Augmented Fluorescence Signaling on a Single BaTiO3 Microbead Optical Booster toward High-Sensitive Biosensing.

In this work, we report a new generation of single microbead bioassay that employs a single BaTiO3 microbead as an optical booster for target biomarker enrichment and optical enhancement toward protein and nucleic acid analysis. The single BaTiO3 microbead can not only concentrate the target molecules by nearly 104-fold but also act as an optical booster to prominently enhance the target-induced fluorescence signal by the whispering gallery mode for improving the excitation efficiency and the microlens effect for promoting the signal collecting efficiency, respectively. Compared with using a conventional single microbead, this optical booster exhibits nearly 2 orders of magnitude higher sensitivity without the assistance of any signal amplification techniques or costly instruments. Moreover, this single microbead optical booster is capable of detecting different kinds of protein and nucleic acid biomarkers in a simple mix-and-read manner, holding great potential for early clinical diagnosis.

Ultrasensitive protein and exosome analysis based on a rolling circle amplification assisted-CRISPR/Cas12a strategy.

CRISPR/Cas12a system has attracted extensive concern in biosensing due to its high specificity and programmability. Nevertheless, existing Cas12a-based assays mainly focus on nucleic acid detection and have limitations in non-nucleic acid biomarker analysis. To broaden the application prospect of the CRISPR/Cas technology, a cascade Cas12a biosensing platform is reported by combining dual-functionalized gold nanoparticles (FGNPs)-assisted rolling circle amplification (RCA) and Cas12a trans-cleavage activity (GAR-Cas) for ultrasensitive protein and exosome analysis. FGNPs serve as a critical component in the transduction of protein or exosome recognition information into nucleic acid amplification events to produce Cas12a activators. In the GAR-Cas assay, by integrating the triple cascade amplification of FGNPs-assisted transduction, RCA, and Cas12a signal amplification, ultralow abundance of target molecules can arouse numerous concatemers to activate Cas12a trans-cleavage activity to release intense fluorescence, allowing the ultrasensitive detection of as low as 1 fg/mL (∼41 aM) cTnI and 5 exosomes per µL. Furthermore, the presented strategy can be applied to detect exosome levels from clinical samples, showing excellent performance in distinguishing cancer patients from healthy individuals. The GAR-Cas sensing platform exhibits great potential in clinical diagnosis and enlarges biosensing toolboxes based on CRISPR/Cas technology for non-nucleic acid target analysis.

Forecasting China carbon price using an error-corrected secondary decomposition hybrid model integrated fuzzy dispersion entropy and deep learning paradigm.

Forecasting China's carbon price accurately can encourage investors and manufacturing industries to take quantitative investments and emission reduction decisions effectively. The inspiration for this paper is developing an error-corrected carbon price forecasting model integrated fuzzy dispersion entropy and deep learning paradigm, named ICEEMDAN-FDE-VMD-PSO-LSTM-EC. Initially, the improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) is used to primary decompose the original carbon price. Subsequently, the fuzzy dispersion entropy (FDE) is conducted to identify the high-complexity signals. Thirdly, the variational mode decomposition (VMD) and deep learning paradigm of particle swarm optimized long short-term memory (PSO-LSTM) models are employed to secondary decompose the high-complexity signals and perform out-of-sample forecasting. Finally, the error-corrected (EC) method is conducted to re-modify and strengthen the above-predicted accuracy. The results conclude that the forecasting performance of ICEEMDAN-type secondary decomposition models is significantly better than the primary decomposition models, the deep learning PSO-LSTM-type models have superiority in forecasting China carbon price, and the EC method for improving the forecasting accuracy has been proved. Noteworthy, the proposed model presents the best forecasting accuracy, with the forecasting errors RMSE, MAE, MAPE, and Pearson's correlation are 0.0877, 0.0407, 0.0009, and 0.9998, respectively. Especially, the long-term forecasting ability for 750 consecutive trading prices is outstanding. Those conclusions contribute to judging the carbon price characteristics and formulating market regulations.

Tyramine-Invertase Bioconjugate-Amplified Personal Glucose Meter Signaling for Ultrasensitive Immunoassay.

