Search Results (661)

The development of highly sensitive and reliable strategies for microcystin-LR (MC-LR) monitoring remains critical for environmental safety and public health protection. Herein, we report a metallene-enabled electrochemiluminescence (ECL) biosensing platform based on ultrathin PdMoCu trimetallic metallenes for femtogram-level MC-LR detection. The two-dimensional PdMoCu metallenes provide abundant active sites and accelerated interfacial charge-transfer kinetics through synergistic electronic modulation among Pd, Mo, and Cu atoms, significantly enhancing the Ru(bpy)₃²⁺/TPrA ECL efficiency. By integrating a programmable H1–aptamer duplex interface, electrostatic enrichment of Ru(bpy)₃²⁺ was achieved, enabling target-responsive luminophore release via aptamer-triggered structural switching. This cooperative amplification mechanism, combining catalytic acceleration and DNA-mediated signal modulation, results in a sensitive signal-off detection mode. Under optimized conditions, the biosensor exhibited a wide linear response from 0.1 pg mL⁻¹ to 50 ng mL⁻¹ with a detection limit as low as 37 fg mL⁻¹. The platform demonstrated excellent selectivity against structural analogues, high reproducibility, and satisfactory recovery (99.3–102.0%) in real tap water samples. This work not only highlights the catalytic potential of trimetallic metallenes in ECL systems but also establishes a generalizable interfacial engineering strategy for ultrasensitive detection of trace environmental contaminants. Full article

The plague, caused by Yersinia pestis, has resulted in significant mortality over the past century. Despite advances in antimicrobial therapy, plague remains a re-emerging infectious disease with ongoing outbreaks and increasing concerns regarding antimicrobial resistance. Today, plague cases are still being reported, and the loss of effectiveness of treatment methods remains a major challenge. Therefore, effective treatment strategies are needed. In this study, we aimed to develop aptamers specific to Yersinia outer protein M (YopM), a key immunosuppressive protein that is essential for virulence. Our goal was to develop an aptamer that binds to YopM and inhibits its interaction with the human DEAD-box helicase 3 (DDX3) protein. YopM-DDX3 protein interaction was targeted because of its key role in nucleocytoplasmic shuttling of YopM. To achieve this, we developed the YopM16 aptamer using magnetic bead-based (Systematic Evolution of Ligands by Exponential Enrichment) (SELEX). The selected YopM16 aptamer exhibited a half-maximal inhibitory concentration(IC₅₀) value of 103.3 ± 2 nM and effectively inhibited the interaction between YopM and DDX3. The inhibitory effect of the aptamer on protein interaction was confirmed using a pull-down assay and colorimetric test. Given that protein–protein interaction surfaces are considered undruggable, YopM16 is a promising inhibitor with the potential to serve as a molecular tool to investigate the virulence mechanism of YopM, as well as a novel antibacterial agent upon validation of its inhibition in cellular models. Full article

Cancer therapy is increasingly shaped by the need for agents that are both mechanistically precise and clinically tolerable. Sulforaphane (SFN), a dietary isothiocyanate enriched in cabbage-family vegetables such as cauliflower and Brussels sprouts, has emerged as a pleiotropic modulator of tumor biology. This review synthesizes current evidence that SFN regulates diverse cancer-relevant processes, including redox homeostasis, cell-cycle progression, apoptosis, autophagy and epigenetic remodeling, largely through coordinated effects on transcriptional (for example, Nrf2, MAPK, NF-κB and AP-1), post-transcriptional (microRNAs and messenger RNAs) and epigenetic (DNA methyltransferases and histone deacetylases) networks. We then examine how functional nucleic acids, including aptamers, small interfering RNAs, microRNAs and tetrahedral DNA nanostructures, can be engineered to guide SFN to tumor cells, amplify pathway-specific effects and overcome resistance. Particular emphasis is placed on nanotechnology-enabled delivery platforms that enhance SFN stability, bioavailability and tumor selectivity. Finally, we outline key challenges, such as context-dependent Nrf2 activity, inter-individual variability in metabolism and incomplete clinical validation, and propose priorities for translating SFN-based functional nucleic acid systems into rational, combination-ready strategies for precision oncology. Full article

