Multivalent Aptamers Research Articles

Enzymatic interlocking aptamer-micelles for enhanced cellular internalization and nucleus-targeted cancer phototherapy

Multifunctional micelles that permit both diagnosis and treatment present enormous advantage and potential for precision medicine. However, the inherent complexities and structural instability of these systems often cause unsatisfactory targeting and therapeutic performances. Herein, by ingenious design of a 2,5-bis(2-thienyl)pyrrole (SNS) modifier to covalently link with AS1411 aptamer and lipid segment, a simple strategy is proposed for one-step enzymatic preparation of interlocked aptamer-micelle (IApM) under bio-friendly conditions. The interlocked poly(SNS) skeleton in IApM can not only stabilize the micelle structure but also enhance near-infrared (NIR) absorption ability, thus further enhancing cellular internalization and photothermal therapy. In addition, the multivalent AS1411 aptamers tethered in the hydrophilic shell can simultaneously increase the specific binding affinity of DNA micelles and induce nucleus-targeted accumulation for DNA damage-triggered apoptosis. This DNA micelle achieves “best of both worlds” with enhanced biostability for cellular internalization and improved NIR photothermal conversion efficiency for nucleus-targeted therapy, which provides a promising formulation strategy for precision cancer treatment.

Star-shaped flexible arm multivalent aptamers for largely improved virus binding affinity

Here we explore the click chemistry-based synthesis of high affinity multivalent aptamers and their application for virus detection. In contrast to attempts based on rigid constructs, such as aptamer-modified nanoparticles or hybridization-connected constructs, we propose highly flexible “star-shaped” multivalent aptamers to facilitate the cooperative binding to randomly distributed viral proteins on the surface of pleomorphic viruses such as the respiratory syncytial virus (RSV). Polyethylene glycols (PEGs) with 4 azide terminated flexible arms spanning from a pentaerythritol core were conjugated to aptamer strands with dibenzocyclooctyne and a fluorescent label at their, 3’ and 5’ terminus, respectively. By controlling the aptamer - PEG ratio and following electrophoretic separation all the different valency aptamer conjugates could be prepared. For proof of concept, we used an aptamer selected for the G protein of RSV. We show that significantly higher apparent affinities can be obtained by using multivalent aptamers for both the G protein and RSV virus than with the single stranded aptamer, i.e. with up to ca. 2 orders of magnitude. The inherent convenience of synthesizing fluorescently labelled multivalent aptamers leads to a versatile class of affinity ligands for sensing as demonstrated through the improved detection sensitivity of tetravalent aptamer tagged RSV by fluorescence nanoparticle tracking analysis.

Electrochemical Monitoring of Respiratory Infectious Disease on Nanostructured Surface Functionalized with Biosynthetic Multimer Aptamers

Multivalent aptamers have gained substantial interest owing to their enhanced affinity towards target analytes compared to their monomeric counterparts due to their capability to bind simultaneously to diverse regions of a target molecule, fostering more robust and enduring interactions. This study focuses on engineering the surface-based production and modification of multivalent aptamers through room temperature rolling circle amplification technique and chemically modified primers. This process starts with immobilizing modified primers onto an electrode to generate and arrange biosynthesised multivalent aptamers. These bio-engineered multivalent aptamers are utilized as bio-receptors for capturing a specific target (in this case, the SARS-CoV-2 spike protein). The entire surface amplification procedure is extensively characterized using electrochemical, microscopy, and spectroscopy methods, determining the optimal amplification duration for biosensing applications. Impressively, multivalent aptasensors shows substantially increased response signals and affinity compared to monomeric aptasensors. Moreover, the influence of surface structures on response signals is explored by employing both flat screen-printed gold electrodes and nano-/microisland (NMI) electrodes. NMIs-based multimeric aptasensors demonstrate notably heightened sensitivity in detecting SARS-CoV-2 spike protein within the range of 10 to 106 fg/mL in saliva and buffer media. Finally, the signal of the proposed aptasensor has been successfully assessed using several patient samples.

Rolling Circle Amplification-Based Self-Assembly to Form a "GPS-Nanoconveyor" for In Vitro Targeted Imaging and Enhanced Gene/Chemo (CRISPR/DOX) Synergistic Therapy.

