Recent advances in nanomaterial-based biosensors for antibiotics detection

Single iron catalyst with bi-atomic matching site to construct electrochemical chip for on-site inspection of antibiotic chloramphenicol

Chloramphenicol (CAP) as an amide-alcohol antibiotic is extensively used in aquaculture industries and can accumulate in the human body through the food chain and water sources, leading to various diseases. On-site inspection of CAP remains a challenge due to the lack of portable and sensitive sensing platforms. Herein, a bi-atomic matching catalyst that comprises atomic Fe uniformly distributed on an N-doped graphene matrix (A-Fe-NG) is synthesized. An electrochemical sensor based on A-Fe-NG is constructed for CAP, demonstrating a high sensitivity of 164.2 μA μM-1 cm-2 and a fast response time of 1.2 s, among the best of Fe-based electrochemical CAP sensors. The high performance should be attributed to the high active site density of A-Fe-NG as well as the bi-atomic matching-catalysis mechanism. A portable electrochemical chip based on A-Fe-NG is also built, delivering accurate monitoring of CAP in river water for practical on-site inspection.

Nanopsychiatry: Advancing psychiatric diagnosis and monitoring through nanotechnology-based detection

Nanopsychiatry, operating at the nanoscale, leverages engineered nanomaterials and nanodevices to revolutionize psychiatric diagnostics and therapeutics. This review systematically analyzes the implementation of advanced nanomaterials, including quantum dots, carbon nanotubes (CNTs), and metal nanoparticles, in neural interface systems for neurotransmitter detection and drug monitoring. We evaluate the integration of nanoscale architectures in developing high-specificity biosensors for key neurotransmitters such as dopamine, serotonin, and glutamate. The review critically examines recent advances in nanomaterial-based electrochemical and optical sensing platforms, incorporating modified electrodes with conducting polymers, metallic nanocomposites, and functionalized graphene derivatives. These systems demonstrate enhanced sensitivity and selective multi-analyte detection capabilities in complex biological matrices. We analyze how these nanosensors complement conventional neuroimaging techniques, enabling monitoring of neurochemical dynamics in psychiatric conditions with improved spatial and temporal resolution. Furthermore, we assess the development of flexible, nanomaterial-enhanced wearable biosensors incorporating screen-printed electrodes and microfluidic systems. These devices achieve continuous monitoring of neurological biomarkers, facilitating quantitative assessment of psychiatric symptoms and treatment responses. The integration of machine learning algorithms with these nanoscale sensing platforms enables data processing and pattern recognition for personalized psychiatric interventions.

Facile fabrication of sensing electrode based on CoFe-MOFs/MXene for ultrasensitive detection of picomolar chloramphenicol

Precise detection of ultralow-level antibiotics, such as picomole, in aqueous environments is significant for human health, however, it presents a great challenge to the adsorption capacity and electrocatalytic ability of sensing materials. Here, we used a one-step hydrothermal method to in situ grow spindle-like CoFe-based metal-organic frameworks (MOFs) with a size of about 50 nm in the region of hydrophilic MXene-loading hydrophobic carbon paper. By combining MOFs with abundant adsorption sites and MXene with high conductivity, the problems of adsorption and electrons transfer of ultralow-level antibiotics have been solved, and achieving precise detection of picomole-level antibiotics. As a result, the CoFe-MOFs/MXene/HCP sensing electrode exhibits the ultralow limit of detection with 33 pM and a wide detection range with 0.1 nm-2.0 mM for chloramphenicol (CAP) detection, as well as the designed sensor has excellent anti-interference, reproducibility, and stability. Importantly, the prepared sensing electrode exhibits reliable analytical results for CAP in real water samples, such as bottled water, milk, and urine, indicating that the prepared sensors have a great potential for application in the analysis of antibiotics in real samples.

Electrochemiluminescent/colorimetric monitoring 25(OH)D3 based on HOFs-g-C3N4-CeO2 functional composite

Vitamin D, mainly in the active form of 25-hydroxy vitamin D3 (25(OH)D3), participates in blood circulation and plays a vital role in metabolic homeostasis. Herein, an electrochemiluminescent (ECL)/colorimetric dual-analytical biosensing platform based on HOFs-g-C3N4-CeO2 (HCC) composite was developed for 25(OH)D3 detection. In the ECL system, electrochemiluminescence-resonance energy transfer (ECL-RET) occurred utilizing HCC as the ECL donor and gold nanorods (Au NRs) as the acceptor. The binding of the complementary aptamer chain (ssDNA) labeled with Au NRs to the aptamer chain VDBA14 immobilized on the surface of HCC quenched the ECL emission via ECL-RET. After adding the target 25(OH)D3, ECL response was recovered due to the competition for VDBA14 between ssDNA and 25(OH)D3, resulting in the reduction of Au NRs and attenuation of the ECL-RET on the electrode. In the colorimetric system, VDBA14 immobilized on magnetic beads (MBs) captured ssDNA tagged with HCC through complementary base pairing. VDBA14 could specifically recognize 25(OH)D3 to release ssDNA competitively, and then, the released HCC was used as the nanozyme to catalyze the chromogenic reaction between tetramethylbenzidine (TMB) and H2O2. The bimodal analysis showed a good response to 25(OH)D3 in the linear range 20 ~ 80 ng/mL, with detection limits of 15.91 ng/mL (for the ECL system) and 7.28 ng/mL (for the colorimetric system). The proposed dual-analytical biosensor improved the reliability of detecting 25(OH)D3 and performed satisfactorily in practical applications, which is of great significance in immunomodulation, skin physiology, and other important aspects of human health.

Recent Advances of Fluorescent Aptasensors for the Detection of Antibiotics in Food

Antibiotics can accumulate in the body via ingestion, presenting serious health and safety risks to humans, and have garnered extensive international attention in recent years. Meanwhile, aptamers have been applied in the detection of antibiotics, mainly because of their good stability, high specificity, easy synthesis, and low cost. Among various kinds of aptasensors, fluorescent dye-based or nanomaterial-based fluorescent aptasensors serve as highly efficient tools for the rapid quantification of antibiotics owing to their remarkable sensitivity, specificity, and selectivity. In addition, some novel techniques such as aptamer tailoring, signal amplification, and artificial intelligence for aptasensors are also presented. This paper provides a detailed and comprehensive review of fluorescent aptasensors for antibiotic detection. Moreover, it pinpoints the challenges encountered during the development of the aforesaid fluorescent aptasensors and puts forward future research directions.

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.