We performed a protein-docking study for eight DNA aptamers (SEQ1–SEQ8) against chicken Cluster of Differentiation 40 (chCD40), which were experimentally identified via SELEX in our previous study. In silico and molecular docking analyses were performed to predict and obtain the secondary and tertiary structures of the aptamers. Aptamers SEQ3 and SEQ4, which showed the best inhibitory effects, were selected and utilized to produce a DNA-based vaccine adjuvant using rolling circle amplification (RCA). These aptamers had been previously characterized via mass spectroscopy to determine their molecular weight and regions that could potentially interact with chCD40. In the present study, these results were corroborated and expanded. A series of free software methods, including Mfold v.1.0, 3dADN v.2.0, ClusPro v.2.0, Hdock v.1.0, and PLIP v.1.0, were used to determine the aptamers’ secondary and tertiary structures and docking interactions, as well as the specific residues involved in the interactions and their distances. The structures were used to explain and thus understand their effect on the binding, selectivity, and stability of the aptamers. The main objective of the study was to determine whether these aptamers could be used as vaccine adjuvants against viral and bacterial pathogens, specifically chicken avian influenza. The docking results were in good agreement with the experimental and biological results. The procedure employed in this study could be an easy and effective tool for exploring the potential of the new technology of systematic evolution of ligands by exponential enrichment (SELEX) in the preparation of aptamers to control viral and bacterial infections as well as diseases, such as cancer and Alzheimer’s. Full article

Mercury ions (Hg²⁺), a heavy metal contaminant of strong biotoxicity, pose a serious threat to ecosystems and human health in aquatic environments. Developing highly sensitive and specific detection methods is therefore of great importance. This study presents a novel label-free fluorescent biosensor for Hg²⁺ by ingeniously coupling target-induced aptamer switching with rolling circle amplification (RCA). Upon Hg²⁺ binding, the conformational change releases a sequestered primer to initiate RCA, generating G-quadruplex-rich DNA products that produce a strong “turn-on” signal with N-methylmesoporphyrin IX (NMM). Under optimized conditions, the assay exhibits excellent linearity from 10 to 1000 nM with a detection limit of 3.2 nM, along with high selectivity over competing metal ions. Validation using spiked environmental water samples yielded accurate and reproducible recoveries in the range of 93.8% to 106.0%. With its operational simplicity, high sensitivity, and robust performance in complex matrices, this label-free strategy offers a reliable and promising platform for detecting Hg²⁺ in environmental waters. Full article

Heavy metal mercury is one of the most significant and toxic environmental contaminants. Its inorganic form (Hg²⁺) and organic form (organic mercury, OrHg) can cause irreversible harm to human health and the ecological environment, and the latter is particularly prone to bioaccumulation and bioamplification in the food chain. Therefore, there is an urgent need for a rapid, reliable and specific detection of Hg²⁺ and OrHg to evaluate the potential risk for human health. Here, a novel label-free fluorescent sensing platform based on ssDNA aptamer (A_A-T7)-templated AuNCs was established for sensitive recognition and specific detection of Hg²⁺ and OrHg. In the presence of OrHg, the fluorescence of pure A_A-T7-templated AuNCs was visibly enhanced through forming Ag/AuNCs based on Ag⁰-doped AIEE effect. However, they were obviously quenched because of generating non-fluorescent Au/Ag/Hg ANPs via metallophilic interactions among Au³⁺, Ag⁺, and Hg²⁺ (5d¹⁰-4d¹⁰-5d¹⁰) when only Hg²⁺ existed. This fluorescent sensing platform could detect as low as 20.0 nM (4.0 ng Hg/g) and has a good linear detection range, with target concentrations ranging from 0.25 μM to 2.00 μM, recoveries of 98.0–108.0%, and RSD ≤ 5.0%. Low-toxic A_A-T7-templated AuNCs could be used for cytotoxicity analysis and intracellular fluorescent imaging. The method has been successfully applied to the determination of Hg²⁺ and OrHg in tap water, seawater and dried golden pomfret fish muscle samples, demonstrating promising prospects for the assay of mercury species in environmental samples and aquatic products to ensure human health and food safety. Full article

