Browsing by Author "Suludere, Zekiye"

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The Comparison of Antioxidant Capacity and Cytotoxic, Anticarcinogenic, and Genotoxic Effects of Fe@au Nanosphere Magnetic Nanoparticles
(Tubitak Scientific & Technological Research Council Turkey, 2017) Yegenoglu, Hande; Aslim, Belma; Guven, Burcu; Zengin, Adem; Boyaci, Ismail Hakki; Suludere, Zekiye; Tamer, Ugur
Magnetic gold nanoparticles are used in various biomedical, biochemistry, and biotechnology applications due to their controllable size distribution, long-term stability, reduced toxicity, and biocompatibility. Different coating materials, such as proteins, carbohydrates, lipids, and polyphenols, are applied to enhance the biocompatibility of nanoparticles. In this study, the effects of surface coatings of core-shell structured Fe@Au nanosphere magnetic nanoparticles with regard to antioxidant capacity and cytotoxic, anticarcinogenic, and genotoxic properties were investigated. The obtained results demonstrated that avidin-coated Fe@Au nanospheres had higher antioxidant capacities than uncoated nanospheres. Neither avidin-coated nor uncoated nanoparticles had a cytotoxic effect on normal cells (human gingival fibroblast cell line, HGF-1). In addition, they had anticarcinogenic effects on human cervical carcinoma (HeLa), human breast adenocarcinoma (MCF-7), and human colorectal adenocarcinoma (CCL-221). The genotoxic effects of nanoparticles were also evaluated with DNA tail damage ratio.
Construction of a Sensitive and Selective Plasmonic Biosensor for Prostate Specific Antigen by Combining Magnetic Molecularly-Imprinted Polymer and Surface-Enhanced Raman Spectroscopy
(Elsevier, 2022) Turan, Eylem; Zengin, Adem; Suludere, Zekiye; Kalkan, Nurhan Onal; Tamer, Ugur
Selective and sensitive detection of cancer biomarkers in serum samples is critical for early diagnosis of cancer. Prostate specific antigen is an important biomarker of prostate cancer, which ranks high among cancer-related deaths of men over 50 years old. Herein, a novel analytical method was introduced for detection of PSA by combining high selectivity of molecularly-imprinted polymers and high sensitivity of surface-enhanced Raman spectroscopy (SERS). Firstly, magnetic nanoparticles were grafted with an imprinted layer by using tannic acid as a functional monomer, diethylenetriamine as a cross-linker and prostate specific antigen as a template molecule. Detailed surface characterization and re-binding experiment results indicated that the imprinting of the antigen was successful with an imprinting factor of 5.58. The prepared magnetic molecularly imprinted polymers (MMIPs) were used as an antibody-free capture probe and labeled with gold nanoparticles that were modified with anti-PSA and a Raman reporter, namely 5,5'-dithiobis-(2-nitrobenzoic acid). Thus, a plasmonic structure (sandwich complex) was formed between MMIP and the SERS label. The limit of detection and limit of quantification of the designed sensor were 0.9 pg/mL and 3.2 pg/mL, respectively. The sensor also showed high recovery rates (98.0-100.1% for healthy person and 99.0-101.3% for patient) with low standard deviations (less than 4.3% for healthy person and less than 3.3% for patient) for PSA in serum samples. Compared with the traditional immunoassays, the proposed method has several advantages like low cost, reduced detection procedure, fast response, high sensitivity and selectivity. It is believed that the proposed method can be potentially used for selective and sensitive determination of tumor marker of prostate cancer in clinical applications.
Immunomagnetic Separation and Listeria Monocytogenes Detection With Surface-Enhanced Raman Scattering
(Tubitak Scientific & Technological Research Council Turkey, 2020) Akcinar, Hande Yegenoglu; Aslim, Belma; Torul, Hilal; Guven, Burcu; Zengin, Adem; Suludere, Zekiye; Tamer, Ugur
Background/aim: We aimed to develop a rapid method to enumerate Listeria monocytogenes (L. monocytogenes) utilizing magnetic nanoparticle based preconcentration and surface-enhanced Raman spectroscopy measurements. Materials and methods: Biological activities of magnetic Au-nanoparticles have been observed to have the high biocompatibility, and a sample immunosensor model has been designed to use avidin attached Au-nanoparticles for L. monocytogenes detection. Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium) bacteria cultures were chosen for control studies. Antimicrobial activity studies have been done to identify bio-compatibility and bio-characterization of the Au-nanoparticles in our previous study and capturing efficiencies to bacterial surfaces have been also investigated. Results: We constructed the calibration graphs in various population density of L. monocytogenes as 2.2 x 10(1) to 2.2 x 10(6) cfu/mL and the capture efficiency was found to be 75%. After the optimization procedures, population density of L. monocytogenes and Raman signal intensity showed a good linear correlation (12 2 - 0.991) between 10(2) to 10(6) cfu/ml, L. monocylogenes. The presented sandwich assay provides low detection limits and limit of quantification as 12 cfu/mL and 37 cfu/mL, respectively. We also compared the experimental results with reference plate-counting methods and the practical utility of the proposed assay is demonstrated using milk samples. Conclusion: It is focused on the enumeration of L. monocytogenes in milk samples and the comparision of results of milk analysis obtained by the proposed SERS method and by plate counting method stay in food agreement. In the present study, all parameters were optimized to select SERS-based immunoassay method for L. monocytogenes bacteria to ensure LOD, selectivity, precision and repeatablity.