Highly sensitive and facile detection of low levels of protein markers is of great significance for the early diagnosis and efficacy monitoring of diseases. Herein, aided by an efficient tyramine-signal amplification (TSA) mechanism, we wish to report a simple but ultrasensitive immunoassay with signal readout on a portable personal glucose meter (PGM). In this study, the bioconjugates of tyramine and invertase (Tyr-inv), which act as the critical bridge to convert and amplify the protein concentration information into glucose, are prepared following a click chemistry reaction. Then, in the presence of a target protein, the sandwich immunoreaction between the immobilized capture antibody, the target protein, and the horseradish peroxidase (HRP)-conjugated detection antibody is specifically performed in a 96-well microplate. Subsequently, the specifically loaded HRP-conjugated detection antibodies will catalyze the amplified deposition of a large number of Tyr-inv molecules onto adjacent proteins through highly efficient TSA. Then, the deposited invertase, whose dosage can faithfully reflect the original concentration of the target protein, can efficiently convert sucrose to glucose. The amount of finally produced glucose is simply quantified by the PGM, realizing the highly sensitive detection of trace protein markers such as the carcinoembryonic antigen and alpha fetoprotein antigen at the fg/mL level. This method is simple, cost-effective, and ultrasensitive without the requirement of sophisticated instruments or specialized laboratory equipment, which may provide a universal and promising technology for highly sensitive immunoassay for in vitro diagnosis of diseases.

Fuzzy-Inspired Sensing for Time-Domain Brain Stroke Diagnosis: Disease Retrospective Monitoring Strategy.

This paper propose a novel disease retrospective monitoring strategy (DRMS) for optimal brain stroke diagnosis. We describe the disease monitoring process using a fuzzy-based model and demonstrate the use of information at different time points to improve disease diagnosis accuracy under the framework of fuzzy-inspired sensing (FIS). Numerical examples are used to demonstrate how the proposed DRMS can be used to determine the optimal treatment strategy with the least amount of fuzziness.

Composite Nanomaterials of Conjugated Polymers and Upconversion Nanoparticles for NIR-Triggered Photodynamic/Photothermal Synergistic Cancer Therapy.

Phototherapies such as photodynamic therapy (PDT) and photothermal therapy (PTT) have attracted great attention in the field of cancer treatment. However, the individual PDT or PTT makes it difficult to achieve optimal antitumor effects compared to the PDT/PTT combined therapy. Also, the effect of PDT is usually limited by the penetration depth of the UV-vis light source. Herein, we designed and synthesized novel composite nanoparticles UCNPs-CPs, which are constructed from two conjugated polymers and upconversion nanoparticles ß-NaYF4:Yb,Tm (UCNPs) via a coordination reaction. By virtue of the excellent spectral overlap between absorption of conjugated polymers and emission of UCNPs, the UCNPs can absorb NIR light and effectively excite conjugated polymers by energy transfer to produce massive reactive oxygen species under 980 nm excitation and heat energy under 808 nm laser irradiation, achieving photodynamic/photothermal synergistic therapy. The in vitro cellular investigation proves that the dual modal phototherapy exhibits enhanced antitumor ability compared to single PDT or PTT. Furthermore, UCNPs-CPs inhibit tumor growth 100% in a 4T1 breast tumor mice model with both NIR laser irradiation, indicating that UCNPs-CPs is an excellent platform for synergistic PDT/PTT treatment. Thus, this study provides a promising strategy for NIR-triggered dual modal phototherapy.

An immunoassay-like recognition mechanism-based lateral flow strategy for rapid microRNA analysis.

A rapid lateral flow assay (LFA) is developed for the colorimetric and surface-enhanced Raman scattering (SERS) dual-mode detection of microRNA (miRNA) based on the robust immunoassay-like (immuno-like) recognition mechanism of S9.6 antibody to DNA/miRNA duplexes. Different from the traditional target-mediated sandwich-type hybridization-based LFA methods, the formation of S9.6 antibody/miRNA/DNA complexes is more rapid and stable, achieving 40 times higher sensitivity with only 10 min assaying time. Furthermore, taking benefit of the versatility of the immuno-like recognition mode, the multiplexed detection of miRNAs can be realized with the SERS signal readout, providing a versatile LFA design towards sensitive, specific, and multiplexed miRNA analysis.

Digital-like Enzyme Inhibition Mechanism-Based Strategy for the Digital Sensing of Heparin-Specific Biomarkers.

A new microbead (MB)-based digital flow cytometric sensing system is proposed for the sensitive detection of heparin-specific biomarkers, including heparin-binding protein (HBP) and heparinase. This strategy takes advantage of the inherent space-confined enzymatic behavior of T4 polynucleotide kinase phosphatase (T4 PNKP) around a single MB and the heparin's digital-like inhibitory effect on T4 PNKP. By integrating with an on-bead terminal deoxynucleotidyl transferase (TdT)-catalyzed fluorescence signal amplification technology, the concentration of HBP and heparinase can be digitally determined by the number of fluorescence-positive/-negative MBs which can be easily counted by flow cytometry. This is not only the first test to expand the application scenario of T4 PNKP to the digital detection of different biomarkers but also pioneers a new direction for fabricating digital biosensing platforms based on the enzyme inhibition mechanism.