The GPS-Nanoconveyor (MA-NV@DOX-Cas13a) is a targeted nanoplatform designed for the imaging and gene/chemotherapy synergistic treatment of melanoma. It utilizes rolling circle amplification (RCA) products as a scaffold to construct a DNA "Nanoconveyor" (NV), which incorporates a multivalent aptamer (MA) as a "GPS", encapsulates doxorubicin (DOX) in the transporter, and equips it with CRISPR/Cas13a ribonucleoproteins (Cas13a RNP). Carrying MA enhances the ability to recognize the overexpressed receptor nucleolin on B16 cells, enabling targeted imaging and precise delivery of MA-NV@DOX-Cas13a through receptor-mediated endocytosis. The activation of signal transducer and activator of transcription 3 (STAT3) in cancer cells triggers cis-cleavage of CRISPR/Cas13a, initiating its trans-cleavage function. Additionally, deoxyribonuclease I (DNase I) degrades MA-NV, releasing DOX for intracellular imaging and as a chemotherapeutic agent. Experiments demonstrate the superior capabilities of this versatile nanoplatform for cellular imaging and co-treatment while highlighting the advantages of these nanodrug delivery systems in mitigating DOX side effects.

Structural basis of a small monomeric Clivia fluorogenic RNA with a large Stokes shift.

RNA-based fluorogenic modules have revolutionized the spatiotemporal localization of RNA molecules. Recently, a fluorophore named 5-((Z)-4-((2-hydroxyethyl)(methyl)amino)benzylidene)-3-methyl-2-((E)-styryl)-3,5-dihydro-4H-imidazol-4-one (NBSI), emitting in red spectrum, and its cognate aptamer named Clivia were identified, exhibiting a large Stokes shift. To explore the underlying molecular basis of this unique RNA-fluorophore complex, we determined the tertiary structure of Clivia-NBSI. The overall structure uses a monomeric, non-G-quadruplex compact coaxial architecture, with NBSI sandwiched at the core junction. Structure-based fluorophore recognition pattern analysis, combined with fluorescence assays, enables the orthogonal use of Clivia-NBSI and other fluorogenic aptamers, paving the way for both dual-emission fluorescence and bioluminescence imaging of RNA molecules within living cells. Furthermore, on the basis of the structure-based substitution assay, we developed a multivalent Clivia fluorogenic aptamer containing multiple minimal NBSI-binding modules. This innovative design notably enhances the recognition sensitivity of fluorophores both in vitro and in vivo, shedding light on future efficient applications in various biomedical and research contexts.

Synthesis of dual models multivalent activatable aptamers based on HCR and RCA for ultrasensitive detection of Salmonella typhimurium

Aptamers have superior structural properties and have been widely used in bacterial detection methods. However, the problem of low affinity still exists in complex sample detection. In contrast, hybridization chain reaction (HCR)-based model I and rolling circle amplification (RCA)-based model II multivalent activatable aptamers (multi-Apts) can fulfill the need for low-cost, rapid, highly sensitive and high affinity detection of S. typhimurium. In our research, two models of multi-Apts were designed. First, a monovalent activatable aptamer (mono-Apt) was constructed by fluorescence resonance energy transfer (FRET) with an S. typhimurium aptamer and its complementary chain of BHQ1. Next, the DNA scaffold was obtained by HCR and RCA, and the multi-Apts were obtained by self-assembly of the mono-Apt with a DNA scaffold. In model I, when target was presented, the complementary chain BHQ1 was released due to the binding of multi-Apts to the target and was subsequently adsorbed by UIO66. Finally, a FRET-based fluorescence detection signal was obtained. In mode II, the multi-Apts bound to the target, and the complementary chain BHQ1 was released to become the trigger chain for the next round of amplification of HCR with a fluorescence detection signal. HCR and RCA based multi-Apts were able to detect S. typhimurium as low as 2 CFU mL−1 and 1 CFU mL−1 respectively. Multi-Apts amplification strategy provides a new method for early diagnosis of pathogenic microorganisms in foods.

