HCR-Assisted RTF-EXPAR-Based Lateral Flow Analysis for Sensitive Detection of H1N1 Influenza Virus.

The H1N1 influenza virus is a significant pathogen responsible for seasonal influenza, and its frequent outbreaks pose substantial challenges to global public health. The present study successfully developed a lateral flow analysis platform that integrates reverse transcription-free exponential amplification reaction (RTF-EXPAR) and hybridization chain reaction (HCR) processes with functionalized quantum dots for the direct detection of H1N1 influenza virus RNA, eliminating the need for reverse transcription. The fluorescence signal on the band recorded with a smartphone can be utilized for the quantitative determination of the target. Interestingly, the dual signal amplification strategy exhibits high sensitivity with a remarkably low detection limit of 10 aM. Moreover, this platform exhibits excellent flexibility and universality, where the various pathogens can be determined by replacing the specific nucleic acid fragments in RTF-EXPAR. The aforementioned advantages reveal its huge potential in the early diagnosis of H1N1 influenza virus infection and developing point-of-care testing (POCT) equipment for nucleic acid analysis.

Advancements of CRISPR technology in public health-related analysis.

Pathogens and contaminants in food and the environment present significant challenges to human health, necessitating highly sensitive and specific diagnostic methods. Traditional approaches often struggle to meet these requirements. However, the emergence of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) system has revolutionized nucleic acid diagnostics. The present review provides a comprehensive overview of the biological sensing technology based on the CRISPR/Cas system and its potential applications in public health-related analysis. Additionally, it explores the enzymatic cleavage capabilities mediated by Cas proteins, highlighting the promising prospects of CRISPR technology in addressing bioanalysis challenges. We discuss commonly used CRISPR-Cas proteins and elaborate on their application in detecting foodborne bacteria, viruses, toxins, other chemical pollution, and drug-resistant bacteria. Furthermore, we highlight the advantages of CRISPR-based sensors in the field of public health-related analysis and propose that integrating CRISPR-Cas biosensing technology with other technologies could facilitate the development of more diverse detection platforms, thereby indicating promising prospects in this field.

A stable ratiometric fluorescent probe for hypochlorous acid detection and rheumatoid arthritis evaluation.

A ratiometric fluorescent probe (MeO-CNPPV Pdots) based on the principle of fluorescence resonance energy transfer (FRET) was designed for hypochlorous acid (HOCl) and rheumatoid arthritis (RA) detection. The presence of HOCl can block the energy transfer from CNPPV to MeOTPATBT, resulting in a ratio change in the fluorescence of Pdots (I600 nm/I680 nm). This strategy provides a valuable paradigm in early RA evaluation.

Strategies and materials for the prevention and treatment of biofilms.

Biofilms are aggregates of organized microbial growth that function as barriers and create a stable internal environment for cell survival. The bacteria in the biofilms exhibit characteristics that are quite different from the planktonic bacteria, such as strong resistance to antibiotics and other bactericides, getting out of host immunity, and developing in harsh environments, which all contribute to the persistent and intractable treatment. Hence, there is an urgent need to develop novel materials and strategies to combat biofilms. However, most of the reviews on anti-biofilms published in recent years are based on specific fields or materials. Microorganisms are ubiquitous, except in the context of medical and health issues; however, biofilms exert detrimental effects on the advancement and progress of various fields. Therefore, this review aims to provide a comprehensive summary of effective strategies and methodologies applicable across all industries. Firstly, the process of biofilms formation was introduced to enhance our comprehension of the "enemy". Secondly, strategies to intervene in the important links of biofilms formation were discussed, taking timely action during the early weak stages of the "enemy". Thirdly, treatment strategies for mature biofilms were summarized to deal with biofilms that break through the defense line. Finally, several substances with antibacterial properties were presented. The review concludes with the standpoint of the author about potential developments of anti-biofilms strategies. This review may help researchers quickly understand the research progress and challenges in the field of anti-biofilms to design more efficient methods and strategies to combat biofilms.

Polymeric engineering of AIEgens for NIR-II fluorescence imaging and detection of abdominal metastases of ovarian cancer in vivo.

