Deaths from the accidental ingestion of poisonous Amanita mushrooms occur every year due to the lack of a specific antidote against α-amanitin poisoning. Intervention and treatment can be promptly carried out to avoid serious consequences when the toxin can be effectively detected in whole blood before liver toxicity develops. Aptamers are molecular recognition units similar to antibodies, capable of specifically recognizing and detecting small molecules such as α-amanitin for which monoclonal antibodies are difficult to prepare. However, α-amanitin has a small molecular size and limited binding sites, which bring difficulties to aptamer selection. Moreover, achieving highly specific detection of α-amanitin in whole blood remains challenging due to the presence of potentially interfering components, such as human serum albumin (HSA). For these problems, we propose an aptamer selection method for small-molecule target α-amanitin, combining target-immobilized and library-immobilized SELEX to select high-affinity aptamers. To exclude HSA interference, counter-selection was introduced to remove HSA-bound sequences. Through these strategies, we successfully selected a highly specific α-amanitin aptamer with nanomolar affinity.

Modern research in nutrition science is transitioning from classical methodologies to advanced analytical strategies, in which Raman spectroscopy plays a crucial role. Raman spectroscopy and its derived techniques are gaining recognition in nutrition science for their features, such as high-speed, non-destructive analysis, label-free multiple detection and high sensitivity. Raman-enhancing techniques have further improved the sensitivity of Raman spectroscopy and widely extended its detection and imaging applications in nutrient analysis, as well as in ancillary tasks for nutrition research, such as nutrient status evaluation, nutrient interaction and metabolism studies. Further development of Raman-based analytical approaches lies in the improvement of instruments with higher precision, as well as the incorporation of other analytical techniques and advanced data analysis tools. This paper provides a comprehensive review of the application of nanoscience and nanotechnology, with a specific focus on Raman technology, in the field of food and nutrition science research. Instead of delving into the quantitative or qualitative detection capabilities of Raman technology, we highlight the remarkable food analysis and nutrition research methods established by this technology. Generally, this review introduces the characteristics and applications of Raman technology in nutrition analysis and discusses the limitations and future prospects of Raman spectroscopy for nutrition monitoring.

Developing active and stable oxygen evolution reaction(OER) electrocatalysts for water‐splitting hydrogen production under neutral conditions is crucial. Introducing Lewis acid (LA) on catalysts surface can build local alkaline microenvironment to enhance OER, but it may reduce active site exposure. In this work, atomic‐level LA sites (Fe–O and Cr–O ligands) are constructed and decorated CoO (designated as FeCr‐CoO), in which the Cr–O ligands can accelerate the transfer of * OH to OH⁻ and form a local alkaline environment, Fe–O ligands can prevent Cr–O ligands from being oxidized and thus improving the durability of FeCr‐CoO during the OER process. Moreover, the synergistic effect between Fe–O and Cr–O ligands can not only boosts the Lewis acidity, but also effectively promotes the water dissociation process (H 2 O * → * OH+ * H) and ensures the prompt supply of * OH in the elementary reaction from * O to * OOH. Therefore, the FeCr‐CoO achieved a low OER overpotential of 214 mV at 10 mA cm −2 and displayed negligible degradation in 1000 h in neutral electrolyte. Additionally, the overall water‐splitting electrolyzer can reach 10 mA at 1.50 V, and is kept stable for over 500 h with a degradation of only 5.3%. This study provides a new way for designing efficient OER catalysts under neutral conditions by constructing local alkaline microenvironments.

As a common food additive, nitrites are used in processed meat products, primarily for color enhancement and preservation. Excessive intake of nitrites can lead to high toxicity to pose a significant risk to human health, including potential carcinogenicity and even death. Consequently, developing a rapid and sensitive method for nitrite detection is crucial for food safety monitoring. Herein, this study is developing a nitrite detection system utilizing blue‐fluorescent carbon dots (CDs) derived from carboxylate cellulose. This system operates by detecting the quenching of CDs fluorescence, which is caused by Fe 3 ⁺ ions generated via the oxidation of Fe 2 ⁺ by nitrite under acidic conditions. Within a concentration range of 1–1000 µ m , the system demonstrates a strong linear relationship between CDs fluorescence intensity and nitrite concentration, with a detection limit of 0.42 µ m . Furthermore, this study is designing a novel CDs‐based fluorescent test strip for rapid and visual nitrite quantification in pakchoi cabbage samples, enabling detection within 30 min. Overall, the CDs‐based fluorescent test strips hold great promise for enhancing food safety monitoring, ensuring effective nitrite control, and protecting public health from the potential risks associated with excessive nitrite consumption.

