Tungsten disulfide (WS2) nanosheet-based photoelectrochemical aptasensing of chloramphenicol

Determination of chloramphenicol in food using nanomaterial-based electrochemical and optical sensors-A review

Chloramphenicol (CAP) is a widely used antibiotic for the treatment of sick animals owing to its potent action and low cost. However, the accumulation of CAP in the human body can cause irreversible aplastic anemia and hematopoietic toxicity. Accordingly, development of various analytical techniques for the rapid detection of CAP in animal products and the related processed foods is necessary. Among these analytical techniques, electrochemical and optical sensors offer many advantages for CAP detection, including high sensitivity, simple operation and fast analysis speed. In this review, we summarize recent application of carbon nanomaterials, metal nanoparticles, metal oxide nanoparticles and metal organic framework in the development of electrochemical and optical sensors for CAP detection (2010-2022). Based on the advantages and disadvantages of nanomaterials, electrochemical and optical sensors are summarized in this review. The preparation and synthesis of electrochemical and optical sensors and nanomaterials in the field of rapid detection are prospected.

A graphene-oxide-based aptasensor for fluorometric determination of chloramphenicol in milk and honey samples utilizing exonuclease III-assisted target recycling and Nb.BbvCI-powered DNA walker cascade amplification

Herein, a graphene oxide (GO)-based fluorescence aptasensor was developed for the sensitive and selective detection of chloramphenicol (CAP), based on exonuclease III (Exo III)-assisted target recycling and Nb.BbvCI-driven DNA walker cascade amplification. Interactions between CAP, hairpin1(HP1), hairpin2 (HP2), and 3'-amino modified hairpin3 (HP3) labeled with carboxyfluorescein (FAM) and covalently coupled to GO enabled efficient CAP detection. CAP was quantitatively assayed by measuring fluorescence at excitation/emission wavelengths of 480/514 nm, resulting from the accumulation of released FAM. A good linear range of 1 fM to 1 nM and a limit of detection (LOD) of 0.875 fM (signal-to-noise (S/N)= 3) were achieved. This aptasensor can distinguish the CAP from interference antibiotics with good specificity and selectivity, even if the concentration of the interfering substance is ten-fold higher than the target concentration. Moreover, the developed fluorescence aptasensor was successfully applied for the detection of CAP in spiked milk and honey samples. Thus, this method is potentially applicable for assaying CAP in foods and provides a promising strategy for the development of fluorescence aptasensors for environmental sample analysis.

Turn -on FRET-based cysteine sensor by sulfur-doped carbon dots and Au nanoparticles decorated WS2 nanosheet

Cysteine is an essential biothiol that plays various functions in the human body. Decrease or exceeding of this excellent antioxidant from the expected range will lead to so many problems. Thus, appropriate sensing of it would be of great importance. Sulfur-doped carbon Dots(S-CDs) owe excellent fluorescence emission. Therefore, designing a Fluorescence resonance energy transfer (FRET) system between S-CDs as donor and Au nanoparticles (AuNPs) decorated tungsten disulfide nanosheet (WS2 NSs) would be a perfect strategy for cysteine detection. Excitation at 340 nm will give the maximum quantum yield of S-CDs (21%) and fluorescence emission peak at 460 nm. In the presence of cysteine, the FRET mechanism inhibited through the affinity of cysteine's functional groups (-SH and -NH2) toward AuNPs and S-CDs fluorescence emission was recovered. To find the best efficiency of the system, optimization of pH, temperature, and time was investigated. Here the linear range of 3-275 µM and limit of detection of 0.01 µM was obtained. Finally, the fluorescence method was applied to the analysis of cysteine in human blood serum, which poses the potential of rapid and sensitive sensing. It can detect both lower and higher amounts of serum cysteine.

Fabrication of eco-friendly chitosan functionalized few-layered WS2 nanocomposite implanted with ruthenium nanoparticles for in vitro antibacterial and anticancer activity: Synthesis, characterization, and pharmaceutical applications

The abundance of two-dimensional (2D) components has provided them with a broad material platform for building nano and atomic-level applications. So, 2D nanomaterials are unique because of their physicochemical properties. Over many years, graphene is a conventional 2D layered element that has significant attention in the scientific community. In recent years numerous new 2D nanomaterials other than graphene have been reported. The study of 2D nanomaterials is also in its infant stages, with the majority of research focusing on the explanation of special material properties, but very few articles are focusing on the biological applications of 2D nanomaterials. As a result, we focused on the transition metal dichalcogenides (TMDCs) such as MoS₂ and WS₂, which were emerging and exciting groups of elements with display great opportunities in several fields, such as cancer nanomedicine. Herein, we synthesized biologically active CS/WS₂/Ru composite by liquid exfoliation approach. The CS/WS₂/Ru composites exhibit significant antibacterial action towards (S. aureus, and E. coli) bacteria. Also, the composite suggests synergetic anticancer action against MCF-7 cancer cells. These reports are possible to explore the innovative aspects of biological outcomes in carcinological applications.