Salmonella enteritidis (SE) is recognized as a primary etiological agent of foodborne infection and food poisoning. Selective and sensitive determination of SE in animal-derived products is of great importance for ensuring safety in the food industry. Here, we report a highly sensitive and specific competition assay for detecting SE in eggs without interference from background fluorescence, by using persistent luminescent nanoparticles (PLNPs) as luminescent probes in combination with aptamer recognition and magnetic separation. Initially, the SE-specific aptamer (SEapt), as previously reported, was conjugated onto the surface of Fe₃O₄ magnetic nanoparticles to serve as both the recognition and separation unit. Meanwhile, the ZnGa₂O₄:Cr (PLNPs) were functionalized with the aptamer-complementary DNA (cDNA), serving as the PL signal generator. The constructed PL aptasensor is composed of the aptamer-conjugated MNPs (MNPs-SEapt) and cDNA-functionalized PLNPs (PLNPs-cDNA), integrating the merits of the long-lasting luminescence of PLNPs, the magnetic separation ability of MNPs and the selectivity of the aptamer. This integration offers a promising approach for autofluorescence-free determination of SE in food samples. The proposed aptasensor exhibited excellent linearity in the range from 1.0 × 10²–1.0 × 10⁷ CFU mL⁻¹ with a limit of detection as low as 32 CFU mL⁻¹. The precision for 11 replicate determinations of 1.0 × 10³ CFU mL⁻¹ SE was 3.4% (relative standard deviation). The developed aptasensor achieved recoveries ranging from 98.8% to 102.8% for the determination of SE in the presence of common foodborne bacterial interferents. The method was successfully applied to the analysis of Salmonella genus in egg samples. In principle, the proposed platform may be adapted to other food matrices by substituting the target-specific aptamer, pending target-dependent optimization and validation. Full article

Bone defects remain a significant challenge in bone tissue engineering, driving an urgent need for advanced materials with enhanced therapeutic properties. Additive manufacturing highlights a unique capacity for customization, which enables the precise realization of complex and personalized composite scaffolds. This study innovatively integrates the superior mechanical properties of polycaprolactone (PCL) with the antibacterial characteristics of S53P4 bioactive glass. Utilizing thermal melt extrusion processing and fused deposition modeling (FDM) technology, we fabricated gradient-structured S53P4@PCL composite three-dimensional porous scaffolds with varying doping ratios (5 wt%, 10 wt%, 20 wt%). To further improve the antibacterial efficacy of the scaffold, exosomes (EXO) derived from grouper eggs were functionalized with bacteria-targeting aptamers (APTs), a type of functional DNA capable of binding to bacterial peptidoglycan, and EXO-APT-20%S53P4@PCL was fabricated. The resulting EXO-APT-20%S53P4@PCL scaffold was able to facilitate the targeted capture and subsequent eradication of bacteria. This study pioneers the synergistic integration of aptamer-modified exosomes into 3D composite scaffolds. Our analysis confirmed that the incorporation of APTs enabled targeted bacterial capture, and antibacterial EXO further enhanced the overall bacterial killing capability of the S53P4@PCL scaffolds. The fabrication of porous S53P4@PCL scaffolds through an innovative composite-molding strategy, combined with EXO-APT functionalization, establishes a new paradigm for customized bone repair. Full article

Background: Gene expression and cellular identity are regulated by epigenetics that occurs through chromatin modifications, RNA changes, chromatin accessibility, and three-dimensional genome organization. Although DNA methylation has been the focus of most epigenetics studies in the past, other non-methyl epigenetic processes, including histone post-translational modifications (PTMs), epitranscriptomic marks, and chromatin remodeling, are dynamic, reversible, and context-dependent, and thus are difficult to accurately interrogate using endpoint sequencing-based assays, especially in heterogeneous tissues, developing systems, and therapeutic response environments. Scope and Approach: The present review discusses epigenetic modifications other than DNA methylation regarding sensor-based technologies that can measure live, dynamic, and spatially resolved measurements. Epigenetic sensors include any genetically encoded sensors (GECs) based on resonance energy transfer, CRISPR/dCas-derived sensors, or aptamer-based sensors, and hybrid biochemical/imaging sensors that can be used in live or semi-live settings. It lays emphasis on the technologies, which have been developed recently, that allow real-time kinetic measurements, working in three-dimensional and organoid models, and being applied to disease-relevant perturbations. On these platforms, performance properties such as specificity, sensitivity, spatial and temporal resolution, ability to perform dynamic versus locus-specific interrogation, and perturbed endogenous chromatin states are compared. Key Conclusions and Outlook: Together, these sensing strategies are complementary to the traditional methods of measuring epigenomics in that they show epigenetic dynamics unobservable with static measurements. We list the important technical issues, including specificity, quantitation, multiplexing, and chromatin perturbation, and report the barriers and solutions in development and design. Lastly, we provide a conceptual map of how live epigenetic sensing and multi-omics and translational models can be integrated, and how the two methodologies can be used to develop functional epigenetics and guide disease modeling and drug development. Full article