Ganoderma lingzhi (G. lingzhi) is a Basidiomycete macrofungus valued for its secondary metabolites with pharmacological activity. To enhance the biosynthesis of secondary metabolites, various exogenous additives have been introduced to fungal fermentation processes. Metal nanomaterials, while known to influence cellular metabolism in mammalian systems, exhibit unclear effects when applied to macrofungal cultivation systems. The study systematically evaluates the impact of three distinct gold nanostructures-nanoparticles (AuNPs), nanorods (AuNRs), and nanoclusters (AuNCs)-on bioactive metabolite production during G. lingzhi submerged fermentation, employing integrated macroscopic process analytics and microscopic characterization. The results demonstrate that their impact on mycelial growth and bioactive metabolite production varied with the type, concentration, and addition timing of gold nanomaterials. Microscopic survey on cell surface morphology and nanoparticle distribution also reveals the different patterns of nanomaterial-mycelia cell interaction. Under the optimized addition conditions, AuNPs increased total polysaccharide content by 50.37% compared to the control group, while AuNRs increased triterpenoid content by 42.78%. The work confirms the potential of colloidal gold nanomaterials to facilitate the submerged fermentation of G. lingzhi, which is expected to encourage the development of nanomaterial additives-based approach for efficient microbial bioactive substances production.

Patulin (PAT), a fungal metabolite, which mainly exists in various moldy fruits, is greatly harmful to human. However, there are still many unsolved problems in the current detection of PAT. In the work, an ultra-highly sensitive and effective monitoring strategy for PAT was explored based on a novel electrochemiluminescence (ECL) aptasensor. Here, 3, 4, 9, 10-perylenetetracarboxylic acid (PTCA) was chosen as luminophore and terbium (Tb) metal organic gel (MOG) was prepared as a co-reaction accelerator. The MOG displayed a large surface area for immobilization of sufficient PTCA to catalyze co-reactant K2S2O8 to generate more sulfate radical anions (SO4 & BULL; -), thus accelerating the electron-transfer (ET) rate to facilitate ECL efficiency. In the presence of PAT, the ECL signal was greatly quenched, which could be attributed to the specific binding effect between PAT aptamer and PAT. Based on this process, a wide range of PAT concentrations from 0.1 fg & BULL;mL-1 to 0.1 & mu;g & BULL;mL-1 and a low detection limit of 0.02 fg & BULL;mL-1 (S/N = 3) were analyzed. The aptasensor showed excellent detection properties for trace patulin in terms of selectivity, sensitivity, stability, reproducibility and practicability. The designing ideas could serve as a model for the application of metal organic gels to design ultra-highly sensitive ECL platforms for food safety.

Ganoderma is a prize medicinal macrofungus with a broad range of pharmaceutical values. To date, various attempts have been made to cultivate Ganoderma to improve the production of secondary metabolites with pharmacological activity. Among the adopted techniques, protoplast preparation and regeneration are indispensable. However, the evaluation of protoplasts and regenerated cell walls usually relies on electron microscopy assays, which require time-consuming and destructive sample preparation and merely provide localized information in the selected area. In contrast, fluorescence assays enable sensitive real-time detection and imaging in vivo. They can also be applied to flow cytometry, providing a collective overview of every cell in a sample. However, for macrofungi such as Ganoderma, the fluorescence analysis of protoplasts and regenerated cell walls is difficult owing to the hindrance of the homologous fluorescent protein expression and the lack of an appropriate fluorescence marker. Herein, a specific plasma membrane probe, TAMRA perfluorocarbon nucleic acid probe (TPFN), is proposed for the nondestructive and quantitative fluorescence analysis of cell wall regeneration. Exploiting the perfluorocarbon membrane-anchoring chains, hydrophilic nucleic acid linker, and fluorescent dye TAMRA, the probe is proven to be selective, soluble, and stable, enabling rapid fluorescence detection of a protoplast sample free of transgenic expression or immune staining. Based on the TPFN and flow cytometry techniques, a quantitative approach is constructed to monitor the process of cell wall growth in a fast, quantitative, and high-throughout manner, and the obtained results are consistent with those of conventional electron microscopy. In principle, with slight modifications or integration, the proposed probe and approach can be adapted to the preparation of cell protoplasts, inspection of cell wall integrity under environmental stress, and programmable membrane engineering for cytobiology and physiology research.