Contribution of Nanomaterials to the Development of Electrochemical Aptasensors for the Detection of Antimicrobial Residues in Food Products

The detection of antimicrobial residues in food products of animal origin is of utmost importance. Indeed antimicrobial residues could be present in animal derived food products because of animal treatments for curative purposes or from illegal use. The usual screening methods to detect antimicrobial residues in food are microbiological, immunological or physico-chemical methods. The development of biosensors to propose sensitive, cheap and quick alternatives to classical methods is constantly increasing. Aptasensors are one of the major trends proposed in the literature, in parallel with the development of immunosensors based on antibodies. The characteristics of electrochemical sensors (i.e., low cost, miniaturization, and portable instrumentation) make them very good candidates to develop screening methods for antimicrobial residues in food products. This review will focus on the recent advances in the development of electrochemical aptasensors for the detection of antimicrobial residues in food products. The contribution of nanomaterials to improve the performance characteristics of electrochemical aptasensors (e.g., Sensitivity, easiness, stability) in the last ten years, as well as signal amplification techniques will be highlighted.

Recent development of antibiotic detection in food and environment: the combination of sensors and nanomaterials

In recent years, the abuse of antibiotics has led to the pollution of soil and water environment, not only poultry husbandry and food manufacturing will be influenced to different degree, but also the human body will produce antibody. The detection of antibiotic content in production and life is imperative. In this review, we provide comprehensive information about chemical sensors and biosensors for antibiotic detection. We classify the currently reported antibiotic detection technologies into chromatography, mass spectrometry, capillary electrophoresis, optical detection, and electrochemistry, introduce some representative examples for each technology, and conclude the advantages and limitations. In particular, the optical and electrochemical methods based on nanomaterials are discussed and evaluated in detail. In addition, the latest research in the detection of antibiotics by photosensitive materials is discussed. Finally, we summarize the pros and cons of various antibiotic detection methods and present a discussion and outlook on the expansion of cross-scientific areas. The synthesis and application of optoelectronic nanomaterials and aptamer screening are discussed and prospected, and the future trends and potential impact of biosensors in antibiotic detection are outlined.Graphical abstract.

Recent advances on TMDCs for medical diagnosis

Transition metal dichalcogenides (TMDCs), such as MoS₂ and WS₂, have attracted much attention in biosensing and bioimaging due to its excellent stability, biocompatibility, high specific surface area, and wide varieties. In this review, we overviewed the application of TMDCs in biosensing and bioimaging. Firstly, the synthesis methods and surface functionalization methods of TMDCs were summarized. Secondly, according to the working mechanism, we classified and gave a detailed account of the latest research progress of TMDC-based biosensing for the detection of the enzyme, DNA, and other biological molecules. Then, we outlined the recent progress of applying TMDCs in bio-imaging, including fluorescence, X-ray computed tomographic, magnetic response imaging, photographic and multimodal imaging, respectively. Finally, we discussed the future challenges and development direction of the application of TMDCs in medical diagnosis. Also, we put forward our view on the opportunity of TMDCs in the big data of modern medical diagnosis.

Fabrication of homogeneous waffle-like silver composite substrate for Raman determination of trace chloramphenicol

Waffle-like anodized aluminum oxide homogeneously immobilized with Ag nanoparticles (AAO/Ag) is rationally designed and fabricated as surface-enhanced Raman scattering (SERS) substrate. The as-prepared SERS substrate is characterized with transmission electron microscope (TEM), scanning electron microscopy (SEM), UV-Vis spectrophotometer, and Fourier transform infrared spectrometer (FT-IR). The AAO/Ag substrate shows good uniformity of the Raman signals (RSD = 7.02%) due to waffle-like AAO supporting the well-dispersed Ag nanoparticles. For real application, the AAO/Ag substrate is used for rapid determination of chloramphenicol (CAP) in honey with low detection limit (4.0 × 10^-9 mol L^-1) and good linearity from 1.0 × 10^-5 to 1.0 × 10^-8 mol L^-1 based on the SERS peak at 1348 cm^-1. The better accumulation in the short pore path of AAO improves the target molecule approaching into the vicinity of hot spots of Ag nanoparticles. The high selectivity for CAP is attributed to the strong interaction between -NO₂ group in CAP and the composite substrate. Schematic representation of the preparation of SERS substrate, AAO₁₅₀/Ag₁₀-5 composite nanoparticles, and antibiotic determination.

