Precise pathogen quantification by CRISPR-Cas: a sweet but tough nut to crack.

Pathogen detection is increasingly applied in medical diagnosis, food processing and safety, and environmental monitoring. Rapid, sensitive, and accurate pathogen quantification is the most critical prerequisite for assessing protocols and preventing risks. Among various methods evolved, those based on clustered regularly interspaced short palindromic repeats (CRISPR)-associated proteins (Cas) have been developed as important pathogen detection strategies due to their distinct advantages of rapid target recognition, programmability, ultra-specificity, and potential for scalability of point-of-care testing (POCT).

Acoustofluidic precise manipulation: Recent advances in applications for micro/nano bioparticles.

Acoustofluidic technologies that integrate acoustic waves and microfluidic chips have been widely used in bioparticle manipulation. As a representative technology, acoustic tweezers have attracted significant attention due to their simple manufacturing, contact-free operation, and low energy consumption. Recently, acoustic tweezers have enabled the efficient and smart manipulation of biotargets with sizes covering millimeters (such as zebrafish) and nanometers (such as DNA).

Tuning the Dynamic Reaction Balance of CRISPR/Cas12a and RPA in One Pot: A Key to Switch Nucleic Acid Quantification.

Excavating nucleic acid quantitative capabilities by combining clustered regularly interspaced short palindromic repeats (CRISPR) and isothermal amplification in one pot is of common interest. However, the mutual interference between CRISPR cleavage and isothermal amplification is the primary obstacle to quantitative detection. Though several works have demonstrated enhanced detection sensitivity by reducing the inhibition of CRISPR on amplification in one pot, few paid attention to the amplification process and even dynamic reaction processes between the two.

Evaluating completion rates of COVID-19 contact tracing surveys in New York City.

Importance: Contact tracing is the process of identifying people who have recently been in contact with someone diagnosed with an infectious disease. During an outbreak, data collected from contact tracing can inform interventions to reduce the spread of infectious diseases. Understanding factors associated with completion rates of contact tracing surveys can help design improved interview protocols for ongoing and future programs.

CRISPR-Cas12a-Mediated Hue-Recognition Lateral Flow Assay for Point-of-Need Detection of .

Nucleic acid detection of pathogens in a point-of-need (PON) manner is of great significance yet remains challenging for sensitive and accurate visual discrimination. Here, we report a CRISPR-Cas12a-mediated lateral flow assay for PON detection of () that is a prevailing pathogen disseminated through tainted food. The variation of the fluorescence color of the test line is exploited to interpret the results, enabling the discrimination between positive and negative samples on the basis of a hue-recognition mechanism.

Label-Free Sequence-Specific Visualization of LAMP Amplified via DNA Machine Produces G-Quadruplex DNAzyme.

is one of four key global causes of diarrhea, and in humans, it is generally contracted through the consumption of contaminated food. It is necessary to develop an accurate, simple, and rapid method to monitor in the early phase. Herein, we developed a sequence-specific visualization method based on loop-mediated isothermal amplification (LAMP) for the detection of in milk.

Construction of highly-stable covalent organic framework with combined enol-imine and keto-enamine linkages.

A novel covalent organic framework (COF) (Tp-BI-COF) with combined ketimine-type enol-imine and keto-enamine linkages was prepared through a cascade of ketimine condensation followed by aldimine condensation and characterized by XRD, solid state C NMR, IR, TGA and BET. Tp-BI-COF showed high stability toward acid, organic solvent, and boiling water. The 2D COF exhibited photochromic properties after being irradiated with a xenon lamp.

Rapid Measurement of Residual Kanamycin Using Highly Specific Biomimetic Recognition Paper-Based Chip.

The development of highly specific biomimetic recognition material is a challenge for rapid detection of harmful residues in foodstuff. In this study, a paper-based boronate affinity metal-organic framework/molecularly imprinted polymer microfluidic chip (FZS-BA@MIP) was constructed based on the in situ construction strategy, which was also designed as a highly specific biomimetic recognition module. Here, the homogeneous zeolitic imidazole framework-8 (ZIF-8) membrane served as a great scaffold and enrichment layer.

