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Öğe Beaded chitosan/carrageenan based fiber with bio-medicinal application potentials(Springer, 2022) Kurt, Saliha B.; Şahiner, NurettinChitosan (CS) and carrageenan (CR) are natural polysaccharides with appealing biological properties, biocompatible, antibacterial, antifungal as well as biodegradable. Furthermore, CS and CR are abundant and can be obtained from animals and plants. Here, beaded CS/CR fibers were fabricated as a composite in 90% by volume of aqueous acetic acid solution via electrospinning method. To improve the existing features and generate new properties for the beaded CS/CR fiber, curcumin (Cur) molecule, a fluorescent compound was used as a model drug, added to the fiber precursor before electrospinning. The Cur release from beaded CS/CR-Cur fibers was investigated with spectroscopic methods, UV-Vis, and Fluorescence spectroscopy. The Cur release of the fibers was finished in 25 h with 22.0 +/- 1.1% of the loaded Cur measured by UV-Vis spectroscopy at 436 nm absorption wavelength and 32 h as 13.7 +/- 1.4% by Fluorescence spectroscopy (538 nm emission wavelength). Also, the beaded CS/CR-based fibers were examined for blood compatible with at 1.0 mg/mL concentration and found as 2.5 +/- 0.5% and 83.7 +/- 4.4% hemolysis and blood clotting capacity, respectively. Moreover, the antioxidant capability of beaded CS/CR-Cur fibers was determined as 110.3 +/- 0.9 mu g/mL by total flavonoid content (TFC) catechin equivalent, 152.4 +/- 5.3 mu g/mL by total phenol content (TPC) gallic acid equivalent, and lastly, 5.8 +/- 0.1 mM Trolox equivalent/g by TEAC tests. Anti-bacterial activity of beaded CS/CR-based fibers was also investigated and found that the highest zone inhibition diameter of 2.1 +/- 0.2 cm on E. coli and 1.6 +/- 0.5 cm on S. aureus bacteria.Öğe Biodiverse Properties of Tannic Acid-Based Fibers(Springer, 2021) Şahiner, Mehtap; Kurt, Saliha B.; Şahiner, NurettinTannic acid (TA) is a plant-based polyphenolic molecule with enticing anti-oxidant, anti-bacterial, antiinflammatory and anti-cancer features, making it a valuable material in bio-medicinal applications. To establish whether TA-based fibers are useful tools in potential medical textiles, e.g., as wound dressing material for prophylaxis against infections and diseases, TA fibers were prepared and employed in biological assays. TA fibers were prepared with 55 weight% TA in ethanol-DI water mixture and fabricated by the electrospinning technique. Bare TA-based fibers were examined and were 1.2 +/- 0.1 % non-hemolytic and had 8.7 +/- 1.7 blood clotting index up to 2 mg/ml concentration. Degradation of bare TA-based fibers was completed in 5 minutes; however, degradation of crosslinked TA-based fibers were 98.3 +/- 2.3 % and 83.1 +/- 5.4 % for TA-Ibu and TA in 168 hours. Anti-oxidant activity of TA-based fibers was investigated by TEAC, total phenol content (TPC) and total flavonoid content (TFC) assays. Bare TA fibers possessed the highest anti-oxidant activity of 5.7 +/- 0.5 mM trolox equivalent/g, 168.0 +/- 2.0 gallic acid equivalent mu g/ml and 193.0 +/- 17.0 quercetin equivalent mu g/ml. Anti-bacterial activity was investigated by the disc diffusion method and the highest inhibition zone diameter was measured as 3.5 +/- 0.2 cm against S. aureus (gram +) bacteria; however, the same fiber was detected as producing 2.2 +/- 0.5 cm zone diameter for E. coli (gram -) bacteria.Öğe Biomedical applications of nanofibers(wiley, 2022) Şahiner, Mehtap; Kurt, Saliha B.; Şahiner, NurettinElectrospinning is one of the most convenient and effective techniques in the production of fibers that employs high voltage. The tunable parameters of the electrospinning technique, e.g. flow rate of the polymer solution, voltage, distance between needle and the collector, and viscosity of polymer solution, allow fibers with different sizes and characteristics to be produced, i.e. micro-to nanosized fibers with different types and extent of porosity. Electrospun fibers are well suited for a broad range of applications including environmental, energy, biotechnology, health care, and biomedical applications. Recently, electrospun fibers have attracted great interest for drug delivery, wound healing, and biosensor applications in the biomedical field. The electrospinning technique is attractive due to its simplicity and low cost and is widely employed in both academia and industry. In this chapter, the utilization of the electrospinning technique in the fabrication of nanofibers from various natural and synthetic polymers and their biomedical applications will be discussed. © 2022 John Wiley & Sons, Inc.