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Since only few reported studies propose anti-vascular endothelial growth factor (anti-VEGF) delivery through electrospun scaffolds, this study greatly contributes to the potential prevention of patient’s vision loss, as it explores electrospun polycaprolactone (PCL) coated with anti-VEGF for the blockage of abnormal cornea vascularization. In terms of physicochemical properties, the biological component increased the PCL scaffold fiber diameter (by ~24%) and pore area (by ~82%), while ut slightly reduced its total porosity as the anti-VEGF solution filled the voids of the microfibrous structure. The addition of the anti-VEGF increased the scaffold stiffness almost three-fold at both strains of 5 and 10%, as well as its biodegradation rate (~36% after 60 days) with a sustained release profile after Day 4 of phosphate buffered saline incubation. In terms of scaffold application function, the PCL/Anti-VEGF scaffold proved to be more favorable for the adhesion of cultured limbal stem cells (LSCs) ; this was confirmed by the SEM images, where the cells showed flat and elongated conformations. Further support of the LSC growth and proliferation was con-firmed by the identified p63 and CK3 markers after cell staining. These results demonstrate the advantageous effect of the surface-adsorbed anti-VEGF to stop vision loss and help damaged corneal tissue repair.

Plant proteins are receiving a lot of attention due to their abundance in nature, customizable properties, biodegradability, biocompatibility, and bioactivity. As a result of global sustainability concerns, the availability of novel plant protein sources is rapidly growing, while the extensively studied ones are derived from byproducts of major agro-industrial crops. Owing to their beneficial properties, a significant effort is being made to investigate plant proteins’ application in biomedicine, such as making fibrous materials for wound healing, controlled drug release, and tissue regeneration. Electrospinning technology is a versatile platform for creating nanofibrous materials fabricated from biopolymers that can be modified and functionalized for various purposes. This review focuses on recent advancements and promising directions for further research of an electrospun plant protein-based system. The article highlights examples of zein, soy, and wheat proteins to illustrate their electrospinning feasibility and biomedical potential. Similar assessments with proteins from less-represented plant sources, such as canola, pea, taro, and amaranth, are also described.

Phase change materials (PCMs) have an important role in heat energy storage, due to their ability to absorb and release heat preferably at almost equal temperature. Encapsulation of these materials provides them to perform in their full shape. Recently electrospinning has gained attention as an effective way of producing heat storing nanofibers. This thesis considers two aspects. The first one was to encapsulate a phase change material applying ecologically and economically acceptable technique of emulsion electrospinning from a water soluble polymer, polyvinyl alcohol (PVA) and a mixture of plant oils PCM. The second aspect considers polycaprolactone (PCL) not reported yet as a phase change material in the electrospinning of these types of fibers. The PCL was encapsulated through blend elecrospinning along with polyvinylidene fluoride (PVDF) as the matrix. Although many studies reported on the form stable nanofibers when incorporating PCMs, little attention was given to the effect of high heat exposure on their structure stability and mechanical behaviour. In this thesis systematic research was carried on this issue for both material types. PVDF/PCL nanofibers materials were additionally coated by a thin layer of polypyrrole (PPy) or PPy with reduced-graphene oxide (r-GO) to further investigate materials heat storing performance, crystalline structure change, temperature weight loss, mechanical behaviour as a function of temperature and thermal conductivity. The first system showed reliability in heat storing for 100 cycles of heating and cooling, with stable physical structure and fibers morphology. After heat treatment the electrospun materials with the lowest phase change material loading performed with almost unchanged mechanical properties. The PVDF/PCL showed reliable heat storing function with encapsulation efficiency of almost 50%, for the low molecular weight PCL. The thin layer of polypyrrole on the surface of the fibers resulted in the improvement of the dynamic mechanical behaviour as a function of temperature, after materials exposure to firmly higher temperature than PCL’s melting point. The addition of the r-GO had a negligible effect on the temperature and enthalpies of melting and crystallization, while thermal conductivity increased gradually with the change of fibers surface coating during PCL solid phase. With the rapid development of electrospun nanofibrous materials towards commercialization, these types of materials can be used as thermo-regulating fabrics in protective clothing or passive heat storing devices., Materijali s promjenom stanja (eng. phase change materials - PCMs) imaju važnu ulogu kod latentne pohrane toplinske energije, obzirom na sposobnosti apsorpcije i oslobađanja topline, po mogućnosti, kod gotovo jednake temperature. Kako bi ovi materijali funkcionirali u potpunosti, poglavito u kritičnom trenutku prijelaza iz krutine u kapljevinu, moraju biti kapsulirani. Nedavno se i tehnika elektroispredanja pokazala kao učinkovit način za proizvodnju nanovlakana za pohranu topline. U ovom doktorskom radu najprije su proizvedena nanovlakna iz mješavine biljnih ulja (u nastavku označen kao PCM) i polivinil akolhola (PVA) uz ekološki prihvatljive tehnike elektroispredanja iz emulzije. Zatim su proizvedena nanovlakna iz polikaprolaktona (PCL), s manjom i većom molekulskom masom, koji do sada nije korišten kao materijal s promjenom stanja za elektroispredena vlakna. PCL je kapsuliran u polivinilidenfluoridnu (PVDF) matricu elektroispredanjem iz polimerne mješavine. Istraživanja su do sada pokazala da vlakna koja kapsuliraju materijale s promjenom stanja imaju stabilnu strukturu, međutim vrlo mala pozornost je posvećena na stabilnost strukture, te mehaničko ponašanje nakon izlaganja ovih materijala većim temperaturama, pri kojima je ovaj materijal u stanju kapljevine. Slijedom ovog razmišljanja u ovom doktorskom radu sustavno je provedeno istraživanje u vezi navedene problematike. PVDF/PCL nanovlaknasti materijali dodatno su obrađeni nanosom površinskog sloja polipirola (PPy-a), te PPy-a u kombinaciji s reduciranim grafenovim oksidom (r-GO) kako bi se ispitao njihov utjecaj na sposobnost pohrane topline, kristalnu strukturu, mehaničko ponašanje u ovisnosti o temperaturi, te na toplinsku vodljivost.