Regulating the trans-Cleavage Activity of CRISPR/Cas12a by Using an Elongation-Caged Single-Stranded DNA Activator and the Biosensing Applications.

The CRISPR/Cas12a system exhibits extraordinary capability in the field of biosensing and molecular diagnosis due to its trans-cleavage ability. However, it is still desirable for precise control and programmable regulation of Cas12a trans-cleavage activity to promote the in-depth studies and application expansion of Cas12a-based sensing platforms. In this work, we have developed a new and robust CRISPR/Cas12a regulation mechanism by endowing the activator with the function of caging crRNA ingeniously. Specifically, we constructed an integrated elongation-caged activator (EL-activator) by extending the ssDNA activator on the 3'-end. We found that appending only about 8 nt that is complementary to the crRNA repeat region is enough to cage the crRNA spacer/repeat region, thus effectively inhibiting Cas12a trans-cleavage activity. The inner inhibition mechanism was further uncovered after a thorough investigation, demonstrating that the EL-activator works by impeding the conformation of crRNA required for Cas12a recognition and destroying its affinity with Cas12a. By further switching on the elongated moiety on the EL-activator using target biomarkers, the blocked trans-cleavage activity of Cas12a can be rapidly recovered. Finally, a versatile sensing platform was established based on the EL-activator regulation mechanism, expanding the conventional Cas12a system that only directly recognizes DNA to the direct detection of enzymes and RNA biomarkers. This work has enriched the CRISPR/Cas12a regulation toolbox and expanded its sensing applications.

A polyoxometalate-based heterojunction nanozyme with peroxidase-mimic catalytic activity for sensitive biomolecule detection.

Nanozymes are a class of nanomaterials that can specifically mimic the structures and catalytic activities as well as overcome limitations of natural enzymes and have hence been considered as a competitive alternative to natural enzymes. At present, plenty of nanozymes, especially those with peroxidase (POD)-like catalytic activity, have been extensively explored for biosensing. In this work, we proposed polyoxometalate-based heterojunction GdP5W30O110@WS2 nanoclusters (NCs) to exert intrinsic POD-like catalytic activity even under harsh catalytic conditions. Detailedly, GdP5W30O110@WS2 NCs possessing conducive POD-like catalytic activity can oxidize chromogenic substrates into colored substances in the presence of H2O2. On the strength of the POD-like catalytic activity of GdP5W30O110@WS2 NCs, a reliable analytical platform is then constructed after the optimization of catalytic conditions for the detection of H2O2, glutathione (GSH) and glucose via a simple TMB colorimetric strategy. This work advances the utilization of versatile polyoxometalate-based nanomaterials for biosensing, dramatically broadening the potential applications of other nanozyme-based biosensors.

A Handheld Visible Resonance Raman Analyzer Used in Intraoperative Detection of Human Glioma.

There is still a lack of reliable intraoperative tools for glioma diagnosis and to guide the maximal safe resection of glioma. We report continuing work on the optical biopsy method to detect glioma grades and assess glioma boundaries intraoperatively using the VRR-LRRTM Raman analyzer, which is based on the visible resonance Raman spectroscopy (VRR) technique. A total of 2220 VRR spectra were collected during surgeries from 63 unprocessed fresh glioma tissues using the VRR-LRRTM Raman analyzer. After the VRR spectral analysis, we found differences in the native molecules in the fingerprint region and in the high-wavenumber region, and differences between normal (control) and different grades of glioma tissues. A principal component analysis-support vector machine (PCA-SVM) machine learning method was used to distinguish glioma tissues from normal tissues and different glioma grades. The accuracy in identifying glioma from normal tissue was over 80%, compared with the gold standard of histopathology reports of glioma. The VRR-LRRTM Raman analyzer may be a new label-free, real-time optical molecular pathology tool aiding in the intraoperative detection of glioma and identification of tumor boundaries, thus helping to guide maximal safe glioma removal and adjacent healthy tissue preservation.

Transcriptomic and metabolomic profiling reveal the mechanism underlying the inhibition of wound healing by ascorbic acid in fresh-cut potato.

