Browsing by Author "Erdogan, Omer"

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    PEG4000 modified liposomes enhance the solubility of quercetin and improve the liposome functionality: in vitro characterization and the cellular efficacy
    (Scientific and Technological Research Council Turkey, 2022-01-01) Demirbolat, Gulen Melike; Erdogan, Omer; Coskun, Goknil Pelin; Cevik, Ozge
    Quercetin, a multifunctional therapeutic agent, is used in various types of cancer. However, its therapeutic effect is limited by virtue of poorly aqueous solubility and instability in the physiological medium. To overcome these limitations, we aimed (i) to design quercetin loaded Liposomes with unlinked-PEG4000 with regard to not only surface modification but also solubility enhancement, and (ii) to investigate the antineoplastic effects on HeLa cells. PEG4000 increased the quercetin solubility 2.2 fold. PEG4000 modified Liposomes displayed small particle size (254 +/- 69 nm), low polydispersity index (0.236 +/- 0.018), favorable zeta potential (-35.4 +/- 0.6 mV), high quercetin encapsulation efficiency (87.6 +/- 5.6\%), and drug loading (22.2 +/- 6.9\%). The homogeneity and particle size of stable PEGylated liposomes were proved by transmission electron microscopy. The drug release was reached up to 65.1 +/- 3.8\% in 6 h. The IC50 value of quercetin loaded PEGylated liposomes was 16.3 mu g/mL on HeLa cells, while that of quercetin was 88.3 mu g/mL. PEGylated liposomes remarkably hampered the adherence and colony formation ability of cells according to crystal violet staining tests. The convenience of PEGylated liposomes for the parenteral application was stated by the hemolysis assay. The high-throughput screening assays based on AO/PI staining proved the drastic decrease of viable cell count. Moreover, qPCR tests based on gene expression levels revealed that the quercetin loaded PEGylated liposomes treatment could be more effective than free quercetin on the mitochondrial apoptosis of lieLa cells. These promising results allow considering further in vivo studies for efficient cancer treatment with quercetin loaded PEG4000 modified liposomes.
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    Treatment of glioblastoma by photodynamic therapy with the aid of synthesized silver nanoparticles by green chemistry from Citrus aurantium
    (MARMARA UNIV, 2021-01-01) Erdogan, Omer; Abbak, Muruvvet; Demirbolat, Gulen Melike; Aksel, Mehran; Pasa, Salih; Donmez Yalcin, Gizem; Cevik, Ozge
    Blood brain barrier is very important to provide treatment locally for the treatment of glioblastoma. The use of nanoparticles has shown promise for glioblastoma treatments in recent years. In this study, the effect of the combined treatment of silver nanoparticles (AgNPs) synthesized from Citrus aurantium with photodynamic therapy (PDT) was investigated on U87 glioblastoma cells. AgNPs were characterized by FTIR, zeta potential and SEM images. U87 cells were treated with AgNPs (10 mu g/mL) and/or PDT (0.5 mJ/cm(2)) at 24 h. Cells antiproliferative effect, migration levels, colony formation capability, Bax and Bcl-2 protein/gene expression, and caspase-3 activity levels as apoptotic markers were measured. AgNPs size were found at 141 +/- 3 nm and 18.1 +/- 1.3 mV as zeta potential. It was found that cell proliferation, migration and Bcl-2 protein/gene levels decreased, and Bax protein/ gene levels and caspase-3 activity increased via AgNPs and PDT combined treatment. As a result, nanoparticles synthesized from Citrus aurantium are eco-friendly and their size can cross the blood brain barrier. If AgNPs is used with PDT, it may be a new therapy for clinically treatment of glioblastoma in the future.