CRISPR/Cas12a-based MUSCA-PEC strategy for HSV-1 assay

CRISPR/Cas12a-triggered electrochemiluminescence biosensor to ultrasensitive detect herpes simplex virus via self-enhanced near-infrared selenium-based polymer dots

Herpes simplex virus (HSV) as one of the most popular herpesviruses exhibits nearly identical clinical symptoms among the family of herpesvirus species and it is urgent to develop high specific biosensors to realize accurate detection of HSV. CRISPR/Cas12a systems with programmability and high specificity could serve an essential role in accurate diagnosis of HSV in complex samples. Herein, a novel near-infrared selenium-based polymer dots with self-enhanced effect were unprecedentedly designed and successfully synthesized in this work, and an ultrasensitive biosensor has been constructed together with the CRISPR/Cas12a system for the specific detection of HSV. Notably, the as-prepared selenium-based polymer dots exhibited near-infrared emission with a peak at 760 nm, which could significantly minimize background noise and achieve high sensitivity. The proposed biosensor demonstrated a wide linear range from 1 fM to 1 nM and the limit of detection as low as 0.1 fM (S/N = 3). Undoubtedly, the CRISPR/Cas12a-triggered ECL biosensor proposed in this work could provide a simple, sensitive, and environmentally friendly approach to detect HSV in clinical applications.

Development of Zn-Based Tower-like Photoelectrochemical Sensor Array for Sandwich-Type Immunosensing Analysis of Tau

A novel tower-like photoelectrochemical (PEC) sensor array, incorporating a self-calibration strategy, has been developed. In this study, Zn foil was folded into a quadrangular prism, upon which ZnO nanorods were grown in situ via a hydrothermal process. Subsequently, these ZnO nanorods were sensitized with narrow bandgap CdSe nanospheres. The resultant Zn/ZnO/CdSe have a stepped bandgap structure, effectively minimizing electron-hole pair recombination, enhancing electron transfer, and boosting PEC efficiency. The quadrangular structure is partitioned into four layers by light shields, creating a tower-like electrode equipped with 16 detection points. Furthermore, ZnFe2O4 is used as a detection antibody label for signal amplification. By rotating and moving the tower-like electrode, continuous multiple points detections are achieved, which reduces the operation time and helps to minimize the batch-to-batch variability. Additionally, the integration of a self-calibration strategy allows for selecting a point on the working electrode as a reference for calibration, thereby enhancing detection accuracy and sensitivity. In addition, the PEC immunosensor demonstrates a good linear correlation with microtubule-associated protein tau (Tau) within a measurement range of 0.01-50 ng·mL-1, with a detection limit of 1.1 pg·mL-1. This immunosensor is portable, highly stable, repeatable, and has strong specificity, with good storage stability.

Entropy driven-based catalytic biosensors for bioanalysis: From construction to application-A review

The rapid advancement of precision medicine and the continuous emergence of novel pathogens have presented new challenges for biosensors, necessitating higher requirements. Target amplification technology serves as the core component in biosensor construction. Enzyme-based amplification methods are often sensitive and selective but involve relatively complex operational steps, whereas enzyme-free amplification methods offer simplicity but frequently fail to meet both sensitivity and selectivity simultaneously. Existing research has confirmed that entropy-driven catalyst (EDC) biosensors not only fulfills the demands for sensitivity and selectivity concurrently but also offers ease of operation and flexibility in construction. In this review, we summarize the key advantages of EDC, explore how to construct DNA nanomachines based on these advantages to achieve intracellular detection and simultaneous detection of multiple targets, as well as point-of-care testing (POCT) to address practical issues in clinical diagnosis and treatment. We also anticipate potential challenges, propose corresponding solutions, and outline future development directions for EDC-based biosensors in practical clinical applications. We firmly believe that EDC sensors will emerge as a crucial branch within the realm of biosensor development.

An 18-connected wheel-shaped molybdenum(V) nickel-phosphate cluster for photoelectrochemical sensing of levofloxacin

An 18-connected {Mo16Ni16P24}-based 2-D layered network was constructed for photoelectrochemical sensing of levofloxacin, and it represents the highest connection number of the {Mo16Ni16P24} wheel cluster to date. The detection limit is as low as 6.46 nM with a high sensitivity of 110.87 μA μM-1 and good practicality in a milk sample.