Ascorbic acid (AsA) inhibits wound healing in fresh-cut potatoes (FCP); however, the comprehensive regulatory mechanisms of the chemical during wound healing remain unclear. Here, physiobiochemical, transcriptomic, and metabolomic analyses were performed. In total, 685 differentially expressed genes (DEGs) and 1921 differentially accumulated metabolites (DAMs) were identified between control and AsA-treated samples. The level of the majority of DEGs expression and DAMs abundance in AsA-treated samples were similar to data of newly cut samples. The collective data indicated that the AsA treatment inhibited wound healing in FCPs by regulating glutathione metabolism, enhancing starch metabolism, and inhibiting phenylalanine metabolism, sucrose degradation, and fatty acid synthesis. Major genes and metabolites affected by AsA treatment included StGST, StPAL, StPHO1 and StLOX5, and starch, sucrose, and linoleic acid. AsA treatment increased starch content and amylase and lipoxygenase activity and decreased free fatty acid level. Our research provides fundamental insights into wound healing mechanisms in FCP.

A novel full solar light spectrum responsive antimicrobial agent of WS2 quantum dots for photocatalytic wound healing therapy.

Photocatalytic antimicrobial therapy (PCAT) is considered to be a potential therapeutic treatment for bacterial-infection diseases. However, the antibacterial efficiency is unsatisfactory due to the limited application scope of photocatalysis. In this work, full-spectrum responsive tungsten disulfide quantum dots (WS2 QDs) are prepared for killing bacteria and enabling wound healing through photocatalytic reactive oxygen species (ROS) generation and glutathione (GSH) depletion. On the one hand, these ultrasmall WS2 QDs exhibit an excellent full spectrum (UV-Vis-NIR)-responsive photocatalytic effect by hindering the recombination of electron-hole pairs, thereby achieving the full use of the energy spectrum. Furthermore, the full-spectrum photocatalytic property of the as-prepared WS2 QDs can be effectively strengthened by redox reaction to deplete GSH for accelerated wound healing. In a word, the as-prepared nanoplatform exhibits the ability to act as an admirable antibacterial reagent with full-spectrum catalytic performance for photocatalytic wound healing therapy. Therefore, this work will not only provide an effective full-spectrum photocatalytic reagent for anti-bacteria therapy and wound healing, but also provide a rational idea for the development of other novel antibacterial agents for applications in the biomedical field.

Advances in optical counting and imaging of micro/nano single-entity reactors for biomolecular analysis.

Ultrasensitive detection of biomarkers is of paramount importance in various fields. Superior to the conventional ensemble measurement-based assays, single-entity assays, especially single-entity detection-based digital assays, not only can reach ultrahigh sensitivity, but also possess the potential to examine the heterogeneities among the individual target molecules within a population. In this review, we summarized the current biomolecular analysis methods that based on optical counting and imaging of the micro/nano-sized single entities that act as the individual reactors (e.g., micro-/nanoparticles, microemulsions, and microwells). We categorize the corresponding techniques as analog and digital single-entity assays and provide detailed information such as the design principles, the analytical performance, and their implementation in biomarker analysis in this work. We have also set critical comments on each technique from these aspects. At last, we reflect on the advantages and limitations of the optical single-entity counting and imaging methods for biomolecular assay and highlight future opportunities in this field.

Integration of transcriptome, miRNA and degradome sequencing reveals the early browning response in fresh-cut apple.

Surface browning negatively impacts the shelf-life of fresh-cut apple. Herein, we found that the browning of fresh-cut apple aggravated rapidly after 24 h post-cutting, then the transcriptomic and miRNA expression profiles of fresh-cut apple immediately after cutting (T0) and 24 h post-cutting (T24) were analyzed to explore the molecular mechanism of early browning response. A total of 3156 differentially expressed mRNAs (DEGs) and 23 differentially expressed miRNAs (DEmiRNAs) were identified in T24 vs T0. Most DEGs related to respiratory, energy, antioxidant, lipid and secondary metabolism were activated in the early stage of browning. There were 63 target genes of 10 DEmiRNAs validated by degradome sequencing and among them, mdm-miR156aa_L + 1_1 targets 12-oxophytodienoate reductase, ptc-miR6478_R-1 targets patatin-like protein, mdm-miR156aa_L + 1_1 and mdm-miR156aa_L + 1_2 co-target SPLs might participate in the early browning response through regulating antioxidant, lipid and secondary metabolism. Our results will be beneficial for the technological innovation of browning amelioration for fresh-cut apple.

A versatile CRISPR/Cas12a-based biosensing platform coupled with a target-protected transcription strategy.

