Self-phosphorylating DNAzyme DK1 enables programmable multi-analyte readout via PfAgo.

DNAzymes possessing kinase-like activities have long held theoretical promise, yet their practical implementation has remained significantly limited. Notably, DNAzyme kinase 1 (DK1), discovered over two decades ago, exhibits a unique self-phosphorylation capability upon encountering specific substrates like ATP, but its broad-based and programmable applications have not yet been fully realized. In this study, we innovatively couple DK1's autophosphorylation mechanism with the PfAgo to establish a novel programmable cascade sensing platform named RASTEN (Robust pfAgo-based Strategy for POC Testing Non-nucleic Acid and Nucleic Acid).

Ascorbic acid-amplified robust fluorescent assay for versatile detection of acid phosphatase activity.

Background: Acid phosphatase (ACP) serves as a crucial clinical biomarker for early detection of various diseases, most notably prostate cancer (PCa), which ranks as the second most common cancer among men worldwide and remains typically asymptomatic in its initial developmental phase. Enzyme-triggered fluorescent reactions under mild conditions offer significant potential for advancing in-situ enzyme activity assays. Despite this promise, the development of acid phosphatase (ACP)-specific detection systems remains challenging due to the scarcity of efficient fluorescent response mechanisms and undesirable fluorescence under acidic conditions.

Free reactive oxygen species-independent dual enzymatic activity of iron single-atom catalyst for hydrogel-assisted portable visual analysis.

Since the enzymatic-like activity of FeO was reported, research on iron-based nanozymes has undergone vigorous development. However, most of previously reported iron-based nanozymes, including iron single-atom nanozymes, always rely on free reactive oxygen species (ROS) to exert their catalytic effects, especially the OH derived from Fenton-like reaction mediated by HO. In this study, we present an iron single-atom nanozyme (SA-FeNC) with catalytic mechanisms akin to that of natural cytochrome c oxidase and horseradish peroxidase.

NAPTUNE: nucleic acids and protein biomarkers testing via ultra-sensitive nucleases escalation.

In an era where swift and precise diagnostic capabilities are paramount, we introduce NAPTUNE (Nucleic acids and Protein Biomarkers Testing via Ultra-sensitive Nucleases Escalation), an innovative platform for the amplification-free detection of nucleic acids and protein biomarkers in less than 45 minutes. Using a tandem cascade of endonucleases, NAPTUNE employs apurinic/apyrimidinic endonuclease 1 (APE1) to generate DNA guides, enabling the detection of target nucleic acids at femtomolar levels. The sensitivity is elevated to attomolar levels through the action of Pyrococcus furiosus Argonaute (PfAgo), which intensifies probe cleavage, thereby boosting both sensitivity and specificity within an innovative in-situ cascade circuit.

A one-pot CRISPR-RCA strategy for ultrasensitive and specific detection of circRNA.

Accurate and precise detection of circular RNA (circRNA) is imperative for its clinical use. However, the inherent challenges in circRNA detection, arising from its low abundance and potential interference from linear isomers, necessitate innovative solutions. In this study, we introduce, for the first time, the application of the CRISPR/Cas12a system to establish a one-pot, rapid (30 minutes to 2 hours), specific and ultrasensitive circRNA detection strategy, termed RETA-CRISPR (reverse transcription-rolling circle amplification (RT-RCA) with the CRISPR/Cas12a).

Fluorometric "AND" logic gate for detection of tyramine and tyrosinase based on in-situ formation of silicon-containing nanoparticles.

Background: Tyramine is an important index of food freshness degree, and tyrosinase that can specifically oxidized monophenolamine to catecholamine plays a crucial part in the occurrence and development of melanin-related skin diseases. Therefore, it is crucial to develop sensitive and efficient methods for the detection of tyramine and tyrosinase.

Results: In this work, encouraged by tyrosinase-triggered specific oxidation of tyramine to dopamine and the unique fluorescent reaction between dopamine and amino silane, we have developed a one-step synthetic strategy of silicon containing nanoparticles (Si CNPs) for "turn-on" detection of tyramine and tyrosinase.