Öğe Chitosan based fibers embedding carbon dots with anti-bacterial and fluorescent properties(Wiley, 2021) Kurt, Saliha B.; Şahiner, NurettinDue to the intriguing properties of Chitosan (CS), many efforts have been paid for CS-based fiber preparation. As it is impossible to prepare CS fiber directly, facilitating polymers such as polyvinyl alcohol (PVA) possessing necessary properties that enable CS-based fiber fabrication is used. For this purpose, 3 wt% of CS in 90% acetic acid solution and 6 wt% PVA solution in DI water used in CS/PVA fiber preparation at different proportions for example, 2:1, 9:1 and 10:1 by weight to fabricate fibers by electrospinning method. Furthermore, to render fluorescent property to CS/PVA (9:1) fibers, N-doped carbon dots (C-dots) added into fiber precursor during fiber preparation. The emission peak of C-dots based fibers that with fluorescent features was observed at around 436 nm. The morphological, structural and, thermal characterizations of CS-based fibers were done with scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analyzer, respectively. Anti-bacterial activity of bare CS/PVA was increased with the increase in amounts of C-dots embedding. The inhibition of zone of CS/PVA (9:1) fibers was increased from 1.8 +/- 0.2 cm to 2.1 +/- 0.3 cm and 2.9 +/- 0.4 cm against E. coli by increasing the amounts of C-dots from 2.9 mg and 5 mg. Also, the same behavior was observed against S. aureus where the inhibition zone is increased from 2.5 +/- 0.1 cm to 3.2 and 3.5 cm by doubling the C-dots amounts in CS/PVA fiber. Moreover, bare and C-dots containing CS/PVA fibers were found blood compatible (nonhemolytic) up to 1 mg/mL concentration according to hemolysis and blood clotting tests.Öğe HA particles as resourceful cancer, steroidal and antibiotic drug delivery device with sustainable and multiple drug release capability(Taylor & Francis Group, LLC, 2021) Şahiner, Nurettin; Suner, Selin S.; Kurt, Saliha B.; Can, Mehmet; Ayyala, Ramesh S.Hyaluronic acid (HA) particles with divinyl sulfone (DVS) crosslinking at 10% mole ratio (HA macromolecule repeating units) were prepared and demonstrated as versatile drug carriers with sustainable and long-term release capabilities for cancer drugs, corticosteroid, and antibiotics. Two different methods were chosen in drug loading process; encapsulation for cancer drugs, 5-fluorouracil (5FU), mitomycin C (MMC), and doxorubicin (Dox), and dual drug conjugation for anti-inflammatory glucocorticoid dexamethasone (Dex) and antibiotic ciprofloxacin (Cipro) drugs, respectively. It was demonstrated that HA particles prepared during drug encapsulation were attained smaller sizes with 833 ± 46, 867 ± 50, 728 ± 41 nm for 5FU, MMC, and Dox, respectively. Bare and drug loaded HA particles were shown to be blood compatible with the highest hemolytic ratio of 3.1 ± 0.12% for HA-Dex-Cipro conjugates and fairly good blood clotting index with minimum 71.7 ± 6.0% for MMC encapsulated HA particles. Drug release studies from HA particles indicated that depending on the types of cancer drugs, it is possible to gradually release the drug in long-term up to 300 h in linear fashions with the highest release of 9.34 ± 2.25 mg/g for 5FU. Similarly, drug conjugated HA-Dex-Cipro particles were also showed linear dual drug release up to 100 h at physiological conditions, pH 7.4 and 37.5 °C.