Antibiotic residue detection by novel photoelectrochemical extended-gate field-effect transistor sensor

Residual antibiotics in the environment may pose threats to both ecological system and public health, necessitating the development of efficient analytical strategy for monitoring and control. This study proposes a photoelectrochemical extended-gate field-effect transistor (PEGFET) sensor for specific and sensitive detection of kanamycin. The sensor utilizes ITO glass as the extended gate electrode (photoelectrode) and titanium dioxide as the photosensitive material. It leverages the interaction between kanamycin and its corresponding aptamer to influence the ability of gold nanocluster to catalyze the oxidation of 3,3'-diaminobenzidine (DAB). This interaction results in different amounts of DAB precipitate on the photoelectrode surface, leading to gate voltage shift and source-drain current response. This sensing platform achieves trace detection of kanamycin with a limit of detection (LOD) at nM level and a wide linear detection range from 10 nM to 100 μM. The results demonstrate that the PEGFET with incorporated photoelectrochemical process can significantly enhance the sensitivity of traditional EGFET sensor, and the photoelectric signal originates from the change in electron transfer ability of the photoelectrode. The reported PEGFET with photo-responsive extended gate presents a new and promising structure in FET sensor design for enhanced detection performances in chemical and biological sensing.

Modification of Fe3O4 magnetic nanoparticles for antibiotic detection

The manufacture, modification, and application of surface-functionalized Fe3O4 nanoparticles in the extraction and isolation of antibiotics are reviewed in this paper. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) can be used to characterize the morphological features of Fe3O4 nanoparticles, while Fourier Transform Infrared Spectrometer (FTIR) and X-ray diffractometry (XRD) can be used to determine the crystalline shapes and distinctive functional groups of these particles. We gathered a lot of data to investigate the effects of experimental parameters like pH, adsorbent dosage, contact time, and ionic strength on the extraction of antibiotics from Fe3O4 magnetic nanoparticles. We additionally talked about the mechanism of action of magnetic nanoparticles for the extraction of separated antibiotics and how they are utilized in practical detection methods. This work concluded with an overview of the potential for environmental friendliness and dispersion of functionalized Fe3O4 nanoparticles, as well as potential challenges and directions.

Graphene-based electrochemical sensors for antibiotics: sensing theories, synthetic methods, and on-site monitoring applications

Owing to the extensive use of antibiotics for treating infectious diseases in livestock and humans, the resulting residual antibiotics are a burden to the ecosystem and human health. Hence, for human health and ecological safety, it is critical to determine the residual antibiotics with accuracy and convenience. Graphene-based electrochemical sensors are an effective tool to detect residual antibiotics owing to their advantages, such as, high sensitivity, simplicity, and time efficiency. In this work, we comprehensively summarize the recent advances in graphene-based electrochemical sensors used for detecting antibiotics, including modifiers for electrode fabrication, theoretical elaboration of electrochemical sensing mechanisms, and practical applications of portable electrochemical platforms for the on-site monitoring of antibiotics. It is anticipated that the current review will be a valuable reference for comprehensively comprehending graphene-based electrochemical sensors and further promoting their applications in the fields of healthcare, environmental protection, and food safety.

Interfacial Self-Assembly Nanostructures: Constructions and Applications

Interfacial self-assembly nanoarrays refer to the spontaneously organized nanostructures at interfaces, relying on the intrinsic properties of involved materials, such as surface energy, molecular structure, and interactions. In recent years, the exponential growth of self-assembly nanotechnology has substantially expanded the utility of nanomaterials. Particularly, non-covalent interactions-based interfacial self-assembly represents a viable and promising approach for the synthesis of novel nanostructure. This review introduces the significance and current development status of interfacial self-assembly technology, focusing on the driving mode, application, and prospects of interfacial self-assembly nanoarrays over the past few years.

A ratiometric fluorescence sensor with different responsive modes based on carbon dots-embedded Tb-MOFs for the determination of norfloxacin and levofloxacin

Norfloxacin (NOR) and levofloxacin (LEV) are the two most frequently used fluoroquinolones (FQs) in clinic. Their residues seriously endanger the ecosystem and human health. Due to their similarity in structure and properties, it is urgent to develop an efficient and sensitive strategy for detection and differentiation. Herein, we synthesized a novel ratiometric fluorescent sensor for the first time by combining N, S co-doped carbon dots (CDs) and the precursors of Tb-MOFs through a facile one-pot method. The introduction of CDs effectively facilitated the energy transfer between Tb3+ and FQs, overcoming the limitation that single Tb-MOFs could not identify similar antibiotics. Specifically, the presence of NOR resulted in reverse signal response through the inner filter effect and antenna effect. The synergistic effect of these two mechanisms contributed to achieving signal amplification accompanied by a distinguishable color transition. The limit of detection (LOD) was 0.036 μM. Different from NOR, the addition of LEV reduced the electron density of the system, weakened the coordination ability of Tb3+ with LEV, and induced a single signal response with Tb3+ fluorescence intensity as a reference signal (LOD = 0.383 μM). Furthermore, the method proved to be rapid and visual, allowing for the straightforward analysis of FQs residues in water, food matrices, and biological samples with satisfactory precision. By integrating N, S-CDs@Tb-MOFs with flexible substrates, the paper-based sensor facilitated the visual quantitative determination of FQs by reading RGB values. The developed sensor presents a promising strategy for the identification and real-time monitoring of antibiotics.

Electro-, photo-, and photoelectrochemical degradation of chloramphenicol on self-doping Ti nanotubes

In this work, the photo-, electro-, and photo-electro-oxidation of chloramphenicol was investigated. The photo-experiments were carried out with different irradiation sources (an ultraviolet and a simulated solar source) using self-doped titanium nanotubes (SDTNT), a very promising and innovative material that deserves further investigations in the degradation of different pollutants. The photo-electrooxidation (j = 15 mA cm-2) under simulated solar irradiation presented the best efficiency, with ca. 100% degradation and kinetic constant of k = 0.04427 min-1. The FTIR analysis demonstrated a structural modification of the standard molecule occurred for all conditions used, suggesting a modification in functional groups responsible for the biological activity. Furthermore, the TOC analysis showed a significant mineralization of the pollutant (66% from the initial concentration). In addition, both photo-electrooxidation approaches have demonstrated a positive value of S, where the simulated solar irradiation reached the highest value S = 0.6960. The experimental results pointed out evidence that the methodology employed herein for chloramphenicol degradation is greatly interesting and the photo-electrooxidation under simulated solar irradiation is a promising approach for this purpose.

