Carbon Dots-Modified Nanoporous Membrane and Fe3O4@Au Magnet Nanocomposites-Based FRET Assay for Ultrasensitive Histamine Detection

A sea urchin-shaped nanozyme mediated dual-mode immunoassay nanoplatform for sensitive point-of-care testing histamine in food samples

Rapid detection of histamine remains a challenge due to the complexity of food matrices. Based on the high peroxidase-like activity of sea urchin-shaped Pt@Au NPs (SU-Pt@Au NPs), a novel dual-mode nanoplatform is developed for the sensitive detection of histamine utilizing an indirect competitive enzyme-linked immunosorbent assay. According to the colorimetric-based UV-vis nanoplatform, histamine is sensitively detected with a liner range from 0.5 to 100 ng/mL and a limit of detection (LOD) as low as 0.3 ng/mL. Then, a smartphone-loaded color picker APP can intelligently detect histamine in point-of-care testing (POCT) based on the R/B ratio of the color channels, with a detection range of 0.5 to 1000 ng/mL and a LOD as low as 0.15 ng/mL, significantly expanding the detection range. Such an easy-to-use and sensitive detection system is employed to quantify histamine in Pacific saury, crab, and pork samples, indicating outstanding application potential in protein-rich meat food safety.

Cucurbit[7]uril-based carbon dots for recognizing histamine

Fluorescent carbon quantum dots (CQDs) were synthesized from cucurbit[7]uril (Q[7]) and 2,2-bis(hydroxymethyl)propionic (DMPA) by a hydrothermal method. The Q[7]-DMPA complex was confirmed by X-ray crystallography. The CQDs showed blue fluorescence, photostability, and ionic strength stability. They were used to detect histamine with a low limit of 2.33 × 10-6 M.

Recent advances in meat freshness "magnifier": fluorescence sensing

To address the serious waste of meat resources and food safety problems caused by the decrease in meat freshness due to the action of microorganisms and enzymes, a low-cost, time-saving and high-efficiency freshness monitoring method is urgently needed. Fluorescence sensing could act as a "magnifier" for meat freshness monitoring due to its ability to sense characteristic signal produced by meat spoilage. Here, the magnification mechanism of meat freshness via sensing the water activity, adenosine triphosphate, hydrogen ion, total volatile basic nitrogen, hydrogen sulfide, bioamines was comprehensively analyzed. The existing "magnifier" forms including paper chips, films, labels, arrays, probes, and hydrogels as well as the application in livestock, poultry and aquatic meat freshness monitoring were reviewed. Future research directions involving innovation of principles, visualization and quantification capabilities for various meats freshness were provided. By critically evaluating the potential and limitations, efficient and reliable meat freshness monitoring strategies wish to be developed for the post-epidemic era.

Recent advances in the application of Raman spectroscopy for fish quality and safety analysis

Fish is one of the highly demanded aquatic products, and its quality and safety play a pivotal role in daily diet. However, the possible hazardous substance in perishable fish both in pre- and postharvest periods may decrease their values and pose a threat to public health. Laborious and expensive traditional methods drive the need of developing effective tools for detecting fish quality and safety properties in a rapid, nondestructive, and effective manner. Recent advances in Raman spectroscopy (RS) and surface-enhanced Raman scattering (SERS) have shown enormous potential in various aspects, which largely boost their applications in fish quality and safety evaluation. They have incomparable merits such as providing molecule fingerprint information and allowing for rapid, sensitive, and noninvasive detection with simple sample preparation. This review provides a comprehensive overview focusing on the applications of RS and SERS for fish quality assessment and safety inspection, highlighting the hazardous substance and illegal behavior both in preharvest (veterinary drug residues and environmental pollutants) and postharvest (freshness and illegal behavior) particularly. Moreover, challenges and prospects are also proposed to facilitate the vigorous development of RS and SERS. This review is aimed to emphasize potential opportunities for applying RS and SERS as promising techniques for routine food quality and safety detection. PRACTICAL APPLICATION: With these applications, it can be clearly indicated that RS and SERS are promising and powerful in fish quality and safety surveillance, thereby reducing the occurrence of commercial fraud and food safety issues. More efforts still should be concentrated on exploiting the high-performance Raman instruments, establishing a universal Raman database, developing reproducible SERS substrates and combing RS with other versatile spectral techniques to promote these technologies from laboratory to practice. It is hoped that this review should arouse more research interests in RS and SERS technologies for fish quality and safety surveillance, as well as provide more insights to make a breakthrough.

Recent Progress of Fluorescence Sensors for Histamine in Foods

Biological amines are organic nitrogen compounds that can be produced by the decomposition of spoiled food. As an important biological amine, histamine has played an important role in food safety. Many methods have been used to detect histamine in foods. Compared with traditional analysis methods, fluorescence sensors as an adaptable detection tool for histamine in foods have the advantages of low cost, convenience, less operation, high sensitivity, and good visibility. In terms of food safety, fluorescence sensors have shown great utilization potential. In this review, we will introduce the applications and development of fluorescence sensors in food safety based on various types of materials. The performance and effectiveness of the fluorescence sensors are discussed in detail regarding their structure, luminescence mechanism, and recognition mechanism. This review may contribute to the exploration of the application of fluorescence sensors in food-related work.