Clinical observation and influence on nutritional status of intensive nutritional nursing combined with 3-day dietary diary intervention in peritoneal dialysis patients.

Background: Peritoneal dialysis is a commonly used treatment for chronic kidney failure patients. Studies have shown that long-term peritoneal dialysis can lead to various degrees of malnutrition. Therefore, it is of great significance to improve the nutritional conditions of patients with peritoneal dialysis.

Light-Triggered Signal Enhancement Strategy Integrated with a CRISPR/Cas13a-Based Assay for Ultrasensitive and Specific miRNA Detection.

The development of facile, accurate, and affordable assays for microRNAs (miRNAs) in early cancer is greatly desirable but encounters an obstacle due to low cellular abundance in biofuids. In this study, we present a novel approach called a ight-triggered onential mplification strategy coupled with a /Cas13a-based diagnostic system (LEXPA-CRISPR), which directly transduces rare miRNA targets into photocontrolled signal enhancement response. This innovative platform leverages trans-cleavage of CRISPR/Cas13a, activated by the miRNA target, to cleave specific RNA fragments within the MB@PC-NAC assembly, thus releasing free PC-single-stranded DNA (PC-ssDNA) that is modified by a photocleavable linker (PC linker).

A one-tube dual-readout biosensor for detection of nucleic acids and non-nucleic acids using CRISPR-ALP tandem assay.

Clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics have been considered a next-generation molecular diagnosis tool. Single-readout mode has been extensively employed in massive CRISPR/Cas12a-based biosensors. In this work, we propose a one-tube dual-readout biosensor (CRISAT) for the first time for the detection of ultrasensitive nucleic acids and non-nucleic acids developed by harnessing CRISPR-ALP tandem assay.

Fluorescence detection of 4-nitrophenol and α-glucosidase activity based on 4-nitrophenol-regulated fluorescence of silicon nanoparticles.

A fluorescence assay for the detection of 4-nitrophenol (4-NP), α-glucosidase (α-Glu) activity and α-Glu inhibitors (AGIs) is developed based on the inner filter effect (IFE), a flexible and simple signal transfer strategy. In this assay, silicon nanoparticles (Si NPs) synthesized under mild and easily accessible conditions are employed as fluorescent indicators. 4-NP efficaciously quenches the fluorescence of Si NPs through the IFE at a very rapid rate, thus achieving 4-NP detection in a mix-to-read manner, which is suitable for on-site detection.

Malathion detection based on polydopamine enhanced oxidase-mimetic activity of palladium nanocubes.

Nowadays, fabricating simple and efficient pesticide detection methods become a research focus due to the great threat pesticide residues posed to human health and environment. Herein, we constructed a high-efficiency and sensitive colorimetric detection platform for malathion detection based on polydopamine-dressed Pd nanocubes (PDA-Pd/NCs). The Pd/NCs coated with PDA exhibited excellent oxidase-like activity, which was attributed to the substrates accumulation and accelerated electron transfer induced by PDA.

Regulating the N Coordination Environment of Co Single-Atom Nanozymes for Highly Efficient Oxidase Mimics.

Single-atom catalysts with well-defined atomic structures and precisely regulated coordination environments have been recognized as potential substitutes for natural metalloenzymes. Inspired by the metal coordination structure of natural enzymes, we show here that the oxidase-like activity of single-atom Co catalysts greatly depends on their local N coordination around the Co catalytic sites. We synthesized a series of Co single-atom catalysts with different nitrogen coordination numbers (Co-N(C), = 2, 3, and 4) and demonstrated that the oxidase-like activity of single-atom Co catalysts could be effectively tailored by fine-tuning the N coordination.

Platinum nanoparticles confined in metal-organic frameworks as excellent peroxidase-like nanozymes for detection of uric acid.

High levels of uric acid (UA) in humans can cause a range of diseases, and traditional assays that rely on uric acid enzymes to break down uric acid are limited by the inherent deficiencies of natural enzymes. Fortunately, the rapid development of nanozymes in recent years is expected to solve the above-mentioned problems. Hence, we used a host-guest strategy to synthesize a platinum nanoparticle confined in a metal-organic framework (Pt NPs@ZIF) that can sensitively detect UA levels in human serum.