Recent advances on nanomaterial-based glutathione sensors

Glutathione (GSH) is one of the most common thiol-containing molecules discovered in biological systems, and it plays an important role in many cellular functions, where changes in physiological glutathione levels contribute to the progress of a variety of diseases. Molecular imaging employing fluorescent probes is thought to be a sensitive technique for online fluorescence detection of GSH. Although various molecular probes for (intracellular) GSH sensing have been reported, some aspects remain unanswered, such as quantitative intracellular analysis, dynamic monitoring, and compatibility with biological environment. Some of these drawbacks can be overcome by sensors based on nanostructured materials, that have attracted considerable attention owing to their exceptional properties, including a large surface area, heightened electro-catalytic activity, and robust mechanical resilience, for which they have become integral components in the development of highly sensitive chemo- and biosensors. Additionally, engineered nanomaterials have demonstrated significant promise in enhancing the precision of disease diagnosis and refining treatment specificity. The aim of this review is to investigate recent advancements in fabricated nanomaterials tailored for detecting GSH. Specifically, it examines various material categories, encompassing carbon, polymeric, quantum dots (QDs), covalent organic frameworks (COFs), metal-organic frameworks (MOFs), metal-based, and silicon-based nanomaterials, applied in the fabrication of chemo- and biosensors. The fabrication of nano-biosensors, mechanisms, and methodologies employed for GSH detection utilizing these fabricated nanomaterials will also be elucidated. Remarkably, there is a noticeable absence of existing reviews specifically dedicated to the nanomaterials for GSH detection since they are not comprehensive in the case of nano-fabrication, mechanisms and methodologies of detection, as well as applications in various biological environments. This research gap presents an opportune moment to thoroughly assess the potential of nanomaterial-based approaches in advancing GSH detection methodologies.

Sustainable synthesis of fluorescent polymer carbon dots@PVA for sensitive chlortetracycline detection

Antibiotic residues persist in the environment and represent serious health hazards; thus, it is important to develop sensitive and effective detection techniques. This paper presents a bio-inspired way to make water-soluble fluorescent polymer carbon dots (PCDs@PVA) by heating biomass precursors and polyvinyl alcohol (PVA) together. For example, the synthesized PCDs@PVA are very stable with enhanced emission intensity. This property was observed in a wide range of environmental conditions, including those with changing temperatures, pH levels, UV light, and ionic strength. PCDs@PVA detected the antibiotic chlortetracycline (CTCs) with great selectivity against structurally related compounds and a low detection limit of 20 nM, demonstrating outstanding sensitivity and specificity. We confirmed the sensor's practical application through real sample analysis, yielding recovery rates of 98%-99% in samples of milk, honey, and river water. The synthesized PCDs@PVA fluorescence sensor was successfully used for CTCs detection in real samples.

2D MXene-Based Nanoscale Materials for Electrochemical Sensing Toward the Detection of Hazardous Pollutants: A Perspective

MXenes (Mn+1XnTx), a subgroup of 2-dimensional (2D) materials, specifically comprise transition metal carbides, nitrides, and carbonitrides. They exhibit exceptional electrocatalytic and photocatalytic properties, making them well-suited for the detection and removal of pollutants from aqueous environments. Because of their high surface area and remarkable properties, they are being utilized in various applications, including catalysis, sensing, and adsorption, to combat pollution and mitigate its adverse effects. Different characterization techniques like XRD, SEM, TEM, UV-Visible spectroscopy, and Raman spectroscopy have been used for the structural elucidation of 2D MXene. Current responses against applied potential were measured during the electrochemical sensing of the hazardous pollutants in an aqueous system using a variety of electroanalytical techniques, including differential pulse voltammetry, amperometry, square wave anodic stripping voltammetry, etc. In this review, a comprehensive discussion on structural patterns, synthesis, properties of MXene and their application for electrochemical detection of lethal pollutants like hydroquionone, phenol, catechol, mercury and lead, etc. are presented. This review will be helpful to critically understand the methods of synthesis and application of MXenes for the removal of environmental pollutants.

Recent Progress in Organic Electrochemical Transistor-Structured Biosensors

The continued advancement of organic electronic technology will establish organic electrochemical transistors as pivotal instruments in the field of biological detection. Here, we present a comprehensive review of the state-of-the-art technology and advancements in the use of organic electrochemical transistors as biosensors. This review provides an in-depth analysis of the diverse modification materials, methods, and mechanisms utilized in organic electrochemical transistor-structured biosensors (OETBs) for the selective detection of a wide range of target analyte encompassing electroactive species, electro-inactive species, and cancer cells. Recent advances in OETBs for use in sensing systems and wearable and implantable applications are also briefly introduced. Finally, challenges and opportunities in the field are discussed.

A novel fluorescence platform for specific detection of tetracycline antibiotics based on [MQDA-Eu3+] system

Tetracycline antibiotics (TCs) are extensively used in clinical medicine, animal husbandry, and aquaculture because of their cost-effectiveness and high antibacterial efficacy. However, the presence of TCs residues in the environment poses risks to humans. In this study, an inner filter effect (IFE) fluorescent probe, 2,2'-(ethane-1,2-diylbis((2-((2-methylquinolin-8-yl)amino)-2-oxoethyl)azanediyl))diacetic acid (MQDA), was developed for the rapid detection of Eu3+ within 30 s. And its complex [MQDA-Eu3+] was successfully used for the detection of TCs. Upon coordination of a carboxyl of MQDA with Eu3+ to form a [MQDA-Eu3+] complex, the carboxyl served as an antenna ligand for the effective detection of Eu3+ to intensify the emission intensity of MQDA via "antenna effect", the process was the energy absorbed by TCs via UV excitation was effectively transferred to Eu3+. Fluorescence quenching of the [MQDA-Eu3+] complex was caused by the IFE in multicolor fluorescence systems. The limits of detection of [MQDA-Eu3+] for oxytetracycline, chlorotetracycline hydrochloride, and tetracycline were 0.80, 0.93, and 1.7 μM in DMSO/HEPES (7:3, v/v, pH = 7.0), respectively. [MQDA-Eu3+] demonstrated sensitive detection of TCs in environmental and food samples with satisfactory recoveries and exhibited excellent imaging capabilities for TCs in living cells and zebrafish with low cytotoxicity. The proposed approach demonstrated considerable potential for the quantitative detection of TCs.