Application of Biosensors for Detection of Pathogenic Food Bacteria: A Review

The use of biosensors is considered a novel approach for the rapid detection of foodborne pathogens in food products. Biosensors, which can convert biological, chemical, or biochemical signals into measurable electrical signals, are systems containing a biological detection material combined with a chemical or physical transducer. The objective of this review was to present the effectiveness of various forms of sensing technologies for the detection of foodborne pathogens in food products, as well as the criteria for industrial use of this technology. In this article, the principle components and requirements for an ideal biosensor, types, and their applications in the food industry are summarized. This review also focuses in detail on the application of the most widely used biosensor types in food safety.

Impedimetric ultrasensitive detection of chloramphenicol based on aptamer MIP using a glassy carbon electrode modified by 3-ampy-RGO and silver nanoparticle

In this research work, a biosensor with a dual recognition system was fabricated and founded on a combination of aptasensing and the molecular imprinting union of the chloramphenicol (CAP) selective detection. CAP, is an antibiotic, was applied in veterinary and human in order to treat gram-positive and gram-negative infections. It is worth mentioning that CAP residue brings about earnest side effects on human health. According to this, in this sensing system, 3-aminomethyl pyridine functionalized graphene oxide (GO) (3-ampy-RGO) has been coated on the surface of GCE. Afterwards, the silver nanoparticle (AgNPs) was coated on the 3-ampy-RGO/GCE and, then, the CAP complex-amino-aptamer (NH₂-Apt[CAP]) was attached to the AgNP/3-ampy-RGO/GCE using a kind of bonding formation of Ag-N. In this sense, it is worth noting that the resorcinol electropolymerization around the complex of aptamer/CAP would confine the complex and, then, retain the aptamer. Following the CAP removal, the MIP cavity, as it was supposed, synergistically acted with that of the embedded aptamer in order to construct a nanohybrid receptor. Interestingly, the double exact property of the molecular imprinting polymers and aptamers led to the superb sensing properties. In the mentioned system it was illustrated that the linear range was from 1.0 pM to 1.0 nM with the detection limit of 0.3 pM; consequently, as observed, it was better than or as good as other similar assays. Moreover, the mentioned system whose activity was observed in the various interferences presence showed great selectivity in detected the CAP. Finally, the designed sensor exhibited outstanding results when applied to detect CAP in milk samples.

Electrochemical aptasensor for sulfadimethoxine detection based on the triggered cleavage activity of nuclease P1 by aptamer-target complex

Herein, a simple and selective electrochemical method was developed for sulfadimethoxine detection based on the triggered cleavage activity of nuclease P1 by the formation of aptamer and sulfadimethoxine conjugate. After probe DNA was immobilized on gold electrode surface, aptamer DNA labeled with biotin at its 5'-terminal was then captured on electrode surface through the hybridization reaction between probe DNA and aptamer DNA. The formed double-stranded DNA (dsDNA) can block the digestion activity of Nuclease P1 towards the single-stranded probe DNA. Then, the anti-dsDNA antibody was further modified on electrode surface based on the specific interaction between dsDNA and antibody. Due to the electrostatic repulsion effect and steric-hindrance effect, a weak electrochemical signal was obtained at this electrode. However, in the presence of sulfadimethoxine, it can interact with aptamer DNA, and then the formation of dsDNA can be blocked. As a result, the probe DNA at its single-strand state can be digested by Nuclease P1, which leads to the failure of the immobilization of anti-dsDNA antibody. At this state, a strong electrochemical signal was obtained. Based on the change of the electrochemical signal, sulfadimethoxine can be detected with linear range of 0.1-500 nmol/L. The detection limit was 0.038 nmol/L. The developed method possesses high detection selectivity and sensitivity. The applicability of this method was also proved by detecting sulfadimethoxine in veterinary drug and milk with satisfactory results.

Photoelectrochemical aptamer-based sensing of the vascular endothelial growth factor by adjusting the light harvesting efficiency of g-C3N4 via porous carbon spheres

A "signal-off" sensor is described for sensitive photoelectrochemical (PEC) determination of the vascular endothelial growth factor (VEGF₁₆₅). Graphitic carbon nitride (g-C₃N₄) is used as the signalling material, and porous carbon spheres as efficient quenchers of the photocurrent. The quenching efficiency of carbon spheres is the result of two effects, viz. (a) the competitive light absorption and (b) competitive electron donor activity which decreases the number of light-generated electrons and holes and also reduces the charge separation efficiency. This new mechanism differs from the previous quenching mechanisms which usually are based on the suppression of electron transport or steric hindrance. A glassy carbon electrode was modified with an aptamer against VEGF₁₆₅. On binding of analyte (VEGF₁₆₅), the reduction of current is measured (at a typical potential of 0 V) using H₂O₂ as the electrochemical probe. The sensor has a linear response in the 10^-5 nM to 10² nM VEGF₁₆₅ concentration range, and the detection limit is 3 fM. Graphical abstract Schematic presentation of the quenching mechanism of carbon spheres: the competitive light absorption and competitive electron donor reduce the number of light-generated electrons in the conduction band (CB) and holes in the valence band (VB) and also reduce the charge separation efficiency.