Graphdiyne (GDY), a novel one‐atom‐thick carbon allotrope that features assembled layers of sp‐ and sp2‐hybridized carbon atoms, has attracted great interest from both science and industry due to its ...unique and fascinating structural, physical, and chemical properties. GDY‐based materials with different morphologies, such as nanowires, nanotube arrays, nanosheets, and ordered stripe arrays, have been applied in various areas such as catalysis, solar cells, energy storage, and optoelectronic devices. After an introduction to the fundamental properties of GDY, recent advances in the fabrication of GDY‐based nanostructures and their applications, and corresponding mechanisms, are covered, and future critical perspectives are also discussed.
Recent progress on graphdiyne, with its fascinating structure and physical and chemical properties, is summarized. Research efforts toward controllable electronic structure, chemical modification, and applications of graphdiyne in different research fields and corresponding mechanisms are discussed, and critical research insights into the future development of graphdiyne materials are proposed and presented.
New tools for single‐cell interrogation enable deeper understanding of cellular heterogeneity and associated cellular behaviors and functions. Information of RNA expression in single cell could ...contribute to our knowledge of the genetic regulatory circuits and molecular mechanism of disease development. Although significant progresses have been made for intracellular RNA analysis, existing methods have a trade‐off between operational complexity and practical feasibility. We address this challenge by combining the ionic current rectification property of nanopipette reactor with duplex‐specific nuclease‐assisted hybridization chain reaction for signal amplification to realize a simple and practical intracellular nanosensor with minimal invasiveness, which enables single‐cell collection and electrochemical detection of intracellular RNA with cell‐context preservation. Systematic studies on differentiation of oncogenic miR‐10b expression levels in non‐malignant breast cells, metastatic breast cancer cells as well as non‐metastatic breast cancer cells were then realized by this nanotool accompanied by assessment of different drugs effects. This work has unveiled the ability of electrochemistry to probe intracellular RNA and opened new opportunities to study the gene expression and heterogeneous complexity under physiological conditions down to single‐cell level.
A DSN‐assisted ICR‐nanopipette was fabricated for tracking the drug‐induced variation of the oncogenic miR‐10b expression levels of a dynamic manner. This method unveils the ability of electrochemistry to probe intracellular RNA and to study the gene expression and heterogeneous complexity under physiological conditions down to single‐cell level.
The nucleus accumbens (NAc) plays an important role in regulating multiple behaviors, and its dysfunction has been linked to many neural disorders. However, the molecular, cellular and anatomic ...heterogeneity underlying its functional diversity remains incompletely understood. In this study, we generated a cell census of the mouse NAc using single-cell RNA sequencing and multiplexed error-robust fluorescence in situ hybridization, revealing a high level of cell heterogeneity in this brain region. Here we show that the transcriptional and spatial diversity of neuron subtypes underlie the NAc's anatomic and functional heterogeneity. These findings explain how the seemingly simple neuronal composition of the NAc achieves its highly heterogenous structure and diverse functions. Collectively, our study generates a spatially resolved cell taxonomy for understanding the structure and function of the NAc, which demonstrates the importance of combining molecular and spatial information in revealing the fundamental features of the nervous system.
We tested the hypothesis that de novo copy number variation (CNV) is associated with autism spectrum disorders (ASDs). We performed comparative genomic hybridization (CGH) on the genomic DNA of ...patients and unaffected subjects to detect copy number variants not present in their respective parents. Candidate genomic regions were validated by higher-resolution CGH, paternity testing, cytogenetics, fluorescence in situ hybridization, and microsatellite genotyping. Confirmed de novo CNVs were significantly associated with autism (P = 0.0005). Such CNVs were identified in 12 out of 118 (10%) of patients with sporadic autism, in 2 out of 77 (3%) of patients with an affected first-degree relative, and in 2 out of 196 (1%) of controls. Most de novo CNVs were smaller than microscopic resolution. Affected genomic regions were highly heterogeneous and included mutations of single genes. These findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.
This study reported on a novel sandwich enzyme linked immunosorbent assay (ELISA) for the sensitive determination of Escherichia coli O157:H7 (E. coli O157:H7) by using DNA-based hybridization chain ...reaction (HCR) and biotin–streptavidin signal amplification. The anti-E. coli O157:H7 polyclonal antibody (pAb) was immobilized in the ELISA wells. The anti-E. coli O157:H7 monoclonal antibody (mAb) and initiator strand (DNA1) were labeled on gold nanoparticle (AuNP) to form a mAb–AuNP–DNA1 complex. In the presence of the target E. coli O157:H7, the sandwiched immunocomplex, which is pAb–E. coli O157:H7–mAb–AuNP–DNA1, could be formed. Two types of biotinylated hairpin were subsequently added in the ELISA well. A nicked double-stranded DNA (dsDNA) that contained abundant biotins was formed after HCR. Detection was performed after adding horseradish peroxidase–streptavidin and substrate/chromogen solution. Under optimal conditions, E. coli O157:H7 could be detected in the range of 5×102 CFU/mL to 1×107 CFU/mL; the limit of detection was 1.08×102 CFU/mL in pure culture. The LOD of the novel ELISA was 185 times lower than that of traditional ELISA. The proposed method is considerably specific and can be applied in the detection of whole milk samples inoculated with E. coli O157:H7. The coefficient of variation of in pure culture and in whole milk was 0.99–5.88% and 0.76–5.38%, respectively. This method offers a promising application in the detection of low concentrations of food-borne pathogens.