Synergizing Nanomaterials and Artificial Intelligence in Advanced Optical Biosensors for Precision Antimicrobial Resistance Diagnosis

Antimicrobial resistance (AMR) poses a critical global One Health concern, ensuing from unintentional and continuous exposure to antibiotics, as well as challenges in accurate contagion diagnostics. Addressing AMR requires a strategic approach that emphasizes early stage prevention through screening in clinical, environmental, farming, and livestock settings to identify nonvulnerable antimicrobial agents and the associated genes. Conventional AMR diagnostics, like antibiotic susceptibility testing, possess drawbacks, including high costs, time-consuming processes, and significant manpower requirements, underscoring the need for intelligent, prompt, and on-site diagnostic techniques. Nanoenabled artificial intelligence (AI)-supported smart optical biosensors present a potential solution by facilitating rapid point-of-care AMR detection with real-time, sensitive, and portable capabilities. This Review comprehensively explores various types of optical nanobiosensors, such as surface plasmon resonance sensors, whispering-gallery mode sensors, optical coherence tomography, interference reflection imaging sensors, surface-enhanced Raman spectroscopy, fluorescence spectroscopy, microring resonance sensors, and optical tweezer biosensors, for AMR diagnostics. By harnessing the unique advantages of these nanoenabled smart biosensors, a revolutionary paradigm shift in AMR diagnostics can be achieved, characterized by rapid results, high sensitivity, portability, and integration with Internet-of-Things (IoT) technologies. Moreover, nanoenabled optical biosensors enable personalized monitoring and on-site detection, significantly reducing turnaround time and eliminating the human resources needed for sample preservation and transportation. Their potential for holistic environmental surveillance further enhances monitoring capabilities in diverse settings, leading to improved modern-age healthcare practices and more effective management of antimicrobial treatments. Embracing these advanced diagnostic tools promises to bolster global healthcare capacity to combat AMR and safeguard One Health.

State-of-the-art nanosensors and kits for the detection of antibiotic residues in milk and dairy products

Antibiotic resistance is increasingly seen as a future concern, but antibiotics are still commonly used in animals, leading to their accumulation in humans through the food chain and posing health risks. The development of nanomaterials has opened up possibilities for creating new sensing strategies to detect antibiotic residues, resulting in the emergence of innovative nanobiosensors with different benefits like rapidity, simplicity, accuracy, sensitivity, specificity, and precision. Therefore, this comprehensive review provides pertinent and current insights into nanomaterials-based electrochemical/optical sensors for the detection of antibitic residues (ANBr) across milk and dairy products. Here, we first discuss the commonly used ANBs in real products, the significance of ANBr, and also their binding/biological properties. Then, we provide an overview of the role of using different nanomaterials on the development of advanced nanobiosensors like fluorescence-based, colorimetric, surface-enhanced Raman scattering, surface plasmon resonance, and several important electrochemical nanobiosensors relying on different kinds of electrodes. The enhancement of ANB electrochemical behavior for detection is also outlined, along with a concise overview of the utilization of (bio)recognition units. Ultimately, this paper offers a perspective on the future concepts of this research field and commercialized nanomaterial-based sensors to help upgrade the sensing techniques for ANBr in dairy products.

Innovative Detection of Biomarkers Based on Chemiluminescent Nanoparticles and a Lensless Optical Sensor

The identification and quantification of biomarkers with innovative technologies is an urgent need for the precise diagnosis and follow up of human diseases. Body fluids offer a variety of informative biomarkers, which are traditionally measured with time-consuming and expensive methods. In this context, lateral flow tests (LFTs) represent a rapid and low-cost technology with a sensitivity that is potentially improvable by chemiluminescence biosensing. Here, an LFT based on gold nanoparticles functionalized with antibodies labeled with the enzyme horseradish peroxidase is combined with a lensless biosensor. This biosensor comprises four Silicon Photomultipliers (SiPM) coupled in close proximity to the LFT strip. Microfluidics for liquid handling complete the system. The development and the setup of the biosensor is carefully described and characterized. C-reactive protein was selected as a proof-of-concept biomarker to define the limit of detection, which resulted in about 0.8 pM when gold nanoparticles were used. The rapid readout (less than 5 min) and the absence of sample preparation make this biosensor promising for the direct and fast detection of human biomarkers.

Screening of broad-spectrum aptamer and development of electrochemical aptasensor for simultaneous detection of penicillin antibiotics in milk

Penicillin antibiotics (PENs) play an important role in killing pathogenic bacteria. However, the residues of various penicillin antibiotics in milk gradually accumulate in the human body with the increase of milk intake, which causes direct harm to the human body. Aptamers can be used as recognition element of sensors. It is great significance to use broad-spectrum aptamers for simultaneous detection of PENs. In this study, we reported the screening and identification of DNA aptamers for PENs. The aptamers were screened by graphene oxide-systematic evolution of ligands by exponential enrichment (GO-SELEX). The broad-spectrum aptamers with high affinity and specificity were successfully obtained after 13 rounds of screening. The affinity and specificity of candidate aptamers were analyzed by a GO fluorescence competition method. Further sequence analysis revealed that a truncated 47 nt aptamer (P-11-1) had a higher affinity than the original 79 nt aptamer. The truncated aptamer P-11-1 was used as a recognition element, and an electrochemical aptasensor was prepared using gold nanoparticles (AuNPs) combined with ferroferric oxide-multi walled carbon nanotube (Fe3O4-MWCNTs) complex. The results showed that the developed aptasensor achieved the simultaneous detection of PENs in milk samples across a concentration range of 2 nM-10,000 nM, achieving a limit of detection of 0.667 nM. This methodology provided a simple and sensitive new thinking for antibiotic multi-residue detection.

Co-based Nanozymatic Profiling: Advances Spanning Chemistry, Biomedical, and Environmental Sciences

Nanozymes, next-generation enzyme-mimicking nanomaterials, have entered an era of rational design; among them, Co-based nanozymes have emerged as captivating players over times. Co-based nanozymes have been developed and have garnered significant attention over the past five years. Their extraordinary properties, including regulatable enzymatic activity, stability, and multifunctionality stemming from magnetic properties, photothermal conversion effects, cavitation effects, and relaxation efficiency, have made Co-based nanozymes a rising star. This review presents the first comprehensive profiling of the Co-based nanozymes in the chemistry, biology, and environmental sciences. The review begins by scrutinizing the various synthetic methods employed for Co-based nanozyme fabrication, such as template and sol-gel methods, highlighting their distinctive merits from a chemical standpoint. Furthermore, a detailed exploration of their wide-ranging applications in biosensing and biomedical therapeutics, as well as their contributions to environmental monitoring and remediation is provided. Notably, drawing inspiration from state-of-the-art techniques such as omics, a comprehensive analysis of Co-based nanozymes is undertaken, employing analogous statistical methodologies to provide valuable guidance. To conclude, a comprehensive outlook on the challenges and prospects for Co-based nanozymes is presented, spanning from microscopic physicochemical mechanisms to macroscopic clinical translational applications.