Hydrovoltaic-Photoelectric Coupling Strategy Triggered a Robust Output Signal for High-Performance Self-Powered Electrochemical Sensing

Hydrovoltaic self-powered electrochemical sensors hold significant potential for constructing wearable, portable, and real-time detection devices, but the low output signal due to the slow phase transition rate of water molecules and the intricate nature of integration limits their applications. In this work, a hydrovoltaic-photovoltaic coupling effect-enhanced self-powered electrochemical sensor was prepared by combining zinc oxide (ZnO) nanowire arrays with cerium-organometallic framework (Ce-MOF) materials, which greatly improved the electrical output of self-powered electrochemical systems and provided a new detection strategy for an efficient self-powered electrochemical sensing system. The heterojunction constructed by ZnO arrays and Ce-MOF could generate a built-in electric field under the action of light irradiation and promote the separation of the photocarriers. Moreover, the number of charged particles in the film further boosted the water evaporation effect. Notably, the optimal ZnO/Ce-MOF-based self-powered electrochemical device by hydrovoltaic-photoelectric coupling strategy displayed an outstanding output signal, which was 11-fold that of a pure hydrovoltaic-based device. As a proof of concept, the self-powered electrochemical sensing platform was explored for sensitive detection of lincomycin via electrostatic adsorption for the binding of an aptamer. The self-powered sensor showed superior performances, including a wide linear range from 1 fM to 1 nM with a detection limit of 0.2 fM, good stability, and satisfactory recoveries for the determination of lincomycin in real samples, holding great promise in environmental monitoring and food analysis. This study provides a promising avenue to boost the energy conversion efficiency with a high output signal for constructing sensitive self-powered biosensors.

Control of HSV-1 Infection: Directions for the Development of CRISPR/Cas-Based Therapeutics and Diagnostics

It is estimated that nearly all individuals have been infected with herpesviruses, with herpes simplex virus type 1 (HSV-1) representing the most prevalent virus. In most cases, HSV-1 causes non-life-threatening skin damage in adults. However, in patients with compromised immune systems, it can cause serious diseases, including death. The situation is further complicated by the emergence of strains that are resistant to both traditional and novel antiviral drugs. It is, therefore, imperative that new methods of combating HSV-1 and other herpesviruses be developed without delay. CRISPR/Cas systems may prove an effective means of controlling herpesvirus infections. This review presents the current understanding of the underlying molecular mechanisms of HSV-1 infection and discusses four potential applications of CRISPR/Cas systems in the fight against HSV-1 infections. These include the search for viral and cellular genes that may serve as effective targets, the optimization of anti-HSV-1 activity of CRISPR/Cas systems in vivo, the development of CRISPR/Cas-based HSV-1 diagnostics, and the validation of HSV-1 drug resistance mutations.

CRISPR/Cas12a-Triggered Visible-Light-Driven Photoelectrochemical Assay with Single-Nucleotide Resolution for Drug-Resistant Foodborne Salmonella Detection

The prevalence of foodborne pathogenic bacteria, especially drug-resistant strains, such as Salmonella enterica, poses serious threats to public health, highlighting the requirement for the development of rapid and precise detection methods. Herein, a CRISPR/Cas12a-triggered visible-light-driven photoelectrochemical (PEC) assay (CasPEC) was developed using a SiO2-quenched BiVO4/MoS2 p/n-type heterojunction as the photoactive material. The CRISPR/Cas12a recognition endowed the CasPEC assay with high specificity capable of resolving single-nucleotide polymorphisms (SNPs) and identifying SNP-involved drug-resistant bacteria. SiO2 was linked to the surface of the BiVO4/MoS2 heterojunction by single-stranded DNA (ssDNA), which would be cleaved by target-activated CRISPR/Cas12a. This cleavage of ssDNA resulted in the detachment of SiO2, thereby achieving a "signal-on" PEC output. Leveraging the multiple-turnover CRISPR cleavage and the outstanding photoactive performance of PEC signaling, the CasPEC assay for S. enterica showed a detection limit of 103 colony-forming units (CFU)/mL and the ability to detect as few as 0.01% drug-resistant strains. The CasPEC assay can accurately sense the S. enterica contamination in complex food matrices, including beef and milk. These findings demonstrated the great potential of the CasPEC assay for detecting pathogenic bacterial contamination in food, particularly concerning food safety related to SNP-involved drug-resistant bacteria.