Ochratoxin A (OTA) is a highly toxic mycotoxin commonly detected in food and agricultural products, requiring sensitive analytical methods for reliable monitoring. Herein, we report an ultrasensitive turn-on electrochemical aptasensor for OTA detection based on a target-induced displacement of an aptamer–complementary DNA (cDNA) duplex assembled on an electrochemically reduced graphene oxide (ERGO)-modified glassy carbon electrode (GCE). In the absence of OTA, a methylene blue (MB)-labeled aptamer hybridized with cDNA is immobilized on the ERGO surface via π–π stacking interactions, forming a rigid duplex that suppresses electron transfer and yields a low electrochemical signal. Upon OTA binding, the aptamer undergoes a conformational transition into a G-quadruplex structure, leading to dissociation of the cDNA strand. This target-induced folding brings the MB redox tag into close proximity to the ERGO surface, markedly accelerating electron transfer and enhancing the cathodic reduction current of MB, thereby producing a pronounced signal-on response in square-wave voltammetry (SWV). The ERGO-modified electrode provides a conductive and stable interface without chemical linkers. Under optimized conditions, the aptasensor shows a linear response to OTA from 10 fM to 100 pM with an ultralow LOD of 0.67 fM, together with high selectivity, good reproducibility, and satisfactory stability. This work demonstrates a simple and effective turn-on aptasensing strategy for sensitive electrochemical detection of OTA. Full article

Aptamers, short single-stranded DNA or RNA oligonucleotides, are emerging as transformative tools in cardiology for the diagnosis, treatment, and theranostics of cardiovascular diseases (CVDs). This review highlights their dual utility. In diagnostics, aptamers enable the construction of highly sensitive biosensors for key cardiac biomarkers (e.g., troponins, myoglobin, C-reactive protein, natriuretic peptides), outperforming conventional assays and enabling early detection and point-of-care testing. Therapeutically, aptamers offer targeted, controllable, and reversible anticoagulation, as demonstrated by clinical-stage candidates like BT200 (anti-vWF) and NU172 (anti-thrombin), whose action can be rapidly reversed with antidote oligonucleotides. Furthermore, aptamers serve as precision delivery vehicles (e.g., Gint4.T, RNA-Apt30) for transporting therapeutic peptides or nucleic acids specifically to cardiomyocytes. Recent integration with nanomaterials (quantum dots, graphene, liposomes, DNA origami) has led to advanced biosensing and drug delivery platforms. Despite challenges like stability and the polyethylene glycol (PEG) immunogenicity, ongoing clinical trials underscore the significant potential of aptamer technology to bridge precise diagnostics and targeted therapy, paving the way for innovative, personalized CVD interventions.) Full article

Background/Objectives: Leishmaniasis is a disease affecting millions of people caused by parasites of the genus Leishmania. The GP63 protein of Leishmania infantum (LiGP63) is one of its major surface antigens and a main virulence factor, playing a role in the adhesion of extracellular promastigote stages to macrophages and in the survival of intracellular amastigotes. Methods: Here, DNA aptamers have been developed against LiGP63 through the systematic evolution of ligands by exponential enrichment. Results: Twenty individual aptamer sequences were characterized using confocal fluorescence microscopy and flow cytometry analysis, and 14 of them had targeting to more than 70% of L. infantum promastigotes with different subcellular localization patterns. Subsequent dot blot analyses narrowed down the selection to five candidates for further characterization through an aptamer-linked immobilized sorbent assay where it was possible to detect endogenous LiGP63 in L. infantum promastigote lysates. The five selected aptamers recognized the recombinant LiGP63 protein with binding affinities ranging from 0.3 to 2.1 µM. Promastigotes preincubated with LiGP63Apt-4, -27 and -28 exhibited a significantly reduced adhesion to and infection of RAW 264.7 macrophages. Moreover, when LiGP63Apt-4 and -28 were conjugated to liposomes, these two aptamers significantly enhanced the targeting to L. infantum promastigotes compared to plain liposomes. Conclusions: Given their improved stability and cost-effectiveness over antibodies, the aptamers evolved here represent promising candidates for new therapeutic and diagnostic approaches and for future nanoparticle-based drug delivery strategies in leishmaniasis. Full article