Öğe Poly(vinyl amine) microparticles derived from N-Vinylformamide and their versatile use(Springer Science and Business Media Deutschland GmbH, 2022) Demirci, Şahin; Sutekin, S. Duygu; Kurt, Saliha B.; Güven, Olgun; Şahiner, NurettinCationic polymers with primary amine groups that can easily be functionalized or coupled with substrates by complexation or hydrogen bonding are especially advantageous in preparing particles for biomedical applications. Poly(vinyl amine) (PVAm) is a cationic polyelectrolyte containing the highest number of primary amine groups among any other polymers. Here, we introduce a general method in synthesizing PVAm microparticles via a surfactant-free water-in-oil emulsion technique using cyclohexane as the oil phase and aqueous PVAm solution as the dispersed phase. PVAm particles were prepared to employ two different bifunctional chemical crosslinkers, divinyl sulfone (DVS) and poly(ethylene glycol) diglycidyl ether (PEGGE). The prepared particles were further treated with HCl to protonate the amine groups of PVAm within particles. The effect of crosslinker types and pH on the hydrolytic degradation of PVAm particles were also investigated at three different solution pHs, 5.4, 7.4, and 9, to simulate the skin, blood, and intestinal pH environments, respectively. The blood compatibility of the PVAm particles was evaluated by in vitro hemolysis and blood clotting assays. Furthermore, antifungal and antibacterial efficacy of PVAm-based particles and their protonated forms were tested against C. albicans yeast and E. coli, S. aureus, B. subtilis, and P. aeruginosa bacterial strains.Öğe Stabilisation of lavender essential oil extracted by microwave-assisted hydrodistillation: Characteristics of starch and soy protein-based microemulsions(Elsevier B.V., 2021) Çelebi Uzkuç, Nesrin Merve; Uzkuç, Hasan; Berber, Mehmet Mert; Tarhan Kuzu, Kübra; Togay, Sine Özmen; Kırca Toklucu, Ayşegül; Kurt, Saliha B.; Şahiner, Nurettin; Karagül Yüceer, YoncaIn this work, microwave-assisted hydrodistillation (MAHD) technique was used to obtain lavender essential oil (LEO) with a yield of 5.5 %. Oil in water microemulsions of LEO were prepared with starch and soy protein by ultrasonic emulsification. Total phenolic content and antioxidant capacity of the samples were evaluated. Microemulsions exhibited antimicrobial effect against S. aureus and B. cereus. The major volatiles of LEO were linalool L (29.0 %), 1,8-cineole (13.9 %), camphor (12.3 %) and linalyl acetate (11.9 %). Camphene, 1,8-cineole, (Z)-ocimene, linalool, and 2,6-nonadienal were determined as aroma-active compounds by gas chromatography-olfactometry. The stability of emulsions at different pH (3, 6 and 9) and temperatures (4 and 25 °C) were evaluated by measuring their size distribution, zeta potential, viscosity and color during storage. The stable droplets of LEO microemulsion that ranged between 392 and 732 nm were obtained with starch at pH 6. The formulated starch-based emulsions of LEO at pH 6 revealed the highest stability at 25 °C.Öğe The advances in functionalized carbon nanomaterials for drug delivery(Elsevier, 2022) Sağbaş Suner, Selin; Kurt, Saliha B.; Demirci, Şahin; Şahiner, NurettinCarbon-derived nanostructures, including carbon nanotubes (CNTs), graphene oxide (GO) nanosheets, fullerenes, carbon black (CB) nanomaterials, carbon nanoparticles (CNPs), and carbon dots (CDs), have attracted much attention in a wide range of biomedical areas related to low-toxicity, high bioavailability, low cost, and perfect performances. These carbon-based nanomaterials were generally functionalized by various modification agents such as ionic liquids, amphiphilic polymers, aptamers, biomacromolecules, etc. to improve their utilization and provide advantages in clinical areas. Diagnostics is the most important action to detect and prevent the transmission of disease to others and begin treatment with drug and stem cell therapies. The carbon-derived nanostructures with or without any functionalization can be used for diagnostic purposes as bioimaging and biosensor devices due to their unique optical and electrochemical properties. Nowadays, studies state that functionalized carbon