Bioreaction-Compatible Bivariate Lanthanide MOF Sensor Enables Stimulus-Multiresponsive Platform for ctDNA On-Site Detection

Detection of circulating tumor DNA (ctDNA) in liquid biopsy is of great importance for tumor diagnosis but difficult due to its low amount in bodily fluids. Herein, a novel ctDNA detection platform is established by quantifying DNA amplification by-product pyrophosphate (PPi) using a newly designed bivariable lanthanide metal-organic framework (Ln-MOF), namely, Ce/Eu-DPA MOF (CE-24, DPA = pyridine-2,6-dicarboxylic acid). CE-24 MOF exhibits ultrafast dual-response (fluorescence enhancement and enzyme-activity inhibition) to PPi stimuli by virtue of host-guest interaction. The platform is applied to detecting colon carcinoma-related ctDNA (KARS G12D mutation) combined with the isothermal nucleic acid exponential amplification reaction (EXPAR). ctDNA triggers the generation of a large amount of PPi, and the ctDNA quantification is achieved through the ratio fluorescence/colorimetric dual-mode assay of PPi. The combination of the EXPAR and the dual-mode PPi sensing allows the ctDNA assay method to be low-cost, convenient, bioreaction-compatible (freedom from the interference of bioreaction systems), sensitive (limit of detection down to 101 fM), and suitable for on-site detection. To the best of our knowledge, this work is the first application of Ln-MOF for ctDNA detection, and it provides a novel universal strategy for the rapid detection of nucleic acid biomarkers in point-of-care scenarios.

A novel universal small-molecule detection platform based on antibody-controlled Cas12a switching

Molecular diagnostics play an important role in illness detection, prevention, and treatment, and are vital in point-of-care test. In this investigation, a novel CRISPR/Cas12a based small-molecule detection platform was developed using Antibody-Controlled Cas12a Biosensor (ACCBOR), in which antibody would control the trans-cleavage activity of CRISPR/Cas12a. In this system, small-molecule was labeled around the PAM sites of no target sequence(NTS), and antibody would bind on the labeled molecule to prevent the combination of CRISPR/Cas12a, resulting the decrease of trans-cleavage activity. Biotin-, digoxin-, 25-hydroxyvitamin D3 (25-OH-VD3)-labeled NTS and corresponding binding protein were separately used to verify its preformance, showing great universality. Finally, one-pot detection of 25-OH-VD3 was developed, exhibiting high sensitivity and excellent specificity. The limit of detection could be 259.86 pg/mL in serum within 30 min. This assay platform also has the advantages of low cost, easy operation (one-pot method), and fast detection (∼30 min), would be a new possibilities for the highly sensitive detection of other small-molecule targets.

A rapid isothermal CRISPR-Cas13a diagnostic test for genital herpes simplex virus infection

Prompt diagnosis is essential for managing herpes simplex virus types 1 and 2 (HSV-1/2). Existing diagnostic methods are not widely available that required expensive or additional equipment for conducting examinations and result readouts, which can limit their utility in resource-constrained settings. We successfully developed a CRISPR-Cas13a-based assay for the detection and genotyping of HSV. Our assay demonstrated a high sensitivity of 96.15% and 95.15% for HSV-1 and HSV-2, respectively, with a specificity of 100% compared to a commercial qPCR assay when tested on 194 clinical samples. Remarkably, the assay enables a limit of detection of 1 copy/μL of viral DNA, facilitated by an enhanced input of RPA product and is designed for both mobile app integration and colorimetric interpretation, allowing for semiquantitative readings. These findings highlight the excellent performance of our CRISPR-based diagnostic in detecting HSV and its potential for point-of-care testing in resource-constrained settings.