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Flavonoid glycosides are formed by dehydration condensation of aglycones and sugar molecules. Therefore, discrimination of flavonoid glycosides from their corresponding aglycones is a challenging task because they contain the same aglycone part in their molecular structures. Herein, boric acid-functional Eu(III)-organic framework (BA-Eu-MOF) was applied to discriminate flavonoid glycosides including baicalin (Bai), wogonoside (Wog), rutin (Rut), puerarin (Pue), quercitrin (Que) and astragalin (Ast) from their corresponding aglycones for the first time. Besides as organic ligand to sensitize the luminescence of Eu³⁺ through "antenna" effect, 5-boronobenzene-1,3 dicarboxylic acid provided recognition site for flavonoid glycosides. Infrared, fluorescence, UV-vis, and mass spectra were used to investigate the recognition reaction between BA-Eu-MOF and flavonoid glycosides. The data indicated that the cis-diols of flavonoid glycosides from sugars covalently bonded to boric acid group to form cyclic boronic esters, which quenched the fluorescence of BA-Eu-MOF at 620 nm through decreasing the intersystem efficiency, inner filter effect and photoelectron transfer. In contrast, aglycones could not alter the fluorescence of BA-Eu-MOF because of no covalent bond between them. This probe exhibited high sensitivity towards flavonoid glycosides with the low detection limits of 3.3 nM, 3.5 nM, 33 nM, 56 nM, 5.1 nM and 5.5 nM for Bai, Que, Wog, Ast, Pue and Rut, respectively. The unique recognition ability of boric acid group enables selective and sensitive detection of flavonoid glycosides without the interference of their corresponding aglycones.

CYFRA21-1 is a tumor marker for lung cancer, and its rapid and accurate detection can provide evidence for the early diagnosis of lung cancer. In this work, Bi-Fe turnbull blue analogues (Bi-Fe-TBA) were synthesized by the self-templating method. Bi₂O₃-SFNs was prepared by simple oxidation in air using Bi-Fe-TBA as a template. Bi₂O₃ Star-like Flower Nanoclusters (Bi₂O₃-SFNs) and CdS Hollow Nanorods (CdS-HNRs) were used to form a unique type II heterojunction for the first time. The arrangement of energy levels between CdS-HNRs and Bi₂O₃-SFNs, along with their hollow structure and star shape, effectively suppressed the recombination of photogenerated electrons and holes while shortening carrier transport distance. An ultra-sensitive PEC biosensor was developed to detect the lung cancer marker CYFRA21-1, leveraging the superior photoelectric conversion capabilities of Bi₂O₃-SFNs/CdS-HNRs. The sensor demonstrates outstanding stability, specificity, reproducibility as well as a wide linear range (10^-4 - 10 ng mL^-1) and low detection limit (4.23 × 10^-5 ng mL^-1). This study is valuable for the preparation of other functional materials using TBA as a template.

The growing demand for glycolate, fueled by economic development, requires the advancement of production methods. Escherichia coli (E. coli), a preferred host for glycolate production, has undergone extensive metabolic engineering to improve yield. Developing rapid and precise methods for quantifying glycolate concentration is essential for screening high-yielding strains. Here, we present the engineering of a novel circularly permuted green fluorescent protein (cpGFP)-based glycolate sensor, termed GLYCO. GLYCO exhibits high specificity (minimal interference from other metabolites), stability (no decrease in performance after 15 days at -80 °C), and ease of detection via fluorescence measurement, enabling effective in vitro glycolate quantification. GLYCO spans a quantification range from 10 μM to 1 mM, facilitating effective monitoring of glycolate production in metabolically engineered E. coli strains. This biosensor represents a significant advancement in the metabolic engineering toolkit, facilitating efficient detection and optimization of glycolate production in E. coli, with potential applications in industrial biotechnology.

Directly detecting biomarkers in liquid biopsy for diagnosis and personalized treatment plays a crucial role in managing cancer relapse and increasing survival rates. Typically, the standard analysis of circulating tumour DNA requires lengthy isolation, extraction, and amplification steps, leading to sample contamination, longer turnaround time and higher assay costs. Surface plasmon resonance is an emerging and promising technology for rapid and real-time dynamic biomarker monitoring in liquid biopsy. Here, we propose a new SPR imaging biosensing approach to detect tumour DNA circulating in the blood of colorectal cancer patients by exploiting the unique properties of superparamagnetic particles. Micrometer beads functionalized with a biotinylated oligonucleotide can directly capture DNA target sequences bearing single-nucleotide variations of KRAS oncogene in human blood plasma. Mutated and wild-type peptide nucleic acid probes immobilized on an SPR gold surface recognize complementary and non-complementary DNA targets by discriminating a single nucleotide mismatch. The new assay allows for detecting p.G13D mutated DNA in buffer and spiked human plasma at attomolar level (down to 300 copies mL^-1) with minimal sample manipulation and in just a few microliters. The assay was validated using plasma samples from colorectal cancer patients and healthy donors, by discriminating mutated DNA circulating in patients and wild-type DNA found in healthy blood donors. This feature underscores the potential of the liquid biopsy assay as a valuable tool for the diagnosis and monitoring of cancer.

