Split aptazyme-based signal amplification for AβO analysis.

Aptazyme is a chimera of functional nucleic acids, which integrates recognition and amplification elements to simplify the assay process and improve sensing efficiency. However, its application may be limited by signal leakage. In this work, we innovatively integrate the AβO aptamer and an MNAzyme (multicomponent nucleic acid enzyme) for highly efficient detection of AβO.

Effect of Titanium Dioxide Particles on the Thermal Stability of Silica Aerogels.

Silica aerogels exhibit a unique nanostructure with low thermal conductivity and low density, making them attractive materials for thermal isolation under extreme conditions. The TiO particle is one of the common industrial additives used to reduce the thermal radiation of aerogel composites under high-temperature environments, but its influence on thermal resistance is almost unknown. Herein, we report the effect of TiO nanoparticles with different crystal phases and different sizes on the thermal stability of silica aerogel composites.

Triple Amplification Strategy of CHA-PER-DNAzyme for Ultrasensitive Detection of circRNA Associated with Hepatocellular Carcinoma.

Biological and clinical studies have indicated that aberrant expression of circMTO1 served as a crucial biomarker for the diagnosis and prognosis of hepatocellular carcinoma (HCC) patients as well as a potential therapeutic target. However, the detection of circRNAs currently faces challenges such as homologous linear RNA interference and low-expression abundance of certain circRNAs. Therefore, we developed a triple amplification method based on catalytic hairpin assembly (CHA) activation by back-splice junction (BSJ), resulting in CHA products that triggered primer exchange reaction to generate DNAzyme.

Asymmetrically split DNAzyme-based colorimetric and electrochemical dual-modal biosensor for detection of breast cancer exosomal surface proteins.

Exosomal surface proteins are potentially useful for breast cancer diagnosis and awareness of risk. However, some detection techniques involving complex operations and expensive instrumentation are limited to advance to clinical applications. To solve this problem, we develop a dual-modal sensor combining naked-eye detection and electrochemical assay of exosomal surface proteins from breast cancer.

Accelerating Cell-Free Biosensors by Entropy-Driven Assembly of Transcription Templates.

Due to its high efficiency and selectivity, cell-free biosynthesis has found broad utility in the fields of bioproduction, environment monitoring, and disease diagnostics. However, the practical application is limited by its low productivity. Here, we introduce the entropy-driven assembly of transcription templates as dynamic amplifying modules to accelerate the cell-free transcription process.

Heteromultivalent scaffolds fabricated by biomimetic co-assembly of DNA-RNA building blocks for the multi-analysis of miRNAs.

Heteromultivalent scaffolds with different repeated monomers have great potential in biomedicine, but convenient construction strategies for integrating various functional modules to achieve multiple biological functions are still lacking. Here, taking advantage of the heteromultivalent effect of dendritic nucleic acids and the specific biochemical properties of microRNAs (miRNAs), we assembled novel heteromultivalent nucleic acid scaffolds by biomimetic co-assembly of DNA-RNA building blocks. In our approach, two miRNAs were used to initiate and maintain dendritic structures in an interdependent manner; so, the heteromultivalent nanostructure can only form in the presence of both miRNAs.

Long Non-Coding RNA Detection Based on Multi-Probe-Induced Rolling Circle Amplification for Hepatocellular Carcinoma Early Diagnosis.

Long non-coding RNAs (lncRNAs) played vital roles in physiological and pathological conditions. Consistent results from cell experiments, animal experiments, and clinical studies suggested that lncRNA HULC was an oncogenic lncRNA serving as a potential diagnostic and prognostic marker of hepatocellular carcinoma. In this study, we developed a fluorescent biosensor for lncRNA HULC detection based on rolling circle amplification (RCA) induced by multi-primer probes.

Highly Sensitive Aptasensor for Detecting Cancerous Exosomes Based on Clover-like Gold Nanoclusters.

Exosome-based liquid biopsy technologies play an increasingly prominent role in tumor diagnosis. However, the simple and sensitive method for counting exosomes still faces considerable challenges. In this work, the CD63 aptamer-modified DNA tetrahedrons on the gold electrode were used as recognition elements for the specific capture of exosomes.

A functional RNA/DNA circuit for one-pot detection of SARS-CoV-2 RNA.

