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Background: Cerebrospinal fluid (CSF) leaks may occur due to numerous etiologies and are associated with severe morbidity. Currently in the U.S., confirming the presence of a CSF leak requires protein electrophoresis testing, oftentimes involving specialized processing, and there exists no point-of-care (POC) device for CSF detection. We aimed to discover a single-stranded deoxyribonucleic acid (ssDNA) aptamer capable of selectively binding to CSF-specific biomarkers, with the future goal of developing an aptamer-based POC CSF detection device., Methods: To identify a candidate aptamer, we performed Systematic Evolution of Ligands by EXponential enrichment (SELEX) using a DNA library containing a randomized 63-nucleotide (nt) stretch flanked by 2 primer-binding sites. Quantitative polymerase chain reaction (qPCR) and fluorescence anisotropy (FA) assessed aptamer binding affinity and kinetics., Results: Following 14 SELEX cycles, 2 dominant and functionally viable 98-nt ssDNA sequences (C2 and C3) were found. C2 and C3 demonstrated ~586x and ~82x higher affinity for CSF compared to serum, respectively. Increases in FA upon aptamer exposure to higher CSF concentrations demonstrated a K1/2 of 5.0% and 14.1% for C2 and C3, respectively., Conclusions: In vitro selection of a diverse pool of ssDNA sequences yielded 2 aptamers with high selectivity for CSF-specific biomarkers, with potential for integration into a rapid POC electrochemical diagnostic system.

The Mucin1 (MUC1) protein, involved in cytoprotective and signaling pathways, is abnormally elevated in various cancers, making it a key cancer indicator. Exosomes, which reflect the status of their originating cells, offer potential for cancer diagnosis. Thus, developing a method to detect MUC1-positive exosomes is crucial for the early diagnosis of certain cancers. In this study, we developed a highly sensitive, specific, and simple UV-visible signal amplification method to detect MUC1-positive exosomes using terminal deoxynucleotidyl transferase (TdT). Initially, exosomes were captured on magnetic beads using a CD63 aptamer(apt). The Primer-AuNPs-MUC1 apt complex which we synthesized by low pH loading method was then attached MUC1 proteins on the surface of the exosomes to create a sandwich structure. TdT catalyzed the extension of Biotin-dATP at the 3' end of the primer, introducing multiple biotin sites into the sandwich structure. These sites subsequently bound multiple streptavidin-horseradish peroxidase (streptavidin-HRP), which catalyzed the oxidative color change of the substrate, which can be detected by colorimetric method. This method can detect A549 exosomes in the range of 1.4E+6 to 4.2E+8 particles/mL and shows high specificity for cell lines with different MUC1 expression. Additionally, it successfully distinguished cholangiocarcinoma (CCA) patients (n=11) from healthy individuals (n=7) in clinical serum assays, demonstrating good performance in real sample detection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Drug abuse is a major public problem in the workplace, traffic, and forensic issues, which requires a standardized test device to monitor on-site drug use. For field testing, the most important requirements are portability, sensitivity, non-invasiveness, and quick results. Motivated by this problem, a point of care (POC) test based on lateral flow assay (LFA) was developed for the detection of cocaine (COC) and methamphetamine (MET) in saliva which has been selected as the matrix for this study due to its rapid and non-invasive collection process. In the design strategy of an LFA test, the use of gold nanoparticles (AuNPs) with strong optical properties has been combined with the advantages of selecting aptamers under in vitro conditions, making it a highly specific and stable recognition probe for the detection of small molecules in saliva. The developed aptamer-based LFA in a competitive format, was able to detect COC and MET in synthetic saliva at concentrations as low as 5.0 ng/mL. After analytical performance studies, the test system also detected COC and MET in real patient samples, which was verified by chromatographic methods.

Nucleic acid aptamers are single-stranded oligonucleotides that are selected through exponential enrichment (SELEX) technology from synthetic DNA/RNA libraries. These aptamers can specifically recognize and bind to target molecules, serving as specific recognition elements. Surface-enhanced Raman scattering (SERS) spectroscopy is an ultra-sensitive, non-destructive analytical technique that can rapidly acquire the "fingerprint information" of the measured molecules. It has been widely applied in qualitative and trace analysis across various fields, including food safety, environmental monitoring, and biomedical applications. Small molecules, such as toxins, antibiotics, and pesticides, have significant biological effects and are harmful to both human health and the environment. In this paper, we mainly introduced the application and the research progress of SERS detection with aptamers (aptamer-based SERS techniques) in the field of small-molecule detection, particularly in the analysis of pesticide (animal) residues, antibiotics, and toxins. And the progress and prospect of combining the two methods in detection were reviewed.

Alzheimer's disease (AD) is a representative neurodegenerative disease that is characterized by the overaccumulation of amyloid beta (Aβ) proteins. Since AD is accompanied by excessive oxidative stress, which aggravates neurological pathologies, the use of antioxidants has been considered to prevent disease development. NXP031, a combination of vitamin C (VitC) and an optimized aptamer that binds to VitC and stabilizes the reactivity of VitC, was designed. This study aimed to evaluate the effects of NXP031 on AD pathology, including Aβ accumulation, Aβ-induced oxidative stress, neuronal damage, and neuroinflammation. When NXP031 was administered to 5xFAD transgenic mice, NXP031 exerted a strong inhibitory action on Aβ accumulation, superior to that of VitC, by inducing an increase in Aβ-degrading endopeptidase expression. NXP031 diminished lipid peroxidation levels, activated Nrf2-mediated antioxidant pathways, and suppressed overactivated neuroinflammation. An in vitro study using Neuro2a cells revealed that NXP031 protects the cells against oxidative stress by regulating the MAPK signaling pathway-mediated apoptosis. Additionally, the neuroprotective effects of NXP031 were confirmed in a dose-dependent manner when administered to intrahippocampal Aβ-injected mice, as NXP031 attenuated memory decline, neuronal apoptosis, synaptic degeneration, and excessive glial activation, and reduced NOX-2 expression in the hippocampus. Taken together, NXP031 reduced the Aβ burden by regulating Aβ-degeneration and attenuated memory impairment, neuronal death, synaptic degeneration, and neuroinflammation induced by Aβ toxicity. These results suggest the potential of NXP031 as a therapeutic agent for AD., Competing Interests: Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

High-throughput proteomic platforms are crucial to identify novel Alzheimer's disease (AD) biomarkers and pathways. In this study, we evaluated the reproducibility and reliability of aptamer-based (SomaScan ® 7k) and antibody-based (Olink ® Explore 3k) proteomic platforms in cerebrospinal fluid (CSF) samples from the Ace Alzheimer Center Barcelona real-world cohort. Intra- and inter-platform reproducibility were evaluated through correlations between two independent SomaScan ® assays analyzing the same samples, and between SomaScan ® and Olink ® results. Association analyses were performed between proteomic measures, CSF biological traits, sample demographics, and AD endophenotypes. Our 12-category metric of reproducibility combining correlation analyses identified 2428 highly reproducible SomaScan CSF measures, with over 600 proteins well reproduced on another proteomic platform. The association analyses among AD clinical phenotypes revealed that the significant associations mainly involved reproducible proteins. The validation of reproducibility in these novel proteomics platforms, measured using this scarce biomaterial, is essential for accurate analysis and proper interpretation of innovative results. This classification metric could enhance confidence in multiplexed proteomic platforms and improve the design of future panels.