Anchoring red blood cell with tetrahedral DNA nanostructure: Electrochemical biosensor for the sensitive signage of circulating tumor DNA.

Circulating tumor cells (CTCs), as a type of tumor, have attracted wide attention because of their characteristics of shedding from the primary tumor and spreading to other tissues and organs through peripheral blood. The circulating tumor DNA (ctDNA), the DNA released by CTCs and other tumor cells into the peripheral blood, was considered as a promising detection substance for clinical application. By utilizing the biocompatibility of red blood cells to realize the attachment of tetrahedral DNA (TDN), as well as the specific target recognition ability of TDN to enable efficient recognition of targets, a biocompatible electrochemical biosensor for effective and rapid detection of ctDNA was developed using methylene blue (MB) as the signal probe.

Self-assembled tetrahedral DNA nanostructures-based ultrasensitive label-free detection of ampicillin.

Antibiotics are widely used for improving the living conditions of livestock. However, residual antibiotics present in animal products induce several human diseases. Therefore, a simple, rapid, and cost-effective system for detecting and monitoring the presence of antibiotics in foods is in great demand to alleviate safety concerns.

Label-Free Colorimetric Method for Detection of by Trimming the G-Quadruplex DNAzyme with CRISPR/Cas12a.

(), which may cause gastrointestinal disorders in humans, is a pathogen commonly found in seafood. There are many methods for detecting , yet they have some shortcomings, such as high cost, labor-intensiveness, and complicated operation, which are impractical for resource-limited settings. Herein, we present a sequence-specific, label-free, and colorimetric method for visual detection of .

Engineering DNA G-quadruplex assembly for label-free detection of Ochratoxin A in colorimetric and fluorescent dual modes.

Colorimetric and fluorescent methods for Ochratoxin A (OTA) detection are convenient and well received. However, the pigments and autofluorescence originated from food matrices often interfere with detection signals. We have developed a strategy with colorimetric and fluorescent dual modes to solve this challenge.

Recent progress in visual methods for aflatoxin detection.

Aflatoxins (AFs) contamination in food and agricultural products poses a significant threat to human health. Sensitive and accurate detection of AFs provides a strong guarantee for ensuring food safety. Conventional chromatographic-based or mass spectrum methods, which rely on bulky instrument and skilled personnel, are not suitable for on-site surveillance.

Template-assisted CuO@Fe(OH) yolk-shell nanocages as biomimetic peroxidase: A multi-colorimetry and ratiometric fluorescence separated-type immunosensor for the detection of ochratoxin A.

The convenient and effective detection of toxins is urgently demanded for food security and human health. Herein, based on the catalytic activity of mimetic peroxidase from the CuO@Fe(OH) yolk-shell nanocages, a dual-modal multi-colorimetric and ratiometric fluorescence immunosensor for the sensitive detection of ochratoxin A (OTA) was successfully developed. For the multi-colorimetric detection, HO can be effectively decomposed by CuO@Fe(OH) to form ·OH groups, thus Au nanorods (Au NRs) can be etched to exhibit vivid color variations and localized surface plasmon resonance (LSPR) shifts.

Visual detection of in vitro nucleic acid replication by submicro- and nano-sized materials.

The rapid growth of in vitro nucleic acid replication has offered a powerful tool for clinical diagnosis, food safety detection and environmental monitorning. Successful implementation of various isothermal nucleic acid amplification methods enables rapid replication of target sequences without the participant of a thermal cycler. Point-of-need analysis possesses great superiorities in user-friendly, instant results analysis, low manufacturing, and consumable costs.

Study of photodegradation kinetics of aflatoxins in cereals using trilinear component modeling of excitation-emission matrix fluorescence data.

In this work, a smart analytical strategy that combines excitation-emission matrix (EEM) fluorescence detection with alternating trilinear decomposition (ATLD) algorithm was developed for fast, on-line and interference-free study on the photodegradation kinetics of aflatoxin B (AFB) and aflatoxin G (AFG) in rice and wheat under UV-Vis light (λ = 250-500 nm) treatment. With the aid of prominent "second-order advantage" of ATLD method, pure fluorescence signals of two targeted analytes can be directly resolved out from heavily overlapping spectral environment and accurately quantified even in the presence of unknown matrix interferences. Cereal samples in kinetic processing of photodegradation were detected without complex pretreatment steps except for a simple extraction using methanol/water solution (4:1, v/v), which solves the problem facing varied matrix interferences in the case of on-line monitoring of aflatoxins.

