Browsing by Author "Yazgan, I."

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A colorimetric immunoassay for the detection of human vascular endothelial growth factor 165 (VEGF165) based on anti-VEGF-iron oxide nanoparticle conjugation
(2024.01.01) Ceylan, H.K.; Kirbay, F.O.; Yazgan, I.; Elibol, M.
Vascular endothelial growth factor (VEGF) is an indispensable element in many physiological processes, while alterations in its level in the circulating system are signs of pathology-associated diseases. Therefore, its precise and selective detection is critical for clinical applications to monitor the progression of the pathology. In this study, an optical immunoassay biosensor was developed as a model study for detecting recombinant VEGF(165). The VEGF(165) sample was purified from recombinant Kluyveromyces lactis GG799 yeast cells. Indirect ELISA was used during the detection, wherein iron oxide nanoparticles (FeNPs) were utilized to obtain optical signals. The FeNPs were synthesized in the presence of lactose p-amino benzoic acid (LpAB). VEGF(165) antibody was conjugated to the LpAB-FeNPs through EDC/NHS chemistry to convert the iron oxide nanoparticles into VEGF(165) specific probes. The specificity of the prepared system was tested in the presence of potential serum-based interferents (i.e., glucose, urea, insulin, C-reactive protein, and serum amyloid A), and validation studies were performed in a simulated serum sample. The proposed immunoassay showed a wide detection range (0.5 to 100 ng/mL) with a detection limit of 0.29 ng/mL. These results show that the developed assay could offer a sensitive, simple, specific, reliable, and high-throughput detection platform that can be used in the clinical diagnostics of VEGF.
Identification of Marker Molecules in Aqueous Plant Extracts Affecting the Gold Nanostructures' Morphology and Size
(2024.01.01) Elgaleidh, M.A.M.; Tepe, H.D.; Doyuk, F.; Çeter, T.; Yazgan, I.
This work was performed as a comparative study using nine different aqueous pollen grain extracts from eight different genera (Juniperus, Biota, Cupressus, Abies, Pinus, Cedrus, Populus and Corylus) to synthesize gold nanostructures (AuNSs) to understand if there is any possible marker that helps to predict the final morphology and size of the AuNSs. Principal component analysis (PCA) revealed that Apigenin and Pinoresinol compounds are the marker molecules in determination of the AuNSs physical characteristics while total protein, reducing carbohydrate, flavonoid and phenol contents did not show any statistically meaningful outcome. The "dominancy hypothesis" was tested by paying attention to the most concentrated phenolic acids and flavonoids in the control of AuNSs morphology and size, for which correlation analysis were performed. The statistical findings were tested using two new more pollen extracts to validate the models. Three main findings of the study were (i) determination of Apigenin and Pinoresinol levels in pollen extract can give an insight into the AuNSs physical characters, (ii) the most concentrated phenolic acids and flavonoids don't need to be same to pose same dictative effect on AuNSs morphology and size, rather relatively abundant ones in the extract play the key role and (iii) differences in the polymeric structures (e. g. lignin, cellulosic compounds etc.) have minor effect on the final morphology and size of the AuNSs.
Identification of Marker Molecules in Aqueous Plant Extracts Affecting the Gold Nanostructures' Morphology and Size
(2023) Elgaleidh, M.A.M.; Tepe, H.D.; Doyuk, F.; Çeter, T.; Yazgan, I.
Hereby, we performed a comparative study using nine different aqueous pollen grain extracts from eight different genus to synthesize gold nanostructures (AuNSs) to understand if there is any possible marker that helps to predict the final morphology and size of the AuNSs. Principal component analysis (PCA) revealed that Apigenin and Pinoresinol content are the marker molecules in determination of the AuNSs physical characteristics while total protein, reducing sugar, flavonoid and phenol contents did not show any statistically meaningful outcome. We also tested the "dominancy hypothesis" by paying attention to the most concentrated phenolic acids and flavonoids in the control of AuNSs morphology and size. Three main findings of the study are (i) determination of Apigenin and Pinoresinol levels in pollen extract can give an insight into the AuNSs physical characters, (ii) the most concentrated phenolic acids and flavonoids don't need to be same to pose same dictative effect on AuNSs morphology and size, rather relatively abundant ones in the extract play the key role and (iii) differences in the polymeric structures (e.g. lignin, cellulosic compounds etc.) have minor effect on the final morphology and size of the AuNSs.