Staphylococcus aureus ( S. aureus ) represents one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. It is a part of the infamous ESKAPE group, which is highly connected with increased rates of healthcare-associated infections and antimicrobial resistance. S. aureus can cause a large variety of diseases. Protein A (PrA) is a cell-wall-anchored protein of S. aureus with multiple key roles in colonization and pathogenesis and can be considered as a marker of S. aureus . The development of aptasensors, having an aptamer as a specific biorecognition element, increases selectivity, especially when working with complex matrices. The association with state-of-the-art materials, such as MXenes, can further improve the analytical performance. A competitive aptasensor configuration based on a ferrocene (Fc)-labeled cDNA hybridized (cDNA-Fc S13) on a specific aptamer (APT) for PrA in the presence of MXene nanosheets was designed for the indirect detection of S. aureus . The aptasensor displayed a linear range of 10-125 nM, an LOD of 3.33 nM, and a response time under 40 min. This configuration has been tested in real samples from volunteers diagnosed with S. aureus infections with satisfactory results, enabling the perspective to develop decentralized devices for the rapid detection of bacterial strains.

Metal nanoclusters (NCs) are promising alternatives to organic dyes and quantum dots. These NCs exhibit unique physical and chemical properties, such as fluorescence, chirality, magnetism and catalysis, which contribute to significant advancements in biosensing, biomedical diagnostics and therapy. Through adjustments in composition, size, chemical environments and surface ligands, it is possible to create NCs with tunable optoelectronic and catalytic activity. This review focuses on the integration of aptamers with metal NCs, detailing molecular detection strategies that utilise the effect of aptamers on optical signal emission of metal NC-based biosensing systems. This review also highlights recent advancements in biosensing and biomedical applications, as well as illustrative case studies. To conclude, the strengths, limitations, current challenges and prospects for metal NC-based systems were examined.

Introduction: Sublingual immunotherapy (SLIT) is an effective and injection-free route for allergen-specific immunotherapy (AIT). Mesenchymal stromal/stem cell (MSC)-derived exosomes (Exo) has been identified as a novel delivery platform with immunomodulatory capacities. In addition, targeting agents such as aptamers (Apt) have been extensively used for specific delivery approaches such as direct delivery of allergen formulations to dendritic cells (DC) to improve the efficacy of specific immunotherapy. In this study, we assessed the effects of MSC-derived Exos containing ovalbumin (Ova) which decorated with DC-specific aptamer in allergic rhinitis mice model., Materials and Methods: Exos were harvested from adipose tissue-derived MSCs, and Exo-Apt-Ova complex was formulated. Then, Ova-induced allergic asthma model was simulated and sensitized BALB/c mice were treated sublingually with Exo-Apt-Ova complex (5 µg Ova) twice weekly for 8 weeks. Ova-specific IgE levels in serum and concentrations of interferon-gamma (IFN-γ), interleukin (IL)-4, and transforming growth factor-beta (TGF-β) in the supernatant of cultured splenocytes were evaluated using enzyme-linked immunosorbent assay (ELISA). In addition, lung histologic analysis and nasopharyngeal lavage fluid (NALF) cell count were performed., Results: Administration of Ova-incorporated Apt-modified Exos dramatically increased IFN-γ and TGF-β levels, and decreased IL-4 and IgE levels. In addition, inflammatory responses in the lung tissue and the number of eosinophils in NALF decreased., Conclusion: SLIT using Exo-Ova (5 µg) decorated with DC-specific aptamer induced immunomodulatory responses and remarkably attenuated allergic airway inflammation in mice., Competing Interests: Declarations. Ethics approval and consent to participate: This study is based on the approved project entitled “Evaluation the efficacy of sublingually administrated OVA-encapsulated Adipose-derived mesenchymal stem cell-derived exosome nanoparticles modified by DC-specific aptamer in allergic mouse model”. All experiments were approved by the Institutional Animal Ethics Committee of the Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran (Approval number: IR.AJUMS.ABHC.REC.1399.059) (Date of approval: 2021.1.12). In addition, this work has been reported in line with the ARRIVE guidelines 2.0. Conflict of interest: All authors declare no potential conflict of interest. AI declaration: The authors declare that they have not use AI-generated work in this manuscript., (© 2024. The Author(s).)

Leptospirosis is a neglected zoonosis caused by a pathogenic spirochete Leptospira. Diagnosis of leptospirosis in the early stage is difficult and can be easily confused with other infections. The existing detection methods are considered chronophagous and labor-intensive. Leptospira survives in the kidney tubules of reservoir animals such as rodents and shed into the environment through their urine. In this study, we developed an Aptamer-DNAzyme-based biosensor for detecting pathogenic Leptospira in environmental water samples. The cell-specific aptamer with an extensive affinity binds to the cell surface proteins to detect the Leptospira interrogans. The DNAzyme that mimics as a peroxidase enzyme, acts as a transducing agent in the colorimetric reaction positively conditioned by the presence of L. interrogans. The Leptospira-specific aptamer coupled with DNAzyme is coated onto carbon nanotubes, to provide a cost-effective nanomaterial-based detection platform. L. interrogans contamination in the samples is detected with a color change of a peroxidase substrate, ABTS. The dissociation constant of the aptazyme was found to be 356.6 nM. The aptazyme system was able to detect up to 119 CFU/mL of L. interrogans exhibiting a high range of selectivity towards the pathogenic spirochete. This simple detection methodology makes the system promising for the environmental monitoring of L. interrogans., Competing Interests: Declarations. Conflict of interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Aptamers are short, single-stranded oligonucleotides that selectively bind to target biomolecules. Although they generally exhibit good binding specificity, their affinities are often limited because of the relative lack of hydrophobic groups in nucleic acids. Chemically modified nucleotides incorporating hydrophobic structures into uracil have been synthesized to address this obstacle. Modified DNA aptamers containing such nonstandard nucleotides have been developed for >20 different complement proteins. These modified aptamers show increased affinity and enhanced serum stability and have potential value as therapeutic agents. We recently conducted a structure/function study on a family of modified DNA aptamers that bind specifically to complement Factor B (FB). This work revealed that these aptamers selectively inhibit the complement alternative pathway (AP) by preventing the formation of the AP complement component C3 (C3) proconvertase complex, C3bB. Certain patients with atypical hemolytic uremic syndrome express gain-of-function variants of FB that enhance the formation of the proconvertase complex and/or decrease the efficacy of endogenous regulators against the C3 convertases they form. To investigate whether these FB-binding aptamers could override the effects of disease-causing mutations in FB, we examined how they interacted with several FB variants, including D279G, F286L, K323E, and K350N, in various assays of complement function. We found that the inhibitory effect of the FB-binding aptamers superseded the gain-of-function mutations in FB, although the aptamers could not dissociate preformed C3 convertases. These findings suggest that FB-binding aptamers could be further developed as a potential treatment for certain atypical hemolytic uremic syndrome patients or those with other diseases characterized by excessive complement activity., (Copyright © 2024 by The American Association of Immunologists, Inc.)