Versatile MOF@COF catalyzed and magnetically multivalent aptamer assisted biosensing platform for rapid and ultrasensitive dual-mode detection of multidrug-resistant bacteria

Given the frequent occurrence of multidrug-resistant bacteria (MDRB), which pose a severe threat towards public hygiene, it is important to construct facile and sensitive strategies for the detection of MDRB. We developed a fluorescent/colorimetric dual-mode biosensing platform for the analysis of MDRB by integrating the remarkable peroxidase-like activity of boric acid-decorated fluorescent framework hybrid (MOF@COF) nanozyme and enhanced bacterial affinity of DNA programmable multivalent aptamer scaffold. The efficiency and sensitivity of the proposed analysis approach were dramatically increased due to richer aptamers and high-performance MOF@COF nanozyme. Compared with commonly used single recognition methods, multivalent aptamers and bacteria-affinity boric acid groups on the nanozyme surface could identify multiple sites of MDRBs to improve site utilization for ultrasensitive biosensing. The platform realized selective detection of Acinetobacter baumannii (AB) and Pseudomonas aeruginosa (PA) in two modes with consistent results. In colorimetry and fluorescence modes, the linear ranges of AB were 102-108 and 10–108 CFU/mL with corresponding detection limits of 12 and 2 CFU/mL, and the linear ranges of PA were 102-108 and 10–108 CFU/mL with corresponding detection limits of 10 and 3 CFU/mL, respectively. More importantly, the biosensing platform could be applied for MDRB quantification in biological specimens, including human serum, cerebrospinal fluid, and urine with remarkable recoveries (96.8–105.0%) in both modes, indicating the bright prospect of the biosensing platform for MDRB determination in clinical diagnosis.

DNA nanoflowers encapsulating horseradish peroxidase as a signal amplification tag for rapid diagnosis in cytology specimens

Rapid analysis of cytology samples obtained by minimally invasive sampling is essential in clinical diagnosis, yet existing diagnostic methods are often cumbersome and time-consuming. To rapidly detect the scanty number of cells in specimens, a multifunctional detection probe based on DNA nanoflower structure was prepared in this study, which possesses both signal output capability of fluorescence and oxidation reaction (colorimetric assay) for ultra-sensitive cancer cell detection. Firstly, DNA nanoflowers encapsulating horseradish peroxidase (HRP-DNA Nanoflowers, HDFs) were prepared by the rolling circle amplification (RCA) reaction and then hybridized with the aptamers labeled with fluorophores to construct the multivalent aptamer HDFs (Multi-Aptamer-HDFs) with fluorescence effect and efficient cancer cell targeting. The Multi-Aptamer-HDFs probe can be used to detect fresh clinical cytology specimens directly for fluorescence observation with sensitivity and specificity of 88.64%, and 84.85%, respectively. In addition, Multi-Aptamer-HDFs has peroxidase activity due to the encapsulation of HRP, which can catalyze the oxidation of substrates such as ABTS and DAB for color development. Therefore, we applied Multi-Aptamer-HDFs to one-step staining of clinical cytology cell blocks with a sensitivity of 88.41% and a specificity of 83.33%, which required fewer steps and reagents with a significantly shorter time required for immunocytochemical staining. The multifunctional probe, Multi-Aptamer-HDFs, prepared in this study is expected to be better applied in the rapid cellular analyses and one-step immunostaining, which is expected to provide a new means for rapid on-site assessment and on-site preliminary diagnosis.

Rapid and ultra-sensitive lateral flow assay for pathogens based on multivalent aptamer and magnetic nanozyme

