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Fibroin svile (FS) jedinstven je i obećavajući prirodni polimer te zbog svoje biokompatibilnosti, biorazgradivosti i netoksičnosti ima velik potencijal za primjenu kao biomedicinski materijal. Unatoč svojoj čvrstoći, sam FS nije prikladan zbog svoje slabe fleksibilnosti. S druge strane, termoplastični poliuretan (TPU) vrlo je poželjan materijal za medicinsku primjenu upravo zbog njegove fleksibilnosti. Problem slabe fleksibilnosti FS-a mogao bi se riješiti miješanjem fleksibilnog TPU-a s FS-om. Cilj ovoga rada bio je pripremiti mješavine na osnovi TPU-a i prirodnog polimera FS-a. Mješavine TPU-a s FS-om pripremljene su umješavanjem FS-a u TPU u omjerima 5, 10, 15 i 20 mas. % FS-a u laboratorijskoj gnjetilici Brabender. Uzorci su dobiveni prešanjem na hidrauličkoj preši. Određena je struktura te toplinska i viskoelastična svojstva čistog TPU-a, FS-a i mješavina TPU/FS primjenom infracrvene spektroskopije s Fourierovim transformacijama (FTIR), diferencijalne pretražne kalorimetrije (DSC), dinamičko-mehaničke analize (DMA) i termogravimetrijske analize (TGA). Dobiveni rezultati FTIR analize pokazuju da je FS ugrađen u TPU matricu. Rezultati dobiveni mjerenjem DSC i DMA pokazali su da se dodatkom FS-a u TPU temperature staklastog prijelaza (Tg) izražene kao Teig, Tmg i Tefg snižavaju zbog smještanja amorfne faze FS-a (asparaginska kiselina) u amorfnu fazu TPU-a, čime dolazi do veće pokretljivosti polimernih lanaca. Temperature taljenja (Tm) izražene kao Teim, Tpm i Tefm u mješavinama TPU/FS neznatno se snižavaju u odnosu na čisti TPU zbog nastajanja slabije uređene kristalne strukture dodatkom FS-a. Toplinska postojanost neznatno se smanjuje dodatkom FS-a zbog njegove slabije toplinske postojanosti., Silk fibroin (SF), a unique and promising natural material extracted from silkworm, has gained much attention for its use as biomedical material, because of its biocompatibility, biodegradability, and nontoxicity. Despite its strength, SF alone is not appropriate because of its poor flexibility. Thermoplastic polyurethane (TPU) is a very desirable material for medical applications because of its flexibility. A solution to the problem of SF’s poor flexibility can be achieved by mixing flexible TPU with SF. The aim of this work was to examine the influence of FS content on the physical and thermal properties of TPU/FS blends. Blends of SF and TPU were prepared with melt mixing of TPU with 5, 10, 15, and 20 wt% of SF in a laboratory Brabender kneading chamber. The specimens of the neat components and their blends were moulded in a hydraulic press. The structural characteristics, thermal, and viscoelastic properties of neat TPU, SF and their blends (TPU/SF blends) were examined by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The FTIR results showed that the SF was successfully introduced to TPU matrix. Results obtained with DSC and DMA measurements showed that, when the SF content increased in the TPU/SF blends, the Tg, expressed as Teig, Tmg, and Tefg of the TPU, slightly shifted to lower temperature due to the incorporation of the amorphous phase of FS (aspartic acid) in the amorphous phase of TPU, and mobility of polymer chains increased. The melting temperature (Tm), expressed as Teim, Tpm, and Tefm, decreased because of the less organised crystal structure with the addition of SF. Thermal stability was determined by TGA, which showed that, with the addition of SF, the thermal stability decreased because of the lower thermal stability of SF.