A simple method is proposed in this work for the detection of SARS-CoV-2 RNA based on a functional RNA/DNA circuit. By ingeniously integrating the nucleic acid circuit technology and CRISPR/cas12a system, this method can achieve femtomolar detection of the target RNA in one step and successfully distinguish COVID-19 positive cases from clinical samples, proving its great potential for clinical application.

Universal and Flexible Signal Transduction Module Based on Overload Triggering Probe Escape for Sensitive Detection of Tau Protein.

Aptamer-based methods have attracted increasing interest due to flexible engineering, but their generality is limited by the heterogeneity of signal transduction mechanisms. Given the fact that nonlinear and large molecules are more likely to make the nanosurface overloaded, we investigated a novel signal transduction process to extend the application of aptasensors. In this work, an aptamer complementary element (ACE) is designed with a primer region to serve as the signal probe, which can fully hybridize with an aptamer and be separated by magnetic beads (MBs).

Highly Sensitive Detection of the Immune Checkpoint PD-L1-Positive Circulating Tumor Cells Based on Steric Hindrance.

Programmed-death ligand 1 (PD-L1), as one of major immune checkpoints, is highly expressed on cancer cells and participates in the immune escape process of tumor cells. The level of PD-L1 in patients is closely related to the efficacy of anti-PD-L1 immunotherapy, and patients with a high level have better response to immunotherapy. Therefore, PD-L1 can be an indicator of patient classification and medication guidance.

A simple and rapid method to assay SARS-CoV-2 RNA based on a primer exchange reaction.

A simple method is proposed in this work for the detection of SARS-CoV-2 RNA based on a primer exchange reaction (PER). By ingeniously integrating the PER cascade and CRISPR/cas12a system, this method can achieve convenient detection of the target RNA in 40 min and distinguish a single-base mutation from the target sequence, demonstrating its superior analytical performance.

Dual aptamer recognition-based G-quadruplex nanowires to selectively analyze cancer-derived exosomes.

Cancer-derived exosomes have emerged as a valuable biomarker for cancer diagnosis and prognosis. However, the heterogeneity of exosomes often leads to low selectivity based on the single recognition method. Given this, we have developed a dual-aptamer recognition strategy based on G-quadruplex nanowires for selective analysis of exosomes.

Biomimetic recognition strategy for efficient capture and release of circulating tumor cells.

Efficient capture and release of circulating tumor cells play an important role in cancer diagnosis, but the limited affinity of monovalent adhesion molecules in existing capture technologies leads to low capture efficiency, and the captured cells are difficult to be separated. Inspired by the phenomenon that the long tentacles of jellyfish contain multiple adhesion domains and can effectively capture moving food, we have constructed a biomimetic recognition strategy to capture and release tumor cells. In details, gold-coated magnetic nanomaterials (Au@FeO NPs) were first prepared and characterized by scanning electron microscopy, UV-vis absorption spectra, and Zeta potential.

Development of a two-in-one integrated assay for the analysis of circRNA-microRNA interactions.

The competitive endogenous RNA hypothesis is a new mechanism of RNA dialogue, in which circRNA-miRNA interaction (cmRRI) is found to be widely involved in the regulation of gene expression in tumors and other diseases. It is urgent but challenging to develop a convenient and efficient method to study the interaction between target circRNA and the candidate miRNAs. In this work, a biosensing method that allows directly analyzing cmRRI has been developed, so as to reveal the RNA dialogue strategy.

Detection of locus-specific -methyladenosine modification based on Ag-assisted ligation and supersandwich signal amplification.

Emerging evidence reveals that the epitranscriptomic mark N6-methyladenosine (m6A) plays vital roles in organisms, including gene regulation and disease progression. However, developing sensitive methods to detect m6A modification, especially the identification of m6A marks at the single-site level, remains a challenge. Therefore, based on target-specific triggered signal amplification, we developed a highly sensitive electrochemical method to detect site-specific m6A modifications in DNA.

Polyvalent Biotinylated Aptamer Scaffold for Rapid and Sensitive Detection of Tau Proteins.

Biomimetic construction of artificial scaffolds has attracted increasing attention. However, the construction methods usually require redundant materials and procedures, which is inconvenient for further application. Herein, inspired by the polyvalent multifunctional structure in nature, we have designed a polyvalent biotinylated aptamer scaffold (PBAS) which can conduct analytical performance with high sensitivity and simplified procedures.