Introduction: Aptamers refer to short ssDNA/RNA sequences that target small molecules, proteins, or cells. Aptamers have significantly advanced diagnostic applications, including biosensors for detecting specific biomarkers, state-of-the-art imaging, and point-of-care technology. Molecular computation helps identify aptamers with high-binding affinity, enabling high-throughput screening, predicting 3D structures, optimizing aptamers for improved stability, specificity, and complex target interactions., Area Covered: Aptamers are versatile in the development of specific and sensitive diagnostics. However, there needs to be more understanding of the precise workflow that integrates sequence, structure, and interaction with the target. In this review, the author discusses how significant progress has been made in aptamer discovery using bioinformatics for sequence analysis, docking to model interactions, and MD simulations to account for dynamicity and predict free-energy. Furthermore, the author discusses how quantum chemical calculations are critical for modelling electronic structures and assignin spectroscopic signals., Expert Opinion: Incorporating machine learning into the aptamer discovery brings a transformative advancement. With NGS datasets, SELEX, and experimental structures, the implementation of newer workflows yields aptamers with improved binding affinity. Leveraging transfer learning to models using experimental structures and aptamer sequences expands the aptamer design space significantly. As ML continues to evolve, it is poised to become central in accelerating aptamer discovery for biomedical applications in the next 5 years.

Accurate identification and isolation of target cells are crucial for precision diagnosis and treatment. DNA aptamer-based logic devices provide a distinct advantage in this context, as they can logically analyze multiple cell surface markers with high efficiency. However, the susceptibility of natural DNA (D-DNA) to degradation can compromise the sensitivity and specificity of these devices, potentially leading to false-positive and false-negative results, particularly in complex biological environments. To address this issue, dual- and triple-aptamer-based cell-surface logic devices are designed and developed using mirror-image L-DNA, a chiral molecule of D-DNA with high biostability. These devices allow for simultaneous analysis of multiple cell surface proteins, achieving greater specificity in cell identification and isolation than D-DNA-based logic devices. The L-DNA probes realized 98.7% and 70.5% sensitivities in FBS buffer with dual- and triple-aptamer-based logic devices for target cell identification, while D-DNA probes only showed 27.9% and 0.1%. It is believed that the high stability of L-DNA and the high efficiency of the devices for labeling cell subpopulations will have broad applications in the life sciences, biomedical engineering, and personalized medicine., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Controlling the spread of bacterial infectious diseases is a major public health issue, particularly in view of the pandemic of bacterial resistance to antibiotics. In this context, the detection and identification of pathogenic bacteria is a prerequisite for the implementation of control measures. Current reference methods are mainly based on culture methods, which generate a delay in obtaining a result and requires equipment. Consequently, focusing on the detection of the whole bacterium represents a very attractive alternative, since no culture is required. Several techniques have already been deployed to identify whole-cell bacteria. In recent decades, growing interest in nucleic acid aptamers has emerged as a viable alternative to antibodies as recognition elements, offering preferable stability, cost-efficiency, good specificity and affinity. This review explores current alternative methods for the detection of whole-cell bacteria, with particular emphasis on aptamer-based assays. These assays have shown promising results in various transduction mechanisms, including optical, electrochemical, and mechanical approaches, enhancing their versatility in different diagnostic platforms. The integration of aptamers in these detection methods offers rapid, sensitive, versatile and portable solutions for pathogen identification, positioning them as valuable tools in the fight against bacterial infections., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Chronic immunoinflammatory rheumatic diseases, such as axial spondyloarthritis (AxSpA), are accompanied by a dysregulation of bone remodeling. Among potential biomarkers of bone metabolism, the Wnt pathway antagonist, Dickkopf-1 (DKK-1), is of particular interest because of its potential to reflect a shift towards joint ossification or osteoporosis, but its diagnostic value needs validation. There is still a lack of stable and efficient methods of measuring serum DKK-1 levels suitable for longitude studies. The use of aptamer-based diagnostic assays could be very promising for this purpose. We generated novel anti-DKK-1 DNA aptamers from a combinatorial library with a pre-defined sequence pattern in the randomized region. This approach showed high efficacy, as only four SELEX rounds of selection produced high-affinity aptamers with dissociation constants ranging from 1.3 to 3.7 nM. A family of their truncated versions was also developed by rational design. Novel DNA aptamers functioned as capture components in a microplate ELISA-like assay with HRP-conjugated anti-DKK-1 antibody as a reporter component. We succeeded in revealing the aptamer/aptamer sandwich pairs that provided an aptamer-only sandwich colorimetric assay. The aptamer/antibody colorimetric test systems were also examined in the analyses of blood serum from AxSpA patients and shown sufficient workability. However, in a number of cases we registered significant differences between assays based on TD10 and DK4 aptamers and made some suggestions about the origin of this effect.

Androgen deprivation therapy has been the primary treatment strategy for advanced prostate cancer (PCa). But most patients develop castration resistance over time. For FDA-approved second-generation androgen receptor (AR) antagonists, including enzalutamide (ENZ) and abiraterone (AA), patients who initially respond to them eventually develop resistance. The key mechanism for resistance to ENZ/AA involves AR splice variants (AR-Vs) and specifically AR-V7. Current AR antagonists cannot target AR-V7 due to its lack of the C-terminal ligand-binding domain (LBD) but keeping the AR N-terminal domain (NTD) which still can activate androgen-responsive genes. Therefore, targeting the AR NTD and AR-V7 is critically important to overcome ENZ resistance. Unfortunately, AR NTD has been considered an "undruggable" target due to the difficulty in defining its three-dimensional (3D) structure. In this context, siRNA is highly suitable to address this undruggable target. However, siRNA cannot freely diffuse into cells, and a carrier is needed. In this regard, nucleic acid-based aptamers are highly suitable for cell type-specific delivery of siRNA in vivo. In this study, we have developed a serum-stable bivalent prostate-specific membrane antigen (PSMA) aptamer-AR-V7 siRNA chimera (PAP). The results show that PAP can knock down both AR-full length and AR-V7 in PSMA-expressing castration-resistant cells. It can resensitize ENZ in cell lines and PCa xenografts. ENZ combined with PAP can significantly inhibit 22Rv1 xenograft growth in mice without experiencing castration. Owing to the low toxicity, PAP has potential to offer a new antiandrogen treatment for current ENZ-resistant PCa.

