Aptamer melting biosensors for thousands of signaling and regenerating cycles.

Due to their recognition abilities and inherent regenerability, aptamers have great potential in biosensing applications. However, effective signal transduction and regeneration strategies are still required. Herein, we develop a melting-based aptamer sensing strategy capable of homogeneous signaling with over 1000 regenerating cycles without significant deterioration of performance.

Covalent Self-Assembly of Bio-HCP Nanoparticles for Shell-Programmed Encapsulation of Microbial Cells.

Modifying the bacterial surface through grafting functional nanoparticles is a common strategy for programing bacteria. At this moment, the targeted nanoparticles face a dilemma of no multifunctional structure, high toxicity, and weak chemical driving forces, which restrict the broad practical applications. Like a multistage booster of a rocket, we propose a multistage covalent self-assembly strategy to protect, expand, and control the encapsulated shells of microbial cells via biocompatible hyper-cross-linked polymer nanoparticles (Bio-HCP NPs) with internal porosity and surface functional groups.

Ultra-sensitive detection of SARS-CoV-2 S1 protein by coupling rolling circle amplification with poly(N-isopropylacrylamide)-based sandwich-type assay.

In the past few years, the COVID-19 pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) seriously threatens global public health security due to its high contagiousness. It remains of vital importance to develop a rapid and sensitive assay for SARS-CoV-2. In this work, we proposed a sandwich-type assay based on poly(N-isopropylacrylamide) (PNIPAM), allowing efficient detection of the SARS-CoV-2 S1 protein in the homogeneous solution.

Removal of calcium and magnesium ions from reverse osmosis concentrate using a two-stage precipitation with carbonation process.

The reverse osmosis (RO) technique has been extensively employed in the advanced treatment of industrial water and wastewater. However, this process results in the production of a significant quantity of reverse osmosis concentrate (ROC), which contains high levels of salinity and organic contaminants, thereby posing serious environmental problems. This study reported a two-stage precipitation process utilizing quicklime (CaO) and caustic soda (NaOH) in conjunction with air blowing (carbonation) for the removal of Ca and Mg from real brackish water ROC of factory.

Target-induced DNA nanomachine operation for the detection of proteins.

Accurate and sensitive detection of disease-associated proteins in early stage of patients plays an important role in timely treatment and successfully extending patients' lives. To meet this demand, we herein rationally designed a flexible target-induced DNA nanomachine operation (TIDNMO) sensor for the detection of proteins. The TIDNMO system was composed of DNA nanoswitch and DNA walker.

A simple, rapid and sensitive sandwich immunoassay based on poly(N-isopropylacrylamide) for the detection of alpha-fetoprotein.

Alpha-fetoprotein (AFP), as a tumor marker, plays a vital role in the diagnosis of liver cancer. In this work, a novel sandwich immunoassay based on a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), was developed for the detection of AFP. This immunoassay could realize one-step rapid reaction within 1 h, and facilitate the separation of the target molecules by incorporating PNIPAM.

A Facile Strategy for Multiplex Protein Detection by a Fluorescent Microsphere-Based Digital Immunoassay.

The digital immunoassay is a highly sensitive detection technique based on single-molecule counting and is widely used in the ultrasensitive detection of biomarkers. Herein, we developed a fluorescent microsphere-based digital immunoassay (FMDIA) by employing fluorescent microspheres as both the carriers for immunoreaction and fluorescent reports for imaging. In this approach, the target protein in the sample was captured by fluorescent microspheres to form a biotin-labeled sandwich immunocomplex, and then, the fluorescent microspheres containing the target protein molecules were captured by adding streptavidin-coated magnetic beads (SA-MBs).

Amplification-free detection of Mpox virus DNA using Cas12a and multiple crRNAs.

Mpox virus (MPXV) is a zoonotic DNA virus that caused human Mpox, leading to the 2022 global outbreak. MPXV infections can cause a number of clinical syndromes, which increases public health threats. Therefore, it is necessary to develop an effective and reliable method for infection prevention and control of epidemic.