A polymeric engineering design principle is proposed for the construction of small-sized (∼20 nm) NIR-II AIEgen-doped nanodots (AIEdots) with high brightness and prolonged circulation time in blood vessels. With the utilization of the as-designed NIR-II AIEdots, the successful achievement of high-resolution NIR-II fluorescence imaging of tumor vessels and precise detection of abdominal metastases of ovarian cancer has been attained.

A General Strategy for Developing Ultrasensitive "Transistor-Like" Thermochromic Fluorescent Materials for Multilevel Information Encryption.

Thermochromic fluorescent materials (TFMs) exhibit great potential in information encryption applications but are limited by low thermosensitivity, poor color tunability, and a wide temperature-responsive range. Herein, a novel strategy for constructing highly sensitive TFMs with tunable emission (450-650 nm) toward multilevel information encryption is proposed, which employs polarity-sensitive fluorophores with donor-acceptor-donor (D-A-D) type structures as emitters and long-chain alkanes as thermosensitive loading matrixes. The structure-function relationships between the performance of TFMs and the structures of both fluorescent emitters and phase-change molecules are systematically studied. Benefiting from the above design, the obtained TFMs exhibit over 9500-fold fluorescence enhancement toward the temperature change, as well as ultrahigh relative temperature sensitivity up to 80% K-1 , which are first confirmed. Thanks to the superior transducing performance, the above-prepared TFMs can be further developed as information-storage platforms within a relatively narrow interval of temperature variation, including temperature-dominated multicolored information display and multilevel information encryption. This work will not only provide a novel perspective for designing superior TFMs for information encryption but also bring inspiration to the design and preparation of other response-switching-type fluorescent probes with ultrahigh conversion efficiency.

Multiple fluorescence polymer dots-based differential array sensors for highly efficient heavy metal ions detection.

Water pollution caused by harmful heavy metal ions (HMIs) can significantly impact aquatic ecosystems and pose a high risk to human health. In this work, equipped with ultra-high fluorescence brightness, efficient energy transfer, and environmentally friendly performance, polymer dots (Pdots) were employed to construct a pattern recognition fluorescent HMIs detection platform. A single-channel unary Pdots differential sensing array was first developed to identify multiple HMIs with 100% classification accuracy. Then an "all-in-one" multiple Förster resonance energy transfer (FRET) Pdots differential sensing platform was constructed to discriminate HMIs in the artificial polluted water samples and actual water samples, exhibiting high classification accuracy in distinguishing HMIs. The proposed strategy leverages the compounded cumulative differential variation of diverse sensing channels for analytes, which is anticipated to find extensive applications in other fields for detection purposes.

Functionalized graphene-based electrochemical array sensors for the identification of distinct conformational states of Amyloid Beta in Alzheimer's disease.

Aß oligomers have been widely accepted as significant biomarkers for Alzheimer's disease (AD) detection, monitoring, and therapy since they are highly correlated with AD development. In this work, an electrochemical array-based sensing platform was successfully built using a group of functionalized graphene with different physicochemical features. Since the electro-insulated Aß peptide species severely interfered with the electron transport on the electrode surface, the presence of Aß led to a significant change in the electrochemical impedance signal. The resulting variety of the impedance was then classified and processed by linear discriminant analysis. The constructed sensing platform can discriminate different Aß forms, the mixture of various Aß forms, and different ratios of Aß42 to Aß40 with 100% accuracy by only the combination of dual probes. Furthermore, it also exhibited excellent performance for screening Aß inhibitors and metal chelators. The strategy utilizes the infinitesimal general discrepancy instead of specific biomarker recognition, exhibiting the advantage of no requirement to know the exact information about the specific ligand and receptor in advance, which is promising to be widened for the other biosensing detection fields.

Target Recognition- and HCR Amplification-Induced In Situ Electrochemical Signal Probe Synthesis Strategy for Trace ctDNA Analysis.

An electrochemical-DNA (E-DNA) sensor was constructed by using DNA metallization to produce an electrochemical signal reporter in situ and hybridization chain reaction (HCR) as signal amplification strategy. The cyclic voltammetry (CV) technique was used to characterize the electrochemical solid-state Ag/AgCl process. Moreover, the enzyme cleavage technique was introduced to reduce background signals and further improve recognition accuracy. On the basis of these techniques, the as-prepared E-DNA sensor exhibited superior sensing performance for trace ctDNA analysis with a detection range of 0.5 fM to 10 pM and a detection limit of 7 aM. The proposed E-DNA sensor also displayed excellent selectivity, satisfied repeatability and stability, and had good recovery, all of which supports its potential applications for future clinical sample analysis.

