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A novel photosensitive dual-sensor for simultaneous detection of nucleic acids and small chemical molecules
摘要： Sensors that can rapidly and specifically detect nucleic acids and chemical molecules can revolutionize the diagnosis and treatment of diseases by allowing molecular-level informations to be used during the routine medicines. In this study, we demonstrated a novel dual-sensor that can be used to simultaneously detect any nucleic acids and chemical molecules whose binding aptamers can be found or synthesized. In the developed dual-sensor, the specifically designed PTG (a photosensitive azobenzene derivative carrying one photo-isomerizable azobenzene moiety, one threoninol terminal and one guanidinium terminal) molecules are introduced into the unwinding region of two T7 promoters, and two DNA bubbles are introduced upstream of the two T7 promoters. Without the target, the indicating gene in the dual-tensor would not be expressed since the binding with RNAPs (RNA polymerases) cannot melt the T7 promoter for the indicating gene due to the integration of the DNA double strands via the PTG molecules, manifesting the absence of the target nucleic acid and chemical molecule. While with the presence of the target nucleic acid and/or chemical molecule, the indicating gene would be expressed as the T7 promoter contained in the enlarged DNA bubble can be melted and transcribed by the bound RNAPs as the enlarged DNA bubble can help the separation of the two DNA strands, demonstrating the existence of target nucleic acid and/or chemical molecule.
关键词： Nucleic acids,DNA melting,Gene expression,DNA nanotechnology,Dual-sensor
更新于2025-09-23 15:23:52
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Electrochemiluminescent functional nucleic acids-based sensors for food analysis
摘要： Foodborne contaminants widely exist in foods, which can lead to various foodborne diseases and food safety issues. The development of quick, sensitive and universal analytical approaches for foodborne contaminants is imperative. Electrochemiluminescent functional nucleic acids (ECL FNAs)-based sensors are a series of sensing devices using FNAs as the recognition elements and ECL as the transducer. Contributing to the specific recognition ability of FNA and the high sensitivity of ECL, ECL FNA-based sensors are considered to be of great application potential for foodborne contaminants monitoring. This review mainly presents the applications of ECL FNA-based sensors for foodborne contaminants (including microorganisms, mycotoxins, allergens, antibiotics, heavy metal ions, pesticides and some illegal additives). In general, the application of ECL FNA-based sensors in the field of food analysis is just in its infancy. Although there are several limitations and challenges, it is envisaged that ECL FNA-based sensors will have broad prospects for food analysis in the future.
关键词： foodborne contaminants,functional nucleic acids (FNAs),electrochemiluminescent (ECL),sensor
更新于2025-09-19 17:15:36
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Automated nanoplasmonic analysis of spherical nucleic acids clusters in single cells
摘要： Spherical nucleic acids (SNAs) have been extensively used in the field of biosensing, drug delivery and theranostics. Precise engineering of SNAs and their clinical application require better understanding of their cellular internalization process. We demonstrate a colorimetry-based algorithm (CBA) that can analyze the aggregation states of SNAs clusters based on the changes of plasmonic colors of SNAs. The dark field microscopy (DFM) images of cytoplasmic region of single cells are imported as raw data. All the image spots are analyzed in the interference reduction process, and the clustering states of target image spots are assigned based on the distribution of coordinates of all the pixels in the CIE map. This method provides faster analysis on clustering states of extracellular and intracellular SNAs with good accuracy. Moreover, the clustering states of SNAs in 20 single cells (generally more than 1000) can be efficiently distinguished within 200 seconds. Therefore, our method provides an automatic, quantitative, objective and repeatable way to analyze SNAs aggregations, and shows good application potential in robust and quantitative nanoplasmonic analysis in single cells.
关键词： Single-cell analysis,Plasmonic analysis,Single-particle analysis,Spherical nucleic acids,Clustering states
更新于2025-09-12 10:27:22
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Quantum dot nanoconjugates for immuno-detection of circulating cell-free miRNAs
摘要： Argonaute protein (AGO2) bound circulating cell-free miRNAs (ccf-miRs), in the recent years, has attracted great attention due to their differential abundance in biological fluids. In the present work, a selective and technically uncomplicated quantum dot (QD) nanoconjugate has been fabricated combining the specific affinity of the antibody and fluorescent property of QDs for the precise immuno-detection of AGO2-bound ccf-miRs in plasma samples. The electrophoretic mobility assay confirmed the conjugation of antibody with QDs. The detection methodology involves a highly specific antigen-antibody reaction between the AGO2 proteins of miRNA-induced silencing complex and the anti-AGO2 antibody conjugated with QDs. The recognition efficiency of QD-Ab nanoconjugates was analysed using flow cytometry and fluorometry.The flow cytometry results demonstrated a significant change in the fluorescence intensity of the prepared nanoconjugates upon capture of ccf-miRs in the plasma samples with respect to the samples devoid of any miRNAs. Fluorometry measurements exhibited corroboration with the flow cytometry results indicating the selectivity and reproducibility of the developed method. Current research highlights the translational significance of the methodology as a novel flow cytometry based immunoassay for detection of differentially expressed AGO2-bound miRNAs in clinical and field settings.
