Dual-Mechanism Tuned Engineered Polyphenols with Cascade Photocatalytic Self-Fenton Reaction for Sustainable Biocidal Coatings

Traditional disposable personal protective equipment (PPE) only blocks pathogenic bacteria by mechanical filtration, with the risk of recontamination and transmission remaining. Herein, inspired by phenolic-enabled nanotechnology (PEN), we proposed engineered polyphenol coatings by plant-derived aromatic aldehydes and metal involvement, denoted as FQM, to obtain the desired photocatalysis-self-Fenton antibacterial performance. Experiments and theoretical analysis proved the dual mechanism of Fe-induced enhancement: (1) tuning of molecular structure realized improved optical properties; (2) Fe­(III)/Fe­(II) triggered photocatalytic cascade self-Fenton reaction. Mechanism study reveals FQM killing bacteria by direct-contact ROS attack and gene regulation. Further, the FQM was developed as the ideal antibacterial coating on different fabrics (cloth cotton, polyester, and N95 mask), killing more than 93% of bacteria after 5 cycles of use. Such photocatalysis-self-Fenton coatings based on engineered polyphenols endowed with desirable safety, sustainability, and efficient antibacterial features are promising solutions to meet the challenges of the currently available PPE

Differential Recognition of Deacetylated PNAG Oligosaccharides by a Biofilm Degrading Glycosidase

Exopolysaccharides consisting of partially de-N-acetylated poly-β-d-(1→6)-N-acetyl-glucosamine (dPNAG) are key structural components of the biofilm extracellular polymeric substance of both Gram-positive and Gram-negative human pathogens. De-N-acetylation is required for the proper assembly and function of dPNAG in biofilm development suggesting that different patterns of deacetylation may be preferentially recognized by proteins that interact with dPNAG, such as Dispersin B (DspB). The enzymatic degradation of dPNAG by the Aggregatibacter actinomycetemcomitans native β-hexosaminidase enzyme DspB plays a role in biofilm dispersal. To test the role of substrate de-N-acetylation on substrate recognition by DspB, we applied an efficient preactivation-based one-pot glycosylation approach to prepare a panel of dPNAG trisaccharide analogs with defined acetylation patterns. These analogs served as effective DspB substrates, and the rate of hydrolysis was dependent on the specific substrate de-N-acetylation pattern, with glucosamine (GlcN) located +2 from the site of cleavage being preferentially hydrolyzed. The product distributions support a primarily exoglycosidic cleavage activity following a substrate assisted cleavage mechanism, with the exception of substrates containing a nonreducing GlcN that were cleaved endo leading to the exclusive formation of a nonreducing disaccharide product. These observations provide critical insight into the substrate specificity of dPNAG specific glycosidase that can help guide their design as biocatalysts

Nature-Derived Hollow Micron-Tubular Signal Tracers Conquering the Size Limitations for Multimodal Immunochromatographic Detection of Antibiotics

Developing signal tracers (STAs) with large size, multifunctionality, and high retention bioaffinity is believed to be a potential solution for achieving high-performance immunochromatographic assays (ICAs). However, the size limitations of STAs on strips are always a challenge because of the serious steric hindrance. Here, based on metal-quinone coordination and further metal etching, hollow micron-tubular STAs formed by natural alizarin and Fe3+ ions (named ALIFe) are produced to break through size limitations, provide more active sites, and achieve three-mode ICAs (ALIFe STAs-ICAs). Thanks to the special tubular morphology, ALIFe can successfully pass through the strip and provide an ideal signal intensity within 7 min at low mAb and probe dosages to achieve stable ICA analysis. Importantly, ALIFe shows excellent antibody enrichment and bioaffinity retention capability. With a proof-of-concept for streptomycin, the ALIFe STAs-ICAs showed the limit of detection (LOD) at 0.39 ng mL–1 for colorimetric mode, 0.32 ng mL–1 for catalytic mode, and 0.016 ng mL–1 for photothermal mode with total recoveries ranging from 80.46 to 121.59% in mike and honey samples. We anticipate that our study will help expand the ideas for the design of high-performance STAs with large size and broaden the practical application of ICA