Ultra-sensitive LFA methods for pathogen detection commonly depended on tedious and time-consuming nucleic acid amplification. Here, a high affinity multivalent aptamer (multi-Apt) for S. aureus was obtained through exquisite engineering design. The scaffold and conformation of the multi-Apt were found to be key factors in the detection signal of aptsensors. After optimization, the binding affinity of the multi-Apt to S. aureus was improved by more than 8-fold from 135.9 nM to 16.77 nM. By the joint use of the multi-Apt and a multifunctional nanozyme Fe3O4@MOF@PtPd, a fast and ultra-sensitive LFA for S. aureus was developed (termed MA-MN LFA). In this method, a Fe3O4@MOF@PtPd nanozyme was modified with vancomycin and could efficiently capture and separate S. aureus. Moreover, the multi-Apt worked together with the nanozyme to bind with S. aureus to form a ternary complex at the same time, which simply the fabrication of LFA strip. The developed MA-MN LFA could detect S. aureus as low as 2 CFU/mL within 30 min and a wide linear range of 10–1 × 108 CFU/mL was obtained. The detection is easily operated, fast (can be completed within 30 min) and versatile for Gram-positive pathogens, thus has great potential as a powerful tool in pathogen detection.

Triple multivalent aptamers within DNA tetrahedron on reduced graphene oxide electrode: Unlocking enhanced sensitivity and accelerated reactions in electrochemical sensing

DNA nanostructures are emerging as promising biosensing platforms due to their programmability, predictable assembly, and compatibility with aptamers for enhanced selectivity. This study focuses on a triple-multivalent aptamer (tApt) complex immobilized on a tetrahedral DNA nanostructure (TDN) and integrated with an electrochemically reduced graphene oxide (ERGO) electrode for highly sensitive mercury ion (Hg2+) detection. Compared to a linear multivalent aptamer-modified electrode (S2/ERGO-GCE), the 3D tApt/ERGO-GCE aptasensor exhibits superior sensitivity, signal amplification, and reaction kinetics. The tApt/ERGO-GCE sensor achieves an exceptional limit of detection (LOD) of 4.1 zM, surpassing the LOD of 0.71 fM for S2/ERGO-GCE. Additionally, the tApt/ERGO-GCE sensor demonstrates faster response times, with a half-saturation time (T1/2) of 6 minutes compared to 17 minutes for S2/ERGO/GCE. The 3D tApt aptamer's superior performance is attributed to its tetrahedral DNA structure integrated on ERGO, providing multiple aptamer binding sites, facilitating oriented immobilization on the electrode surface, and enhancing analyte capture and concentration. In contrast, the linear S2 aptamers lack rigidity, resulting in a disordered orientation on the electrode surface, hindering efficient Hg2+ binding and reducing target molecule binding efficiency. This study underscores the potential of triple-multivalent aptamer-based nanostructures for ultrasensitive and rapid biosensing applications. The tApt/ERGO-GCE aptasensor's exceptional sensitivity, signal amplification, and reaction kinetics make it a promising tool for Hg2+ detection and other biosensing applications.

A novel electrochemiluminescent cytosensor using 3D multivalent aptamer recognition and covalent organic frameworks-associated DNA walker for highly efficient capture and detection of rare CTCs

Circulating tumor cells (CTCs) are regarded as promising biomarkers for early clinical diagnosis, prognosis evaluation, and treatment monitoring. However, their limited abundance in peripheral blood and phenotypic heterogeneity resulting from epithelial-mesenchymal transition (EMT) present significant challenges for accurate detection of CTCs. Herein, we developed an ultrasensitive and highly specific cytosensor to address these limitations. Firstly, to overcome the EMT property of CTCs, we designed a novel 3D multivalent aptamer recognition strategy (MARS), which not only contributed to highly efficient capture of heterogeneous CTCs, but also guaranteed detection sensitivity of the developed cytosensor. Meanwhile, we integrated an exonuclease III (Exo III)-mediated DNA walking signal amplification strategy into the electrochemiluminescence (ECL) cytosensor, enhancing its sensitivity in detecting rare CTCs. Furthermore, in combination with the excellent ECL performance of the luminescent nanomaterials (Au@COF-LZU1@Ru), the cytosensor exhibited a wide detection range from 8 to 1 × 105 cells/mL with a detection limit as low as 2 cells/mL. The analytical performance of the constructed cytosensor was validated through real sample analysis (AUC = 0.97), demonstrating its potential for clinical applications. The novel cytosensor offers an effective and reliable tool for the detection of rare CTCs, thereby paving the way for improved clinical significance.

Multivalent dendritic DNA aptamer molecules for the enhancement of therapeutic effects.

