Yazar "Tamahkar, Emel" seçeneğine göre listele

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    A novel multilayer hydrogel wound dressing for antibiotic release
    (Elsevier, 2020) Tamahkar, Emel; Özkahraman, Bengi; Kılıç Süloğlu, Aysun; İdil, Neslihan; Perçin, Işık
    In this study, the novel multilayer (ML) hydrogels were developed as antibacterial wound dressings. ML hydrogels were prepared as four layers using carboxylated polyvinyl alcohol (PVA-C), gelatin (G), hyaluronic acid (HA) and gelatin respectively. The upper layers (PVA-C and G) provide the moist control and physical barrier for microorganisms. The HA based middle layer was designed as an antibiotic-loaded layer. The lower layer serves as the controlling membrane for antibiotic release and provides the removal of excess exudate from the wound site. The ML hydrogels were characterized with FT-IR, SEM, DSC, swelling tests and hydrolytic degradation tests. Cell viability assay was also performed in L929 fibroblast cells in vitro. The in-vitro drug release profile of ML hydrogels was investigated at pH 7.4 at 37 degrees C and it was found that 63% of the antibiotic was released after 7 days.
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    Advancements and future directions in the antibacterial wound dressings - A review
    (Wiley, 2021) Bal Öztürk, Ayça; Özkahraman, Bengi; Özbaş, Zehra; Yaşayan, Gökçen; Tamahkar, Emel; Alarçin, Emine
    Wound repair is a complex process that has not been entirely understood. It can conclude in several irregularities. Hence, designing an appropriate wound dressing that can accelerate the healing period is critical. Infections, a major obstacle to wound repair, cause an elevated inflammatory responses and result in ultimate outcome of incomplete and prolonged wound repair. To overcome these shortcomings, there is a growing requirement for antibacterial wound dressings. Dressings with antibacterial activities and multifunctional behaviors are highly anticipated to avoid the wound infection for successful healing. The aim of this review is not only to concentrate on the importance of antibacterial dressings for wound healing applications but also to discuss recent studies and some future perspectives about antibacterial wound dressings.
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    Aloe vera-based antibacterial porous sponges for wound dressing applications
    (Springer, 2021) Tamahkar, Emel; Özkahraman, Bengi; Özbaş, Zehra; İzbudak, Burçin; Yarimcan, Filiz; Boran, Filiz; Bal Öztürk, Ayça
    The antibacterial sponges with high macroporosity, high interconnectivity and high biocompatibility is a significant concern for wound healing applications. In this work, novel Aloe vera (AV) based sponges were developed via subsequent lyophilization with further chemical crosslinking throughout the double network sponges. Single network was composed of gelatin-sodium alginate (G-SA) while the double network using gelatin-sodium alginate- sodium hyaluronate (G-SA-HA) was produced with the addition of hyaluronic acid solution into the gelatin-sodium alginate matrix. Lastly, Aloe vera as the bioactive agent was fabricated throughout the gelatin-sodium alginate-sodium hyaluronate matrix. The AV-based sponges demonstrated large pores with high interconnectivity. The swelling degree of the AV-based sponges were higher than that of G-SA and G-SA-HA sponges. The release of AV from the sponges reached an equilibrium value after 24 h showing a more controlled release at pH 5.5 than at pH 7.4. AV-based sponges showed antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus pneumoniae and Bacillus cereus and displayed any cytotoxicity against Mesenchymal stem cells.
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    Characterization and antibacterial activity of gelatin-gellan gum bilayer wound dressing
    (Taylor & Francis As, 2021) Özkahraman, Bengi; Özbaş, Zehra; Bayrak, Gülşen; Tamahkar, Emel; Perçin, Işık; Kılıç Süloğlu, Aysun; Bor, Filiz
    Bilayer wound dressing systems consisting of various biopolymers have been preferred in biomedical applications due to its enhanced advantages in comparison with conventional systems. The aim of this research was to develop a novel bilayer wound dressing based on gelatin (G) and gellan gum (GG). The bilayer was composed of an upper layer impregnated with antibiotic drug sodium ampicillin and a drug-free lower sponge layer. The bilayer hydrogels were characterized by FTIR, TGA, DSC and SEM analyses including swelling behaviors and hydrolytic degradation tests. To achieve faster healing of the wound by prevention of the bacterial infection, the bilayer hydrogels were developed as antibiotic-releasing vehicles. Herein, release study of sodium ampicillin was performed in PBS to simulate the physiological micro-environment. Additionally, cyto-compatibility tests of L929 fibroblast cells showed the high proliferation and survival through drug-loaded GG and G hydrogels (GG-G-D) after 24h, 48h and 72h incubation. This novel GG-G bilayer hydrogel could be a good candidate as wound dressing.
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    Evaluation of hyaluronic acid nanoparticle embedded chitosan-gelatin hydrogels for antibiotic release
    (Wiley, 2021) Özkahraman, Bengi; Tamahkar, Emel; İdil, Neslihan; Kılıç Süloğlu, Aysun; Perçin, Işık
    The development of chitosan-gelatin (CS-G) hydrogels embedded with ampicillin-loaded hyaluronic acid nanoparticles (HA-NPs) for wound dressing is proposed. It was aimed to provide controlled ampicillin delivery by incorporation of HA-NPs into biocompatible CS-G hydrogel structure. According to in vitro ampicillin release studies, 55% of ampicillin was released from CS-G/HA-NPs hydrogels after 5 days. Antibacterial performance of CS-G/HA-NPs hydrogels was proven with agar disc diffusion test. For cytotoxicity assay, fibroblast cell viability increased in CS-G/HA-NPs hydrogels compared with CS-G group after 24 hr incubation. Consequently, the potential ability of CS-G/HA-NPs hydrogels as a controlled drug delivery system has been verified.
