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Aptamers are single-stranded DNA or RNA oligonucleotides with a unique secondary structure. Target binding induces conformational changes in the secondary structure. Conformation-induced changes in some characteristic Raman bands of DNA aptamer, upon binding to aflatoxin B1 (AFB1), were probed using surface enhanced Raman spectroscopy (SERS). The self-assembled monolayers of thiol-linked DNA aptamer on gold nanoparticles (AuNPs) surface provided a direct, label-free detection method through three adenine bases close to the surface of an AuNPs SERS substrate. The spectra of the DNA aptamer were dominated by the adenine ring breathing mode at 734 cm. Upon binding to AFB1 and conformational changes of the aptamer, the 5'-end of the aptamer with three adenine bases moved away from the surface of AuNPs, resulting in the decreased Raman intensity of the adenine band at 734 cm (I). In addition to the adenine band, the deoxyribose phosphate backbone (O-P-O) band at 1004 cm (I) was decreased after aptamer binding to AFB1. The change of I, corresponding to the AFB1 concentration, was employed for quantitative measurement of AFB1 in the range of 0.1-5000 pg mL. The aptamer-based SERS assay exhibited high sensitivity with a limit of detection (LOD) of 0.24 pg mL for I calibration curve.
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http://dx.doi.org/10.1016/j.saa.2025.126511 | DOI Listing |
Nucleosides Nucleotides Nucleic Acids
September 2025
School of Basic Medical Sciences, Yan'an University, Yan'an, China.
Live-cell imaging of intracellular proteins enables real-time observation of protein dynamics under near-physiological conditions, providing pivotal insights for both fundamental life science research and medical applications. However, due to limitations such as poor probe permeability and cytotoxicity associated with conventional antibody-based or genetically encoded labeling techniques, live-cell imaging remains a significant challenging. To address these limitations, here in this study, we developed and rigorously validated a novel aptamer-based fluorescent probe for real-time imaging of NEK9 kinase in living cells.
View Article and Find Full Text PDFBioconjug Chem
September 2025
Division of Organic Chemistry, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki 210-9501, Kanagawa, Japan.
Proteolysis-targeting chimeras (PROTACs) have emerged as a powerful modality for selectively degrading intracellular proteins via the ubiquitin-proteasome system. However, their development is often hindered by the limited availability of high-affinity small-molecule ligands, particularly for challenging targets, such as transcription factors. Aptamers─synthetic oligonucleotides with high affinity and specificity─offer a promising alternative as target-binding modules in the PROTAC design.
View Article and Find Full Text PDFAdv Drug Deliv Rev
September 2025
Biochemistry, CUNY Graduate Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, United States; Molecular, Cellular, and Developmental Biology, CUNY Graduate Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, United States; Chemistry, CUNY Gradua
Targeted drug delivery significantly enhances therapeutic efficacy across various diseases, particularly in cancer treatments, where conventional approaches such as chemotherapy and radiotherapy often cause severe side effects. In this context, nucleic acid aptamers-short, single-stranded DNA or RNA oligonucleotides capable of binding specific targets with high affinity-have emerged as promising tools for precision drug delivery and therapy. Aptamers can be selected against whole, living cells using SELEX and chemically modified for diverse applications.
View Article and Find Full Text PDFNucleic Acids Res
September 2025
Key Laboratory of Clinical Laboratory Diagnostics (Chinese Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, P. R. China.
Local pH variations play a pivotal role in numerous critical biological processes. However, achieving the tunability and selectivity of pH detection remains a challenge. Here, we present a DNA-based strategy that enables programmable and selective pH responses, which is termed shadow-strand hybridization-actuated displacement engineering (SHADE).
View Article and Find Full Text PDFAnal Chem
September 2025
Institute of Molecular Medicine (IMM), Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China.
Membrane receptor recognition is a specific biotargeting strategy for disease diagnosis and treatment, but it suffers from insufficient receptor expression levels. Hydrophobic interaction-based membrane anchoring strategy allows high anchoring density, but it lacks specificity. In this study, we present a DNA nanocage-based artificial receptor generator (DNARG) that combines the advantages of high specificity of receptor recognition and high density of hydrophobic membrane anchoring.
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