CRISPR/Cas12a-Enabled Multiplex Biosensing Strategy Via an Affordable and Visual Nylon Membrane Readout.

Most multiplex nucleic acids detection methods require numerous reagents and high-priced instruments. The emerging clustered regularly interspaced short palindromic repeats (CRISPR)/Cas has been regarded as a promising point-of-care (POC) strategy for nucleic acids detection. However, how to achieve CRISPR/Cas multiplex biosensing remains a challenge.

Rational design and fabrication of MoS nanoclusters decorated MnCdS nanorods with promoted interfacial charge transfer toward robust photocatalytic H generation.

In this work, we report a novel MoS/MnCdS composite catalyst that has been designed and fabricated by in situ coupling MoS nanoclusters with 1D MnCdS nanorods for photocatalytic H production. The catalyst features a 1D nanostructure with MoS nanoclusters uniformly dispersed along the MnCdS nanorod. It was found that an intimate interface is built between MoS nanoclusters and MnCdS nanorods thanks to the facile in situ photoreduction route, which contributes to a high-efficiency interfacial charge separation.

Multienzyme Cascades Based on Highly Efficient Metal-Nitrogen-Carbon Nanozymes for Construction of Versatile Bioassays.

Distinguished by the coupled catalysis-facilitated high turnover and admirable specificity, enzyme cascades have sparked tremendous attention in bioanalysis. However, three-enzyme cascade-based versatile platforms have rarely been explored without resorting to tedious immobilization procedures. Herein, we have demonstrated that formamide-converted transition metal-nitrogen-carbon (f-MNC, M = Fe, Cu, Mn, Co, Zn) with a high loading of atomically dispersed active sites possesses intrinsic peroxidase-mimetic activity following the activity order of f-FeNC > f-CuNC > f-MnNC > f-CoNC > f-ZnNC.

Emerging interstitial/substitutional modification of Pd-based nanomaterials with nonmetallic elements for electrocatalytic applications.

Palladium (Pd)-based nanomaterials have been identified as potential candidates for various types of electrocatalytic reaction, but most of them typically exhibit unsatisfactory performances. Recently, extensive theoretical and experimental studies have demonstrated that the interstitial/substitutional modification of Pd-based nanomaterials with nonmetallic atoms (H, B, C, N, P, S) has a significant impact on their electronic structure and thus leads to the rapid development of one kind of promising catalyst for various electrochemical reactions. Considering the remarkable progress in this area, we highlight the most recent progress regarding the innovative synthesis and advanced characterization methods of nonmetallic atom-doped Pd-based nanomaterials and provide insights into their electrochemical applications.

Peroxidase-like activity of Ru-N-C nanozymes in colorimetric assay of acetylcholinesterase activity.

Herein, the Ru-N-C nanozymes with abundant active Ru-N sites have been successfully prepared by pyrolyzing Ru(acac) trapped zeolitic-imidazolate-frameworks (Ru(acac)@ZIF-8). Taking advantages of the remarkable peroxidase-mimicking activity, outstanding stability and reusability of Ru-N-C nanozymes, a novel biosensing system with explicit mechanism is strategically fabricated for sensitively determining acetylcholinesterase (AChE) and tacrine. The limit of detection for AChE activity can achieve as low as 0.

Manganese-doped iron coordination polymer nanoparticles with enhanced peroxidase-like activity for colorimetric detection of antioxidants.

A convenient and sensitive antioxidant assay with high performance is essential for assessing food quality and monitoring the oxidative stress level of biological matrices. Although coordination polymer nanoparticles (CPNs)-based nanozymes have emerged as candidates in the analytical field, strategies to improve the catalytic activity of CPNs have been scarcely revealed and studied. Herein, we demonstrate a manganese (Mn) doping strategy to enhance the peroxidase-mimetic activity of Fe-based CPNs.