Nanobiosensors: Concepts and Emerging Clinical Applications

Biosensors have been one of the most fascinating topics for scientists for a long time. This is because biological moieties are multifaceted and are unswervingly related to the presence of a healthy atmosphere. The biosensor approach has also endured profound changes in recent years. Biosensors have been emphasized for various applications, including food quality estimation, surveillance systems, and health and metabolic abnormality diagnostics. The advances in nanotechnology have led to a considerable potential to enhance biosensors' sensitivity, robustness, and anti-interference capabilities. Several new nanomaterials (such as nanoparticles, nanotubes, nanorods, and nanowires) have been fabricated due to the evolution of nanotechnology, and their unique features are gradually being identified, allowing for much faster detection and reproducibility. Biosensor performance has also been enhanced substantially as a result of their use. Because of their capacity to detect a wide range of compounds at deficient concentrations, nanobiosensors have sparked much interest. This article discusses biosensors based on various nanomaterials, their evolution, accompanying features, and their applications in multiple fields.

Functionalities of electrochemical fluoroquinolone sensors and biosensors

Fluoroquinolones (FQs) are a class of broad-spectrum antimicrobial agents that are used to treat variety of infectious diseases. This class of antibiotics was being used for patients exhibiting early symptoms of a human respiratory disease known as the COVID-19 virus. As a result, this outbreak causes an increase in drug-resistant strains and environmental pollution, both of which pose serious threats to biota and human health. Thus, to ensure public health and prevent antimicrobial resistance, it is crucial to develop effective detection methods for FQs determination in water bodies even at trace levels. Due to their characteristics like specificity, selectivity, sensitivity, and low detection limits, electrochemical biosensors are promising future platforms for quick and on-site monitoring of FQs residues in a variety of samples when compared to conventional detection techniques. Despite their excellent properties, biosensor stability continues to be a problem even today. However, the integration of nanomaterials (NMs) could improve biocompatibility, stability, sensitivity, and speed of response in biosensors. This review concentrated on recent developments and contemporary methods in FQs biosensors. Furthermore, a variety of modification materials on the electrode surface are discussed. We also pay more attention to the practical applications of electrochemical biosensors for FQs detection. In addition, the existing challenges, outlook, and promising future perspectives in this field have been proposed. We hope that this review can serve as a bedrock for future researchers and provide new ideas for the development of electrochemical biosensors for antibiotics detection in the future.

Advances in colorimetric aptasensors for heavy metal ion detection utilizing nanomaterials: a comprehensive review

Heavy metal ion contamination poses significant environmental and health risks, necessitating rapid and efficient detection methods. In the last decade, colorimetric aptasensors have emerged as powerful tools for heavy metal ion detection, owing to their notable attributes such as high specificity, facile synthesis, adaptability to modifications, long-term stability, and heightened sensitivity. This comprehensive overview summarizes the key developments in this field over the past ten years. It discusses the principles, design strategies, and innovative techniques employed in colorimetric aptasensors using nanomaterials. Recent advancements in enhancing sensitivity, selectivity, and on-site applicability are highlighted. The review also presents application studies of successful heavy metal ion detection using colorimetric aptasensors, underlining their potential for environmental monitoring and health protection. Finally, future directions and challenges in the continued evolution of these aptasensors are outlined.

A Polyamidoamine-Based Electrochemical Aptasensor for Sensitive Detection of Ochratoxin A

Sensitive detection of ochratoxin A (OTA) is significant and essential because OTA may pose risks to human and animal health. Here, we developed an electrochemical aptasensor for OTA analysis using polyamidoamine (PAMAM) dendrimers as a signal amplifier. As a carrier, PAMAM has numerous primary amino groups that can be coupled with thiolated complementary strand DNA (cDNA), allowing it to recognize aptamers bound to the surface of horseradish peroxidase (HRP)-modified gold nanoparticles (AuNPs), thereby improving the sensitivity of the aptasensor. When monitoring the positive samples, OTA was captured by the aptamer fixed on the HRP-conjugated AuNP surface by specific recognition, after which the formed OTA-aptamer conjugates were detached from the electrode surface, ultimately decreasing the electrochemical signal monitored by differential pulse voltammetry. The novel aptasensor achieved a broad linear detection range from 5 to 105 ng L-1 with a low detection limit of 0.31 ng L-1. The proposed aptasensor was successfully applied for OTA analysis in red wine, with recovery rates ranging from 94.15 to 106%. Furthermore, the aptasensor also exhibited good specificity and storage stability. Therefore, the devised aptasensor represents a sensitive, practical and reliable tool for monitoring OTA in agricultural products, which can also be adapted to other mycotoxins.

Highly selective and sensitive determination of doxycycline integrating enrichment with thermosensitive magnetic molecular imprinting nanomaterial and carbon dots based fluorescence probe

Doxycycline (DOX), a typical tetracycline antibiotic, is widely used because of its excellent antibacterial activity. To develop effective method for DOX has attracted much more attention. Herein, a new detection technology integrating magnetic solid phase extraction (MSPE) based on thermosensitive magnetic molecularly imprinted polymers (T-MMIPs) and fluorescence spectrometry based on carbon dots (CDs) was established. Thermosensitive magnetic molecularly imprinted polymers (T-MMIPs) was designed for selective enrichment of trace DOX. The synthesized T-MMIPs showed excellent selectivity for DOX. The adsorption performance of T-MMIPs varied with temperature in different solvents, which could achieve the enrichment and rapid desorption of DOX. In addition, the synthesized CDs had stable fluorescent property and better water-solubility, and the fluorescence of CDs was significantly quenched by DOX due to the internal filtration effect (IFE). Under the optimized conditions, the method resulted in good linearity over the range from 0.5 to 30 μg L-1, and the limit of detection was 0.2 μg L-1. The constructed detection technology was validated with real water samples, and excellent spiked recoveries from 92.5 % to 105.2 % were achieved. These data clearly indicated that the proposed technology was rapid, highly selective, environmentally friendly, and possessed significant potential application and development prospects.

Competitive immunoassay using enzyme-regulated Fe3O4@COF/Fe3+ fluorescence probe for natural chloramphenicol detection

Accurate and sensitive detection of chloramphenicol (CAP) in natural samples is essential for ensuring human health. Herein, an enzyme-regulated fluorescence sensor using Fe3O4@COF/Fe3+ probe, is developed for CAP determination. Fe3O4@COF, synthesized via hydrothermal method, exhibits dual functions as a magnetic carrier and signal probe. Bovine serum albumin conjugated-chloramphenicol, adsorbed on the surface of Fe3O4@COF, competes with CAP for antibody binding. The antibody interacts with alkaline phosphatase via the biotin-streptavidin system. Meanwhile, ascorbic acid, produced from the enzyme-catalyzed reaction dominated by alkaline phosphatase, effectively restores the fluorescence of Fe3O4@COF that is quenched by Fe3+. After experimental verification and gradual optimization, a logarithmic linear relationship between CAP concentration and fluorescence intensity is established in the range of 2 × 10-4∼10 μg mL-1, with a good limit of detection (9.2 × 10-5 μg mL-1). Proposed method exhibits excellent stability (15 days) and reusability (8 cycles), providing a sensitive and reliable method for accurate CAP detection. The readouts show good agreement with HPLC and recoveries during laboratory and natural CAP analysis.

