Aptamers are nucleic acid-based scaffolds that can bind with high affinity to a variety of biological targets. Aptamers are identified from large DNA or RNA libraries through a process of directed molecular evolution (SELEX). Chemical modification of nucleic acids considerably increases the functional and structural diversity of aptamer libraries and substantially increases the affinity of the aptamers. Additionally, modified aptamers exhibit much greater resistance to biodegradation. The evolutionary selection of modified aptamers is conditioned by the possibility of the enzymatic synthesis and replication of non-natural nucleic acids. Wild-type or mutant polymerases and their non-natural nucleotide substrates that can support SELEX are highlighted in the present review. A focus is made on the efforts to find the most suitable type of nucleotide modifications and the engineering of new polymerases. Post-SELEX modification as a complementary method will be briefly considered as well.
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http://dx.doi.org/10.1007/s12033-015-9907-9 | DOI Listing |
Biomed Microdevices
January 2025
Department of Physics, Faculty of Philosophy, Science and Letter, University of São Paulo, Ribeirão Preto, SP, 14040-901, Brazil.
The overexpression of Human Epidermal Growth Factor Receptor 2 (HER2) protein is specifically related to tumor cell proliferation in breast cancers. Its presence in biological serum samples indicates presence or progression of cancer, becoming a promise biomarker. However, their detection needs a simple and high accuracy platform.
View Article and Find Full Text PDFBioelectrochemistry
January 2025
School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China. Electronic address:
A ratiometric electrochemical aptasensor was developed for ultra-sensitive detection of cortisol using aptamer (Apt) as recognition element, methylene blue (MB) as signal probe, and zirconium metal-organic framework (Zr-MOF) as carrier loaded with abundant MB for signal amplification. The carboxylated multi-walled carbon nanotubes (cMWCNTs)-modified Au electrode showed excellent electrochemical performance to immobilize complementary DNA (cDNA) for hybridizing with MB@Zr-MOF-Apt via amide bonds. In the presence of cortisol, it would compete with cDNA for binding the Apt, resulting in the detachment of MB@Zr-MOF-Apt complex from the electrode surface, and the electrochemical signal of MB was decreased, while that of [Fe(CN)] was basically unchanged.
View Article and Find Full Text PDFAnal Chem
January 2025
State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China.
Timely and accurate detection of trace mycotoxins in agricultural products and food is significant for ensuring food safety and public health. Herein, a deep learning-assisted and entropy-driven catalysis (EDC)-Argonaute powered fluorescence single-particle aptasensing platform was developed for ultrasensitive detection of fumonisin B (FB) using single-stranded DNA modified with biotin and red fluorescence-encoded microspheres as a signal probe and streptavidin-conjugated magnetic beads as separation carriers. The binding of aptamer with FB releases the trigger sequence to mediate EDC cycle to produce numerous 5'-phosphorylated output sequences, which can be used as the guide DNA to activate downstream Argonaute (Ago) for cleaving the signal probe, resulting in increased number of fluorescence microspheres remaining in the final reaction supernatant after magnetic separation.
View Article and Find Full Text PDFAnal Methods
January 2025
Institute of Medical Engineering, Department of Biophysics, School of Basic Medical Sciences, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China.
Adenosine triphosphate (ATP) is crucial for cellular activity. The need for ATP detection in the field of biomedicine is rapidly increasing. Several biosensor-based approaches have been developed as a result of the growing demand for ATP detection.
View Article and Find Full Text PDFPharmaceutics
January 2025
Division of Pharmaceutical Sciences, James L Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH 45267, USA.
RNA nanoparticles, derived from the packaging RNA three-way junction motif (pRNA-3WJ) of the bacteriophage phi29 DNA packaging motor, have been demonstrated to be thermodynamically and chemically stable, with promise as a nanodelivery system. : A previous study showed that RNA nanoparticles with antiangiogenic aptamers (anti-vascular endothelial growth factor (VEGF) and anti-angiopoietin-2 (Ang2) aptamers) inhibited cell proliferation via WST-1 assay. To further investigate the antiangiogenic potential of these RNA nanoparticles, a modified three-dimensional (3D) spheroid sprouting assay model of human umbilical vein endothelial cells was utilized in the present study.
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