Besides the critical role in gene editing, CRISPR/Cas system also brings a new signal amplification mechanism to the development of next generation biosensing technologies. Herein, we have developed a versatile CRISPR/Cas12a sensing platform by combining a target protection-based transcription amplification strategy with the Cas12a-based signal amplification mechanism, which allows for the sensitive detection of both nucleic acid and non-nucleic acid targets. In this design, a rationally designed transcription template sequence is able to avoid Exonuclease I (Exo I) degradation only in the existence of the target-mediated binding events including either nucleic acid hybridization or protein-based affinity interactions. This target binding-induced protection effect can facilitate the subsequent transcription amplification to generate crRNA and activate the subsequent Cas12a trans-cleavage signal amplification mechanism to yield target dosage-responsive fluorescence signal. In contrast, if the target is absent, the protection-free transcription template will be completely digested by Exo I, thus no fluorescence response is produced. This new strategy well eliminates the T7 polymerase-associated non-specific transcription background and realizes the sensitive detection of various kinds of biomolecules including microRNA, protein, as well as exosome, broadening the application scenarios of CRISPR/Cas system in the field of bioanalysis and biosensing.

Recent Progress of Perovskite Nanocrystals in Chem/Bio Sensing.

Perovskite nanocrystals (PNCs) are endowed with extraordinary photophysical properties such as wide absorption spectra, high quantum yield, and narrow emission bands. However, the inherent shortcomings, especially the instability in polar solvents and water incompatibility, have hindered their application as probes in chem/bio sensing. In this review, we give a fundamental understanding of the challenges when using PNCs for chem/bio sensing and summarize recent progress in this area, including the application of PNCs in various sensors and the corresponding strategies to maintain their structural integrity. Finally, we provide perspectives to promote the future development of PNCs for chem/bio sensing applications.

Tumor microenvironment-activated single-atom platinum nanozyme with H2O2 self-supplement and O2-evolving for tumor-specific cascade catalysis chemodynamic and chemoradiotherapy.

Nanozyme-based tumor collaborative catalytic therapy has attracted a great deal of attention in recent years. However, their cooperative outcome remains a great challenge due to the unique characteristics of tumor microenvironment (TME), such as insufficient endogenous hydrogen peroxide (H2O2) level, hypoxia, and overexpressed intracellular glutathione (GSH). Methods: Herein, a TME-activated atomic-level engineered PtN4C single-atom nanozyme (PtN4C-SAzyme) is fabricated to induce the "butterfly effect" of reactive oxygen species (ROS) through facilitating intracellular H2O2 cycle accumulation and GSH deprivation as well as X-ray deposition for ROS-involving CDT and O2-dependent chemoradiotherapy. Results: In the paradigm, the SAzyme could boost substantial ∙OH generation by their admirable peroxidase-like activity as well as X-ray deposition capacity. Simultaneously, O2 self-sufficiency, GSH elimination and elevated Pt2+ release can be achieved through the self-cyclic valence alteration of Pt (IV) and Pt (II) for alleviating tumor hypoxia, overwhelming the anti-oxidation defense effect and overcoming drug-resistance. More importantly, the PtN4C-SAzyme could also convert O2·- into H2O2 by their superior superoxide dismutase-like activity and achieve the sustainable replenishment of endogenous H2O2, and H2O2 can further react with the PtN4C-SAzyme for realizing the cyclic accumulation of ∙OH and O2 at tumor site, thereby generating a "key" to unlock the multi enzymes-like properties of SAzymes for tumor-specific self-reinforcing CDT and chemoradiotherapy. Conclusions: This work not only provides a promising TME-activated SAzyme-based paradigm with H2O2 self-supplement and O2-evolving capacity for intensive CDT and chemoradiotherapy but also opens new horizons for the construction and tumor catalytic therapy of other SAzymes.

All on size-coded single bead set: a modular enrich-amplify-amplify strategy for attomolar level multi-immunoassay.

Ultrasensitive protein analysis is of great significance for early diagnosis and biological studies. The core challenge is that many critical protein markers at extremely low aM to fM levels are difficult to accurately quantify because the target-induced weak signal may be easily masked by the surrounding background. Hence, we propose herein an ultrasensitive immunoassay based on a modular Single Bead Enrich-Amplify-Amplify (SBEAA) strategy. The highly efficient enrichment of targets on only a single bead (enrich) could confine the target-responsive signal output within a limited tiny space. Furthermore, a cascade tyramide signal amplification design enables remarkable in situ signal enhancement just affixed to the target. As a result, the efficient but space-confined fluorescence deposition on a single bead will significantly exceed the background and provide a wide dynamic range. Importantly, the SBEAA system can be modularly combined to meet different levels of clinical need regarding the detection sensitivity from aM to nM. Finally, a size-coded SBEAA set (SC-SBEAA) is also designed that allows ultrasensitive multi-immunoassay for rare samples in a single tube.