Two birds with one stone: Ratiometric sensing platform overcoming cross-interference for multiple-scenario detection and accurate discrimination of tetracycline analogs

Environmental pollution caused by tetracycline antibiotics (TCs) is a major concern for public health worldwide. Trace detection and reliable discrimination of tetracycline and its analogs are consequently essential to determine the distribution characteristics of various tetracycline family members. Here, a dual-response sensor was constructed by integrating the fluorescence emission of fluorescein isothiocyanate (FITC) doped SiO2 and Eu3+. A portable Lab-on-Paper device is further fabricated through probe immobilization, which allows convenient visual detection of tetracycline using a smartphone. In addition, for the coexistence of multiple tetracycline analogs, dimensionality reduction via principal component analysis is applied to the spectra, realizing accurate differentiation of the four most widely used tetracycline analogs (tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC), and doxycycline (DOX)). The dual-response nanoplatform enabled a wide-gamut color variation crossing from green to red, with limit of detection (LOD) of 2.9 nM and 89.8 nM for spectrometer- and paper-based sensors, respectively. Analytical performance was examined in multiple real samples, including food, environmental, and biological settings, confirming robust environmental adaptability and resistance. Compared to previous TC sensors, this method has several notable improvements, including improved ecological safety, accessibility, reproducibility, practicality, and anti-cross-interference capacity. These results highlight the potential of the proposed "two birds with one stone" strategy, providing an integrated methodology for synchronous quantitative detection and derivative identification toward environmental contaminants.

Computer Vision-Based Artificial Intelligence-Mediated Encoding-Decoding for Multiplexed Microfluidic Digital Immunoassay

Digital immunoassays with multiplexed capacity, ultrahigh sensitivity, and broad affordability are urgently required in clinical diagnosis, food safety, and environmental monitoring. In this work, a multidimensional digital immunoassay has been developed through microparticle-based encoding and artificial intelligence-based decoding, enabling multiplexed detection with high sensitivity and convenient operation. The information encoded in the features of microspheres, including their size, number, and color, allows for the simultaneous identification and accurate quantification of multiple targets. Computer vision-based artificial intelligence can analyze the microscopy images for information decoding and output identification results visually. Moreover, the optical microscopy imaging can be well integrated with the microfluidic platform, allowing for encoding-decoding through the computer vision-based artificial intelligence. This microfluidic digital immunoassay can simultaneously analyze multiple inflammatory markers and antibiotics within 30 min with high sensitivity and a broad detection range from pg/mL to μg/mL, which holds great promise as an intelligent bioassay for next-generation multiplexed biosensing.

Current Trends in Nanomaterials-Based Electrochemiluminescence Aptasensors for the Determination of Antibiotic Residues in Foodstuffs: A Comprehensive Review

Veterinary pharmaceuticals have been recently recognized as newly emerging environmental contaminants. Indeed, because of their uncontrolled or overused disposal, we are now facing undesirable amounts of these constituents in foodstuff and its related human health concerns. In this context, developing a well-organized environmental and foodstuff screening toward antibiotic levels is of paramount importance to ensure the safety of food products as well as human health. In this case, with the development and progress of electric/photo detecting, nanomaterials, and nucleic acid aptamer technology, their incorporation-driven evolving electrochemiluminescence aptasensing strategy has presented the hopeful potentials in identifying the residual amounts of different antibiotics toward sensitivity, economy, and practicality. In this context, we reviewed the up-to-date development of ECL aptasensors with aptamers as recognition elements and nanomaterials as the active elements for quantitative sensing the residual antibiotics in foodstuff and agriculture-related matrices, dissected the unavoidable challenges, and debated the upcoming prospects.

Signal-amplified electrochemiluminescence aptasensor for mucin 1 determination using CdS QDs/g-C3N4 and Au NPs@TEOA

A novel electrochemiluminescence (ECL) aptasensor, using graphite carbonitride (g-C₃N₄) capped CdS quantum dots (CdS QDs@g-C₃N₄) and Au nanoparticles decorated triethanolamine (AuNPs@TEOA) as dual coreactants, was proposed for the determination of mucin 1 (MUC1). Higher ECL efficiency was acquired due to the double enhancement contribution of CdS QDs and TEOA to Ru (bpy)₃²⁺ ECL. Additionally, AuNPs@TEOA also acted as nanocarrier for MUC1 aptamer immobilization. After the aptasensor was incubated in target MUC1, the decreased ECL emission was obtained because of the poor conductivity of MUC1. The ECL aptasensor displayed a good linear correlation for MUC1 in the range 0.1 pg mL^-1 -1000 ng mL^-1, and the detection limit was 33 fg mL^-1. MUC1 spiked into human serum samples was quantified to assess the practicability of the ECL aptasensor.

Nanozymatic degradation and simultaneous colorimetric detection of tetracycline

Tetracycline (TC) is a broad-spectrum antibiotic that can enter and accumulate in the human body via the food chain. Even in small concentrations, TC can cause several malignant health effects. We developed a system to simultaneously degrade the presence of TC in food matrices using titanium carbide MXene (FL-Ti₃C₂T_x). The FL-Ti₃C₂T_x exhibited biocatalytic property that activates hydrogen peroxide (H₂O₂) molecules in 3, 3', 5, 5'-tetramethylbenzidine (TMB environment. During the FL-Ti₃C₂T_x reaction, the catalytic products released turn the color of the H₂O₂/TMB system bluish-green. However, when TC is present, the bluish-green color does not appear. Via quadrupole time-of-flight mass spectrometry, we found that the TC is degraded by FL-Ti₃C₂T_x / H₂O₂ in preference to H₂O₂/TMB redox reaction, which intervenes in the color change. Hence, we developed a colorimetric assay to detect TC with a LOD of 615.38 nM and proposed two TC degradation pathways that facilitate the highly sensitive colorimetric bioassay.

Aptamer Sensors for the Detection of Antibiotic Residues- A Mini-Review

Food security is a global issue, since it is closely related to human health. Antibiotics play a significant role in animal husbandry owing to their desirable broad-spectrum antibacterial activity. However, irrational use of antibiotics has caused serious environmental pollution and food safety problems; thus, the on-site detection of antibiotics is in high demand in environmental analysis and food safety assessment. Aptamer-based sensors are simple to use, accurate, inexpensive, selective, and are suitable for detecting antibiotics for environmental and food safety analysis. This review summarizes the recent advances in aptamer-based electrochemical, fluorescent, and colorimetric sensors for antibiotics detection. The review focuses on the detection principles of different aptamer sensors and recent achievements in developing electrochemical, fluorescent, and colorimetric aptamer sensors. The advantages and disadvantages of different sensors, current challenges, and future trends of aptamer-based sensors are also discussed.