Ascertaining the biochemical function of an essential pectin methylesterase in the gut microbe .

Pectins are a major dietary nutrient source for the human gut microbiota. The prominent gut microbe was recently shown to encode the founding member (BT1017) of a new family of pectin methylesterases essential for the metabolism of the complex pectin rhamnogalacturonan-II (RG-II). However, biochemical and structural knowledge of this family is lacking.

Lighting Up CircRNA Using a Linear DNA Nanostructure.

Accurate analysis of circular RNA (circRNA) is essential for the elucidation of circRNA-mediated signaling pathways and its association with diseases. Here we present a new tool, namely, linear DNA nanostructure (LDN), for efficient assay of circRNA. In this assay, target circRNA initiates cascade displacement reaction between two hairpin probes sequentially assembled along the LDN and finally lights up the whole LDN.

DNA nanoscaffold-based SARS-CoV-2 detection for COVID-19 diagnosis.

COVID-19 pandemic outbreak is the most astounding scene ever experienced in the 21st century. It has been determined to be caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the global pandemic, the lack of efficient rapid and accurate molecular diagnostic testing tools has hindered the public opportunely response to the emerging viral threat.

Identification of a unique 1,4-β-D-glucan glucohydrolase of glycoside hydrolase family 9 from Cytophaga hutchinsonii.

Cytophaga hutchinsonii is an aerobic cellulolytic soil bacterium that rapidly digests crystalline cellulose. The predicted mechanism by which C. hutchinsonii digests cellulose differs from that of other known cellulolytic bacteria and fungi.

Homogenous Electrochemical Method for Ultrasensitive Detection of Tumor Cells Designed by Introduction of Poly(A) Tails onto Cell Membranes.

Rapid and efficient detection of tumor cells is one of the central challenges for modern analytical technology. In this paper, we report a polyadenine (poly(A)) tail-based strategy for ultrasensitive detection of tumor cells in aqueous solution with an electrochemical technique. Specifically, tumor cell-specific EpCAM aptamers without any modification can tightly bind on cell membranes and facilitate the subsequent introduction of multiple poly(A) tails via programmable terminal deoxynucleotidyl transferase (TdT)-mediated elongation.

Transcription Factor Atf1 Regulates Expression of Cellulase and Xylanase Genes during Solid-State Fermentation of Ascomycetes.

Transcriptional regulation of cellulolytic and xylolytic genes in ascomycete fungi is controlled by specific carbon sources in different external environments. Here, comparative transcriptomic analyses of grown on wheat bran (WB), WB plus rice straw (WR), or WB plus Avicel (WA) as the sole carbon source under solid-state fermentation (SSF) revealed that most of the differentially expressed genes (DEGs) were involved in metabolism, specifically, carbohydrate metabolism. Of the DEGs, the basic core carbohydrate-active enzyme-encoding genes which responded to the plant biomass resources were identified in , and their transcriptional levels changed to various extents depending on the different carbon sources.

Characterization of a novel theme C glycoside hydrolase family 9 cellulase and its CBM-chimeric enzymes.

In bacterial cellulase systems, glycoside hydrolase family 9 (GH9) cellulases are generally regarded as the major cellulose-degrading factors besides GH48 exoglucanase. In this study, umcel9A, which was cloned from uncultured microorganisms from compost, with the encoded protein being theme C GH9 cellulase, was heterologously expressed in Escherichia coli, and the biochemical properties of the purified enzyme were characterized. Hydrolysis of carboxylmethylcellulose (CMC) by Umcel9A led to the decreased viscosity of CMC solution and production of reducing sugars.

Cellulase with high β-glucosidase activity by Penicillium oxalicum under solid state fermentation and its use in hydrolysis of cassava residue.

In this study, we investigated cellulase production by Penicillium oxalicum EU2106 under solid-state fermentation (SSF) and its hydrolysis efficiency toward NaOH-HO-pretreated cassava residue (NHCR) produced after bioethanol fermentation. Optimization of SSF cultivation conditions for P. oxalicum EU2106 using a Box-behnken design-based response-surface methodology resulted in maximal cellulase activity of 34.