The SARS-CoV-2 pandemic has challenged more scientists to detect viruses and to visualize virus-containing spots for diagnosis and infection control; however, detection principles of commercially available technologies are not optimal for visualization. Here, a convenient and universal homogeneous detection platform named proximity-unlocked luminescence by sequential enzymatic reactions from antibody and antibody/aptamer (PULSERAA) is developed. This is designed so that the signal appears only when the donor and acceptor are in proximity on the viral surface. PULSERAA specifically detected in the range of 25-500 digital copies/mL of inactivated SARS-CoV-2 after simply mixing reagents; it is elucidated that the accumulation of chemical species in a limited space of the viral surface contributed to such high sensitivity. PULSERAA was quickly adapated to detect another virus variant, inactivated influenza A virus, and infectious SARS-CoV-2 in a clinical sample. Furthermore, on-site (direct, rapid, and portable) visualization of the inactivated SARS-CoV-2-containing spots by a conventional smartphone camera was achieved, demonstrating that PULSERAA can be a practical tool for preventing the next pandemic in the future., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Current methods for therapeutic drug monitoring (TDM) have a long turnaround time as they involve collecting patients' blood samples followed by transferring the samples to medical laboratories where sample processing and analysis are performed. To enable real-time and minimally invasive TDM, a microneedle (MN) biosensor to monitor the levels of two important antibiotics, vancomycin (VAN) and gentamicin (GEN) is developed. The MN biosensor is composed of a hydrogel MN (HMN), and an aptamer-functionalized flexible (Flex) electrode, named HMN-Flex. The HMN extracts dermal interstitial fluid (ISF) and transfers it to the Flex electrode where sensing of the target antibiotics happens. The HMN-Flex performance is validated ex vivo using skin models as well as in vivo in live rat animal models. Data is leveraged from the HMN-Flex system to construct pharmacokinetic profiles for VAN and GEN and compare these profiles with conventional blood-based measurements. Additionally, to track pH and monitor patient's response during antibiotic treatment, an HMN is developed that employs a colorimetric method to detect changes in the pH, named HMN-pH assay, whose performance has been validated both in vitro and in vivo. Further, multiplexed antibiotic and pH detection is achieved by simultaneously employing the HMN-pH and HMN-Flex on live animals., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Endometrial cancer poses a significant threat to women's health. Doxorubicin is commonly used in chemotherapy for advanced and recurrent cases; however, low sensitivity frequently limits its effectiveness. In this study, we verified that SRC modulates the sensitivity of endometrial cancer to chemotherapy of doxorubicin and developed a targeted silencing drug delivery platform that employs rolling circle amplification and dual-multivalent aptamers to precisely deliver therapeutics directly to tumor cells. This platform enhanced endometrial cancer cell sensitivity to doxorubicin by modulating drug responsiveness at the genetic level. Our results suggest that this approach may improve cancer cell susceptibility to ferroptosis. The efficacy and safety of this platform were validated in both cellular and animal models. This study provides a new solution for realizing the precision treatment of endometrial cancer and lays a theoretical foundation for exploring the mechanism of endometrial cancer., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Fluorescence-based aptasensors have been regarded as innovative analytical tools for the detection and quantification of analytes in many fields, including medicine and therapeutics. Using DNA aptamers as the biosensor recognition component, conventional molecular beacon aptasensor designs utilise target-induced structural switches of the DNA aptamers to generate a measurable fluorescent signal. However, not all DNA aptamers undergo sufficient target-specific conformational changes for significant fluorescence measurements. Here, the use of complementary 'antisense' strands is proposed to enable fluorescence measurement through strand displacement upon target binding. Using a published target-specific DNA aptamer against the receptor binding domain of SARS-CoV-2, we designed a streptavidin-aptamer bead complex as a fluorescence displacement assay for target detection. The developed assay demonstrates a linear range from 50 to 800 nanomolar (nM) with a limit of detection calculated at 67.5 nM and a limit of quantification calculated at 204.5 nM. This provides a 'fit-for-purpose' model assay for the detection and quantification of any target of interest by adapting and functionalising a suitable target-specific DNA aptamer and its complementary antisense strand.

Biomarker testing plays a crucial role in the early detection of liver cancer. Herein, we developed a dual-signal amplification approach utilizing magnetic aggregation and a recognition competition strategy for the simultaneous detection of alpha-fetoprotein (AFP) and manganese superoxide dismutase (MnSOD) in serum. 4-MBA@AuNPs@H1 and DTNB@AuNPs@H2 were synthesized by functionalizing Raman signaling molecules and aptamer complementary chains onto the surface of gold nanoparticles (AuNPs). The detection complex Raman signal molecule@AuNPs@H-Fe 3 O 4 @cDNA was assembled by conjugating 4-MBA@AuNPs@H1 and DTNB@AuNPs@H2 with two nucleic acid aptamers (cDNA1 and cDNA2) modified with Fe 3 O 4 through partial base complementary pairing. The target protein exhibited specific binding with the aptamer, leading to the competitive displacement of 4-MBA@AuNPs@H1 and DTNB@AuNPs@H2 from the Fe 3 O 4 array surface, consequently resulting in a reduction of the Surface-Enhanced Raman Spectroscopy (SERS) signal. Through this approach, the limit of detection (LOD) for AFP and MnSOD in serum was achieved at remarkably low levels of 5.89 pg/mL and 6.23 pg/mL, respectively, with a reaction incubation period of only 5 min. Finally, the platform was utilized for the quantification of AFP and MnSOD in the serum of a nude mouse hepatocellular carcinoma model. The results obtained through SERS were consistent with those from enzyme-linked immunosorbent assay (ELISA), validating its accuracy. This methodology presents a novel approach for the swift and concurrent detection of proteins, holding significant clinical promise for the early diagnosis of hepatocellular carcinoma., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Extracellular vesicles (EVs), or exosomes, play important roles in physiological and pathological cellular communication and have gained substantial traction as biological drug carriers. EVs contain both short and long non-coding RNAs that regulate gene expression and epigenetic processes. To fully capitalize on the potential of EVs as drug carriers, it is important to study and understand the intricacies of EV function and EV RNA-based communication. Here we developed a genetically encodable RNA-based biomaterial, termed EXO-Probe, for tracking EV RNAs. The EXO-Probe comprises an EV-loading RNA sequence (EXO-Code), fused to a fluorogenic RNA Mango aptamer for RNA imaging. This fusion construct allowed the visualization and tracking of EV RNA and colocalization with markers of multivesicular bodies; imaging RNA within EVs, and non-destructive quantification of EVs. Overall, the new RNA-based biomaterial provides a useful and versatile means to interrogate the role of EVs in cellular communication via RNA trafficking to EVs and to study cellular sorting decisions. The system will also help lay the foundation to further improve the therapeutic efficacy of EVs as drug carriers., Competing Interests: Declaration of competing interest JN, SF, and EB are inventors on the patent applications of the EXO-Code technology evaluated in this paper that have been licensed to Exopharm and have received royalties. These relationships have been disclosed to and are under management by UNC-Chapel Hill., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Gold standard detection of SARS-CoV-2 by reverse transcription quantitative PCR (RT-qPCR) can achieve ultrasensitive viral detection down to a few RNA copies per sample. Yet, the lengthy detection and labor-intensive protocol limit its effectiveness in community screening. In view of this, a structural switching electrochemical aptamer-based biosensor (E-AB) targeting the SARS-CoV-2 nucleocapsid (N) protein was developed. Four N protein-targeting aptamers were characterized on an electrochemical cell configuration using square wave voltammetry (SWV). The sensor was investigated in an artificial saliva matrix optimizing the aptamer anchoring orientation, SWV interrogation frequency, and target incubation time. Rapid detection of the N protein was achieved within 5 min at a low nanomolar limit of detection (LOD) with high specificity. Specific N protein detection was also achieved in simulated positive saliva samples, demonstrating its feasibility for saliva-based rapid diagnosis. Further research will incorporate novel signal amplification strategies to improve sensitivity for early diagnosis.

