Simple and accurate monitoring of urinary dopamine (DA) concentration is significant, which is helpful for the assessment or exclusion of catecholamine-producing tumors, such as pheochromocytoma and paraganglioma. Herein, a fluorescence/colorimetry/smartphone triple-mode sensing platform for DA determination was constructed using copper ion (Cu2+)-modified hydrazone-linked covalent organic frameworks (Cu-BTA-COF). Cu-BTA-COF with 21.67 wt % copper content exhibited peroxidase-mimic activity. After adding H2O2 and 1,3-dihydroxynaphthalene, the Cu-BTA-COF platform can sensitively and selectively detect DA in three modes with consistent results. In fluorescence/colorimetry/smartphone modes, the linear ranges of DA were 1-10, 0.2-40, and 1-10 μM, with related detection limits of 7.2, 8.6, and 23 nM, respectively. Moreover, the Cu-BTA-COF platform can be explored for DA determination in human urine samples with satisfactory recoveries (97.6-100.4%) in all the three modes, suggesting the potential practical application of the Cu-BTA-COF platform for DA detection in urine.

Fluorescence/Colorimetry/Smartphone Triple-Mode Sensing of Dopamine by a COF-Based Peroxidase-Mimic Platform.

Herein, a chemiluminescence (CL) biosensor based on CRISPR-Cas12a and cation exchange reaction was constructed to detect the biomarker microRNA-21 (miRNA-21). The rolling circle amplification (RCA) reaction was introduced to convert each target RNA strand into a long single-stranded DNA with repeated sequences, which acted as triggers to initiate the transcleavage activity of CRISPR-Cas12a. The activated Cas12a could cleave the biotinylated linker DNA of CuS nanoparticles (NPs) to inhibit the binding of CuS NPs to streptavidin immobilized on the surface of the microplate, which strongly reduced the generation of Cu2+ from a cation exchange between CuS NPs and AgNO3, and thus efficiently suppressed the CL of Cu2+-luminol-H2O2 system, giving a "signal off" biosensor. With the multiple amplification, the detection limit of the developed sensor for miRNA-21 reached 16 aM. In addition, this biosensor is not only suitable for a professional chemiluminescence instrument but also for a smartphone used as a detection tool for the purpose of portable and low-cost assay. This method could be used to specifically detect quite a low level of miRNA-21 in human serum samples and various cancer cells, indicating its potential in ultrasensitive molecular diagnostics.

Chemiluminescence Sensor for miRNA-21 Detection Based on CRISPR-Cas12a and Cation Exchange Reaction.

A portable colorimetric point-of-care testing platform for MicroRNA detection based on programmable entropy-driven dynamic DNA network modulated DNA-gold nanoparticle hybrid hydrogel film.

A portable colorimetric point-of-care testing platform for MicroRNA detection based on programmable entropy-driven dynamic DNA network modulated DNA-gold nanoparticle hybrid hydrogel film

Imaging technologies based on chemiluminescence (CL) and bioluminescence (BL) have seen a tremendous growth in the past decade due to their extensive contributions to biochemical analysis and biomedical science. CL and BL imaging technologies have many advantages over commonly used imaging techniques (such as fluorescence and electrochemical systems). CL and BL proceed without an external light source, thus avoiding photobleaching, high interference of background signal, and autofluorescence. Furthermore, CL and BL analytical techniques are characterized by their low detection limit, high selectivity, short assay time, and simple instrumentation. Recently, CL-based imaging technology has been applied successfully for the determination and in vivo imaging of several significant analytes. Meanwhile, an innovative BL imaging technology has been established for the noninvasive real-time tracking of different biomolecules relying on the interaction between luciferase and its substrate. In the current review, we discuss the recent applications of CL and BL imaging approaches over the past five years. Finally, we also discuss the current state of progress and the prospects for CL and BL imaging systems. 

Recent Applications and Future Perspectives of Chemiluminescent and Bioluminescent Imaging Technologies

Bacterial infections seriously threaten human health and also bring huge financial burden. It is critical to construct multifunctional platforms for effectively inactivating bacteria right after point-of-care testing (POCT). Chemiluminescence (CL) bioassays are considered as powerful candidates for POCT as they are free from using an excitation light source, while the flash-type emission limits their further application. Herein, a CL system with long, persistent, and intensive intensity was constructed based on the peroxidase-like property of 4-mercaptophenylboronic acid (MPBA)-functionalized CuSe nanoprobes (CuSeNPs@MPBA), which improved the detection accuracy and sensitivity. By further integrating a smartphone as an analyzer, quantitative POCT of bacteria was realized with high sensitivity. The limit of detection was as low as 1.25 and 1.01 cfu mL-1 for Staphylococcus aureus and Escherichia coli detection, respectively. Specifically, bacteria can be eliminated with high efficiency due to excellent photothermal property of CuSeNPs@MPBA. The developed multifunctional platform also has advantages of simple operation with low cost, suggesting its high potential for use in food safety, environment monitoring, and clinical applications.