Dendritic DNA molecules, referred to as DNA dendrons, consist of multiple covalently linked strands and are expected to improve the cellular uptake and potency of therapeutic oligonucleotides because of their multivalency. In this study, we developed an efficient synthetic method for producing DNA dendrons using strain-promoted azide-alkyne cycloaddition. Integration of the antitumor aptamer AS1411 into DNA dendrons enhanced cellular uptake and antiproliferative activity in cancer cells. These findings demonstrate that the incorporation of multivalent aptamers into DNA dendrons can effectively boost their therapeutic effects.

A Smart DNA Nanoassembly Containing Multivalent Aptamers Enables Controlled Delivery of CRISPR/Cas9 for Cancer Immunotherapy

AbstractCRISPR/Cas9 system is promising for the reversal of tumor immunosuppression in immunotherapy, but the controlled delivery of CRISPR/Cas9 remains challenging. Herein, the study reported a smart DNA nanoassembly containing multivalent aptamers, realizing the controlled delivery of Cas9/sgRNA ribonucleoprotein (RNP) for enhanced cancer immunotherapy. A single‐stranded DNA complementary to sgRNA in the Cas9/sgRNA RNP can initiate a cascade‐clamped hybridization chain reaction (C‐HCR) to wrap the Cas9/sgRNA RNP up in the DNA nanoassembly. After selective internalization of DNA nanoassembly by cancer cells, Cas9/sgRNA RNP is released to cytoplasm in response to endogenous RNase H and enters the nuclei to knock out β‐catenin. The expression of the programmed death‐ligand one gene is effectively suppressed, and the immunosuppressive tumor microenvironment is reprogrammed. Meanwhile, the migration of cancer cells is inhibited, and the apoptosis of cancer cells is promoted. In a breast cancer mouse model, the administration of DNA nanoassembly effectively increased the infiltration of CD8+ T cells, eventually achieving high therapeutic efficacy.

Multivalent DNA Flowers for High-Performance Isolation, Detection, and Release of Tumor-Derived Extracellular Vesicles.

Tumor-derived extracellular vesicles (T-EVs) hold great promise for understanding cancer biology and improving cancer diagnostics and therapeutics. Herein, we developed multivalent DNA flowers (DFs) containing repeated and equidistant EpCAM aptamers for the efficient isolation of T-EVs. The multivalent aptamer chains in DFs had good flexibility to adapt to the surface morphology of T-EVs and achieved multivalent ligand-receptor interactions, thus showing enhanced isolation ability compared to monovalent aptamers. Compared with other materials for isolation of EVs, DFs were generated by rolling circle amplification (RCA) and self-assembled into microspheres in a one-pot reaction, and the recognition molecules (aptamers) were directly replicated and assembled during the RCA reaction instead of chemical modification and immobilization on the surface of solid materials. Moreover, as optically transparent biomaterials, the content of EpCAM+ EVs could be directly reflected via membrane-based hydrophobic assembly of signaling modules in DFs@EpCAM+ EVs complex, and we found that the amount of EpCAM+ EVs showed greater accuracy in cancer diagnosis than total EVs (88.3 vs 69.7%) and was also higher than the clinically commonly used marker carcinoembryonic antigen (CEA) (88.3 vs 76.7%). In addition, T-EVs could be released by lysis of DFs with the nuclease, gently and easily, keeping high intact and activity of EVs for downstream biological function studies. These results demonstrated that DFs are efficient and nondestructive tools for isolation, detection, and release of T-EVs.

Rational Engineering of a Multifunctional DNA Assembly for Enhanced Antibacterial Efficacy and Accelerated Wound Healing.

DNA-based assemblies hold immense prospects for antibacterial application, yet are constrained by their poor specificity and deficient antibacterial delivery. Herein, the fabrication of a versatile rolling circle amplification (RCA)-sustained DNA assembly is reported, encoding simultaneously with multivalent aptamers and tandem antibacterial agents, for target-specific and efficient antibacterial application. In the compact RCA-sustained antibacterial platform, the facilely organized multivalent aptamers guarantee the target bacteria-specific delivery of sufficient antibacterial agents which is assembled through DNA-stabilizing silver nanostructures. It is shown that the biocompatible DNA system could enhance bacteria elimination and simultaneously facilitate wound healing in vivo. By virtue of the programmable RCA assembly, the present RCA-sustained system provides a highly modular and scalable approach to design versatile multifunctional therapeutic systems.