Zero-to-Two Nanoarchitectonics: Fabrication of Two-Dimensional Materials from Zero-Dimensional Fullerene

Nanoarchitectonics of two-dimensional materials from zero-dimensional fullerenes is mainly introduced in this short review. Fullerenes are simple objects with mono-elemental (carbon) composition and zero-dimensional structure. However, fullerenes and their derivatives can create various types of two-dimensional materials. The exemplified approaches demonstrated fabrications of various two-dimensional materials including size-tunable hexagonal fullerene nanosheet, two-dimensional fullerene nano-mesh, van der Waals two-dimensional fullerene solid, fullerene/ferrocene hybrid hexagonal nanosheet, fullerene/cobalt porphyrin hybrid nanosheet, two-dimensional fullerene array in the supramolecular template, two-dimensional van der Waals supramolecular framework, supramolecular fullerene liquid crystal, frustrated layered self-assembly from two-dimensional nanosheet, and hierarchical zero-to-one-to-two dimensional fullerene assembly for cell culture.

Light-Interacting iron-based nanomaterials for localized cancer detection and treatment

To improve the prognosis of cancer patients, methods of local cancer detection and treatment could be implemented. For that, iron-based nanomaterials (IBN) are particularly well-suited due to their biocompatibility and the various ways in which they can specifically target a tumor, i.e. through passive, active or magnetic targeting. Furthermore, when it is needed, IBN can be associated with well-known fluorescent compounds, such as dyes, clinically approved ICG, fluorescent proteins, or quantum dots. They may also be excited and detected using well-established optical methods, relying on scattering or fluorescent mechanisms, depending on whether IBN are associated with a fluorescent compound or not. Systems combining IBN with optical methods are diverse, thus enabling tumor detection in various ways. In addition, these systems provide a wealth of information, which is inaccessible with more standard diagnostic tools, such as single tumor cell detection, in particular by combining IBN with near-field scanning optical microscopy, dark-field microscopy, confocal microscopy or super-resolution microscopy, or the highlighting of certain dynamic phenomena such as the diffusion of a fluorescent compound in an organism, e.g. using fluorescence lifetime imaging, fluorescence resonance energy transfer, fluorescence anisotropy, or fluorescence tomography. Furthermore, they can in some cases be complemented by a therapeutic approach to destroy tumors, e.g. when the fluorescent compound is a drug, or when a technique such as photo-thermal or photodynamic therapy is employed. This review brings forward the idea that iron-based nanomaterials may be associated with various optical techniques to form a commercially available toolbox, which can serve to locally detect or treat cancer with a better efficacy than more standard medical approaches. STATEMENT OF SIGNIFICANCE: New tools should be developed to improve cancer treatment outcome. For that, two closely-related aspects deserve to be considered, i.e. early tumor detection and local tumor treatment. Here, I present various types of iron-based nanomaterials, which can achieve this double objective when they interact with a beam of light under specific and accurately chosen conditions. Indeed, these materials are biocompatible and can be used/combined with most standard microscopic/optical methods. Thus, these systems enable on the one hand tumor cell detection with a high sensitivity, i.e. down to single tumor cell level, and on the other hand tumor destruction through various mechanisms in a controlled and localized manner by deciding whether or not to apply a beam of light and by having these nanomaterials specifically target tumor cells.

A Sensitive FRET Biosensor Based on Carbon Dots-Modified Nanoporous Membrane for 8-hydroxy-2'-Deoxyguanosine (8-OHdG) Detection with Au@ZIF-8 Nanoparticles as Signal Quenchers

A sensitive fluorescence resonance energy transfer (FRET) biosensor is proposed to detect 8-hydroxy-2′-deoxyguanosine (8-OHdG), which is a typical DNA oxidation damage product excreted in human urine. The FRET biosensor was based on carbon dots (CDs)-modified nanoporous alumina membrane with CDs as fluorescence donors. Gold nanoparticles were encapsulated in zeolitic imidazolate framework-8 to form Au@ZIF-8 nanoparticles as signal quenchers. CDs and Au@ZIF-8 nanoparticles were biofunctionalized by 8-OHdG antibody. The capture of 8-OHdG on the membrane substrates can bring Au@ZIF-8 nanoparticles closely to CDs. With 350 nm excitation, the fluorescence of CDs was quenched by Au@ZIF-8 nanoparticles and FRET effect occurred. The quenching efficiency was analyzed. The limit of detection (LOD) was 0.31 nM. Interference experiments of the FRET biosensor showed good specificity for 8-OHdG detection. The biosensor could detect urinary 8-OHdG sensitively and selectively with simple sample pretreatment processes. It shows applicability for detecting biomarkers of DNA damage in urine or other biological fluids.