Correction: Conjugated polymer-based luminescent probes for ratiometric detection of biomolecules.

Correction for 'Conjugated polymer-based luminescent probes for ratiometric detection of biomolecules' by Lingfeng Zhao et al., J. Mater. Chem. B, 2022, https://doi.org/10.1039/d2tb00937d.

Precisely controlled and deeply penetrated micro-nano hybrid multifunctional motors with enhanced antibacterial activity against refractory biofilm infections.

The biofilm resistance of microorganisms has severe economic and environmental implications, especially the contamination of facilities associated with human life, including medical implants, air-conditioning systems, water supply systems, and food-processing equipment, resulting in the prevalence of infectious diseases. Once bacteria form biofilms, their antibiotic resistance can increase by 10-1,000-fold, posing a great challenge to the treatment of related diseases. In order to overcome the contamination of bacterial biofilm, destroying the biofilm's matrix so as to solve the penetration depth dilemma of antibacterial agents is the most effective way. Here, a magnetically controlled multifunctional micromotor was developed by using H2O2 as the fuel and MnO2 as the catalyst to treat bacterial biofilm infection. In the presence of H2O2, the as-prepared motors could be self-propelled by the generated oxygen microbubbles. Thereby, the remotely controlled motors could drill into the EPS of biofilm and disrupt them completely with the help of bubbles. Finally, the generated highly toxic •OH could efficiently kill the unprotected bacteria. This strategy combined the mechanical damage, highly toxic •OH, and precise magnetic guidance in one system, which could effectively eliminate biologically infectious fouling in microchannels within 10 min, possessing a wide range of practical application prospects especially in large scale and complex infection sites.

Conjugated polymer-based luminescent probes for ratiometric detection of biomolecules.

Accurate monitoring of the biomolecular changes in biological and physiological environments is of great significance for the pathogenesis, development, diagnosis and treatment of diseases. Compared with traditional luminescent probes on the basis of an intensity-dependent single-channel readout, ratiometric fluorescence detection is a more reliable sensing or imaging method which can monitor different emission signals in two or more channels with a built-in self-calibration functionality, attracting growing attention in biomolecule detection. As a kind of luminescent material with many prospects, conjugated polymers with an easily functionalized organic molecular structure, high brightness, superior stability, tunable emission, and superior biocompatibility have been widely adopted as ratiometric fluorescent probes in biosensing and bioimaging. This review first summarizes the design principles of luminescent conjugated polymers that have been developed as methods for the ratiometric measurement of biomolecules. Additionally, their potential in accurate biodetection of living biosystems was investigated. This paper aims to provide a comprehensive review of the existing challenges and latest advancements in ratiometric detection of various biomolecules with high selectivity and sensitivity. We sincerely expect that the information presented in this review could inspire broader interests across various disciplines and stimulate more exciting achievements in biodetection for the benefit of biomedical research.

Bifunctional Pdots-Based Novel ECL Nanoprobe with Qualitative and Quantitative Dual Signal Amplification Characteristics for Trace Cytokine Analysis.

In this work, a novel methodology to design bifunctional ECL-luminophores with self-enhanced and TSA-amplified characteristics was proposed for improving the sensing performance of ECL-immunosensor toward trace cytokine analysis. Thanks to the qualitative- and quantitative- dual signal amplification technique, the as-prepared ECL biosensor demonstrated excellent detection performance. By analyzing the prospective cytokine biomarkers (IL-6), the ECL immunosensor exhibited a broad examination range with quite low detection limit and quite high selectivity, which was far superior to commercial ELISA kits and ever reported works. In particular, the novel ECL nanoprobe developed here could also be applied to monitor other immune toxicities or disease-related cytokines by using the respective antibodies corresponding to these targets. Moreover, the concept and construction strategy of self-amplified ECL-luminophores presented here could be further extended to design a series of Pdots-derived multicolored ECL probes to meet the needs of multipathway detection applications.