Occurrence of antibiotics in wastewater: Potential ecological risk and removal through anaerobic-aerobic systems

Antibiotics are intensively used to improve public health, prevent diseases and enhance productivity in animal farms. Contrarily, when released, the antibiotics laden wastewater produced from pharmaceutical industries and their application sources poses a potential ecological risk to the environment. This study provides a discussion on the occurrence of various antibiotics in wastewater and their potential ecological risk in the environment. Further, a critical review of anaerobic-aerobic processes based on three major systems (such as constructed wetland, high-rate bioreactor, and integrated treatment technologies) applied for antibiotics removal from wastewater is performed. The review also explores microbial dynamics responsible for antibiotic biodegradation in anaerobic-aerobic systems and its economic feasibility at wider-scale applications. The operational problems and prospective modifications are discussed to define key future research directions. The appropriate selection of treatment processes, sources control, understanding of antibiotic fate, and adopting precise monitoring strategies could eliminate the potential ecological risks of antibiotics. Integrated bio-electrochemical systems exhibit antibiotics removal ≥95% by dominant Geobacter sp. at short HRT ∼4-10 h. Major process factors like organic loading rate, hydraulic loading rate (HRT), and solid retention time significantly affect the system performance. This review will be beneficial to the researchers by providing in-depth understanding of antibiotic pollution and its abatement via anaerobic-aerobic processes to develop sustainable wastewater treatment technology in the future.

Effects of tidal action on the stability of microbiota, antibiotic resistance genes, and microplastics in the Pearl River Estuary, Guangzhou, China

In this study, the 16S rRNA gene amplicon sequencing technique was used to explore the microbial diversity and differences in the water environment of the Pearl River Estuary in Nansha District with various land use types such as the aquaculture area, industrial area, tourist area, agricultural plantation, and residential area. At the same time, the quantity, type, abundance, and distribution of two types of emerging environmental pollutants, antibiotic resistance genes (ARGs) and microplastics (MPs), are explored in the water samples from different functional areas. The results show that the dominant phyla in the five functional regions are Proteobacteria, Actinobacteria and Bacteroidetes, and the dominant genera are Hydrogenophaga, Synechococcus, Limnohabitans and Polynucleobacter. A total of 248 ARG subtypes were detected in the five regions, belonging to nine classes of ARGs (Aminoglycoside, Beta_Lactamase, Chlor, MGEs, MLSB, Multidrug, Sul, Tet, Van). Blue and white were the dominant MP colors in the five regions; 0.5-2 mm was the dominant MP size, and cellulose, rayon, and polyester comprised the highest proportion of the plastic polymers. This study provides the basis for understanding the environmental microbial distribution in estuaries and the prevention of environmental health risks from ARGs and microplastics.

Metal-organic framework-based nanomaterials as opto-electrochemical sensors for the detection of antibiotics and hormones: A review

Increasing trace levels of antibiotics and hormones in the environment and food samples are concerning and pose a threat. Opto-electrochemical sensors have received attention due to their low cost, portability, sensitivity, analytical performance, and ease of deployment in the field as compared to conventional expensive technologies that are time-consuming and require experienced professionals. Metal-organic frameworks (MOFs) with variable porosity, active functional sites, and fluorescence capacity are attractive materials for developing opto-electrochemical sensors. Herein, the insights into the capabilities of electrochemical and luminescent MOF sensors for detection and monitoring of antibiotics and hormones from various samples are critically reviewed. The detailed sensing mechanisms and detection limits of MOF sensors are addressed. The challenges, recent advances, and future directions for the development of stable, high-performance MOFs as commercially viable next-generation opto-electrochemical sensor materials for the detection and monitoring of diverse analytes are discussed.

Detection and removal technologies for ammonium and antibiotics in agricultural wastewater: Recent advances and prospective

With the extensive development of industrial livestock and poultry production, a considerable part of agricultural wastewater containing tremendous ammonium and antibiotics have been indiscriminately released into the aquatic systems, causing serious harms to ecosystem and human health. In this review, ammonium detection technologies, including spectroscopy and fluorescence methods, and sensors were systematically summarized. Antibiotics analysis methodologies were critically reviewed, including chromatographic methods coupled with mass spectrometry, electrochemical sensors, fluorescence sensors, and biosensors. Current progress in remediation methods for ammonium removal were discussed and analyzed, including chemical precipitation, breakpoint chlorination, air stripping, reverse osmosis, adsorption, advanced oxidation processes (AOPs), and biological methods. Antibiotics removal approaches were comprehensively reviewed, including physical, AOPs, and biological processes. Furthermore, the simultaneous removal strategies for ammonium and antibiotics were reviewed and discussed, including physical adsorption processes, AOPs, biological processes. Finally, research gaps and the future perspectives were discussed. Through conducting comprehensive review, future research priorities include: (1) to improve the stabilities and adaptabilities of detection and analysis techniques for ammonium and antibiotics, (2) to develop innovative, efficient, and low cost approaches for simultaneous removal of ammonium and antibiotics, and (3) to explore the underlying mechanisms that governs the simultaneous removal of ammonium and antibiotics. This review could facilitate the evolution of innovative and efficient technologies for ammonium and antibiotics treatment in agricultural wastewater.

CdSSe Nano-Flowers for Ultrasensitive Raman Detection of Antibiotics

Surface-enhanced Raman scattering (SERS) technique is widely used for the highly sensitive detection of trace residues due to its unparalleled signal amplification ability and plays an important role in food safety, environmental monitoring, etc. Herein, CdSSe nano-flowers (CdSSe NFs) are synthesized via the chemical vapor deposition (CVD) method. CdSSe NFs thin film is used as a SERS substrate with an ultralow limit of detection (LOD, 10−14 M), high apparent enhancement factor (EF, 3.62 × 109), and excellent SERS stability (relative standard deviation, RSD = 3.05%) for probe molecules of Rh6G. Further, CdSSe NFs substrate is successfully applied in the sensitive, quantitative, and label-free analysis of ciprofloxacin (CIP) and enrofloxacin (ENR) antibiotics, which exhibit LODs of below 0.5 ppb. This excellent SERS platform may be widely utilized for sensitive life science and environmental sensing.