A Water-Stable Luminescent Metal-Organic Framework for Rapid and Visible Sensing of Organophosphorus Pesticides.

Metal-organic frameworks (MOFs) have shown considerable prospects for sensing pesticide residues. However, the low stability of MOFs in water hinders them from testing food and environmental samples. Herein, we report an easy and cost-efficient synthesis of a water-stable zirconium luminescent MOF (Zr-LMOF) and its application for rapid, sensitive, and in situ detection of organophosphorous pesticides (OPPs).

Effect of Macro-, Micro- and Nano-Calcium Carbonate on Properties of Cementitious Composites-A Review.

Calcium carbonate is wildly used in cementitious composites at different scales and can affect the properties of cementitious composites through physical effects (such as the filler effect, dilution effect and nucleation effect) and chemical effects. The effects of macro (>1 mm)-, micro (1 μm⁻1 mm)- and nano (<1 μm)-sizes of calcium carbonate on the hydration process, workability, mechanical properties and durability are reviewed. Macro-calcium carbonate mainly acts as an inert filler and can be involved in building the skeletons of hardened cementitious composites to provide part of the strength.

Hapten-Grafted Programmed Probe as a Corecognition Element for a Competitive Immunosensor to Detect Acetamiprid Residue in Agricultural Products.

We have developed an effective competitive electrochemical immunosensor assay based on hapten-grafted programmed probe (HGPP) as a corecognition element for highly sensitive and selective detection of acetamiprid. Starting with the synthesis of hapten, HGPP was prepared using carboxyl group in the hapten and amino group in the 5' end of the programmed probe through covalent conjugation. Acetamiprid present in samples competes with HGPP to bind with capture antibody on the electrodes by specific recognition interaction.

Chaperone-Driven Degradation of a Misfolded Proinsulin Mutant in Parallel With Restoration of Wild-Type Insulin Secretion.

In heterozygous patients with a diabetic syndrome called mutant gene-induced diabetes of youth (MIDY), there is decreased insulin secretion when mutant proinsulin expression prevents wild-type (WT) proinsulin from exiting the endoplasmic reticulum (ER), which is essential for insulin production. Our previous results revealed that mutant proinsulin is triaged by ER-associated degradation (ERAD). We now find that the ER chaperone Grp170 participates in the degradation process by shifting proinsulin from high-molecular weight (MW) complexes toward smaller oligomeric species that are competent to undergo ERAD.

DNA G-Quadruplex-Based Assay of Enzyme Activity.

DNA G-quadruplexes are special three-dimensional (3D) DNA nanostructures formed by specific G-rich DNA sequences. These 3D DNA nanostructures can bind with hemin and significantly improve the intrinsic peroxidase activity of hemin. Besides this function, they also enhance the fluorescence intensity of some G-quadruplex-specific dyes.

Self-Assembled DNA Hydrogel Based on Enzymatically Polymerized DNA for Protein Encapsulation and Enzyme/DNAzyme Hybrid Cascade Reaction.

DNA hydrogel is a promising biomaterial for biological and medical applications due to its native biocompatibility and biodegradability. Herein, we provide a novel, versatile, and cost-effective approach for self-assembly of DNA hydrogel using the enzymatically polymerized DNA building blocks. The X-shaped DNA motif was elongated by terminal deoxynucleotidyl transferase (TdT) to form the building blocks, and hybridization between dual building blocks via their complementary TdT-polymerized DNA tails led to gel formation.

A biomimetic colorimetric logic gate system based on multi-functional peptide-mediated gold nanoparticle assembly.

In natural biological systems, proteins exploit various functional peptide motifs to exert target response and activity switch, providing a functional and logic basis for complex cellular activities. Building biomimetic peptide-based bio-logic systems is highly intriguing but remains relatively unexplored due to limited logic recognition elements and complex signal outputs. In this proof-of-principle work, we attempted to address these problems by utilizing multi-functional peptide probes and the peptide-mediated nanoparticle assembly system.