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ÜNAL YILDIRIM, SEMRA

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ÜNAL YILDIRIM

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SEMRA

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2022 - 20233
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Subject: Engineering and Technology ×

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Now showing 1 - 3 of 3
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    PublicationOpen Access
    Synthesis and characterization of interpenetrating network (IPN) based levan-polyacrylamide hydrogels and their application in conservation of cultural heritage
    (2023-11-01) ÜNAL YILDIRIM, SEMRA; OKTAR, FAİK NÜZHET; GENÇ, SEVAL; TOKSOY ÖNER, EBRU; Özen Sağlam R., Ünal Yıldırım S., Oktar F. N., Genç S., Erdem G., Toksoy Öner E.
    In this study, an IPN based enzymatic levan-polyacrylamide hydrogel (EL-PA) was developed and characterized for its structural, morphological, rheological properties and swelling kinetics to underline hydrogel properties and its potential use in paper conservation. The addition of levan also led to changes in the viscoelastic behavior of the hydrogels, with the complex viscosity of EL-PA samples showing pronounced dependence on shear rate. The swelling and the overall surface area of the hydrogels were increased with the addition of levan into the polymer network. Source associated structural differences were found to be negligible such that both microbially produced linear and enzymatically produced branched forms of levan performed equally well. Solvent loaded hydrogels were then applied on an artifact, a 19th century book of Namık Kemal, and investigated using FTIR, SEM, XRD and colorimetric analysis. Old adhesive layers were successfully removed, and hydrogels showed good compatibility and ease of application. This study has shown that levan has improved hydrogel properties and levan based systems bear high potential in conservation science.
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    PublicationOpen Access
    Marine-derived bioceramics for orthopedic, reconstructive and dental surgery applications
    (2022-11-01) OKTAR, FAİK NÜZHET; ÜNAL YILDIRIM, SEMRA; GÜNDÜZ, OĞUZHAN; EKREN, NAZMİ; ALTAN, ERAY; OKTAR F. N. , Unal S., GÜNDÜZ O., Ben Nissan B., Macha I. J. , Akyol S., Duta L., EKREN N., ALTAN E., YETMEZ M.
    Bioceramics are a fast-growing materials group, which are widely used in orthopedics, maxillofacial, dental, and reconstructive surgeries. They are produced using raw materials either from synthetic or natural sources. As naturally originated resources, the bones of sheep and cows are used after converting to calcium phosphates. Human-originated sources in the past were obtained from human cadaver bones, however now-a-days this has been discontinued. On the other hand, the \"golden standard\" in the reconstruction surgery has been using patients own bones, -i.e., autogenous bones, which heal better than other alternatives. Besides natural products, synthetic materials are produced from a range of inorganic raw and natural materials based on marine sources, such as corals, and other marine-derived materials (i.e., seashells, nacre). These are used to produce bioceramics and hence implants, devices, and bone grafts. Although during the last four decades a number of excellent books and book chapters have been published, no comprehensive review has been yet reported to cover the available marine materials and to indicate the related work and corresponding references to allow for both medical and ceramic scientists to access directly and open new avenues for further research on marine structures and their applications in orthopedic, maxillofacial, and reconstructive surgery areas. Hence, this review covers the general marine structures, their locations and availability in different countries and, current research on production methods of these unique structures that are difficult to fabricate synthetically. The authors are confident that this comprehensive review will be an excellent source not only for the ceramists, but also for the medical scientists.
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    PublicationOpen Access
    Evaluation of bacterial cellulose/quince seed mucilage composite scaffold for wound dressing
    (2022-04-01) ÜNAL YILDIRIM, SEMRA; GÜNDÜZ, OĞUZHAN; Oran D., Unal S., GÜNDÜZ O.
    Bacterial cellulose (BC) and quince seed mucilage are very promising biological materials. In this study, we reported the design and fabrication of a novel biocompatible scaffold with excellent fibroblast cell proliferation, making it a promising composite scaffold for wound dressings. The composite scaffold was fabricated by ex situ modification of bacterial cellulose by quince seed mucilage. The products were investigated to determine their morphological features, chemical features, and thermal and swelling behaviors. Cell culture and proliferation tests were performed to obtain information on biocompatibility of the scaffolds. This work indicates the novel scaffold provides great potential in wound dressing for clinical application.