Browsing by Author "Ozalp, V. Cengiz"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Article Citation Count: 0Aptamer decorated PDA@magnetic silica microparticles for bacteria purification(Springer Wien, 2024) Özalp, Veli Cengiz; Babaie, Zahra; Kavruk, Murat; Cetin, Barbaros; Yesilkaya, Hasan; Amrani, Yassine; Ozalp, V. Cengiz; Basic Sciences; Nutrition and DieteticsOne significant constraint in the advancement of biosensors is the signal-to-noise ratio, which is adversely affected by the presence of interfering factors such as blood in the sample matrix. In the present investigation, a specific aptamer binding was chosen for its affinity, while exhibiting no binding affinity towards non-target bacterial cells. This selective binding property was leveraged to facilitate the production of magnetic microparticles decorated with aptamers. A novel assay was developed to effectively isolate S. pneumoniae from PBS or directly from blood samples using an aptamer with an affinity constant of 72.8 nM. The capture experiments demonstrated efficiencies up to 87% and 66% are achievable for isolating spiked S. pneumoniae in 1 mL PBS and blood samples, respectively.Article Citation Count: 1Biosensor for ATP detection via aptamer-modified PDA@POSS nanoparticles synthesized in a microfluidic reactor(Springer Wien, 2024) Özalp, Veli Cengiz; Sahinoglu, O. Berkay; Kilincli, Betul; Erdem, E. Yegan; Cetin, Barbaros; Ozalp, V. Cengiz; Basic SciencesThis study introduces aptamer-functionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticles for adenosine triphosphate (ATP) detection where the POSS nanoparticles were synthesized in a one-step, continuous flow microfluidic reactor utilizing thermal polymerization. A microemulsion containing POSS monomers was generated in the microfluidic reactor which was designed to prevent clogging by using a continuous oil flow around the emulsion during thermal polymerization. Surfaces of POSS nanoparticles were biomimetically modified by polydopamine. The aptamer sequence for ATP was successfully attached to POSS nanoparticles. The aptamer-modified POSS nanoparticles were tested for affinity-based biosensor applications using ATP as a model molecule. The nanoparticles were able to capture ATP molecules successfully with an affinity constant of 46.5 mu\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu $$\end{document}M. Based on this result, it was shown, for the first time, that microfluidic synthesis of POSS nanoparticles can be utilized in designing aptamer-functionalized nanosystems for biosensor applications. The integration of POSS in biosensing technologies not only exemplifies the versatility and efficacy of these nanoparticles but also marks a significant contribution to the field of biorecognition and sample preparation.Article Citation Count: 0Performance Comparison of Aptamer- and Antibody-Based Biosensors for Bacteria Detection on Glass Surfaces(Taylor & Francis inc, 2024) Özalp, Veli Cengiz; Kurekci, Asli; Ozalp, V. Cengiz; Cetin, Barbaros; Basic SciencesAntibodies are the most common ligands in commercial and research assay systems for detecting whole pathogen cells. On the other hand, aptamers are superior ligands with many advantages over antibodies in sensitive and robust assay development. Extensive comparisons between aptamer-based biosensors and immunosensors are limited to protein analytes. Here, we report a comparison of ligands (four antibodies and one aptamer for each bacteria) to be used as a biosensor for Escherichia coli and Staphylococcus aureus on glass surfaces through systematic experiments. We have demonstrated that anti-E. coli antibody and mouse monoclonal to S. aureus have the best performance among the compared ligands. Hence, the ligands with the best performance were further investigated within the scope of linear range, analytical sensitivity, and reproducibility of the results. We have demonstrated that anti-E. coli antibody with a capture efficiency of 89.1% and mouse monoclonal to S. aureus with a capture efficiency of 88.2% have the best performance among the compared ligands. The results suggest that antibody ligands function with higher efficiency than aptamer ligands but aptamers have strong potential as an analytical tool.