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Öğe Cellular interactions and design principles of glyco-gold nanoparticles for drug delivery applications(Elsevier, 2023) Akturk, Omer; Yilmaz, BengiAn escalating tendency prevails to manipulate gold-based nanoparticles decorated on their surfaces with different types of carbohydrates or glycopolymers for the development of versatile nanoplatforms—the so-called glyco-gold nanoparticles (GAuNPs) here—for drug delivery applications. Due to the ease of their surface modification, inherent inertness, and biocompatible nature, gold nanoparticles (AuNPs) are one of those first preferred candidates in this field. Coating of AuNPs with saccharide moieties also makes them gain unique properties such as multivalent binding abilities, active targeting, receptor-mediated internalization of drugs, enhanced biocompatibility, colloidal stability, stealth ability, and so on. This chapter deals with the synthesis methods and design parameters of GAuNPs followed by very detailed drug delivery applications, mainly focusing on the cellular interactions and design parameters in state-of-the-art research. The chapter ends with a concluding remark emphasizing the hurdles encountered in synthesis methodologies and the translation of the bench-top characterization results to different biomedical applications. © 2024 Elsevier Inc. All rights reserved.Öğe Colloidal stability and biological activity evaluation of microbial exopolysaccharide levan-capped gold nanoparticles(ELSEVIER, 2020) Akturk, OmerThe main objectives of this study were to explore the suitability of the exopolysaccharide levan, biosynthesized by Bacillus subtilis, to aid in the formation of gold nanoparticles (AuNPs) and to investigate the colloidal stability and in vitro biological activity of this biopolymer-AuNPs complex. AuNPs (mainly spherical, 8-10 nm-sized, and monodispersed) were successfully synthesized in levan concentrations up to 0.5% w/v (L-AuNP0.5) while exposed to ultraviolet C (UVC) irradiation. The increase of levan quantity decreased the size of AuNPs according to Transmission Electron Microscopy (TEM) images and enhanced the colloidal stability significantly. The presence of L-AuNP0.5 at the highest treatment dose (1000 mu g/mL) exhibited substantial cytotoxicity towards L-929 mouse fibroblasts for all incubation periods. Dose-dependent toxicity was observed for the first day while, after this threshold value, medium (100 mu g/mL) and the lowest (10 mu g/mL) treatment doses were non-cytotoxic during 7 days of incubation, implying dose and time-independent cell viabilities ( > 95%) compared to the negative control (complete cell culture medium). There occurred a special surface interaction with cells and LAuNP0.5, especially when the cells were subjected to deliberate starvation periods to increase L-AuNP0.5 internalization via passive and active endocytosis. Scanning Electron Microscopy (SEM) images showed high accumulation of L-AuNP0.5 around or inside the cell membrane after 7 days. Overall, this attribute (high uptake of L-AuNP0.5) could make them promising candidates for prospective cancer therapeutics or drug delivery systems by enabling the cell internalization of anticancer drugs.Öğe Evaluation of photochemically cross-linked collagen/gold nanoparticle composites as potential skin tissue scaffolds(Tubitak Scientific & Technological Research Council Turkey, 2023) Yelkuvan, Evrim Meric; Erdemli, Ozge; Yilmaz, Bengi; Akturk, OmerCollagen type I is the main structural unit in skin tissue and is therefore used preferentially in skin tissue scaffolds. However, collagen-based 3D scaffolds have weak aqueous stability and degradation profiles in their uncross-linked states and chemical cross -linking reagents arise toxicity concerns, which generally restrict the spectrum of their biomedical applicability. Here, the research goal is to photochemically cross-link collagen type I with rose bengal (RB) when subjected to green laser light and to investigate the effect of silk sericin-capped gold nanoparticles (S-AuNP) when incorporated into scaffolds on the cross-linking process and thus on the scaffold properties. All the collagen scaffolds, that is plain collagen (C), collagen/S-AuNP (C-Au), cross-linked collagen (C-RBL), and cross-linked collagen/S-AuNP (C-AuRBL) were characterized for their potential as skin tissue scaffolds. C-AuRBL group had the best thermal stability, resistance to enzymatic degradation, and more uniform pore size distribution. None of the groups had cytotoxicity (cell viability > 70%) regarding the microscopic observations and MTT cell viability assays for L929 fibroblasts. L929 fibroblasts and primary adult human epidermal keratinocytes (HEKa) were also separately seeded on C-AuRBL scaffolds and according to microscopy results, they could support the stimulation of adhesion, morphological changes, and spreading of both cells, thereby encouraging the usage of this fabrication strategy for prospective skin tissue scaffolds.