Background Lignin is a complex aromatic heteropolymer comprising 15–30% dry weight of the lignocellulose. The complex structural characteristic of lignin renders it difficult for value-added utilization. Exploring efficient lignin-degrading microorganisms and investigating their lignin-degradation mechanisms would be beneficial for promoting lignin valorization. In this study, a newly isolated white-rot basidiomycete, Trametes hirsuta X-13, with capacity to utilize alkaline lignin as the sole substrate was investigated. Results The analysis of the fermentation properties of T . hirsuta X-13 using alkaline lignin as the sole substrate, including the mycelial growth, activities of ligninolytic enzymes and the rates of lignin degradation and decolorization confirmed its great ligninolysis capacity. The maximum lignin degradation rate reached 39.8% after 11 days of T . hirsuta X-13 treatment, which was higher than that of reported fungi under the same condition. Fourier transform infrared spectrometry (FTIR), gas chromatography–mass spectrometry (GC–MS) scanning electron micrographs (SEM), two-dimensional heteronuclear single quantum coherence NMR analysis (2D-HSQC NMR) collaborated with pyrolysis gas chromatography–mass spectrometry (py-GC/MS) analyses proved that lignin structure was severely deconstructed along with amounts of monomer aromatics generated. Furthermore, according to those chemical analysis, in addition to canonical C α –C β breakage, the cleavage of lignin interunit linkages of β–β might also occur by T . hirsuta X-13. Conclusions This study characterized a newly isolated white-rot basidiomycete T . hirsuta X-13 with impressive alkaline lignin degradation ability and provided mechanistic insight into its ligninolysis mechanism, which will be valuable for the development of lignin valorization strategies.

Exosomes are globular bodies with lipid bilayer membrane structure secreted by living cells. Since researchers have confirmed that the exosomes undertake the function of extracellular RNA transportation, the research on ihe origin and function of exosomes is in the ascendant. In recent years, exosomes have been found to have the potential to be disease biomarkers, which makes exosomes with specific surface proteins and specific carriers become valuable detection objects in biomedical science. From the perspective of chemical essence, the acquisition and analysis of exosomes need to rely on specific molecular recognition process. Aptamers, as molecular recognition units, are characterized by high specificity, high affinity, steady bioactivity, easy synthesis and preservation, as well as facile design and modification. Aptamers have been successfully applied in biosensors for exosomes. In this review, based on the chemical composition of exosomes and their components with physiological and pathological significance, we introduce representative work in the field of extracellular vesicle analysis using aptamers as molecular recognition units, and summarize the existing aptamer sequence information and application scenarios targeting exosomes. In particular, the latest progress of chemical regulation methods to enhance the recognition performance of aptamers is surveyed. We expect that the future progress in the selection and modification of aptamers will open up new and exciting avenues for molecular recognition of exosomes.

In this work, a label-free and highly sensitive fluorescence assay was constructed for microRNA detection. Nicking-enhanced rolling circle amplification (RCA) induced by G-quadruplex formation is coupled with inner filter effect (IFE)-based quenching effects of MoS2 quantum dots (MoS2 QDs). The padlock probe contains a recognition sequence to target microRNA and an accessible nicking site. The padlock probe is cyclized upon hybridization with target microRNA. Sequentially, amplification initiates a production of a long-concatenated sequence of circular probes. Abundant G-quadruplex sequences are produced via the nicking process and then used as the trigger to initiate the next RCA. In the presence of hemin, numerous hemin/G-quadruplex DNAzymes are formed, which catalyze the oxidation of o-phenylenediamine (OPD) into the colored product 2,3-diaminophenazine, resulting in quenching of the fluorescence of MoS2 QDs. This sensing strategy enables detection of microRNA let-7a with high selectivity and a detection limit of 4.6 fM. The as-prepared sensor was applied for detecting microRNA let-7a in dilute human serum samples and achieved a satisfactory recovery rate, demonstrating its potential in clinic diagnosis of microRNA-associated disease and biochemical research.