Respiratory pathogens infecting the human respiratory system are characterized by their diversity, high infectivity, rapid transmission, and acute onset. Traditional detection methods are time-consuming, have low sensitivity, and lack specificity, failing to meet the needs of rapid clinical diagnosis. Nucleic acid aptamers, as an emerging and innovative detection technology, offer novel solutions with high specificity, affinity, and broad target applicability, making them particularly promising for respiratory pathogen detection. This review highlights the progress in the research and application of nucleic acid aptamers for detecting respiratory pathogens, discussing their selection, application, potential in clinical diagnosis, and future development. Notably, these aptamers can significantly enhance the sensitivity and specificity of detection when combined with detection techniques such as fluorescence, colorimetry and electrochemistry. This review offers new insights into how aptamers can address the limitations of traditional diagnostic methods and advance clinical diagnostics. It also highlights key challenges and future research directions for the clinical application of nucleic acid aptamers., (© 2024. The Author(s).)

Infectious diseases represent a significant global health challenge, with bacteria, fungi, viruses, and parasitic protozoa being significant causative agents. The shared symptoms among diseases and the emergence of new pathogen variations make diagnosis and treatment complex. Conventional diagnostic methods are laborious and intricate, underscoring the need for rapid, accurate techniques. Aptamer-based technologies offer a promising solution, as they are cost-effective, sensitive, specific, and convenient for molecular disease diagnosis. Aptamers, which are single-stranded RNA or DNA sequences, serve as nucleotide equivalents of monoclonal antibodies, displaying high specificity and affinity for target molecules. They are structurally robust, allowing for long-term storage without substantial activity loss. Aptamers find applications in diverse fields such as drug screening, material science, and environmental monitoring. In biomedicine, they are extensively studied for biomarker detection, diagnostics, imaging, and targeted therapy. This comprehensive review focuses on the utility of aptamers in managing infectious diseases, particularly in the realms of diagnostics and therapeutics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision, (Copyright © 2024 Sujith, Naresh, Srivisanth, Sajeevan, Rajaramon, David and Solomon.)

While monoclonal antibodies have shown success in cancer immunotherapy, their limitations prompt exploration of alternative approaches such as aptamers and peptides targeting programmed death ligand 1 (PD-L1). Despite the significance of these biotechnological tools, a comprehensive review encompassing both aptamers and peptides for PD-L1 targeting is lacking. Addressing this gap is crucial for consolidating recent advancements and insights in this field. Biotechnological advances leveraging aptamers and peptides represent a cutting-edge approach in refining the targeting proteins. Our review aims to provide valuable guidance for researchers and clinicians, highlighting the biotechnological advances utilizing aptamers and peptides refining PD-L1 targeting., (© 2024 The Author(s). Published by IMR Press.)

Functional assays on intact tumor biopsies can complement genomics-based approaches for precision oncology, drug testing, and organs-on-chips cancer disease models by capturing key therapeutic response determinants, such as tissue architecture, tumor heterogeneity, and the tumor microenvironment. Most of these assays rely on fluorescent labeling, a semiquantitative method best suited for single-time-point assays or labor-intensive immunostaining analysis. Here, we report integrated aptamer electrochemical sensors for on-chip, real-time monitoring of cytochrome C, a cell death indicator, from intact microdissected tissues with high affinity and specificity. The platform features a multi-well sensor layout and a multiplexed electronic setup. The aptasensors measure increases in cytochrome C in the supernatant of mouse or human microdissected tumors after exposure to various drug treatments. Because of the sensor's high affinity, it primarily tracks rising concentrations of cytochrome C, capturing dynamic changes during apoptosis. This approach could help develop more advanced cancer disease models and apply to other complex in vitro disease models, such as organs-on-chips and organoids.

The gut microbiome is shaped early in life by dietary and lifestyle factors. Specific compounds in the gut affect the growth of different bacterial species and the production of beneficial or harmful byproducts. Dysbiosis of the gut microbiome has been linked to various diseases resulting from the presence of harmful bacteria and their byproducts. Existing methods for detecting microbial species, such as microscopic observation and molecular biological techniques, are costly, labor-intensive, and require skilled personnel. Biosensors, which integrate a recognition element, transducer, amplifier, signal processor, and display unit, can convert biological events into electronic signals. This review provides a comprehensive and systematic survey of scientific publications from 2018 to June 2024, obtained from ScienceDirect, PubMed, and Scopus databases. The aim was to evaluate the current state-of-the-art and identify knowledge gaps in the application of aptamer biosensors for the determination of gut microbiota. A total of 13 eligible publications were categorized based on the type of study: those using microbial bioreceptors (category 1) and those using aptamer bioreceptors (category 2) for the determination of gut microbiota. Point-of-care biosensors are being developed to monitor changes in metabolites that may lead to disease. They are well-suited for use in the healthcare system and offer an excellent alternative to traditional methods. Aptamers are gaining attention due to their stability, specificity, scalability, reproducibility, low production cost, and low immunogenicity. While there is limited research on using aptamers to detect human gut microbiota, they show promise for providing accurate, robust, and cost-effective diagnostic methods for monitoring the gut microbiome.