Long-Lasting Chemiluminescence-Based POCT for Portable and Visual Pathogenic Detection and In Situ Inactivation.

Effective identification and real-time inactivation of pathogenic microorganisms is of great importance for preventing their infection and spread in public health, especially considering the huge threat of coronavirus disease 2019 (COVID-19). Herein, a novel multifunctional colorimetric sensor array with 3,3',5,5'-tetramethylbenzidine (TMB) as a single probe has been constructed. TMB can be efficiently oxidized to generate oxidized TMB (oxTMB) by HAuCl4, which displays four characteristic absorption peaks. The presence of different bacteria could inhibit the oxidation reaction and cause diverse changes in the intensity of the four characteristic peaks. Based on linear discriminant analysis (LDA), not only are nine kinds of pathogenic bacteria successfully identified, but also drug-resistant strains are distinguished from sensitive ones. Interestingly, HAuCl4 can be employed as a germicidal agent to inactivate bacteria during the identification and avoid accessional bacterial contaminations. The developed strategy provides a new and simple avenue for bacterial identification and elimination to effectively protect the public from bacterial contamination.

A multifunctional colorimetric sensor array for bacterial identification and real-time bacterial elimination to prevent bacterial contamination.

Nanopesticides in comparison with agrochemicals: Outlook and future prospects for sustainable agriculture.

Targeted killing multidrug-resistant bacteria with high efficiency is urgently needed for the treatment of infection with minimal collateral damage. Herein, we designed and synthesized a new near-infrared (NIR) fluorescence nanoprobe with aggregation-induced emission (AIE) features, which also is excellent reactive oxygen species (ROS) generator. The as-prepared AIE nanoparticles (NPs) present outstanding sterilizing rate on methicillin-resistant Staphylococcus aureus (MRSA) and kanamycin-resistant Escherichia coli (KREC). Meanwhile, considering the differences in the surface structure of animal cells and bacteria, a non-invasive image-guided strategy for precise treatment of bacterial infection has been successfully implemented based on bioorthogonal reaction which can perform and control unnatural chemical reactions inside living organisms. The AIE NPs were thus specifically trapped on the bacterial surface while not on the normal cells, realizing real-time tracking of the infected site distribution in vivo and guiding photodynamic therapy (PDT) for eliminating bacteria in inflammation region. That significantly improves the accuracy and sterilization rate of bacterial-infected wounds with negligible side effects. The investigation developed a potential antibacterial agent and also provides an instructive way for targeting treatment based on bioorthogonal reaction. This article is protected by copyright. All rights reserved.

Aie Bioconjugates for Accurate Identification And in Vivo Targeted Treatment of Bacterial Infection Based on Bioorthogonal Reaction.

Plant microRNAs play critical roles in post-transcriptional gene regulation of many processes, thus motivating the development of accurate and user-friendly microRNA detection methods for better understanding of, e.g., plant growth, development, and abiotic/biotic stress responses. By integrating the capture probe, fuel strand, primer, and template onto the surface of a magnetic nanoparticle (MNP), we demonstrated a magnetic DNA nanomachine that could conduct an on-particle cascade amplification reaction in response to the presence of target microRNA. The cascade amplification consists of an exonuclease III-assisted target recycling step and a rolling circle amplification step, leading to changes in the MNP arrangement that can be quantified by ferromagnetic resonance spectroscopy. After a careful investigation of the exonuclease III side reaction, the biosensor offers a detection limit of 15 fM with a total assay time of ca. 70 min. Moreover, our magnetic DNA nanomachine is capable of discriminating the target microRNA from its family members. Our biosensor has also been tested on total endogenous microRNAs extracted from Arabidopsis thaliana leaves, with a performance comparable to qRT-PCR.

Yuan Fang

Papers

Long-Lasting Chemiluminescence-Based POCT for Portable and Visual Pathogenic Detection and In Situ Inactivation.

A multifunctional colorimetric sensor array for bacterial identification and real-time bacterial elimination to prevent bacterial contamination.

Nanopesticides in comparison with agrochemicals: Outlook and future prospects for sustainable agriculture.

Aie Bioconjugates for Accurate Identification And in Vivo Targeted Treatment of Bacterial Infection Based on Bioorthogonal Reaction.

Magnetic DNA Nanomachine for On-Particle Cascade Amplification-Based Ferromagnetic Resonance Detection of Plant MicroRNA.