Electrochemical Nano-Imprinting of Trimetallic Dendritic Surface for Ultrasensitive Detection of Cephalexin in Pharmaceutical Formulations

Cephalexin (CFX), a first-generation cephalosporin, is used to treat various infectious diseases. Although antibiotics have achieved considerable progress in the eradication of infectious diseases, their incorrect and excessive usage has contributed to various side effects, such as mouth soreness, pregnancy-related pruritus, and gastrointestinal symptoms, including nausea, epigastric discomfort, vomiting, diarrhoea, and haematuria. In addition to this, it also causes antibiotic resistance, one of the most pressing problems in the medical field. The World Health Organization (WHO) claims that cephalosporins are currently the most commonly used drugs for which bacteria have developed resistance. Hence, it is crucial to detect CFX in complex biological matrices in a highly selective and sensitive way. In view of this, a unique trimetallic dendritic nanostructure comprised of cobalt, copper, and gold was electrochemically imprinted on an electrode surface by optimising the electrodeposition variables. The dendritic sensing probe was thoroughly characterised using X-ray photoelectron spectroscopy, scanning electron microscopy, chronoamperometry, electrochemical impedance spectroscopy, and linear sweep voltammetry. The probe displayed superior analytical performance, with a linear dynamic range between 0.05 nM and 105 nM, limit of detection of 0.04 ± 0.01 nM, and response time of 4.5 ± 0.2 s. The dendritic sensing probe displayed minimal response to interfering compounds, such as glucose, acetaminophen, uric acid, aspirin, ascorbic acid, chloramphenicol, and glutamine, which usually occur together in real matrices. In order to check the feasibility of the surface, analysis of a real sample was carried out using the spike and recovery approach in pharmaceutical formulations and milk samples, yielding current recoveries of 93.29–99.77% and 92.66–98.29%, respectively, with RSD < 3.5%. It only took around 30 min to imprint the surface and analyse the CFX molecule, making it a quick and efficient platform for drug analysis in clinical settings.

Different Strategies for the Microfluidic Purification of Antibiotics from Food: A Comparative Study

The presence of residual antibiotics in food is increasingly emerging as a worrying risk for human health both for the possible direct toxicity and for the development of antibiotic-resistant bacteria. In the context of food safety, new methods based on microfluidics could offer better performance, providing improved rapidity, portability and sustainability, being more cost effective and easy to use. Here, a microfluidic method based on the use of magnetic microbeads specifically functionalized and inserted in polymeric microchambers is proposed. The microbeads are functionalized either with aptamers, antibodies or small functional groups able to interact with specific antibiotics. The setup of these different strategies as well as the performance of the different functionalizations are carefully evaluated and compared. The most promising results are obtained employing the functionalization with aptamers, which are able not only to capture and release almost all tetracycline present in the initial sample but also to deliver an enriched and simplified solution of antibiotic. These solutions of purified antibiotics are particularly suitable for further analyses, for example, with innovative methods, such as label-free detection. On the contrary, the on-chip process based on antibodies could capture only partially the antibiotics, as well as the protocol based on beads functionalized with small groups specific for sulfonamides. Therefore, the on-chip purification with aptamers combined with new portable detection systems opens new possibilities for the development of sensors in the field of food safety.

A Minireview for Recent Development of Nanomaterial-Based Detection of Antibiotics

Antibiotics are considered a new type of organic pollutant. Antibiotic residues have become a global issue due to their harm to human health. As the use of antibiotics is increasing in human life, such as in medicine, crops, livestock, and even drinking water, the accurate analysis of antibiotics is very vital. In order to develop rapid and on-site approaches for the detection of antibiotics and the analysis of trace-level residual antibiotics, a high-sensitivity, simple, and portable solution is required. Meanwhile, the rapid nanotechnology development of a variety of nanomaterials has been achieved. In this review, nanomaterial-based techniques for antibiotic detection are discussed, and some reports that have employed combined nanomaterials with optical techniques or electrochemical techniques are highlighted.

Stimulus-Responsive DNA Hydrogel Biosensors for Food Safety Detection

Food safety has always been a major global challenge to human health and the effective detection of harmful substances in food can reduce the risk to human health. However, the food industry has been plagued by a lack of effective and sensitive safety monitoring methods due to the tension between the cost and effectiveness of monitoring. DNA-based hydrogels combine the advantages of biocompatibility, programmability, the molecular recognition of DNA molecules, and the hydrophilicity of hydrogels, making them a hotspot in the research field of new nanomaterials. The stimulus response property greatly broadens the function and application range of DNA hydrogel. In recent years, DNA hydrogels based on stimulus-responsive mechanisms have been widely applied in the field of biosensing for the detection of a variety of target substances, including various food contaminants. In this review, we describe the recent advances in the preparation of stimuli-responsive DNA hydrogels, highlighting the progress of its application in food safety detection. Finally, we also discuss the challenges and future application of stimulus-responsive DNA hydrogels.

Explainable Deep Learning-Assisted Photochromic Sensor for β-Lactam Antibiotic Identification

Photochromic sensors have the advantages of diverse isomers for multi-analysis, providing more sensing information and possessing more recognition units and more sensitivity to external stimulations, but they present enormous complexity with various stimulations as well. Deep learning (DL) algorithms contribute a huge advantage at analyzing nonlinear and multidimensional data, but they suffer from nontransparent inner networks, "black-boxes". In this work, we employed the explainable DL approach to process and explicate photochromic sensing. Spirooxazine metallic complexes were adopted to prepare a multi-state analysis array for β-Lactams identification and quantitation. A dataset of 2520 unduplicated fluorescence intensity images was collected for convolutional neural network (CNN) operation. The method clearly discriminated six β-Lactams with 97.98% prediction accuracy and allowed rapid quantification with a concentration range from 1 to 100 mg/L. The photochromic sensing mechanism was verified via molecular simulation and class activation mapping, which explicated how the CNN model assesses the importance of photochromic sensor states and makes a discrimination decision. The explainable DL-assisted analysis method establishes an end-to-end strategy to ascertain and verify the complicated sensing mechanism for device optimization and even new scientific discovery.

Microfluidic preparation of optical sensors for biomedical applications

Optical biosensors are platforms that translate biological information into detectable optical signals, and have extensive applications in various fields due to their characteristics of high sensitivity, high specificity, dynamic sensing, etc. The development of optical sensing materials is an important part of optical sensors. In this review, we emphasize the role of microfluidic technology in the preparation of optical sensing materials and the application of the derived optical sensors in the biomedical field. We first present some common optical sensing mechanisms and the functional responsive materials involved. Then, we describe the preparation of these sensing materials by microfluidics. Afterward, we enumerate the biomedical applications of these optical materials as biosensors in disease diagnosis, drug evaluation, and organ-on-a-chip. Finally, we discuss the challenges and prospects in this field.