Brojna istraživanja te nova saznanja o materijalima i njihovoj biokompatibilnosti s tkivima potaknula su razvoj tkivnog inženjerstva, što je posljedično dovelo do napretka u regenerativnoj medicini i liječenju pacijenata. Svrha tkivnog inženjerstva je obnova građe i funkcije oštećenih i bolesnih tkiva te olakšanje procesa liječenja za pacijente. Biomaterijali koji se pritom koriste trebaju biti biokompatibilni, biorazgradljivi i netoksični. Fibroin svile je materijal koji se dugi niz godina koristi u biomedicini i pokazuje brojna pozitivna svojstva kao što su dobra mehanička svojstva, biokompatibilnost i biorazgradljivost. Cilj ovog rada je priprema elektroispredenih nosača na osnovi polikaprolaktona (PCL) i različitih udjela fibroina svile (FS) postupkom elektroispredanja. Ispitan je utjecaj FS na strukturu, dinamičko-mehanička svojstva te toplinska svojstva elektroispredenih nosača pomoću infracrvene spektroskopije (FTIR-ATR), dinamičko mehaničke analize (DMA) i termogravimetrijske analize (TGA). Uzorci su podvrgnuti i određivanju mehaničkih svojstava pomoću kidalice. Dobiveni rezultati DMA analize pokazuju da porastom udjela FS dolazi do smanjenja vrijednosti modula gubitka, E'' te povećanja vrijednosti staklišta, Tg. Toplinska stabilnost elektroispredenih nosača određena TGA analizom smanjuje se porastom udjela FS. Dobiveni FTIR spektri pokazuju da je FS uspješno ugrađen u elektroispredeni PCL vlaknasti nosač. Mjerenje mehaničkih svojstava pokazuje da se prekidna čvrstoća smanjuje porastom udjela FS u elektroispredenim nosačima. Many investigations and new findings about materials and their compatibility with tissues have initiated tissue engineering growth. Consequently, that led to progress in regenerative medicine and patients recovery. Main purpose of tissue engineering is to restore damaged and diseased tissues and to ease a healing process for patients. Biomaterials used in tissue engineering should be biocompatible, biodegradable and non-toxic. Silk fibroin is a material that has been used in biomedicine for many years and it shows many positive properties such as mechanical properties, biocompatibility and biodegradability. The aim of this work is to prepare electrospun scaffolds based on polycaprolactone (PCL) and different silk fibroin (SF) content by electrospinning. The effect of SF on the structure, dynamicmechanical properties and thermal properties of electrospun scaffolds were investigated by infrared spectroscopy (FTIR-ATR), dynamic-mechanical analysis (DMA) and thermogravimetric analysis (TGA). The mechanical properties were also determined using a testing machine. Results obtained with DMA showed that with addition of silk fibroin, the loss modulus, E'' decreases and the glass transition temperature, Tg increases. Thermal stability of electrospun scaffolds determined by TGA decreases with the addition of silk fibroin. The FTIR results showed that the silk fibroin was successfully introduced to PCL scaffolds. Mechanical properties showed that the tensile strength decreases with increasing SF content in electrospun scaffolds.

Elektroispredanje je postupak proizvodnje nanovlakana pomoću elektrostatskih sila. Ljudsko tkivo sklono je oštećenju. Manje rane, ogrebotine i iščašenja, pa čak i blaži lomovi kostiju lako zarastaju. Problem su potpuno oštećeni organi koji gube funkciju, kao i veliki lomovi kostiju. U rješavanju ovog problema pomaže tkivno inženjerstvo. Tkivno inženjerstvo i proizvodnja funkcionalnih tkiva i organa dio su modernih biomedicinskih istraživanja i primjena. U tkivnom inženjerstvu stanice se zasijavaju u/na biomaterijale prije transplantacije. Ti materijali zatim služe kao privremeni nosači koji unaprjeđuju reorganizaciju stanica za formiranje funkcionalnog tkiva. Nosači su napravljeni od biokompatibilnih i/ili biorazgradljivih materijala. U zadnje vrijeme koriste se biorazgradljivi vlaknasti polimeri kao matrice za uzgoj i rast različitih tkivnih stanica. Posebice, nosači dobiveni elektroispredanjem poli(ε-kaprolaktona) (PCL-a) pokazuju dobar potencijal kao nosači tkiva za regeneraciju kože. U ovom radu postupkom elektroispredanja pripremljena su nosač od čistog PCL-a te nosači PCL-a u kombinaciji s fibroinom svile (FS) (18% PCL+50% FS), antibiotikom Cefuroximom (18 % PCL+25 % CFU) i nosači 18% PCL+50% FS uz dodatak 0,5 mas% mikro i nano TiO2. Istražen je utjecaj FS, CFU i TiO2 na morfološku stukturu, viskoelastična svojstva i hidrofobnost elektroispredenih vlaknastih nosača elektronskim pretražnim mikroskopom (SEM) , dinamičko mehaničkom analizom (DMA) te određivanjem kontaktnog kuta. Electrospinning is process of nanofiber production using electrostatic forces. Human tissue is prone to damage. Smaller wounds, scratches and sprains, and even milder fractures of the bones are easily healed. The problem are completely damaged organs that lose function as well as large-scale bone fractures. In addressing this problem, tissue engineering has a solution. Tissue engineering and manufacturing of functional tissues and organs are part of modern biomedical research and application. In tissue engineering cells are planted in biomaterials prior to transplantation. These materials then serve as temporary carriers that improve cell reorganization to form functional tissue. The carriers are made of biocompatible and or biodegradable materials. Recently, biodegradable fiber polymers are used as matrices for the cultivation and growth of different tissue cells. Specifically, scaffolds obtained by electrospinning of poly (ε-caprolactone) (PCL) exhibit good potential as skin regeneration tissue carriers. In this work by electrospinning procedure scaffolding materials were produced: polycaprolactone (PCL) scaffold (100% PCL), combined bi-polymer scaffold silk fibroin (SF) (18% PCL+50% FS), (PCL) scaffold with antibiotic Cefuroxim (18 % PCL+25 % CFU) and 18% PCL+50% SF with incorporation of 0,5 mas.% of micro and nano TiO2. Morphology, viscoelastic properties and hydrofobicity of the scaffolds were characterized to evaluate the effect of FS,CFU and TiO2 by means of scanning electron microscopy (SEM), dynamic mechanical analysis and contact angle.