Schiff-Base Chemistry-Coupled Catechol Oxidase-Like Nanozyme Reaction as a Universal Sensing Mode for Ultrasensitive Biosensing

Expanding sensing modes and improving catalytic performance of nanozyme-based analytical chemistry are beneficial to realizing the desired biosensing of analytes. Herein, Schiff-base chemistry coupled with a novel catechol oxidase-like nanozyme (CHzyme) is designed and constructed, exhibiting two main advantages, including (1) improving catalytic performance by nearly 2-fold compared with only the oxidase-like role of CHzyme; (2) increasing the designability of the output signal by signal transduction of cascade reaction. Thereafter, the substrate sensing modes based on a cascade reaction between the CHzyme-catalyzed reaction and Schiff-base chemistry are proposed and comprehensively studied, containing catalytic substrate sensing mode, competitive substrate sensing mode, and generated substrate sensing mode, expecting to be employed in environmental monitoring, food analyses, and clinical diagnoses, respectively. More meaningfully, the generated substrate sensing mode is successfully applied to construct a cascade reaction coupling ratiometric fluorescent immunoassay for the detection of clenbuterol, increasing 15-fold in detection sensitivity compared with the traditional enzyme-linked immunosorbent assay. It is expected that the expanded universal substrate sensing modes and the Schiff-base chemistry-enhanced nanozyme can enlighten the exploration of innovative biosensors

Self-Assembling Antibody Network Simplified Competitive Multiplex Lateral Flow Immunoassay for Point-of-Care Tests

Multiplex lateral flow immunoassay (mLFIA) has attracted great attention due to the increasing need for rapid detection of multiple analytes. However, it has a number of disadvantages with regard to accuracy and interference because of difficulties in simplifying the process of preparing nanomaterial-based probes. In this work, inspired by protein self-assembly, for the first time, a facile natural antibody network (NAN)-based mLFIA for multiple chloramphenicol (CAP) and streptomycin (STR) determination was designed. The NAN structure was constructed by introducing a second antibody (Ab2) as a scaffold to noncovalently combine with various monoclonal antibodies (mAbs), thus permitting each mAb to act as an independent functional unit to maintain bioactivity. Furthermore, the NAN was colored by simple one-step staining using coomassie brilliant blue R-250 (CBBR) to form a chromogenic probe, eliminating the need for complex nanomaterials to improve reproducibility and precision. Under optimal conditions, a satisfactory detection performance (the visual limit of detection (v-LOD) of 3 ng mL–1 for CAP and 20 ng mL–1 for STR) was obtained for whole milk analysis, which met the basic requirement of detection and had good specificity, reproducibility (relative standard deviation (RSD) < 15%), and robustness. In addition, the precision of the detection results was improved usefully since the test procedure was simplified. Overall, the developed system enables fast, simple, and reliable point-of-care assays of multiple analytes

Precise Spectral Overlap-Based Donor–Acceptor Pair for a Sensitive Traffic Light-Typed Bimodal Multiplexed Lateral Flow Immunoassay