Recent progress has been made in adding exogenous vegetable oils in culture media to promote bioactive metabolite production in several medicinal mushrooms, but the mechanism is still unclear. In this study, we found that the vegetable oil coix seed oil (CSO) could induce the biosynthesis of triterpene acids (TAs) and also significantly increase cytoplasmic nitric oxide (NO) and hydrogen peroxide (H2O2) concentrations in the mycelium of Ganoderma lingzhi. The change in TA biosynthesis caused by CSO could be reversed by adding NO scavenger or H2O2 scavenger, and adding NO scavenger or H2O2 scavenger resulted in the reduction of the cytoplasmic H2O2 or NO concentration under CSO treatment, respectively. Moreover, adding NO scavenger or H2O2 scavenger reversed TA biosynthesis, which could be rescued by H2O2 or NO donor, respectively. Taken together, our study indicated that both NO and H2O2 were involved in the regulation of TA biosynthesis, and CSO-activated NO and H2O2 were interdependent but independently regulated the TA biosynthesis under CSO treatment in G. lingzhi.

Exosomes (Exos) are nanoscale natural vehicles for transporting biomolecules to facilitate cell-to-cell communication, indicating a high potential of them for delivering therapeutics/diagnostics. To improve their delivery capacity, a simple, noninvasive, and efficient strategy for functionalizing Exos with effective targeting ligands as well as elucidation of the cellular uptake mechanism of these functionalized Exos was found be to necessary, but remained a challenge. In this work, we used diacyllipid aptamer conjugates as the targeting ligand to develop an aptamer-functionalized Exos (Apt-Exos) nanoplatform for cell type-specific delivery of molecular therapeutics. The cellular uptake mechanism of Apt-Exos was investigated in details, and distinct behavior was observed in comparison to free Exos. By combining the excellent molecular recognition capability of aptamers and the superiority of Exos as natural vehicles, Apt-Exos can efficiently deliver molecular drugs/fluorophores to target cancer cells, providing a promising delivery platform for cancer theranostics.

Exosomes constitute an emerging biomarker for cancer diagnosis because they carry multiple proteins that reflect the origins of parent cells. Assessing exosome surface proteins provides a powerful means of identifying a combination of biomarkers for cancer diagnosis. We report a sensor platform that profiles exosome surface proteins in minutes by the naked eye. The sensor consists of a gold nanoparticle (AuNP) complexed with a panel of aptamers. The complexation of aptamers with AuNPs protects the nanoparticles from aggregating in a high-salt solution. In the presence of exosomes, the non-specific and weaker binding between aptamers and the AuNP is broken, and the specific and stronger binding between exosome surface protein and the aptamer displaces aptamers from the AuNP surface and results in AuNP aggregation. This aggregation results in a color change and generates patterns for the identification of multiple proteins on the exosome surface.

Exosomes are extracellular vesicles (50-100 nm) circulating in biofluids as intercellular signal transmitters. Although the potential of cancerous exosomes as tumor biomarkers is promising, sensitive and rapid detection of exosomes remains challenging. Herein, we combined the strengths of advanced aptamer technology, DNA-based nanostructure, and portable electrochemical devices to develop a nanotetrahedron (NTH)-assisted aptasensor for direct capture and detection of hepatocellular exosomes. The oriented immobilization of aptamers significantly improved the accessibility of an artificial nucleobase-containing aptamer to suspended exosomes, and the NTH-assisted aptasensor could detect exosomes with 100-fold higher sensitivity when compared to the single-stranded aptamer-functionalized aptasensor. The present study provides a proof-of-concept for sensitive and efficient quantification of tumor-derived exosomes. We thus expect the NTH-assisted electrochemical aptasensor to become a powerful tool for comprehensive exosome studies.