Highly sensitive detection of Salmonella based on dual-functional HCR-mediated multivalent aptamer and amplification-free CRISPR/Cas12a system

BackgroundSalmonella infection severely threatens human health and causes substantial medical and financial concerns. Sensitive and specific detection of Salmonella in food samples is crucial but remains challenging. While some traditional assays for S. typhimurium are reliable, they suffer from various limitations, such as being time-consuming (culture-based methods), involving intricate nucleic molecular extraction (polymerization chain reaction, PCR), and exhibiting inadequate sensitivity (enzyme-linked immunosorbent assay, ELISA). In this case, it is essential to establish a rapid, simple-operation, and sensitive method for monitoring S. typhimurium to preserve food quality and prevent contamination. ResultHerein, an amplification-free detection method for Salmonella was developed by coupling the aptamer magnetic separation with dual-functional HCR (hybridization chain reaction)-scaffold multivalent aptamer and the activity of CRISPR/Cas12a. In the detection system, the dual-functional HCR-scaffold multivalent aptamer with high binding affinity and specificity was fabricated in advance by assembling numerous Salmonella specific aptamers on the long HCR products. In addition to the enhanced affinity, the HCR-multiApt also contains a massive amount of repeated CRISPR-targetable DNA units in its HCR scaffold, which could trigger the trans-cleavage activity of Cas12a. In the presence of target bacteria, the HCR-scaffold multivalent aptamer could attach on the surface of bacteria effectively and amplified the signal of bacteria into CRISPR/Cas12a based fluorescent readout. The proposed detection system allowed for ultrasensitive detection of Salmonella in a linear range from 100 to 107 cfu mL−1 with a LOD (limit of detection) of 2 cfu mL−1. SignificanceThe novel dual-functional HCR-multiApt presents a simple and powerful strategy for improving the aptamer binding affinity toward Salmonella. Simultaneously, integrating this dual-functional HCR-multiApt with the CRISPR/Cas12a system significantly enhances the sensitivity by cascade signal amplification in a nucleic acids amplification-free way. Finally, leveraging the versatility of the aptamer, this highly sensitive method can be further extended for application in the detection of other bacteria, food safety monitoring, or clinical diagnostics.

A Colorimetric/Fluorescent Dual-Mode Aptasensor for Salmonella Based on the Magnetic Separation of Aptamers and a DNA-Nanotriangle Programmed Multivalent Aptamer.

Salmonella infection has emerged as a global health threat, causing death, disability, and socioeconomic disruption worldwide. The rapid and sensitive detection of Salmonella is of great significance in guaranteeing food safety. Herein, we developed a colorimetric/fluorescent dual-mode method based on a DNA-nanotriangle programmed multivalent aptamer for the sensitive detection of Salmonella. In this system, aptamers are precisely controlled and assembled on a DNA nanotriangle structure to fabricate a multivalent aptamer (NTri-Multi-Apt) with enhanced binding affinity and specificity toward Salmonella. The NTri-Multi-Apt was designed to carry many streptavidin-HRPs for colorimetric read-outs and a large load of Sybr green I in the dsDNA scaffold for the output of a fluorescent signal. Therefore, combined with the magnetic separation of aptamers and the prefabricated NTri-Multi-Apt, the dual-mode approach achieved simple and sensitive detection, with LODs of 316 and 60 CFU/mL for colorimetric and fluorescent detection, respectively. Notably, the fluorescent mode provided a self-calibrated and fivefold-improved sensitivity over colorimetric detection. Systematic results also revealed that the proposed dual-mode method exhibited high specificity and applicability for milk, egg white, and chicken meat samples, serving as a promising tool for real bacterial sample testing. As a result, the innovative dual-mode detection method showed new insights for the detection of other pathogens.