The efficacy of neurotherapeutic drugs hinges on their ability to traverse the blood-brain barrier and access the brain, which is crucial for treating or alleviating neurodegenerative diseases (NDs). Given the absence of definitive cures for NDs, early diagnosis and intervention become paramount in impeding disease progression. However, conventional therapeutic drugs and existing diagnostic approaches must meet clinical demands. Consequently, there is a pressing need to advance drug delivery systems and early diagnostic methods tailored for NDs. Certain aptamers endowed with specific functionalities find widespread utility in the targeted therapy and diagnosis of NDs. DNA nanoflowers (DNFs), distinctive flower-shaped DNA nanomaterials, are intricately self-assembled through rolling ring amplification (RCA) of circular DNA templates. Notably, imbuing DNFs with diverse functionalities becomes seamlessly achievable by integrating aptamer sequences with specific functions into RCA templates, resulting in a novel nanomaterial, aptamer-bound DNFs (ADNFs) that amalgamates the advantageous features of both components. This article delves into the characteristics and applications of aptamers and DNFs, exploring the potential or application of ADNFs in drug-targeted delivery, direct treatment, early diagnosis, etc. The objective is to offer prospective ideas for the clinical treatment or diagnosis of NDs, thereby contributing to the ongoing efforts in this critical field., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nucleolin is overexpressed on the surface of pancreatic cancer cells and are regarded as the remarkable therapeutic target. Aptamers are capable of binding the external domain of nucleolin on the cell surface with high affinity and specificity. But nucleolin has not been localized on pancreatic cancer cells at very high spatial resolution, and the interactions between nucleolin and aptamers have not been investigated at very high force resolution level. In this work, nucleolin was localized on pancreatic cancer and normal cells by aptamers (9FU-AS1411-NH 2 , AS1411-NH 2 and CRONH 2 ) in Single Molecule Recognition Imaging mode of Atomic Force Microscopy. There are plenty of nucleolin on the surfaces of pancreatic cancer cells (area percentage about 5 %), while there are little nucleolin on the surfaces of normal cells. The interactions between three types of aptamers and nucleolins on the surfaces of pancreatic cancer cells were investigated by Single Molecule Force Spectroscopy. The unbinding forces of nucleolins-(9FU-AS1411-NH 2 ) are larger than nucleolins-(AS1411-NH 2 ). The dissociation activation energy on nucleolin-(9FU-AS1411-NH 2 ) is higher than nucleolin-(AS1411-NH 2 ), which indicates that the former complex is more stable and harder to dissociate than the later complex. There are no unbinding forces between nucleolin and CRONH 2 . All these demonstrate that nucleolin was localized on pancreatic cancer and normal cells at single molecule level quantitatively, and the interactions (unbinding forces and kinetics) between nucleolin and aptamers were studied at picoNewton level. The approaches and results of this work will pave new ways in the investigations of nucleolin and aptamers, and will also be useful in the studies on other proteins and their corresponding aptamers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Aptamers are not so new a concept, however, it is scarcely discussed by medical fraternity. Aptamers are potent, new identification molecules set to rope in a new technique in the diagnostic arena. Aptamers have started almost a revolution in diagnostic assays since their discovery in the 90s. (Radu S. Current and previous disease outbreaks around the world, U.S. News & World Report. 2020 Mar 13 [cited 2024 Jun 17]. Available from: https://www.usnews.com/news/best-countries/slideshows/20-pandemic-and-epidemic-diseases-according-to-who) provides an overview of pandemics and epidemics as reported by the WHO. It is interesting to note that several endemic and epidemic diseases viz. Chikungunya, Cholera, Crimean-Congo haemorrhagic fever, Ebola virus disease, Hendra virus infection, Influenza, Lassa fever, Marburg virus disease, Meningitis, MERS-CoV (Middle East Respiratory Syndrome Corona Virus), Monkeypox, Nipah virus infection, Novel coronavirus, Plague, Rift Valley fever, SARS (Severe Acute Respiratory Syndrome), Smallpox, Tularaemia, Yellow fever, and Zika virus disease have been identified by the WHO and are being explored for applicability of aptamer technology in their identification., Objectives: One of the most important necessities to control epidemic or pandemic diseases is early diagnosis. However, the majority of the diagnostic tests for these diseases are available only in tertiary care centres. The objective of this review is to discuss the potential of aptamer technology to provide undemanding, simple, specific, sensitive, and cost-effective diagnostic assays that are useable in remote and field conditions., Content: Here, we discuss recent advances and approaches in aptamer and aptamer engineering useful in the diagnosis of infectious and non-infectious conditions. This review also discusses a few sensing discoveries which are a gift of advanced engineering and technology using optical and electrochemical aptasensors. It's still a long way to go, and we need to take into account the technological challenges being faced by aptamer-aptasensor technology., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr Raghavendra D. Kulkarni reports administrative support and equipment, drugs, or supplies were provided by SDM College of Medical Sciences and Hospital. Dr Raghavendra D. Kulkarni reports a relationship with SDM College of Medical Sciences and Hospital that includes: employment and non-financial support. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

Macrophages play a critical role in the body's defense against cancer by phagocytosing tumor cells, presenting antigens, and activating adaptive T cells. However, macrophages are intrinsically incapable of delivering targeted cancer immunotherapies. Engineered adoptive cell therapy introduces new targeting and antitumor capabilities by modifying macrophages to enhance the innate immune response of cells and improve clinical efficacy. In this study, we developed engineered macrophage cholesterol-AS1411-M1 (CAM1) for cellular immunotherapy. To target macrophages, cholesterol-AS1411 aptamers were anchored to the surface of M1 macrophages to produce CAM1 without genetic modification or cell damage. CAM1 induced significantly higher apoptosis/mortality than unmodified M1 macrophages in murine breast cancer cells. Anchoring AS1411 on the surface of macrophages provided a novel approach to construct engineered macrophages for tumor immunotherapy., Competing Interests: Declaration of Competing Interest No conflict of interest exits in the submission of this manuscript., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Small molecules are highly relevant targets for detection and quantification. They are also used to diagnose and monitor the progression of disease and infectious processes and track the presence of contaminants. Fluorogenic RNA-based biosensors (FRBs) represent an appealing solution to the problem of detecting these targets. They combine the portability of molecular systems with the sensitivity and multiplexing capacity of fluorescence, as well as the exquisite ligand selectivity of RNA aptamers. In this review, we first present the different sensing and reporting aptamer modules currently available to design an FRB, together with the main methodologies used to discover modules with new specificities. We next introduce and discuss how both modules can be functionally connected prior to exploring the main applications for which FRB have been used. Finally, we conclude by discussing how using alternative nucleotide chemistries may improve FRB properties and further widen their application scope.