Colorimetric detection of acetylcholinesterase and its inhibitor based on thiol-regulated oxidase-like activity of 2D palladium square nanoplates on reduced graphene oxide.

A convenient and sensitive colorimetric assay for acetylcholinesterase (AChE) and its inhibitor has been designed based on the oxidase-like activity of {100}-faceted Pd square nanoplates which are grown in situ on reduced graphene oxide (PdSP@rGO). PdSP@rGO can effectively catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) without the assistance of HO to generate blue oxidized TMB (oxTMB) with a characteristic absorption peak at 652 nm. In the presence of AChE, acetylthiocholine (ATCh), a typical AChE substrate, is hydrolyzed to thiocholine (TCh).

Ultrathin PdCu alloy nanosheet-assembled 3D nanoflowers with high peroxidase-like activity toward colorimetric glucose detection.

Enzyme-mimetic properties of nanomaterials can be efficiently tuned by controlling their size, composition, and structure. Here, ultrathin PdCu alloy nanosheet-assembled three-dimensional (3D) nanoflowers (PdCu NAFs) with tunable surface composition are obtained via a generalized strategy. In presence of HO, the as-synthesized PdCu NAFs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to the oxidized form of TMB (oxTMB) with a characteristic absorption peak at 652 nm.

Inhibited oxidase mimetic activity of palladium nanoplates by poisoning the active sites for thiocyanate detection.

In this work, a novel convenient colorimetric method for sensitive detection of thiocyanate (SCN) has been developed based on its suppression of the oxidase-like activity of palladium square nanoplates on reduced graphene oxide (Pd SP@rGO). SCN can be adsorbed onto the surface of Pd SP@rGO via binding with Pd atoms and blocks the active sites that mimic oxidase, thus inhibiting the corresponding chromogenic reaction of 3,3',5,5'-tetramethylbenzidine, which has been comprehensively revealed by the UV-vis spectra and X-ray photoelectron spectra. The color fading exhibits SCN concentration-dependent behavior and can be easily recorded by either UV-vis spectroscopy or naked-eye observation.

Light-responsive Au nanoclusters with oxidase-like activity for fluorescent detection of total antioxidant capacity.

A fluorescent assay for total antioxidant capacity (TAC) detection based on the light-responsive oxidase-like activity of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) has been developed. Thiamine (TH) as the peroxidase substrate usually works at alkaline conditions and thus limits its practical applications. Here, by utilization the light-responsive oxidase-like activity of BSA-AuNCs, TH is oxidized to fluorescent thiochrome under neutral condition in two minutes due to the single oxygen generated by BSA-AuNCs upon light irradiation.

Formation of 2,3-Diaminophenazine for Evaluation of Alkaline Phosphatase Activity via the Inner Filter Effect.

We report a fluorescence assay for alkaline phosphatase (ALP) detection using generation of 2,3-diaminophenazine (OPDox) through an inner filter effect (IFE). AgNO can oxidize -phenylenediamine in a short time to obtain fluorescent OPDox. -nitrophenol is obtained from ALP-catalyzed hydrolysis of -nitrophenylphosphate, which can result in the fluorescence quenching of OPDox via the IFE.

Alkaline Phosphatase-Triggered in Situ Formation of Silicon-Containing Nanoparticles for a Fluorometric and Colorimetric Dual-Channel Immunoassay.

Enzyme-triggered in situ chromogenic and/or fluorogenic reactions under accessible conditions are significant for developing enzyme activity and related spectroscopic assays. Here, we describe a facile one-pot synthetic strategy to prepare silicon-containing nanoparticles with yellow-green fluorescence and orange-red color by mixing -[3-(trimethoxysilyl)propyl]ethylenediamine and -aminophenol (AP) in aqueous solution at a mild temperature. Encouraged by the AP-regulated simple synthetic procedure and the generation of AP from alkaline phosphatase (ALP)-catalyzed hydrolysis of 4-aminophenol phosphate (APP), a fluorometric and colorimetric dual-readout ALP activity assay can be rationally envisioned and developed by employing APP as the substrate.