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    Molecularly imprinted smart cryogels for selective nickel recognition in aqueous solutions
    (Wiley, 2021) Andac, Muge; Tamahkar, Emel; Denizli, Adil
    Smart polymers with fast response to slight changes show high practicability in separation and removal applications, such as water and wastewater treatment. Molecular imprinted polymers (MIPs) are designed to possess specific binding sites enabling the recognition of the target analytes. In this article, the newly synthesized smart adsorbents were used for the selective removal of nickel [Ni(II)] ions from aqueous solutions, which have dual (pH and temperature) memory for the recognition of Ni(II) ions due to the self-assembled recognition sites in MIP structure. The Ni(II)-MIP smart cryogels were prepared by cryopolymerization ofN-isopropylacrylamide (NIPAm) andN-methacryloyl-l-histidine (MAH) monomers to incorporate their smart features for removal of Ni(II) ions in a selective and temperature-modulated way. The maximum binding capacity of Ni(II) ions onto MIP smart cryogel was determined at pH 6 as 414 mu g g(-1)at 20 degrees C and only 104.5 mu g g(-1)at 40 degrees C, respectively. The adsorption reached an equilibrium within 30 min, while 85% of the bound amount of Ni(II) ions was achieved in only 15 min. This unique MIP cryogel as a smart and selective adsorbent was able to remove Ni(II) ions immediately by a significant temperature and pH change as an alternative application for water and wastewater treatment.
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    Phenol removal from wastewater by surface imprinted bacterial cellulose nanofibres
    (Taylor & Francis Ltd, 2020) Derazshamshir, Ali; Gokturk, Ilgim; Tamahkar, Emel; Yilmaz, Fatma; Saglam, Necdet; Denizli, Adil
    In this study, we have reported a novel wastewater treatment technique by phenol imprinted bacterial cellulose (BC-MIP) nanofibres with high specificity and adsorption capacity. N-methacryloyl-(L) phenylalanine methyl ester (MAPA) functional monomer was used to create specific binding sites for the template molecule phenol via electrostatic and hydrophobic interactions. BC-MIP nanofibres were synthesized by surface imprinting approach in the presence of different amounts of total monomer (% weight), monomer/template ratio and polymerization time. Then, the nanofibres were characterized by FTIR-ATR, surface area analysis (BET), elemental analysis, scanning electron microscopy (SEM) and contact angle measurements. Adsorption studies were performed with respect to pH, temperature and ionic strength, and the adsorption capacity was calculated by using the spectrophotometer. In order to desorb the adsorbed phenol from BC-MIP nanofibres, 0.1 M NaCl solution was used. Besides, BC-MIP nanofibres were applied to real wastewater samples from Ergene basin in Turkey. The suitable equilibrium isotherm was determined as Langmuir isotherm. To evaluate the selectivity of the BC-MIP nanofibres, similar molecules were utilized as competitor molecules, which were 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol. Electrostatic interactions were found to contribute to the generation of specific recognition binding sites. The results have shown that imprinting of phenol was achieved successfully with high adsorption capacity. The phenol removal efficiency was reported up to 97%. BC-MIP nanofibres were used 10 times with a negligible decrease in adsorption capacity. [GRAPHICS] .
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    Poly(vinyl alcohol)/(hyaluronic acid-g-kappa-carrageenan) hydrogel as antibiotic-releasing wound dressing
    (Springer Int Publ Ag, 2021) Özbaş, Zehra; Özkahraman, Bengi; Bayrak, Gülşen; Kılıç Süloğlu, Aysun; Perçin, Işık; Boran, Filiz; Tamahkar, Emel; Boran, Filiz
    The aim of this research was to investigate the potential of ampicillin-loaded hydrogels based on polyvinyl alcohol (PVA), hyaluronic acid (HA) and kappa-carrageenan ((K)-Carr) as an antibiotic-releasing wound dressing. Firstly, the novel polymers (HA-g-(K)-Carr) were synthesized by grafting of HA onto (K)-Carr using 4-dimethylaminopyridine/1-(3-dimethylaminopyl)-3-ethyl-carbodiimide hydrochloride as catalyst system via esterification reaction. The characterization of the polymer structure was performed by Fourier transform infrared spectrum (FTIR), proton nuclear magnetic resonance and thermogravimetric analysis. Secondly, PVA/(HA-g-(K)-Carr) hydrogel with/without loading of ampicillin molecules was formed via freeze-thawing method since PVA/K-Carr and PVA/HA hydrogels were also fabricated as control groups. The hydrogels were subjected to characterizations with FTIR and X-ray diffractometer. PVA/(HA-g-(K)-Carr) hydrogel demonstrated the highest swelling amount and highest ampicillin release amount reaching an equilibrium value after 480 min rather than the other hydrogels. Also, PVA/(HA-g-(K)-Carr) hydrogel exhibited inhibition zone against Escherichia coli and Staphylococcus aureus and no cytotoxic effect for L929 cells. All the results showed that PVA/(HA-g-(K)-Carr) hydrogels are good candidates for wound dressing applications.