Here, a separation-free and label-free portable aptasensor is developed for rapid and sensitive analysis of tumor-derived exosomes (TEXs). It integrated a parallel rolling circle amplification (RCA) reaction, selective binding of metal ions or small molecules to nucleic acid-specific conformations, and a low-cost, highly sensitive handheld fluorometer. Lung cancer, for example, is targeted with two typical biomarkers (mucin 1 and programmed cell death ligand 1 (PD-L1)) on its exosomes. The affinity of aptamers to the targets modulated the amount of RCA products (T-Hg 2+ -T and cytosine (C)-rich single-stranded DNA), which in turn affected the fluorescence intensity of quantum dots (QDs) and methylene blue (MB). The results revealed that the limit of detection (LOD) of the handheld fluorometer for cell-derived exosomes can be as low as 30 particles mL -1 . Moreover, its specificity, sensitivity, and area under the curve (AUC) are 93% (14/15), 92% (23/25), and 0.956, as determined by the analysis of 40 clinical samples. Retesting 16 of these samples with the handheld fluorometer yielded strong concordance between the fluorometer results and those acquired from clinical computed tomography (CT) and pathology., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Among the various targeting ligands for drug delivery, aptamers have attracted much interest in recent years because of their smaller size compared to antibodies, ease of modification, and better batch-to-batch consistency. In addition, aptamers can be selected to target both known and even unknown cell surface biomarkers. For drug loading, liposomes are the most successful vehicle and many FDA-approved formulations are based on liposomes. In this paper, aptamer-functionalized liposomes for targeted drug delivery are reviewed. We begin with the description of related aptamers selection, followed by methods to conjugate aptamers to liposomes and the fate of such conjugates in vivo. Then a few examples of applications are reviewed. In addition to intravenous injection for systemic delivery and hoping to achieve accumulation at target sites, for certain applications, it is also possible to have aptamer/liposome conjugates applied directly at the target tissue such as intratumor injection and dropping on the surface of the eye by adhering to the cornea. While previous reviews have focused on cancer therapy, the current review mainly covers other applications in the last four years. Finally, this article discusses potential issues of aptamer targeting and some future research opportunities., (© 2023 The Authors. Published by Elsevier B.V. on behalf of Chang Gung University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The polymer ionic liquid (1-allyl-3-butylimidazolium bromide) enhanced silica aerogel was modified onto the surface of stainless-steel mesh to immobilize aptamer-1 for the specific recognition of AFB1. The porous channels of silica aerogel could prevent the interference of macromolecules in food samples. Enzyme kinetic analysis showed that the MoS 2 /Au was an effective peroxidase mimic with a relatively low Michaelis constant (K m ) value of 0.17 mM and a high catalytic rate of 3.87 × 10 -8 mol (L·s) -1 , which exhibited obvious superiority compared with horseradish peroxidase. The established "sandwich-structure" biosensor was coupled with the smartphone "Color Picker" application was used to detect AFB1 with a wide linear range (1-100 ng mL -1 ) and low detection limit (0.25 ng mL -1 ). The anti-interference ability of the established biosensor was evaluated by adding different concentrations of standards in corn, peanut, and wheat and matrix effects were 90.84-106.11 %. The results showed that this method demonstrated high specificity, sensitivity, rapidity and low interference in food samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Aptamers are nucleic acid sequences that specifically bind with target molecules and are vital to applications such as biosensing, drug development, disease diagnostics, etc. The traditional selection procedure of aptamers is based on the Systematic Evolution of Ligands by an Exponential Enrichment (SELEX) process, which relies on repeating cycles of screening and amplification. With the rapid development of aptamer applications, RNA and XNA aptamers draw more attention than before. But their selection is troublesome due to the necessary reverse transcription and transcription process (RNA) or low efficiency and accuracy of enzymes for amplification (XNA). In light of this, we review the recent advances in aptamer selection methods and give an outlook on future development in a non-SELEX approach, which simplifies the procedure and reduces the experimental costs. We first provide an overview of the traditional SELEX methods mostly designed for screening DNA aptamers to introduce the common tools and methods. Then a section on the current screening methods for RNA and XNA is prepared to demonstrate the efforts put into screening these aptamers and the current difficulties. We further predict that the future trend of aptamer selection lies in non-SELEX methods that do not require nucleic acid amplification. We divide non-SELEX methods into an immobilized format and non-immobilized format and discuss how high-resolution partitioning methods could facilitate the further improvement of selection efficiency and accuracy.

Developing sensitive and accurate Ochratoxin A (OTA) detection methods is essential for food safety. Herein, a simple and reliable strategy for regulating interenzyme distance based on a rigid DNA quadrangular prism as a scaffold was proposed to establish a new electrochemical biosensor for ultrasensitive detection of OTA. The interenzyme distances were precisely adjusted by changing the sequences of the hybridized portions of hairpins SH1 and SH2 to the DNA quadrangular prism, avoiding the complexity and instability of the previous DNA scaffold-based enzyme spacing adjustment strategies. The electrochemical biosensor constructed at the optimal interenzyme distance (10.4 nm) achieved sensitive detection of OTA in a dynamic concentration range from 10 fg/mL to 250 ng/mL with a detection limit of 3.1 fg/mL. In addition, the biosensor was applied to quantify OTA in real samples, exhibiting great application potential in food safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The selection of an appropriate transducer is a key element in biosensor development. Currently, a wide variety of substrates and working electrode materials utilizing different fabrication techniques are used in the field of biosensors. In the frame of this study, the following three specific material configurations with gold-finish layers were investigated regarding their efficacy to be used as electrochemical (EC) biosensors: (I) a silicone-based sensor substrate with a layer configuration of 50 nm SiO/50 nm SiN/100 nm Au/30-50 nm WTi/140 nm SiO/bulk Si); (II) polyethylene naphthalate (PEN) with a gold inkjet-printed layer; and (III) polyethylene terephthalate (PET) with a screen-printed gold layer. Electrodes were characterized using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to evaluate their performance as electrochemical transducers in an aptamer-based biosensor for the detection of cardiac troponin I using the redox molecule hexacyanoferrade/hexacyaniferrade (K3[Fe (CN)6]/K4[Fe (CN)6]. Baseline signals were obtained from clean electrodes after a specific cleaning procedure and after functionalization with the thiolate cardiac troponin I aptamers "Tro4" and "Tro6". With the goal of improving the PEN-based and PET-based performance, sintered PEN-based samples and PET-based samples with a carbon or silver layer under the gold were studied. The effect of a high number of immobilized aptamers will be tested in further work using the PEN-based sample. In this study, the charge-transfer resistance (Rct), anodic peak height (I pa ), cathodic peak height (I pc ) and peak separation (∆E) were determined. The PEN-based electrodes demonstrated better biosensor properties such as lower initial Rct values, a greater change in Rct after the immobilization of the Tro4 aptamer on its surface, higher I pc and I pa values and lower ∆E, which correlated with a higher number of immobilized aptamers compared with the other two types of samples functionalized using the same procedure.

Extracellular vesicles (EVs) are enclosed by a nanoscale phospholipid bilayer membrane and typically range in size from 30 to 200 nm. They contain a high concentration of specific proteins, nucleic acids, and lipids, reflecting but not identical to the composition of the parent cell. The inherent characteristics and variety of EVs give them extensive and unique advantages in the field of cancer identification and treatment. Recently, EVs have been recognized as potential tumor markers for the detection of cancer. Aptamers, which are molecules of single-stranded DNA or RNA, demonstrate remarkable specificity and affinity for their targets by adopting distinct tertiary structures. Aptamers offer various advantages over their protein counterparts, such as reduced immunogenicity, the ability for convenient large-scale synthesis, and straightforward chemical modification. In this review, we summarized EVs biogenesis, sample collection, isolation, storage and characterization, and finally provided a comprehensive survey of analysis techniques for EVs detection that are based on aptamers., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Esophageal squamous cell carcinoma (ESCC) is a prevalent gastrointestinal cancer characterized by high mortality and an unfavorable prognosis. While combination therapies involving surgery, chemotherapy, and radiation therapy are advancing, targeted therapy for ESCC remains underdeveloped. As a result, the overall five-year survival rate for ESCC is still below 20%. Herein, ESCC-specific DNA aptamers and an innovative aptamer-modified nano-system is introduced for targeted drug and gene delivery to effectively inhibit ESCC. The EA1 ssDNA aptamer, which binds robustly to ESCC cells with high specificity and affinity, is identified using cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX). An EA1-modified nano-system is developed using a natural egg yolk lipid nanovector (EA1-EYLNs-PTX/siEFNA1) that concurrently loads paclitaxel (PTX) and a small interfering RNA of Ephrin A1 (EFNA1). This combination counters ESCC's proliferation, migration, invasion, and lung metastasis. Notably, EFNA1 is overexpressed in ESCC tumors with lung metastasis and has an inverse correlation with ESCC patient prognosis. The EA1-EYLNs-PTX/siEFNA1 nano-system offers effective drug delivery and tumor targeting, resulting in significantly improved therapeutic efficacy against ESCC tumors. These insights suggest that aptamer-modified nano-systems can deliver drugs and genes with superior tumor-targeting, potentially revolutionizing targeted therapy in ESCC., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