Exosomes are membrane-enclosed extracellular vesicles derived from cells, carrying biomolecules that include proteins and nucleic acids for intercellular communication. Owning to their advantages of size, structure, stability, and biocompatibility, exosomes have been used widely as natural nanocarriers for intracellular delivery of theranostic agents. Meanwhile, surface modifications needed to endow exosomes with additional functionalities remain challenging by their small size and the complexity of their membrane surfaces. Current methods have used genetic engineering and chemical conjugation, but these strategies require complex manipulations and have only limited applications. Herein, we present an aptamer-based DNA nanoassemblies on exosome surfaces. This in situ assembly method is based on molecular recognition between DNA aptamers and their exosome surface markers, as well as DNA hybridization chain reaction initiated by an aptamer-chimeric trigger. It further demonstrated selective assembly on target cell-derived exosomes, but not exosomes derived from nontarget cells. The present work shows that DNA nanostructures can successfully be assembled on a nanosized organelle. This approach is useful for exosome modification and functionalization, which is expected to have broad biomedical and bioanalytical applications.

A highly efficient nanozyme system, termed hollow multipod Cu(OH)2 superstructure (HMPS), has been developed via direct conversion from irregular nanoparticles. The HMPS displayed body size around 150 nm and branch lengths in the range of 150~250 nm. Based on the excellent catalytic property of HMPS, we developed a simple and highly sensitive colorimetric assay to detect urine glucose, and the results are in good agreement with hospital examination reports.

Nucleic acids hold promise as biomolecules for future applications in biomedicine and biotechnology. Their well-defined structures and compositions afford unique chemical properties and biological functions. Moreover, the specificity of hydrogen-bonded Watson-Crick interactions allows the construction of nucleic acid sequences with multiple functions. In particular, the development of nucleic acid probes as essential molecular engineering tools will make a significant contribution to advancements in biosensing, bioimaging and therapy. The molecular beacon (MB), first conceptualized by Tyagi and Kramer in 1996, is an excellent example of a double-stranded nucleic acid (dsDNA) probe. Although inactive in the absence of a target, dsDNA probes can report the presence of a specific target through hybridization or a specific recognition-triggered change in conformation. MB probes are typically fluorescently labeled oligonucleotides that range from 25 to 35 nucleotides (nt) in length, and their structure can be divided into three components: stem, loop and reporter. The intrinsic merit of MBs depends on predictable design, reproducibility of synthesis, simplicity of modification, and built-in signal transduction. Using resonance energy transfer (RET) for signal transduction, MBs are further endowed with increased sensitivity, rapid response and universality, making them ideal for chemical sensing, environmental monitoring and biological imaging, in contrast to other nucleic acid probes. Furthermore, integrating MBs with targeting ligands or molecular drugs can substantially support their in vivo applications in theranositics. In this review, we survey advances in bioanalytical and biomedical applications of rationally designed MBs, as they have evolved through the collaborative efforts of many researchers. We first discuss improvements to the three components of MBs: stem, loop and reporter. The current applications of MBs in biosensing, bioimaging and therapy will then be described. In particular, we emphasize recent progress in constructing MB-based biosensors in homogeneous solution or on solid surfaces. We expect that such rationally designed and functionalized MBs will open up new and exciting avenues for biological and medical research and applications.

Although surface-enhanced Raman spectroscopy (SERS) has been featured by high sensitivity, additional signal enhancement is still necessary for trace amount of biomolecules detection. In this paper, a SERS amplified approach, featuring "ions-mediated cascade amplification (IMCA)", was proposed by utilizing the dissolved silver ions (Ag(+)) from silver nanoparticles (AgNPs). We found that using Ag(+) as linkage agent can effectively control the gaps between neighboring 4-aminobenzenethiol (4-ABT) encoded gold nanoparticles (AuNPs@4-ABT) to form "hot spots" and thus produce SERS signal output, in which the SERS intensity was proportional to the concentration of Ag(+). Inspired by this finding, the IMCA was utilized for ultrasensitive detection of single nucleotide polymorphism in human mitochondrial DNA (16189T → C). Combining with the DNA ligase reaction, each target DNA binding event could successfully cause one AgNP introduction. By detecting the dissolved Ag(+) from AgNPs using IMCA, low to 3.0 × 10(-5) fm/μL targeted DNA can be detected, which corresponds to extractions from 200 nL cell suspension containing carcinoma pancreatic β-cell lines from diabetes patients. This IMCA approach is expected to be a universal strategy for ultrasensitive detection of analytes and supply valuable information for biomedical research and clinical early diagnosis.