nanomaterials (FCNMs) are promising nano-vehicles for genes, proteins, growth factors, and stem cells, as well as drugs, depending on advanced properties including high mechanical strength and similarity to extracellular networks. Moreover, tunable surface functions of FCNMs provide high loading capacity even for difficult drug molecules, with controllable and long-term release, and targeting ability for a specific site. FCNMs can be used as a theragnostic agent, which is a nanosized agent in therapeutic and diagnostic systems. Stem cells are undifferentiated cells that are usually utilized in theragnostic applications such as tissue engineering and regenerative medicine. FCNMs possess the ability to attach to diverse molecules including the ligands of the cells. This chapter discusses the functionalization and potential use of carbon nanomaterials in diagnosis, drug delivery systems, and stem cell therapy. © 2023 Elsevier Ltd. All rights reserved.Öğe Tunable fluorescent and antimicrobial properties of poly(vinyl amine) affected by the acidic or basic hydrolysis of poly(N-vinylformamide)(Wiley, 2021) Demirci, Şahin; Kurt, Saliha B.; Güven, Olgun; Şahiner, Nurettin; Sütekin, S. DuyguSynthesis of poly(N-vinylformamide) (PNVF) and its subsequent hydrolysis toconvert it to poly(vinyl amine) (PVAm) were performed. Kinetics of acidic andbasic hydrolysis of poly(N-vinylformamide) (PNVF), and products of hydroly-sis were investigated by using Fourier transform infrared, size exclusion chro-matography,1H NMR, and13C NMR spectroscopies, and thermogravimetricanalysis. It was observed that amide groups did not completely transform intoamine groups by acidic hydrolysis of PNVF while the conversion of amidesinto amine groups via basic hydrolysis of PNVF was complete in 12 h, as con-firmed by spectroscopic measurements. Results of extensive characterizationrevealed significant structural and conformational differences between acidicand basic hydrolysis products. Fluorescence spectroscopy was used for the firsttime to follow the conversion of amide groups into amine groups. The fluores-cence intensity of PVAm obtained from basic hydrolysis of PVNF showed sig-nificant increase with amide/amine conversion. Finally, PVAm obtained fromacidic hydrolysis of PNVF demonstrated potent antimicrobial activity, 10–20times more, against common pathogens for example,C. albicans asfungalstrain andE. coli,S. aureus,B. subtilis,andP. aeruginosaas bacterial strains ascompared to PVAm obtained from basic hydrolysis.Öğe Versatile poly(maltose) micro/nanoparticles with tunable surface functionality as a biomaterial(John Wiley and Sons Inc, 2021) Kurt, Saliha B.; Ayyala, Ramesh S.; Şahiner, NurettinMaltose, a natural disaccharide, was crosslinked with divinyl sulfone to prepare poly(maltose) (p(MAL)) micro/nanoparticles via one step microemulsion system with ≥90% ± 5% yield in a size rage of 0.5–100 μm for the first time. P(MAL) was modified (m-p(MAL)) with ethylenediamine (EDA), polyethyleneimine (PEI), and taurine (TA) to render additional functionalities, that is, amine and sulfate groups. The isoelectronic point of bare p(MAL) particles were calculated at pH 2.2 ± 0.5 and was changed to 1.3 ± 0.5, 4.3 ± 1.0, and 8.1 ± 0.7 for TA (p(MAL)/TA), EDA (p(MAL)/EDA), and PEI (p(MAL)/PEI) modification, respectively. Bare p(MAL) particles were found to be biocompatible up to 2 mg/ml with hemolysis and blood clotting tests, whereas the modified p(MAL) particles were found to be biocompatible at 1 mg/ml concentration. Additionally, it was found that TA- and PEI-modified p(MAL) particles induced blood clotting mechanisms. Sodium diclofenac as model drug was released at proportions of 8.7% ± 1.3%, 3.9% ± 0.2%, 8.8% ± 0.9%, and 31.6% ± 0.4% of the loaded drug in phosphate buffered saline solution from p(MAL), p(MAL)/TA, p(MAL)/EDA, and p(MAL)/PEI, respectively. The inhibition of antimicrobial activity of p(MAL)/PEI particles at 20 mg/ml concentration for Escherichia coli and Staphylococcus aureus strain was determined as 99.86% ± 0.3% and 99.79% ± 0.25%, respectively.
