Yazar "Tuna, Bilge G." seçeneğine göre listele

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    Genotyping of single nucleotide polymorphism by probe-gated silica nanoparticles
    (Academic Press Inc Elsevier Science, 2017) Ercan, Meltem; Özalp, Veli C.; Tuna, Bilge G.
    The development of simple, reliable, and rapid approaches for molecular detection of common mutations is important for prevention and early diagnosis of genetic diseases, including Thalessemia. Oligonucleotide-gated mesoporous nanoparticles-based analysis is a new platform for mutation detection that has the advantages of sensitivity, rapidity, accuracy, and convenience. A specific mutation in beta-thalassemia, one of the most prevalent inherited diseases in several countries, was used as model disease in this study. An assay for detection of IVS110 point mutation (A > G reversion) was developed by designing probe-gated mesoporous silica nanoparticles (MCM-41) loaded with reporter fluorescein molecules. The silica nanoparticles were characterized by AFM, TEM and BET analysis for having 180 nm diameter and 2.83 nm pore size regular hexagonal shape. Amine group functionalized nanoparticles were analysed with FIR technique. Mutated and normal sequence probe oligonucleotides)about 12.7 nmol per mg nanoparticles) were used to entrap reporter fluorescein molecules inside the pores and hybridization with single stranded DNA targets amplified by PCR gave different fluorescent signals for mutated targets. Samples from IVS110 mutated and normal patients resulted in statistically significant differences when the assay procedure were applied. (C) 2017 Elsevier Inc. All rights reserved.
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    Graphene-based electrochemical aptasensors
    (Wiley Blackwell, 2019) Ozalp, V. Cengiz; Karabiyik, Göktuğ; Bayrac, A. Tahir; Uçak, Samet; Tuna, Bilge G.
    Graphene has remarkable electrical, thermal, and mechanical characters and has been widely used in biosensor development. Various graphene-based materials, including graphene oxide (GO), an aqueous dispersible oxygenated derivative of graphene, have been widely successfully utilized in molecular hybrids or biocompatible scaffolds or substrates, and patterned carbon films after being chemically reduced or modified to tune the material properties. Aptamers are short oligonucleotides that bind targets with high specificity and affinity (in the nanomolar or picomolar ranges). Aptamers have been selected for targets with varying degrees of complexity, from small molecules to whole cells or tissues. Aptamers have high potential as diagnostic and therapeutic tools, with many advantages when compared with antibodies, including their smaller size-which improves access to biological environments "hidden" from antibodies-their lack of immunogenicity, and the lower cost and higher reproducibility of nucleotide production. In addition, aptamers can be chemically modified to become more stable, labeled with fluorophores or other reporters, and can be easily truncated to eliminate sequences not important for interaction. These valuable properties make aptamers flexible and powerful tools for diagnostic and therapeutic purposes. In this chapter, we plan to focus on graphene-aptamer combinations in order to obtain selective and highly sensitive biosensors for medical and food safety purposes. © 2019 John Wiley & Sons, Inc. All rights reserved.
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    Staphylococcus aureus detection in blood samples by silica nanoparticle-oligonucleotides conjugates
    (Elsevier Advanced Technology, 2016) Borsa, Barış Ata; Tuna, Bilge G.; Hernandez, Frank J.; Hernandez, Luiza I.; Bayramoğlu, Gülay; Arıca, M. Yakup; Özalp, Veli Cengiz
    A fast, specific and sensitive homogeneous assay for Staphylococcus aureus detection was developed by measuring the activity of secreted nuclease from the bacteria via a modified DNA oligonucleotide. As biosensor format, an effective system, Nanokeepers as previously reported, were used for triggered release of confined fluorophores, and hence specific detection of S. aureus on nuclease activity was obtained. The interference from blood components for fluorescent quantification was eliminated by a pre purification by aptamer-functionalized silica magnetic nanoparticles. The reported assay system was exclusively formed by nucleic acid oligos and magnetic or mesoporous silica nanoparticles, that can be used on blood samples in a stepwise manner. The assay was successfully used as a sensing platform for the specific detection of S. aureus cells as low as 682 CFU in whole blood. (C) 2016 Elsevier B.V. All rights reserved.