A DNase-mimetic artificial enzyme for the eradication of drug-resistant bacterial biofilm infections.

The construction of multifunctional nano-enzymes is a feasible strategy for fighting multi-drug resistant (MDR) bacterial biofilm-associated infections. Extracellular DNA (eDNA) is an important functional part of biofilm formation, including the initial adherence of bacteria to subsequent development and eventual maturation. A nano-enzyme platform of graphene oxide-based nitrilotriacetic acid-cerium(IV) composite (GO-NTA-Ce) against bacterial biofilm infection has been developed. When located at the site of bacteria-associated infection, GO-NTA-Ce could inhibit the biofilm formation and effectively disperse the formed biofilm by degrading the eDNA. In addition to Ce-mediated deoxyribonuclease (DNase)-like activity, near-infrared laser irradiation of GO-NTA-Ce could produce local hyperthermia to kill the bacteria that lost the protection by the biofilm matrix. In addition, graphene is also a new green broad-spectrum antimicrobial material that can exert its antimicrobial effects through physical damage and chemical damage. In short, our GO-NTA-Ce nano-enzyme platform is capable of effectively eradicating drug-resistant bacterial biofilm infections through the triple action of DNase-like enzyme properties, photothermal therapy, and graphene-based antimicrobial activity, and the nano-composite has excellent potential for the treatment of MDR bacterial biofilm infections.

pH-Dominated Selective Imaging of Lipid Droplets and Mitochondria via a Polarity-Reversible Ratiometric Fluorescent Probe.

Elucidating the intrinsic relationship between mitochondrial pH (pHm) fluctuation and lipid droplets (LDs) formation is vital in cell physiology. The development of small-molecular fluorescent probes for discrimination and simultaneous visualization of pHm fluctuation toward LDs has not yet been reported. In this work, utilizing pH-driven polarity-reversible hemicyanine and rhodamine derivatives, a multifunctional fluorescent probe is developed for selectively identifying mitochondria and LDs under specific pH values via dual-emission channels. This rapid-response probe, Hcy-Rh, has two distinct chemical structures under acidic and alkaline circumstances. In acidic conditions, Hcy-Rh exhibits good hydrophilicity that can target mitochondria and display an intense red fluorescence. Conversely, the probe becomes lipophilic under weakly alkaline conditions and targets LDs, showing a strong blue emission. In this manner, Hcy-Rh can selectively label mitochondria and LDs, exhibiting red and blue fluorescence, respectively. Moreover, this ratiometric probe is applied to map pHm changes in living cells under the stimulus with FCCP, NAC, and H2O2. The interplay of LD-mitochondria under oleic acid treatment and starvation-induced autophagy has been studied using this probe at different pH values. In a word, Hcy-Rh is a potential candidate for further exploring mitochondria-LD interaction mechanisms under pHm fluctuation. Moreover, the polarity-dependent strategy is valuable for designing other functional biological probes in imaging multiple organelles.

A highly sensitive electrochemical cytosensor based on a triple signal amplification strategy using both nanozyme and DNAzyme.

The development of a sensitive cytosensor is beneficial for the early diagnosis and treatment of cancer. Herein, highly sensitive cytosensing was achieved by applying triple signal amplification strategies with Fe3O4@Au nanozymes and DNAzyme hybrids as electrochemical nanoprobes and toluidine blue (Tb) as the electron transfer medium. The Fe3O4@Au nanocomposites not only acted as nanozymes with excellent catalytic performance towards H2O2 reduction but also served as promising scaffolds to carry massive electroactive substances and DNA probes. The dual-functional DNA probes were designed with the sequence of hemin/G-quadruplex to serve as the DNAzyme and the sequence of aptamer to recognize cancer cells. Furthermore, Tb was also conjugated to the surface of the Fe3O4@Au nanohybrids, working as the electron transport medium to magnify the electrochemical response. With the above design, the Fe3O4@Au nanozymes and hemin/G-quadruplex DNAzyme efficiently co-catalyzed the reduction of H2O2 to accelerate the electron transfer of Tb, which realized triple signal amplification and finally improved the performance of the electrochemical cytosensor. The proposed cytosensor achieved a sensitive detection of HepG2 cells with a low detection limit of 20 cells mL-1, and could be potentially used as an effective analysis tool in early cancer diagnosis in the future.