Aptabinding of tumor necrosis factor-α (TNFα) inhibits its proinflammatory effects and alleviates islet inflammation.

Pancreatic islet cell transplantation (ICT) has emerged as an effective therapy for diabetic patients lacking endogenous insulin production. However, the islet graft function is compromised by a nonspecific inflammatory and thrombotic reaction known as the instant blood-meditated inflammatory reaction (IBMIR). Here, we report the characterization of four single-stranded DNA aptamers that bind specifically to TNFα - a pivotal cytokine that causes proinflammatory signaling during the IBMIR process - using single molecule binding analysis and functional assays as a means to assess the aptamers' ability to block TNFα activity and inhibiting the downstream proinflammatory gene expression in the islets. Our single-molecule fluorescence analyses of mono- and multivalent aptamers showed that they were able to bind effectively to TNFα with monoApt2 exhibiting the strongest binding (Kd ∼0.02±0.01nM), which is ∼3 orders of magnitude smaller than the Kd of the other aptamers. Furthermore, the in vitro cell viability analysis demonstrated an optimal and safe dosage of 100μM for monoApt2 compared to 50μM for monoApt1 and significant protection from proinflammatory cytokine-mediated cell death. More interestingly, monoApt2 reversed the upregulation of IBMIR mediating genes induced by TNFα in the human islets, and this was comparable to established TNFα antagonists. Both monoaptamers showed high specificity and selectivity for TNFα. Collectively, these findings suggest the potential use of aptamers as anti-inflammatory and localized immune-modulating agents for cellular transplant therapy.

A Novel Method for Sensitive Detection of Vibrio alginolyticus Based on Aptamer and Hybridization Chain Reaction in Aquaculture

In this study, we developed a novel method for the detection of Vibrio alginolyticus, utilizing the specific recognition of an aptamer for V. alginolyticus and signal amplification via hybridization chain reaction (HCR) and horseradish-peroxidase-conjugated streptavidin. The proposed HCR-based multivalent aptamer (multi-Apt) amplifier allows for sensitive detection of V. alginolyticus in a linear range from 10 to 107 CFU/mL. The linear equation is y = 747.5x + 126.2, R2 = 0.986, and the limit of detection (LOD) is 3 CFU/mL. Seawater and freshwater samples were utilized in the spike recovery experiment, yieldng a recovery rates ranging from 94.3% to 108.8%. The relative standard deviation (RSD) for all samples is below 6.73%. Taken together, the proposed method has great potential for application in monitoring of V. alginolyticus in aquaculture environments.

Self-Assembled Multivalent Aptamer Drug Conjugates: Enhanced Targeting and Cytotoxicity for HER2-Positive Gastric Cancer.

Antibody drug conjugates (ADCs) have shown promise to be the mainstream chemotherapeutics for advanced HER2-positive cancers, yet the issues of poor drug delivery efficiency, limited chemotherapeutic effects, severe immune responses, and drug resistance remain to be addressed before the clinical applications of ADCs. The DNA aptamer-guided drug conjugates (ApDCs) are receiving growing attention for specific tumors due to their excellent tumor affinity and low cost. Therefore, developing a multivalent ApDC nanomedicine by combining anti-HER2 aptamer (HApt), tetrahedral framework nucleic acid (tFNA), and deruxtecan (Dxd) together to form HApt-tFNA@Dxd might help to address these concerns. In this study, the HER2-targeted DNA aptamer modified DNA tetrahedron (HApt-tFNA) was employed as a system for drug delivery, and the adoption of tFNA could effectively enlarge the drug-loading rate compared to aptamer-guided ApDCs previously reported. Compared with free Dxd and tFNA@Dxd, HApt-tFNA@Dxd showed better structural stability, excellent targeted cytotoxicity to HER2-positive gastric cancer, and increased tissue aggregation ability in tumors. These features and superiorities make HApt-tFNA@Dxd a promising chemotherapeutic medicine for HER2-positive tumors. Our work developed a new targeting nanomedicine by combining DNA nanomaterials and chemotherapeutic agents, which represents a critical advance toward developing novel DNA-based nanomaterials and promoting their potential applications for HER2-positive cancer therapy.