Cancer Antigen 125 (CA125), is a high molecular weight mucinous glycoprotein found on the surface of ovarian cancer cells. Generally, 90 % of women may appear a high concentration of CA125 when they got the cancer; thus, CA125 can act as a marker for ovarian cancer diagnosis and therapeutic evaluation. COFs have been widely used for disease detection due to their structural stability, high loading capacity and biocompatibility. However, the limited variety of electroactive COFs used as signal probes, fewer enriched signaling molecules, weaker electrical signals generated, and higher oxidation or reduction potentials of electroactive substances, a series of side reactions are easily triggered causing serious interference. To solve the above problems, [Fe(CN)6]^3/4- as a signal probe and COFs for signal amplification were selected to creating a highly sensitive electrochemical immunosensor for glycan antigen CA125. Firstly, two-dimensional (2D) EP-TD-COF with ultra-high specific surface area was modified on bare GCE, which could covalently bound numerous Ab1 molecules due to the epoxy-rich functional groups. Then, the electropositive AuNPs@2DCOFBTT-DGMH was prepared by the in situ growth of AuNPs, proved an effective platform for loading Ab2 molecules via Au-S bonds. Based on the positively charged AuNPs@COFBTT-DGMH/Ab2 and negatively charged [Fe(CN)6]^3/4- of electrostatic interactions, which could significantly enchaned signal for quantitative and sensitive detection of CA125. The constructed immunosensor exhibits excellent stability performance and high sensitivity, enabling ultrasensitive detection of trace glycan antigens. This study provided a new idea for the use of non-electroactive substances for the construction of electrochemical immunosensors and provided an effective signal amplification strategy.

Measuring the radioactivity of organically bound tritium in environmental samples is difficult. For the past twenty years, many laboratories have been working on the development of reliable tritium measurement methods. In this context, several interlaboratory comparisons have been organised to develop these methods and enable laboratories to compare themselves. However, the trueness of the measurement methods has never been estimated due to the lack of certified reference materials available for use during the analyses. This document presents the production of the first certified reference material for the measurement of organically bound tritium radioactivity in environmental samples.

The low sensitivity of Lateral flow assay (LFA) limits its application in rapid detection for trace targets. LFAs with nanozyme (nanozyme-LFA) as signal labels have demonstrated excellent performance in point of care testing (POCT). However, additional operational steps for substrate catalysis in nanozyme LFA are required, which makes the nanozyme-LFA operation complicated. In this work, we designed a LFA based on delayed substrate release (SGF-LFA), in which a commercialized glass fiber membrane embedded with substrate (SGF) was fixed at the sample pad. The SGF could automatically execute substrate delivery and catalysis, thus eventually achieving a one-step LFA operation for the nucleic acid detection of influenza A virus H1N1. In this SGF-LFA, 3,3 '- diaminobenzidine (DAB) was oxidized and deposited, producing a strong signal amplification under the catalysis of Au@PtNP nanozyme. The SGF-LFA could detect the nucleic acid of H1N1, with a linear range of 0.02-50 nM and a limit of detection (LOD) as low as 0.02 nM, which was 25-fold lower than that of the nanozyme-LFA before catalysis. In addition, the analytical performance was close to that of a manual operation mode of catalysis amplification. The application of SGF-LFA for detecting the H1N1 nucleic acid in serum samples obtained a recovery rate of 96 %-102.7 %, indicating that SGF-LFA has great potential in point-of-care testing.

Anthropogenic activities have led to increased stress on our marine and other aquatic environments. There is a pressing need to monitor, measure, understand and mitigate causes of these pressures. This paper presents a novel optical head for monitoring and measuring marine based optical phenomena. The development and preliminary testing of the optical head were designed to detect optically active constituents in the marine and coastal environments. Potential applications may include the detection of Harmful Algal Blooms (HAB), which due to their production of toxins have deleterious effects on marine ecosystems, dissolved organic matter (DOM), oil spills, through the measurement of dissolved fluorescent petroleum compounds and turbidity, a key metric in marine and water quality measurements. Preliminary laboratory based results indicate that the optical head is well suited for measuring in-vivo Chlorophyll a (Chl a) fluorescence, turbidity, fluorescent dissolved organic matter (fDOM) and petroleum. For turbidity and in-vivo Chl a, analytical performance was benchmarked against off-the-shelf commercial sensors. The developed optical head demonstrates good analytical performance with certified reference standards and a very good agreement with the reference instrument.