UV-induced oxidase activity of carbon dots in visible UVA dosage, Escherichia coli quantification and bacterial typing.

Ultraviolet (UV) light and foodborne pathogenic bacteriais are an important risk to the environment's safety. They endanger human health, and also lead to outbreaks of infectious disease, posing great threats to global public health security, national economy, and social stability. The appearance of carbon dot (CD) nanozymes offers a new perspective to solve the problems of detection of UV light and pathogenic bacteria in environment.

Nucleic Acid Amplification-Free Digital Detection Method for SARS-CoV-2 RNA Based on Droplet Microfluidics and CRISPR-Cas13a.

Most of the methods currently developed for RNA detection based on CRISPR were combined with nucleic acid amplification. As a result, such methods inevitably led to certain disadvantages such as multiple operations, expensive reagents, and amplification bias. To solve the above problems, we developed a highly sensitive and specific nucleic acid amplification-free digital detection method for SARS-CoV-2 RNA based on droplet microfluidics and CRISPR-Cas13a.

A functional nanoflower based lateral flow immunoassay for the rapid and robust detection of pathogens.

In the face of complex public health emergencies and various social medical needs in new situations, it is urgent to establish rapid detection technology for the early detection of pathogens to control their spread and minimize the resultant health and societal impact. Point-of-care testing (POCT) that allows rapid, on-site, and affordable detection and monitoring of health conditions at home or away from clinical labs has received increasing attention in modern medicine. In this work, we have synthesized multifunctional magainin I-human chorionic gonadotropin (hCG)-Cu(PO) nanoflowers and demonstrated a new strategy for the fast diagnosis of pathogenic microorganisms by combining functional nanoflowers with a lateral flow immunoassay device.

CRISPR/Cas13a Trans-Cleavage-Triggered Catalytic Hairpin Assembly Assay for Specific and Ultrasensitive SARS-CoV-2 RNA Detection.

New coronavirus (SARS-CoV-2), which has caused the coronavirus disease 2019 (COVID-19) pandemic, has brought about a huge burden on global healthcare systems. Rapid and early detection is important to prevent the spread of the pandemic. Here, an assay based on CRISPR/Cas13a and catalytic hairpin assembly (CHA), termed as Cas-CHA, was developed for ultrasensitive and specific detection of SARS-CoV-2 RNA.

Dual-Color Fluorescent Hydrogel Microspheres Combined with Smartphones for Visual Detection of Lactate.

Since it is difficult for human eyes to distinguish between two identical colors with only <15% variation in brightness, mono-color fluorescent hydrogel microspheres have some limitations in the detection of lactate. Herein, we prepared novel dual-color fluorescent hydrogel microspheres, which can achieve hue transformation. Microspheres were prepared by introducing a fluorescent nanoparticle as the reference signal while CdTe QDs were used as the response signal.

Ratiometric fluorescent Si-FITC nanoprobe for immunoassay of SARS-CoV-2 nucleocapsid protein.

Unlabelled: Coronavirus disease 2019 (COVID-19) highlights the importance of rapid and reliable diagnostic assays for the management of virus transmission. Here, we developed a one-pot hydrothermal method to prepare Si-FITC nanoparticles (NPs) for the fluorescent immunoassay of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (N protein). The synthesis of Si-FITC NPs did not need post-modification, which addressed the issue of quantum yield reduction during the coupling reaction.

Synthesis of bio-templated clickable quantum dots and a dual-emitting organic/inorganic complex for ratiometric fluorescence visual assay of blood glucose.

With the prevalence of diabetes, rapid and simple blood glucose monitoring has become more and more important. Here, we report the synthesis of bio-templated N-CdZnTeS quantum dots (QDs), which are great fluorescent biological labels and were used for the fabrication of dual-emissive dye@protein-QD conjugates copper-free click chemistry, such as the 5(6)-carboxyfluorescein@glucose oxidase-quantum dot (FAM@GOx-QDs) complex. When adding glucose, the red fluorescence of the CdZnTeS QDs sharply decreased, while the green fluorescence of FAM was invariable.