Ultrabright AIEdots with tunable narrow emission for multiplexed fluorescence imaging.

AIEgen doped fluorescent nanodots (AIEdots) have attracted lots of attention, due to their superior characteristics as fluorescent probes, such as excellent photostability, large Stokes shift, high brightness and tunable emission. Unfortunately, most of the currently available AIEdots exhibit broad emission bandwidth, which limits their applications in multiplexed fluorescence imaging and detection. In this work, the strategy of designing and fabricating narrow emissive AIEdots (NE-AIEdots) with tunable wavelengths was presented by constructing a light-harvesting system with high energy transfer efficiency. Efficient intra-particle energy transfer from highly doped AIEgens, serving as the light-harvesting antenna, to the lightly doped narrow emissive fluorophore, resulted in high brightness and narrow emission. The emission band of NE-AIEdots with the full-width-at-half-maximum varied from 18 to 36 nm was 3-6.3 times narrower than that of traditional AIEdots. The single-particle brightness of NE-AIEdots was over 5-times that of commercial quantum dots under the same excitation and collection conditions. Taking advantage of the superior performance of these NE-AIEdots, multiplexed fluorescence imaging of lymph nodes in living mice was realized, which supported the future applications of NE-AIEdots for in vivo multiplexed labeling and clinical surgery.

Innovative strategies for enhanced tumor photodynamic therapy.

Photodynamic therapy (PDT) is an approved and promising treatment approach that utilizes a photosensitizer (PS) to produce cytotoxic reactive oxygen species (ROS) through irradiation to achieve tumor noninvasive therapy. However, the limited singlet oxygen generation, the nonspecific uptake of PS in normal cells, and tumor hypoxia have become major challenges in conventional PDT, impeding its development and further clinical application. This review summarizes an overview of recent advances for the enhanced PDT. The development of PDT with innovative strategies, including molecular engineering and heavy atom-free photosensitizers is presented and future directions in this promising field are also provided. This review aims to highlight the recent advances in PDT and discuss the potential strategies that show promise in overcoming the challenges of PDT.

Hemoglobin coated oxygen storage metal-organic framework as a promising artificial oxygen carrier.

Hemoglobin-functionalized HKUST-1 as an artificial oxygen carrier has been developed. The new oxygen carrier has excellent oxygen loading capacity and good chemical durability. The sustained electrochemical responses toward H2O2 and O2 make this new material an ideal candidate as a promising artificial blood substitute.

Ultrasensitive DNA methyltransferase activity sensing and inhibitor evaluation with highly photostable upconversion nanoparticle transducer.

Sensitive and accurate detection of DNA methyltransferase (MTase) is conducive to the understanding of the fundamental biological processes related to DNA methylation, clinical disease diagnosis, and drug discovery. Herein, a new fluorescence transducer based on Förster resonance energy transfer (FRET) between the donor upconversion nanoparticles (UCNPs) and the efficient acceptor gold nanorods (AuNRs) for MTase activity analysis and its inhibitor screening is presented. A double-strand DNA linker between UCNPs and AuNRs could be digested by restriction endonuclease HhaI, preventing the FRET process and recovering the upconversion luminescence (UCL) intensity. With the treatment of MTase, the cutting site was disturbed by the methylation of cytosine, blocking the enzyme digestion. The transducer presented here showed an excellent analytical performance toward MTase M.HhaI in the concentration range 0.08~24 U mL-1 with a detection limit of 0.057 U mL-1 calculated according to the UCL intensity changes at 656 nm excited by 980 nm CW laser, which is superior to most of the reported methods. Furthermore, the as-fabricated transducer also demonstrated high testing and screening capability toward enzyme inhibitors' evaluation. The method takes the advantage of low background fluorescence of UCNPs to improve the accuracy of the measurement, which can be developed as a general strategy for the analysis of various disease-related methyltransferase activity and their corresponding inhibitors, offering a promising strategy for high-performance diagnosis, high-efficient drug exploitation, and treatment effectiveness evaluation.