Razvojem tehnika tkivnog inženjerstva omogućila se izrada nosača poželjnih mehaničkih i bioaktivnih svojstava potrebnih za regeneraciju tkiva. Dok alternativu predstavljaju tehnike transplantacijske medicine, metode tkivnog inženjerstva prednjače u in vitro modelima za istraživanje raka te razvoja farmaceutika. Cilj ovog rada bio je ispitati i usporediti biokompatibilnost elektroispredanog sintetskog i kompozitnog nosača sa prirodnim nosačem, nacijepljenih s HeLa stanicama. Nosači su bili izrađeni od polikaprolaktona (PCL), PCL-a kombiniranog sa svilinim fibroinom (PCL-SF) te izvanstaničnog matriksa svinjske jetre (ECM). U svrhu istraživanja, testovi biokompatibilnosti nosača sastojali su se od analize uspješnosti nacjepljivanja stanica te dinamike rasta i transfekcije. Kroz sva tri testa, najbolje rezultate je dao nosač od PCL-SF, dok su najmanje uspješni bili oni na ECM nosaču. Rezultati s primjenom kulture HeLa stanica u izradi modelnog tkiva pokazuju da je tehnologija nano-vlakana napredna tehnika u stvaranju staničnih nosača koji uspješno oponašaju potporanj prirodnih tkiva. The development of tissue engineering enabled the production of cell scaffolds with superior mechanical and bioactive characteristics needed for tissue regeneration. While regenerative medicine offers an acceptable alternative, current methods in tissue engineering still lead the way in in vitro cancer model research as well as drug development. The aim of this study was to test and compare biocompatibility of HeLa seeded, electrospun polymeric synthetic and composite scaffolds with a natural scaffold. The scaffolds were made of polycaprolacton (PCL), PCL composite integrated with silk fibroin protein (PCL-SF) and extracellular matrix isolated from pork liver (ECM). In studying the biocompatibility of scaffolds, three tests were performed: cell seeding efficiency, growth dynamics and transfection efficiency. PCL-SF proved the most successful in all three tests, while porcine ECM performed the worst. HeLa culture results indicate the nano-fibre technology as an advanced technique that is indeed able to successfully mimic the 3D architecture of native tissues.

Termoplastični poliuretan (TPU) je vrlo poželjan materijal za medicinsku primjenu zbog njegove fleksibilnosti, trajnosti i otpornosti na ulja i kemikalije. S druge strane, fibroin svile je jedinstveni i obećavajući prirodni materijal dobiven iz dudovog svilca te zbog svoje biokompatibilnosti, biorazgradivosti i netoksičnosti ima veliki potencijal za primjenu kao biomedicinski materijal. Cilj ovoga rada bio je pripremiti i karakterizirati fizikalna, toplinska i mehanička svojstva mješavina sastavljenih od elastičnog termoplastičnog poliuretana (TPU) u koji je umješan različiti udio fibroina svile (FS). TPU/FS mješavine pripremljene su dodatkom 5%, 10%, 15% i 20 mas% FS umješavanjem u laboratorijskoj Brabender gnjetilici. Uzorci čistih komponenti i mješavina dobiveni su prešanjem na hidrauličkoj preši. Određena je struktura, toplinska i mehanička svojstva čistih komponenata (TPU i FS) i njihovih mješavina (TPU/FS) primjenom infracrvene spektroskopije s Fourierovim transformacijama (FT-IR) i prigušene totalne refleksije (ATR), diferencijalnom pretražnom kalorimetrijom (DSC) i termogravimetrijskom analizom (TGA). Mehanička svojstva čistih komponenata i mješavina određena su testom rasteznog naprezanja upotrebom mehaničke kidalice. Dobiveni rezultati FTIR analize pokazuju da je fibroin svile ugrađen u TPU matricu. Rezultati dobiveni DSC tehnikom pokazali su da se dodatkom fibroina svile temperatura staklastog prijelaza povećava, dok se talište smanjuje, zbog nastajanja slabije uređene kristalne strukture nastale dodatkom fibroina svile. Toplinska stabilnost određena je termogravimetrijskom analizom iz koje se vidi da se dodatkom fibroina svile smanjuje toplinska stabilnost TPU/FS mješavina. Povećanjem udjela fibroina svile prekidna čvrstoća i prekidno istezanje se smanjuju. Thermoplastic polyurethane (TPU) is very desirable for medical applications because of its flexibility , durability, and resistance against oils and chemicals. Silk fibroin (SF), a unique and promising natural material extracted from silkworm, has gained much