Viscoelastic properties of PCL/fibroin/CFU elektrospinning scaffolds

Cilj ovog rada bio je istražiti utjecaj fibroina svile (FS) i različitog udjela antibiotika Cefuroxima (CFU) na viskoelastična, mehanička i toplinska svojstva PCL/FS/CFU elektroispredenih nosača u cilju sprječavanja infekcija oka nakon kirurškog zahvata. Postupkom elektroispredanja pripremili su se 18% PCL/10% FS vlaknasti nosači u koje je dodan CFU u koncentracijama od 4, 8 i 12%. Nakon postupka elektroispredanja uslijedila je karakterizacija materijala. Struktura elektroispredenih nosača određena je FTIR-ATR spektroskopijom, mehanička svojstva rasteznim ispitivanjem na mehaničkoj kidalici, toplinska svojstva termogravimetrijskom analizom te viskoelastična svojstva dinamičko-mehaničkom analizom. Dodatkom FS i CFU te povećanjem udjela CFU dolazi do smanjenja visine pika u području staklastog prijelaza u odnosu na elektroispredeni PCL nosač, ali visina maksimuma raste povećanjem udjela CFU. Na osnovi porasta Tg-a može se zaključiti da se kristalne domene FS smještaju u amorfnu fazu elektroispredenog PCL nosača i dolazi do interakcije između PCL-a i β-pločastih kristala iz FS čime se smanjuje pokretljivost amorfnih segmenata u PCL nosaču. Dodatkom FS u 18% PCL elektroispredeni nosač dolazi do povećanja prekidne čvrstoće i smanjenja prekidnog istezanja. Povećanjem udjela CFU-a u PCL/CFU/FS elektroispredene nosače dolazi do smanjenja prekidne čvrstoće i pada prekidnog istezanja. Na FTIR spektrima PCL/FS/CFU elektroispredenih nosača mogu se vidjeti tri karakteristične vrpce koje se pripisuju CFU. Toplinska stabilnost se smanjuje dodatkom 10% FS-a u 18% PCL elektroispredeni nosač kao i elektroispredenim PCL/FS/CFU nosačima dodatkom FS i CFU i povećanjem udjela CFU.The aim of this work was to investigate the influence of silk fibroin (SF) and different content of antibiotic Cefuroxim (CFU) on the viscoelastic, mechanical and thermal properties of PCL/FS/CFU electrospun carriers in order to prevent eye infections after surgery. Electrospun 18% PCL and 10% FS fiber scaffolds are prepared by electrospinning with the addition of the CFU of 4,8 and 12 wt%. The electrospinning process was followed by characterization of the electrospun scaffolds. The structure of electrospun scaffolds was determined by FTIR-ATR spectroscopy, mechanical properties by tensile testing, thermal properties by thermogravimetric analysis and viscoelastic properties by dynamic-mechanical analysis. With the addition of FS and CFU and the increase of the CFU content, the peak in the glass transition region is reduced relative to the electrospun PCL carrier, but the peak maximum increases with the increase in the CFU content. Based on the increase in Tg, it can be concluded that the FS crystal domains are located in the amorphous phase of the electrospun PCL carrier and an interaction occurs between the PCL and β-plate crystals from FS, thus reducing the mobility of the amorphous segments in the PCL carrier. The addition of FS in an 18% PCL electrospun carriers results in an increase in tensile strength and a decrease elongation at break. Increasing the content of CFUs in PCL/CFU/FS electrospun carriers results in a decrease in tensile strength and elongation at break. On the FTIR spectra of PCL/FS/CFU electrospun carriers, three characteristic bands attributed to the CFU can be seen. Thermal stability is reduced by the addition of 10% FS in 18% PCL electrospun carrier as well as electrospun PCL/FS/CFU carriers by the addition of FS and CFU