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Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene‐based species and polyurethane block copolymers are of great interest. Poly(styrene‐ethylene‐butadiene‐styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO2) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application.

No abstract

Mesenchymal stem cells (MSCs) are multipotent stem cells that can support various tissues including bone marrow, adipose tissue, and synovial fluids, from which they can be readily isolated. The objective of this study is to harness the advantages of microfluidic systems for controlling and enhancing the maintenance and viability, and regenerative properties of MSCs by providing a 3D culture microenvironment with gelatin methacrylate (GelMA) hydrogel and exposing the cells to a slow fluid flow and low shear stress conditions. GelMA has methacryloyl groups and can be crosslinked by a photocuring process using biocompatible photoinitiators. The most common used photoinitiator for cellular encapsulation within hydrogels is the ultraviolet (UV) initiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959 or I2959), but due to its low water solubility and the necessity of using a shorter wavelength light (365 nm), it can lead to cellular phototoxic and genotoxic effects. To overcome these limitations, lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) have recently been used with GelMA as an alternative photoinitiator. Because LAP is highly water soluble and has a 10 times faster polymerization rate, and it requires a visible light (λ = 405 nm) which makes it much safer for the cells, we use 10% GelMA together with 0.05% LAP photoinitiator for bioprinting human adipose tissue derived MSCs (hAT-MSCs) onto a membrane that has a 40 µm mesh size. To demonstrate a microfluidic culture advancement for improving the biological activities and regenerative capacity of the cells including cell adhesion, growth, viability and proliferation capacity as ultimate goals of this study, the membrane carrying the bioprinted construct was placed in a PDMS microchannel and exposed to the fluid to obtain dynamic microenvironments found in the human body. As a result, the cells were successfully maintained in the microfluidic 3D cell culture for two days, with a high cell viability of 99%.

Mezenkimal kök hücreler (MKH), rejeneratif, immunosupresif, non-immunojenik, anjiyojenik, antiapoptotik ve antiinflamatuvar özellikleri sayesinde hem preklinik araştırmalarda hem de kilinikte önem taşımaktadır. MKH'lerin immunosupresif fonksiyonlarının keşfi, otoimmün hastalıklarda patojenik immun yanıtı düşürmek için yeni terapötik araç olarak araştırmalara konu olmuştur. Plasenta, göbek kordonu ve amniyon sıvısı; kemik iliği ve yağ kökenli MKH'lere göre non-invazif eldesi ve pluripotensi kapasitesiyle avantajlı kök hücre kaynakları arasındadır. Bu çalışmada immün yanıtların incelenmesi için in vitro bir model kullanılarak insan amniyotik sıvı kökenli MKH'lerin (iAS-MKH), fitohemaglütinin ile aktive edilmiş T-hücreleri (PHA-T hücreleri) üzerindeki etkisini; hücre proliferasyonu, apoptoz, sitokin düzeyleri ve regülatuar T hücre (Treg) farklılaşması açısından analiz edilmesi amaçlandı. Gereç ve yöntem: Periferik kandan immunoseleksiyon yöntemi ile izole edilen T-hücreleri karakterize edilip PHA ile uyarıldıktan sonra, iAS-MKH'ler ile insertler kullanılarak indirekt yolla 4 gün ko-kültür (transwell) edildi. Kültür sonrasında PHA-T-hücreleri flow sitometri ve ELISA ile hücre canlılığı ve proliferasyon, sitokin düzeyleri, Tregfarklılaşması ve apoptotik açıdan analiz edildi. Bulgular: iAS-MKH'lerin; in vitroda ko-kültür edildikleri PHA-T hücrelerinin sitokin profilini değiştirerek, canlılık ve proliferasyonu azaltarak ve apoptoz ve Treg farklılaşmasını indükleyerek immunosupresif etki gösterdiği gözlendi. Sonuç: Erken dönemde (prenatal-natal) ve non-invazif tekniklerle eldesi ve atık bir doku olması şeklinde avantajları olan amniyon sıvısındaki bu kök hücrelerin, immunosupresif etkileri olduğu ve ileriye yönelik olarak daha ayrıntılı analizlerle ve in vivo çalışmalarla desteklenmesi gerektiği sonucuna varıldı.