Background: This study aimed to develop a superior aptamer-based therapeutic for targeted glioblastoma intervention by conducting a comparative analysis of two DNA aptamers: the original U2 sequence, selected against glioblastoma cells exhibiting high EGFRvIII expression, and its modified, shortened, and stabilized variant, Gol1. Methods: The effects of the investigated aptamers on primary human glioblastoma cells with graded receptor expression levels and on a rat 101/8 glioblastoma tissue model were rigorously studied. Results: The results demonstrated the significant superiority of the stabilized Gol1 aptamer, which exhibited exceptional binding affinity for the EGFRvIII receptor. Pronounced antiproliferative and antimigratory effects against EGFRvIII-positive human tumor cells, ultimately inducing complete cell death. Transcriptomic analysis revealed a sophisticated dual mechanism of action for Gol1: the specific activation of neuronal differentiation genes concurrent with the suppression of key alternative splicing factors. Crucially, in vivo confirmation showed highly selective accumulation of the FAM-labeled Gol1 aptamer exclusively within tumor tissue, with a maximum concentration gradient observed in the invasive border zone and a complete absence of accumulation in intact brain parenchyma. Conclusions: These comprehensive findings confirm that the Gol1 aptamer constitutes a highly promising and versatile platform for developing novel targeted theranostic strategies against glioblastoma, offering a precise approach for both diagnostic imaging and therapeutic intervention. Full article

Breast cancer continues to be a major challenge in global health, in part due to significant inequalities in access to costly diagnostic and therapeutic technologies based on antibodies. Their manufacturing requires complex and expensive bioproduction systems, resulting in limited availability of these tools—essential for early detection and targeted treatment—in many regions, particularly in Latin America. This gap has highlighted the need for cost-effective and scalable theranostic alternatives, increasing interest in aptamers. Obtained through SELEX technology, aptamers are synthetic DNA or RNA oligomers that fold into functional structures. Among their advantages are high affinity for their target, low immunogenicity, and chemical synthesis, which assures reproducible production. Aptamers have expanded the landscape of diagnostic platforms through the development of sensitive aptasensors, liquid biopsy strategies, and imaging systems based on nanomedicines. They also contribute to targeted therapy by recognizing cancer biomarkers selectively and enabling controlled drug delivery. This review presents a critical summary of advances in aptamer-based theranostics for breast cancer, addressing molecular mechanisms, structural folding, selective ligand binding, and nanomaterial interfacing. We also discuss applications in extracellular vesicle capture, cancer stem cell detection, and therapeutic conjugates, emphasizing their advantages and limitations relative to approaches based on antibodies. Overall, current advances show aptamers as emerging tools capable of democratizing precision oncology, particularly in regions where access to advanced technologies remains limited. Full article

Aptamers are powerful tools for detecting and analyzing biomolecules that consist of proteins or nucleic acids. However, their application to aptamers against viroids—highly structured self-replicating RNAs—has not yet been explored. In this study, a magnetic bead- and high-throughput sequencing-based SELEX (MB-HTS-SELEX) protocol for selecting potential aptamers against potato spindle tuber viroid (PSTVd) is presented. Full-length biotinylated-PSTVd RNA was transcribed in vitro, immobilized on streptavidin-coated magnetic beads, and incubated with a library of ~3.32 × 10¹⁴ molecules of random single-stranded oligo-DNAs (oligo-ssDNAs) of 20, 30, or 40 nucleotides (L20, L30, or L40, respectively) flanked by primer binding sites for downstream PCR amplification. Simultaneous biotin labeling of the anti-aptamer strand of the resulting double-stranded DNA (dsDNA) amplicons facilitated strand separation using streptavidin-coated magnetic beads. After 10 selection rounds, high-throughput sequencing, followed by bioinformatics analysis of the generated sequences, allowed for the detection of several enriched sequences, representing putative PSTVd-binding aptamers. Subsequent pull-down assays showed that the most abundant oligo-ssDNA in L30 was docked on PSTVd molecules. This combination method may ameliorate the selection of high-affinity aptamers against PSTVd, reduce the number of selection cycles, time, and other costs of aptamer production, thereby promoting future massive and cost-effective viroid detection and characterization. Full article