Bimodal-type multiplexed immunoassays with complementary mode-based correlation analysis are gaining increasing attention for enhancing the practicability of the lateral flow immunoassay (LFIA). Nonetheless, the restriction in visually indistinguishable multitargets induced by a single fluorescent color and difficulty in single acceptor ineffectual fluorescence quenching due to the various spectra of multiple different donors impede the further execution of colorimetric–fluorescence bimodal-type multiplexed LFIAs. Herein, the precise spectral overlap-based donor–acceptor pair construction strategy is proposed by regulating the size of the nanocore, coating it with an appropriate nanoshell, and selecting a suitable fluorescence donor with distinct colors. By in situ coating Prussian blue nanoparticles (PBNPs) on AuNPs with a tunable size and absorption spectrum, the resultant APNPs demonstrate efficient fluorescence quenching ability, higher colloidal stability, remarkable colorimetric intensity, and an enhanced antibody coupling efficiency, all of which facilitate highly sensitive bimodal-type LFIA analysis. Following integration with competitive-type immunoreaction, this precise spectral overlap-supported spatial separation traffic light-typed colorimetric–fluorescence dual-response assay (coined as the STCFD assay) with the limits of detection of 0.013 and 0.152 ng mL–1 for ractopamine and clenbuterol, respectively, was proposed. This work illustrates the superiority of the rational design of a precise spectral overlap-based donor–acceptor pair, hinting at the enormous potential of the STCFD assay in the point-of-care field

“Potential Scalpel”: A Bioassisted Ultrafast Staining Lateral Flow Immunoassay from De Novo to Results

It is of great importance to overcome potential incompatibility problems between dyestuffs and antibodies (mAbs) for extensive commercial application of a dyestuff-chemistry-based ultrafast colorimetric lateral flow immunoassay (cLFIA). Herein, inspired by traditional staining technologies, a basic dyestuff gallocyanine (GC)-assisted biogenic “potential scalpel”-based cLFIA (GC-ABPS-based cLFIA) by employing clenbuterol (CLE) as proof-of-concept was proposed to solve a high degree of incompatibility between the same potential dyestuffs and mAbs. Goat antimouse immunoglobulin (Ab2) could serve as the “potential scalpel” to form the positive potential value biomolecular network self-assemblers (BNSA) with anti-CLE mAbs (AbCLE) by noncovalent force. The cLFIA completed the entire detection process from de novo to detection results within 30 min thanks to the easy availability and ideal marking efficiency (≤1 min, saving 0.4–10 h) of GC. Encouragingly, the proposed ultrafast GC-ABPS-based cLFIA has also exhibited high sensitivity (0.411 ng mL–1) and low cost (300 times) compared with other cLFIAs. Also, the feasibility of the proposed cLFIA was demonstrated by detecting CLE in beef, pork ham, and skim milk. Finally, the proposed GC-ABPS-based cLFIA has broadened the application range of dyestuffs and provided an effective reference strategy for the application of dyestuffs in food safety monitoring

Plasma methylated GNB4 and Riplet as a novel dual-marker panel for the detection of hepatocellular carcinoma

Early detection of hepatocellular carcinoma (HCC) can greatly improve the survival rate of patients. We aimed to develop a novel marker panel based on cell-free DNA (cfDNA) methylation for the detection of HCC. The differentially methylated CpG sites (DMCs) specific for HCC blood diagnosis were selected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, then validated by the whole genome bisulphite sequencing (WGBS) of 12 paired HCC and paracancerous tissues. The clinical performance of the panel was evaluated using tissue samples [32 HCC, chronic liver disease (CLD), and healthy individuals] and plasma cohorts (173 HCC, 199 CLD, and 98 healthy individuals). The combination of G protein subunit beta 4 (GNB4) and Riplet had the optimal area under the curve (AUC) in seven candidates through TCGA, GEO, and WGBS analyses. In tissue validation, the GNB4 and Riplet showed an AUC of 100% with a sensitivity and specificity of 100% for detecting any-stage HCC. In plasma, it demonstrated a high sensitivity of 84.39% at 91.92% specificity, with an AUC of 92.51% for detecting any-stage HCC. The dual-marker panel had a higher sensitivity of 78.26% for stage I HCC than alpha-fetoprotein (AFP) of 47.83%, and a high sensitivity of 70.27% for detecting a single tumour (size ≤3 cm). In conclusion, we developed a novel dual-marker panel that demonstrates high accuracy in detecting HCC, surpassing the performance of AFP testing.</p