Öğe One-pot facile synthesis of silk sericin-capped gold nanoparticles by UVC radiation: Investigation of stability, biocompatibility, and antibacterial activity(Wiley, 2019) Akturk, Omer; Gok, Zehra Gun; Erdemli, Ozge; Yigitoglu, MustafaHerein, an easy one-pot synthesis method for gold nanoparticles (AuNPs), involving only gold salt and sericin extracted from silkworm cocoon in the presence of ultraviolet C (UVC) radiation, was developed. Nanoparticle formation was confirmed by characteristic surface plasmon resonance peaks at 520-540 nm wavelengths, and the influence of silk sericin on enhancing the colloidal stability of AuNPs was confirmed. Transmission electron microscopy examination showed the average size (<10 nm) and size distribution decreased significantly with higher sericin concentration. No antibacterial activity was observed on Gram-positive Bacillus subtilis or Gram-negative Escherichia coli for sole AuNPs (0.065-0.26 mg/ml), but the conjugation of AuNPs with streptomycin antibiotic decreased significantly the required minimum inhibitory concentration doses, as also confirmed with agar plating, Scanning Electron Microscopy and Atomic Force Microscopy analyses. Furthermore, sericin-capped AuNPs showed high cell viabilities (>100%) and no sign of any detectable apoptosis or necrosis in 1-day incubation. Also, high real-time cell proliferation results of AuNPs competitive with positive control groups implied excellent in vitro biocompatibility. These results evidenced that sericin enhanced the colloidal stability of AuNPs and the biological activities of sericin-capped AuNPs reported here could render them suitable nanoscale vehicles for biomedical applications.Öğe Synthesis and characterization of polyethyleneimine/silk fibroin/gold nanoparticle nanocomposites: Potential application as a gene carrier in breast cancer cell lines(Pergamon-Elsevier Science Ltd, 2023) Tunali, Beste Cagdas; Akturk, Omer; Sahingoz, Durukan; Turk, Mustafa; Keskin, Ayten CelebiThere is a need in advancing the design of non-viral gene carriers, thus herein using the pulsed laser ablation in liquid (PLAL) technique, polyethyleneimine-capped gold nanoparticles (PEI-AuNPs) were synthesized and then combined with Bombyx mori silk fibroin (SF) to form the nanocomposites (PEI-SF-AuNPs). After the characterization analyses were carried out, PEI-AuNPs and PEI-SF-AuNPs were tested for their in vitro biocompatibility in MCF-7 and MDA-MB231 breast cancer cells. Finally, the transfection capability of the selected group was observed. PEI capping enabled the cationic modification of the AuNP surface and SF reduced the surface charge (from 35 to 4 mV). PEI-AuNPs were highly monodispersed in shape and size (8-9 nm). The nanoparticle group synthesized in 5% (w/v) PEI concentration (PEI-AuNP5) had increased cytotoxicity as compared to the group synthesized in 1% (w/v) PEI concentration (PEI-AuNP1), but the conjugation of SF with PEI-AuNPs alleviated this cytotoxic tendency significantly. The group (PEI-AuNP1) with the most negligible cytotoxicity proved to be successful in the transfection of siRNA analog, i.e., siGLO green transfection indicator. Overall, the PEI-AuNP1 nanocomposites could be suggested as potent siRNA carriers due to the above beneficial properties in genebased breast cancer therapies.Öğe The anticancer activity of doxorubicin-loaded levan-functionalized gold nanoparticles synthesized by laser ablation(Elsevier, 2022) Akturk, OmerHere, gold nanoparticles (AuNPs) were synthesized upon exposure to nano-pulsed Nd-YAG laser irradiation in de-ionized water (PLAL) and functionalized with levan polysaccharide for assessing the anticancer efficacy of doxorubicin (DOX)-conjugated levan-capped AuNPs complexes to MCF-7 breast cancer cells. According to the physicochemical test results, the increments in levan amount enhanced the colloidal stability and the drug encapsulation efficiency (DEE) significantly. For the 10L-AuNP group having the highest levan amount (10 mg/ mL levan), DEE was calculated as 92.21 +/- 0.56%. The lean levan, uncapped AuNPs, and 10L-AuNP were found non-cytotoxic (> 80% cell viability) in the studied concentrations with 48 h MTT assays. At higher DOX loadings (25, 50, and 100 mu g/mL) of 10L-AuNP, the cell viability reduced significantly compared to free DOX. Overall, these nanoparticle complexes could be proposed as potent drug delivery vehicles for cancer drugs such as DOX, as well as other drugs in the prospective studies.Öğe Wet electrospun silk fibroin/gold nanoparticle 3D matrices for wound healing applications(Royal Soc Chemistry, 2016) Akturk, Omer; Kismet, Kemal; Yasti, Ahmet C.; Kuru, Serdar; Duymus, Mehmet E.; Kaya, Feridun; Keskin, DilekThis study aimed to fabricate 3D silk fibroin (SF) matrices for skin tissue engineering applications. SF/poly(ethylene oxide) solutions were wet electrospun to obtain a fibrous network (0.7-20 mm diameter), which were then lyophilized to obtain 3D porous nanofibrous matrices (SFM-E: ethanol treated silk fibroin matrices). SF matrices were loaded with citrate-capped gold nanoparticles (AuNPs, 14.27 ppm, D-average = 24 nm) (SFM-AuE: ethanol treated silk fibroin matrices incorporated with AuNPs) and investigated for structural and chemical properties, in vitro biocompatibility and in vivo full-thickness dermal wound healing efficacy in a rat model. AuNP incorporation enhanced the degradation profiles and mechanical properties significantly. SFM-E and SFM-AuE showed similar cell attachment and layer by layer proliferation behaviour, but cells had more spread and flattened morphology on SFM-AuE. Both matrix extracts had high cell viability (>90%), indicating good in vitro biocompatibility. Wound closure was statistically more than the untreated skin control (UTSC) in SFM-E and SFM-AuE applied groups. The recovered tensile strength and elastic modulus of SFM-E and SFM-AuE (40-60%) were not as high as the unwounded skin control (UWSC), but they had elongation at break values similar to UWSC. This was attributed to the still ongoing medium to high inflammation levels leading to a low and immature extent of collagen fibrils on postoperative 14th day. There was only a small amount of epithelialization due to scab formation and medium to high level inflammation for both SFM-E and SFM-AuE, but they were better than UTSC in terms of neovascularization and granulation tissue formation. As a whole, inclusion of AuNPs to SF matrices at 14.27 ppm loading brought some enhancement in the matrix properties and did not cause any toxicity in in vitro and in vivo conditions and even had potency to promote wound healing stages.
