a promising simple, rapid and low reagent consuming means for monitoring antibiotics in water.

A facile solvent extraction method facilitating surface-enhanced Raman spectroscopic detection of ochratoxin A in wine and wheat

The capability of a solvent-mediated liquid-liquid extraction (LLE) method to improve the detection of ochratoxin A (OTA) in food matrixes using surface-enhanced Raman spectroscopy (SERS) is described. SERS detection of mycotoxins with nanoparticle aggregation is a simple method but with low reproducibility due to the heterogeneous distribution of the nanoparticle aggregates. We evaluated three different LLE protocols to analyze their performance in combination with SERS. A facile extraction method based on sample acidification and addition of chloroform as a separation solvent showed to not only extract OTA from wine and wheat but also facilitate the uniform distribution of the nanoparticles leading to an improvement of the detection signals and the reproducibility. This method enables rapid and simple analysis of mycotoxin Ochratoxin A in food systems.

Applications of surface-enhanced Raman spectroscopy in detection fields

Surface-enhanced Raman spectroscopy (SERS) is a Raman spectroscopy technique that has been widely used in food safety, environmental monitoring, medical diagnosis and treatment and drug monitoring because of its high selectivity, sensitivity, rapidness, simplicity and specificity in identifying molecular structures. This review introduces the detection mechanism of SERS and summarizes the most recent progress concerning the use of SERS for the detection and characterization of molecules, providing references for the later research of SERS in detection fields.