Preparation of Molecularly Imprinted Pdms Elastomer for Selective Detection of Folic Acid in Orange Juice
(Elsevier Science Bv, 2019) Zengin, Adem; Badak, M. Utku; Bilici, Mustafa; Suludere, Zekiye; Aktas, Nahit
Herein, it is reported an effective method to prepare novel molecularly imprinted polymers (MIP) on poly(dimethylsiloxane) (PDMS) elastomer via a combination of non-covalent imprinting approach and surface initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization for sensitive and selective detection of folic acid (FA). For this purpose, 2-(2-Methoxyethoxy) ethyl methacrylate (MEOMA), ethylene glycol dimethacrylate (EGDMA), azobisisobutyronitrile (AIBN), FA and dimethylsulfoxide (DMSO) were used as functional monomer, cross-linker, initiator, template molecule, and porogen, respectively. The adsorption behavior followed the Scatchard equation between FA and PDMS-MIP with a saturation adsorption capacity of 4.51 mg/g and pseudo-second-order kinetics with 60 min equilibrium adsorption time. Furthermore, PDMS-MIP elastomer was successfully applied for selective extraction and detection of FA from orange juice with sufficient recovery (95.5-100.5%) and relative standard deviation less than 7.0%. The limit of detection (LOD) for FA was found to be 0.0031 mu g/mL with a linear range between 0.01 and 100 mu g/mL and a correlation coefficient of 0.9997. Results showed the proposed method could easily, efficiently and selectively extracted FA from complex media. Note that this novel proposed method will open a new way to detect any selected molecules such as pesticide, protein, drug, etc. using molecularly imprinted PDMS elastomer materials.
Rapid Bacterial Detection Through Microfluidic Integration With a Glucometer
(Elsevier Science Sa, 2025) Eryilmaz, Merve; Ilbasmis-Tamer, Sibel; Panhwar, Sallahuddin; Tayyarcan, Emine Kubra; Boyaci, Ismail Hakki; Suludere, Zekiye; Tamer, Ugur
We present a novel approach for sensitive and portable detection of pathogenic bacteria, which is crucial for household and clinical practice. Our method employs immunoliposomes, antibodies, and microchip to detect specific pathogens quantitatively. Gold and metal metal-organic nanoparticles and liposomes were characterized using high-resolution techniques like TEM and SEM. Utilizing a commercial, personal glucose meter (PGM), we initially detected released glucose from antibody-modified liposomes and microchips with MOF-NPs. Detection on the microchip was achieved within 30 min, while the PGM analysis took only one minute for targeted bacteria, yielding glucose signals of 66 mg/dL and 69 mg/dL, respectively. Serial dilutions with group A-Streptococcus pyogenes (GAS) (1.4 x 10<<^>>4-1.4 x 10<<^>>8 CFU/mL) demonstrated quantitative measurement applicability. This innovative approach and a portable PGM hold promise for various industries, including physician labs, hospitals, and households.
Synthesis of Magnetic Halloysite Nanotube-Based Molecularly Imprinted Polymers for Sensitive Spectrophotometric Detection of Metoclopramide in Urine Samples
(Elsevier, 2020) Bilici, Mustafa; Badak, M. Utku; Zengin, Adem; Suludere, Zekiye; Aktas, Nahit
A novel molecularly imprinted polymer was synthesized on magnetic halloysite nanotube via surface initiated reversible addition-fragmentation chain transfer polymerization in the presence of 2-aminoethylmethacrylamide, 2-Cyano-2-propyl benzodithioate, ethylene glycol dimethacrylate (EGDMA) and azobis(isobutyronitrile) for sensitive and selective spectrophotometric determination of metoclopramide in urine samples. The synthesized imprinted polymer was characterized by several surface characterization techniques and the results indicated there was a thin polymer network on the magnetic halloysite nanotube. The rebinding properties of the molecularly imprinted magnetic halloysite nanotube were also investigated in detail and the maximum adsorption capacity and imprinting factor were found to be 37.8 mg/g and 4.51, respectively. The application of the proposed method was carried out by enrichment and spectrophotometric determination of metoclopramide via formation of a charge transfer complex between picric acid and eluted metoclopramide. Under the optimized conditions, the calibration curve was linear in the concentration range of 5.0-150.0 ng/mL and the limit of detection and the limit of quantification were calculated to be 1.5 ng/mL and 4.95 ng/mL, respectively. The inter-day and intra-day precisions were below 5% and recoveries were between 92.8% and 99.2%. The results showed that the proposed method increased the sensitivity and selectivity for spectrophotometric determination of metoclopramide.