The accurate and rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) holds significant clinical importance. This work presents a new method for detecting methicillin-resistant Staphylococcus aureus ( S. aureus ) in clinical samples. The method uses an aptamer-based colorimetric assay that combines a recognizing probe to identify the target and split DNAzyme to amplify the signal, resulting in a highly sensitive and direct analysis of methicillin-resistance. The identification of the PBP2a protein on the membrane of S. aureus in clinical samples leads to the allosterism of the recognizing probe, and thus provides a template for the proximity ligation of split DNAzyme. The proximity ligation of split DNAzyme forms an intact DNAzyme to identify the loop section in the L probe and generates a nicking site to release the loop sequence ("3" and "4" fragments). The "3" and "4" fragments forms an intact sequence to induce the catalytic hairpin assembly, exposing the G-rich section. The released the G-rich sequence of LR probe induces the formation of G-quadruplex-hemin DNAzyme as a colorimetric signal readout. The absorption intensity demonstrated a strong linear association with the logarithm of the S. aureus concentration across a wide range of 5 orders of magnitude dynamic range under the optimized experimental parameters. The limit of detection was calculated to be 23 CFU/ml and the method showed high selectivity for MRSA.

Antibodies have been extensively used in numerous applications within proteomics-based technologies, requiring high sensitivity, specificity, a broad dynamic range for detection, and precise, reproducible quantification. Seeking alternatives to antibodies due to several inherent limitations of antibodies is an area of active research of tremendous importance. Recently, aptamers have been receiving increasing attention, because they not only have all of the advantages of antibodies, but also have unique advantages, such as thermal stability, low cost, and unlimited applications. Aptamers are gaining importance in immunological studies and can potentially replace antibodies in immunoassays. B7H3, an immunoregulatory protein belonging to the B7 family, is an attractive and promising target due to its overexpression in several tumor tissues while exhibiting limited expression in normal tissues. This study employed hybrid-SELEX with next-generation sequencing to select ssDNA aptamers specifically binding to the B7H3 protein. These aptamers demonstrated versatility across various assays, including flow cytometry, dot-blot, and immunohistochemistry. Effective performance in sandwich dot-blot assays and western blot analysis suggests their potential for diagnostic applications and demonstrates their adaptability and cost-effectiveness in diverse protein detection techniques., (© 2024. The Author(s).)

Background: Yersinia pestis is a bacterium that causes the disease plague. It has caused the deaths of many people throughout history. The bacterium possesses several virulence factors (pPla, pFra, and PYV). PFra plasmid encodes fraction 1 (F1) capsular antigen. F1 protein protects the bacterium against host immune cells through phagocytosis process. This protein is specific for Y. pestis. Many diagnostic techniques are based on molecular and serological detection and quantification of F1 protein in different food and clinical samples. Aptamers are small nucleic acid sequences that can act as specific ligands for many targets.This study, aimed to isolate the high-affinity ssDNA aptamers against F1 protein., Methods and Results: In this study, SELEX was used as the main strategy in screening aptamers. Moreover, enzyme-linked aptamer sorbent assay (ELASA) and surface plasmon resonance (SPR) were used to determine the affinity and specificity of obtained aptamers to F1 protein. The analysis showed that among the obtained aptamers, the three aptamers of Yer 21, Yer 24, and Yer 25 were selected with a KD value of 1.344E - 7, 2.004E - 8, and 1.68E - 8 M, respectively. The limit of detection (LoD) was found to be 0.05, 0.076, and 0.033 μg/ml for Yer 21, Yer 24, and Yer 25, respectively., Conclusion: This study demonstrated that the synthesized aptamers could serve as effective tools for detecting and analyzing the F1 protein, indicating their potential value in future diagnostic applications., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

In recent years, the conventional preparation of silver nanoclusters (AgNCs) has attracted much attention due to their ultra-small size, tunable fluorescence, easy-to-engineer, as well as biocompatible material. Moreover, its great affinity towards cytosine bases on single-stranded DNA has led to the construction of biosensors, especially aptamers, for a broad variety of applications in food safety and environmental protection. In past years, numerous researchers paid attention to the construction of AgNCs aptasensor. Therefore, this review will be an effort to summarize the synthetic strategy along with the influences of factors on synthesis, categorize the sensing mechanism of aptamer-functionalized AgNCs biosensors, as well as their specific applications in food safety detection including heavy metal, toxin, and foodborne pathogenic bacteria. Furthermore, a brief conclusion and outlook regarding the prospects and challenges of their applications in food safety were drawn in line with the developments in DNA-AgNCs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

An electrochemical aptasensor was developed for the determination of chloramphenicol (CAP) in fresh foods and food products. The aptasensor was developed using Prussian blue (PB) and chitosan (CS) film. PB acts as a redox probe for detection and CS acts as a sorption material. The aptamer (Apt) was immobilized on a screen-printed carbon electrode (SPCE) modified with gold nanoparticles (AuNPs). Under optimum conditions, the linearity of the aptasensor was between 1.0 and 6.0 × 10 6  ng L -1 with a detection limit of 0.65 and a quantification limit of 2.15 ng L -1 . The electrode could be regenerated up to 24 times without the use of chemicals. The aptasensor showed good repeatability (RSD <11.2%) and good reproducibility (RSD <7.7%). The proposed method successfully quantified CAP in milk, shrimp pond water and shrimp meat with good accuracy (recovery = 88.0 ± 0.6% to 100 ± 2%). The proposed aptasensor could be especially useful in agriculture to ensure the quality of food and the environment and could be used to determine other antibiotics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aflatoxin (AFs) contamination is one of the serious food safety issues. Aflatoxin B1 (AFB1) is the most common and toxic aflatoxin, which has been classified as a class 1 carcinogen by the International Agency for Research on Cancer (IARC). It is extremely destructive to liver tissue. Developing a convenient and sensitive detection technique is essential. In this paper, we developed a homogeneous dual recognition strategy based electrochemical aptasensor for accurate and sensitive detection of aflatoxin B1 (AFB1) based on the magnetic graphene oxide (MGO) and UiO-66. The MGO was synthesized for the recognition and magnetic separation of AFB1 from complex samples. UiO-66/ferrocenecarboxylic acid (Fc)/aptamer composites were constructed as both recognition and signal probes. The probes would specifically capture AFB1 enriched by MGO, which enables dual recognition in homogeneous solution, thus further improving the accuracy of AFB1 detection. The electrochemical aptasensor for AFB1 had a linear range from 0.005 to 500 ng mL -1 . Additionally, the limit of detection was 1 pg mL -1 . It shows a favorable potential for both sensitive and accurate detection of AFB1 in real samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)