Browsing by Author "Yildirim-Tirgil, Nimet"

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Citation - WoS: 25
Citation - Scopus: 22
Enhanced Selex Platforms for Aptamer Selection With Improved Characteristics: a Review
(Springernature, 2024) Didarian, Reza; Ozbek, Hatice K.; Ozalp, Veli C.; Erel, Ozcan; Yildirim-Tirgil, Nimet
This review delves into the advancements in molecular recognition through enhanced SELEX (Systematic Evolution of Ligands by Exponential Enrichment) platforms and post-aptamer modifications. Aptamers, with their superior specificity and affinity compared to antibodies, are central to this discussion. Despite the advantages of the SELEX process-encompassing stages like ssDNA library preparation, incubation, separation, and PCR amplification-it faces challenges, such as nuclease susceptibility. To address these issues and propel aptamer technology forward, we examine next-generation SELEX platforms, including microfluidic-based SELEX, capillary electrophoresis SELEX, cell-based aptamer selection, counter-SELEX, in vivo SELEX, and high-throughput sequencing SELEX, highlighting their respective merits and innovations. Furthermore, this article underscores the significance of post-aptamer modifications, particularly chemical strategies that enhance aptamer stability, reduce renal filtration, and expand their target range, thereby broadening their utility in diagnostics, therapeutics, and nanotechnology. By synthesizing these advanced SELEX platforms and modifications, this review illuminates the dynamic progress in aptamer research and outlines the ongoing efforts to surmount existing challenges and enhance their clinical applicability, charting a path for future breakthroughs in this evolving field.
Selection of DNA Aptamers Against Parathyroid Hormone for Electrochemical Impedimetric Biosensor System Development
(John Wiley and Sons Inc, 2025) Didarian, Reza; Bargh, Saharnaz; Gulerman, Almina; Ozalp, Veli Cengiz; Erel, Ozcan; Yildirim-Tirgil, Nimet
This work presents the pioneering development of an aptamer-based electrochemical biosensor for real-time monitoring of parathyroid hormone (PTH) levels, with a focus on intraoperative assessment during parathyroid surgery. It introduces, for the first time, the selection and characterization of aptamers targeting distinct segments of the PTH peptide. The study demonstrates the feasibility and efficacy of the biosensing platform through a precisely designed experimental framework, including SELEX-based aptamer selection, aptamer-peptide interaction analysis, and biosensor fabrication. The SELEX process yields aptamers with notable binding affinities to different fragments of PTH, with the PTH (53-84) aptamer showing particularly sensitive binding to the hormone's C terminus, allowing for precise PTH analysis. Electrochemical characterization reveals significant changes in electrochemical impedance spectroscopy (EIS) signals upon exposure to varying PTH concentrations, highlighting the sensor's sensitivity and selectivity. The increase in charge transfer resistance (Rct) values with rising PTH concentrations underscores the biosensor's capability to detect PTH-induced structural changes, validating its potential for accurate measurement. The biosensor shows remarkable selectivity in the presence of common interferents in serum samples, ensuring precise PTH detection. Stability assessments over a 45-day storage period demonstrate the biosensor's robustness and long-term reliability, affirming its practical suitability. In summary, the developed aptamer-based biosensor represents a promising tool for sensitive and selective PTH detection, with potential applications in biomedical research and clinical diagnostics, particularly for intraoperative PTH analysis during parathyroidectomy. Continued research and optimization efforts hold promise for enhancing its performance and expanding its utility in diverse healthcare settings.