Metabolic labeling of enterovirus 71 with quantum dots for the study of virus receptor usage.

Fluorescent labeling and dynamic tracking is a powerful tool for exploring virus infection mechanisms. However, for small-sized viruses, virus tracking studies are usually hindered by a lack of appropriate labeling methods that do not dampen virus yield or infectivity. Here, we report a universal strategy for labeling viruses with chemical dyes and Quantum dots (QDs).

A fluorescence color card for point-of-care testing (POCT) and its application in simultaneous detection.

Diabetes mellitus has received much attention because its complications include liver, kidney, eye, heart and cerebrovascular diseases. Thus, it would be highly significant to develop a rapid and efficient method for glucose detection in biological samples. In this work, a point-of-care testing (POCT) method of glucose detection was proposed using a standard colorimetric card for semi-quantitative determination patterns.

DNAzyme Sensor Uses Chemiluminescence Resonance Energy Transfer for Rapid, Portable, and Ratiometric Detection of Metal Ions.

DNAzymes have emerged as an important class of sensors for a wide variety of metal ions, with florescence DNAzyme sensors as the most widely used in different sensing and imaging applications because of their fast response time, high signal intensity, and high sensitivity. However, the requirements of an external excitation light source and its associated power increase the cost and size of the fluorometer, making it difficult to be used for portable detections. To overcome these limitations, we report herein a DNAzyme sensor that relies on chemiluminescence resonance energy transfer (CRET) without the need for external light.

Glow-type chemiluminescent hydrogels for point-of-care testing (POCT) of cholesterol.

Cholesterol is an essential compound for human health, and a high or low concentration of cholesterol is closely related to various diseases. Thus, developing a simple method for POCT of cholesterol has great significance in clinical diagnosis. In this work, alginate (Alg) hydrogels with glow-type chemiluminescence (CL) were prepared and applied for rapid and quantitative cholesterol detection via a smartphone.

Investigating the effect of 6-mercaptohexanol on the performance of a biosensor based on nanosurface energy transfer between gold nanoparticles and quantum dots.

Nanosurface energy transfer (NSET)-based sensors have been widely developed using various pairs of nanomaterials including gold nanoparticles (AuNPs) and quantum dots (QDs). However, a low signal to background ratio is one of the most important problems that researchers are continually trying to solve. Herein, we present a 6-mercaptohexanol (MCH) modified MCH/DNA-Au-QD sensor for the detection of nucleic acids and MUC1.

DNAzyme Walker for Homogeneous Detection of Enterovirus EV71 and CVB3.

When dealing with infectious pathogens, the risk of contamination or infection in the process of detecting them is nonnegligible. Separation-free detection will be beneficial in operation and safety. In this work, we proposed a DNAzyme walker for homogeneous and isothermal detection of enterovirus.

Novel Method of Clickable Quantum Dot Construction for Bioorthogonal Labeling.

Bioorthogonal chemistry has been considered as a powerful tool for biomolecule labeling due to its site specificity, moderate reaction conditions, high yield, and simple post-treatment. Covalent coupling is commonly used to modify quantum dots (QDs) with bioorthogonal functional group (azide or cycloalkyne), but it has a negative effect in the decrease of QDs' quantum yield and stability and increase of QDs' hydrodynamic diameter. To overcome these disadvantages, we propose a novel method for the preparation of two kinds of clickable QDs by the strong interaction of -SH with metal ions.

Point-of-care testing (POCT) of patients with a high concentration of uric acid by using alginate hydrogel microspheres embedded with CdZnTeS QDs and urate oxidase (Alg@QDs-UOx MSs).

High concentration of uric acid is usually related to cardiovascular and cerebrovascular diseases. Developing a simple method for the rapid and efficient detection of uric acid has a great significance in clinical diagnosis. In this work, alginate hydrogel microspheres embedded with CdZnTeS QDs and urate oxidase (Alg@QDs-UOx MSs) were prepared for the first time, and further used for point-of-care testing (POCT) of patients with a high concentration of uric acid.