attention for its use as biomedical material, because of its biocompatibility, biodegradability and nontoxicity. The aim of this work was to preparation and characterization the mechanical, physical and thermal properties of blends containing a highly elastic thermoplastic polyurethane (TPU) compounded with different silk contents. TPU/SF blends were prepared with melt mixing of TPU with 5%, 10%, 15% i 20 wt% of SF in a laboratory Brabender mixer. The specimenes of the neat components and their blends were molded in hydraulic press. The structural characteristics, thermal and mechanical properties of the neat TPU, SF and their blends (TPU/SF) were examined by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Mechanical properties of the neat components and their blends were determined by a tensile test using universal testing machine. The FTIR results showed that the silk fibroin was successfully introduced to TPU scaffolds. Results obtained with DSC showed that with addition of silk fibroin, glass transition temperature increases, while melting temperature and degree of crystallinity decreases, because of the less organized crystal structure with addition of silk fibroin. Thermal stability is determined by TGA which shows that with addition of silk fibroin thermal stability decreased. With increasing SF content, the tensile strength and elongation at break decreased.

Fibroin svile stoljećima se koristi u tekstilnoj industriji kao vlakno te već desetljećima u biomedicinske svrhe kao kirurški materijal za šivanje. Zbog svojih dobrih mehaničkih svojstava, biokompatibilnosti i biorazgradljivosti dalje se razvija njegova primjena u različite svrhe. U ovom radu pripremljeni su elektroispredeni nosači na osnovi polikaprolaktona (PCL) i fibriona svile (FS) postupkom elektroispredanja. Istražen je utjecaj FS na morfološku stukturu, kemijski sastav, toplinska svojstva, toplinsku stabilnost i hidrofobnost elektroispredenih PCL/FS vlaknastih nosača SEM analizom, infracrvenom spektroskopijom (FTIR), diferencijalnom pretražnom kalorimetrijom (DSC), termogravimetrijskom analizom (TGA) te određivanjem kontaktnog kuta. Postupkom elektroispredanja dobivena je jednolična struktura PCL/FS vlaknastog nosača s tanjim promjerom vlakana i homogenom raspodjelom SF unutar vlakana. Dobiveni rezultati FTIR analize pokazuju da je fibroin svile uspješno ugrađen u elektroispredeni PCL vlaknasti nosač. Dodatkom FS povećala se hidrofilnost elektroispredenog PCL vlaknastog nosača. Rezultati dobiveni DSC tehnikom pokazali su da se dodatkom fibroina svile temperatura staklastog prijalaza povećava, dok se talište i stupanj kristalnosti smanjuje, zbog nastajanja slabije uređene kristalne strukture nastale dodatkom fibroina svile. Toplinska stabilnost određena je termogravimetrijskom analizom iz koje se vidi da se dodatkom fibroina svile smanjuje toplinska stabilnost. For centuries silk fibroin has been used as a textile fiber. Beyond textiles, silk fibroin has also been used in biomedical applications as a surgical material for decades. Because of his good mechanical properties, biocompatibility and biodegradability silk fibroin is being further developed for various emerging. In this work, electrospun scaffolds composed of polycaprolactone (PCL) and silk fibroin (SF) were prepared by electrospinning technique. Morphology, chemical composition, thermal properties, thermal stability and hydrofobicity of the PCL/SF scaffolds were characterized to evaluate the effect of SF by means of scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle. Electrospinning resulted in uniform fiber morphology with thinner fibers in PCL/SF scaffolds and a homogeneous SF distribution throughout the fibers. The FTIR results showed that the silk fibroin was successfully introduced to PCL scaffolds. The hydrophilicity of PCL modified scaffolds were enhanced. Results obtained with DSC showed that with addition of silk fibroin, glass transition temperature increases, while melting temperature and degree of crystallity decreases, because of the less organized crystal structure with addition of silk fibroin. Thermal stability is determined by TGA which shows that with addition of silk fibroin thermal stability decreased.