关键词： Immunosensor,Circulating nucleic acids,Translational research,Point-of-care assay
更新于2025-09-11 14:15:04
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Comprehensive Supramolecular Chemistry II || Fluorescence Sensing With Functional Nucleic Acids
摘要： A few years after the ground-breaking discovery that RNA can function as enzymes, a powerful technique was devised that enabled researchers to search through large random-sequence DNA and RNA pools for “functional nucleic acids (FNAs)” with tailor-made ability to recognize a target of interest or to catalyze a chosen chemical reaction. This technique is now widely known as “in vitro selection” or “SELEX” (which stands for “Systematic Evolution of Ligands by EXponential enrichment”). Such experiments always start with an extraordinarily large pool containing up to 1016 different DNA or RNA sequences. A small number of the sequences in the pool are separated based on their ability to perform the targeted binding or catalytic function. The isolated sequences are multiplied using nucleic acid amplification techniques. The resulting pool, now much more abundant with functional species, is then used to restart the same cycle. Iterating this process for many rounds leads to the enrichment of a few species that are proficient at performing the desired activity.
关键词： Functional nucleic acids,biosensing,SELEX,fluorescence sensing,in vitro selection
更新于2025-09-10 09:29:36
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Aptamers Improving Fluorescence Anisotropy and Fluorescence Polarization Assays for Small Molecules
摘要： Nucleic acid affinity probes, such as aptamers, have been combined with fluorescence anisotropy (FA) / fluorescence polarization (FP) technology for the development of a diverse range of assays. Formation of a complex between a small fluorescent molecule and its binding partner usually increases the overall size of the fluorescent molecule and decreases its rate of rotation, resulting in increases in fluorescence anisotropy/polarization. Structure-switching of the fluorescently labeled aptamers arising from target binding can also affect molecular volume, local rotation of the fluorophore, and/or fluorescence lifetime, causing changes in anisotropy/polarization. Incorporation of the unique adsorptive properties of single-stranded nucleic acid aptamers on nanomaterials, hybridization of aptamers with complementary sequences, and the amplifiable ability of nucleic acid aptamers have broadened the applications of fluorescence anisotropy assays and enhanced their sensitivity. This review focuses on aptamer-based fluorescence anisotropy assays for the detection of small molecules, such as therapeutic drugs, environmental contaminants, natural toxins, and metabolites.
关键词： aptamer,adenosine triphosphate (ATP),nanomaterials,anisotropy,cocaine,nucleic acids,toxins,DNAzyme,polarization,aflatoxin B1,ochratoxin A (OTA),tyrosinamide
更新于2025-09-10 09:29:36
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Reconfigurable Bioinspired Framework Nucleic Acid Nanoplatform Dynamically Manipulated in Living Cells for Subcellular Imaging
摘要： In nature, the formation of spider silk fibers begins with dimerizing the pH-sensitive N-terminal domains of silk proteins (spidroins) upon lowering pH, which provides a natural masterpiece for programmable assembly. Inspired by the similarity of pH-dependent dimerization behaviors, here we introduce an i-motif-guided model to mimic the initial step of spidroin assembly at the subcellular level. A framework nucleic acid (FNA) nanoplatform is designed using two tetrahedral DNA nanostructures (TDNs) with different branched vertexes carrying a bimolecular i-motif and a split ATP aptamer. Once TDNs enter acidic lysosomes within living cells, they assemble into a hetero-dimeric architecture thereby enabling the formation of a larger-size framework and meanwhile subcellular imaging in response to endogenous ATP, which can be dynamically manipulated via adjusting intracellular pH and ATP level with external drug stimuli.
关键词： silk-mimicking,supermolecular assembly,bioinspired,DNA nanostructures,framework nucleic acids
更新于2025-09-09 09:28:46