•A novel ELISA for the sensitive detection of E. coli O157:H7 using DNA-based HCR.•Biotin was formed after HCR and fixed HRP–streptavidin for higher detection signal.•The LOD of the novel method was 185-fold sensitive than that of traditional ELISA.•The method is specific and can be applied in the detection of milk samples.
We present a protocol for measuring the absolute number of mRNA molecules from a gene of interest in individual, chemically fixed Escherichia coli cells. A set of fluorescently labeled ...oligonucleotide probes is hybridized to the target mRNA, such that each mRNA molecule is decorated by a known number of fluorescent dyes. Cells are then imaged using fluorescence microscopy. The copy number of the target mRNA is estimated from the total intensity of fluorescent foci in the cell, rather than from counting discrete 'spots' as in other currently available protocols. Image analysis is performed using an automated algorithm. The measured mRNA copy number distribution obtained from many individual cells can be used to extract the parameters of stochastic gene activity, namely the frequency and size of transcription bursts from the gene of interest. The experimental procedure takes 2 d, with another 2-3 d typically required for image and data analysis.
DNA hydrogels hold great potential for biological and biomedical applications owing to their programmable nature and macroscopic sizes. However, most previous studies involve spontaneous and ...homogenous gelation procedures in solution, which often lack precise control. A clamped hybridization chain reaction (C‐HCR)‐based strategy has been developed to guide DNA self‐assembly to form macroscopic hydrogels. Analogous to catalysts in chemical synthesis or seeds in crystal growth, we introduced DNA initiators to induce the gelation process, including crosslinked self‐assembly and clamped hybridization in three dimensions with spatial and temporal control. The formed hydrogels show superior mechanical properties. The use of printed, surface‐confined DNA initiators was also demonstrated for fabricating 2D hydrogel patterns without relying on external confinements. This simple method can be used to construct DNA hydrogels with defined geometry, composition, and order for various bioapplications.
A clamped hybridization chain reaction (C‐HCR)‐based strategy is developed to guide DNA self‐assembly to form macroscopic hydrogels. H1, H2=DNA hairpin strands, I=initiator strand.
Genomic evidence supports an important role for selection in shaping patterns of introgression along the genome, but frameworks for understanding the evolutionary dynamics within hybrid populations ...that underlie these patterns have been lacking. Due to the clock-like effect of recombination in hybrids breaking up parental haplotypes, drift and selection produce predictable patterns of ancestry variation at varying spatial genomic scales through time. Here, we develop methods based on the Discrete Wavelet Transform to study the genomic scale of local ancestry variation and its association with recombination rates and show that these methods capture temporal dynamics of drift and genome-wide selection after hybridization. We apply these methods to published datasets from hybrid populations of swordtail fish (
) and baboons (
) and to inferred Neanderthal introgression in modern humans. Across systems, upward of 20% of variation in local ancestry at the broadest genomic scales can be attributed to systematic selection against introgressed alleles, consistent with strong selection acting on early-generation hybrids. Signatures of selection at fine genomic scales suggest selection over longer time scales; however, we suggest that our ability to confidently infer selection at fine scales is likely limited by inherent biases in current methods for estimating local ancestry from contiguous segments of genomic similarity. Wavelet approaches will become widely applicable as genomic data from systems with introgression become increasingly available and can help shed light on generalities of the genomic consequences of interspecific hybridization.
- The analysis of somatic mutations across multiple genes in cancer specimens may be used to aid clinical decision making. The analytical validation of targeted next-generation sequencing panels is ...important to assess accuracy and limitations.
- To report the development and validation of OncoPanel, a custom targeted next-generation sequencing assay for cancer.
- OncoPanel was designed for the detection of single-nucleotide variants, insertions and deletions, copy number alterations, and structural variants across 282 genes with evidence as drivers of cancer biology. We implemented a validation strategy using formalin-fixed, paraffin-embedded, fresh or frozen samples compared with results obtained by clinically validated orthogonal technologies.
- OncoPanel achieved 98% sensitivity and 100% specificity for the detection of single-nucleotide variants, and 84% sensitivity and 100% specificity for the detection of insertions and deletions compared with single-gene assays and mass spectrometry-based genotyping. Copy number detection achieved 86% sensitivity and 98% specificity compared with array comparative genomic hybridization. The sensitivity of structural variant detection was 74% compared with karyotype, fluorescence in situ hybridization, and polymerase chain reaction. Sensitivity was affected by inconsistency in the detection of FLT3 and NPM1 alterations and IGH rearrangements due to design limitations. Limit of detection studies demonstrated 98.4% concordance across triplicate runs for variants with allele fraction greater than 0.1 and at least 50× coverage.
- The analytical validation of OncoPanel demonstrates the ability of targeted next-generation sequencing to detect multiple types of genetic alterations across a panel of genes implicated in cancer biology.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
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