In a computational analysis of deformational behaviour of textile materials their specific tensile nonlinearity needs to be adequately described. Comparison of fitting accuracy for a selection of possible approximate models indicates that the sigmoidal curve offers an excellent fit for a wide spectrum of woven fabrics. In the asymmetric tensile loading, the tensile force is applied to a rectangular fabric specimen via the rigid crossbar, and the linear distribution of strain results in nonlinear stress distribution, including zero stress in the zone of compressive strain at large load eccentricities. The adopted sigmoidal model of tensile response is incorporated into the static conditions of equilibrium between tensile force and stresses in the fabric. The computed results allow a precise estimate of stress concentration and apparent reduction in strength and stiffness resulting from the eccentricity of load application.

Tight elastic clothing items are frequent in general but also play an important role in sports equipment and medical applications. A proper choice of geometry and mechanical properties is essential for good balance between function and comfort. In an appropriate engineering analysis the deformational properties of both body tissue and elastic sock need to be accounted for. The limb is considered here as a composite cylinder consisting of concentric thick walled tube with rigid core. It is loaded by the pressure resulting from the tightly applied cylindrical membrane representing sock or compressive bandage. Linear elastic deformation is considered in all materials involved. The results are given in the form of diagrams of stress distribution in the cylinder. Examples indicate the influence of geometry and material properties to the stress state in the tissue.

Functionalized electrospun materials have many applications one of which includes biomedicine or tissue engineering. These materials act as scaffolds as can simulate the extracellular matrix in tissues thus giving support to cells growth and finally helping tissue regeneration. This study gives an insight into the research concerning development of this type of materials as part of the Croatian Science Foundation project. Electrospun composite scaffolds were prepared by electrospinning of neat polycaprolactone (PCL), as well as PCL blended with an antibiotic or silk fibroin separately and finally by electrospinning both PCL/fibroin and PCL/antibiotic within a layered configuration. The scaffolds were analyzed in regard to their morphology, total porosity, surface wettability and tensile behaviour taking into account the type of filler and layered structure. Firstly the addition of the antibiotic as well as silk fibroin both resulted in the reduction of the water contact angle on the surface of the hydrophobic PCL. Thus, a hydrophilic surface is of paramount importance as it improves scaffolds cells adhesion. The addition of the fillers, antibiotic and silk fibroin, resulted in PCL fibers diameter reduction by 28% and increase by 224%, respectively. Fibers deformations or beads were present in case of the neat PCL and the PCL/fibroin fibers. The biggest pores area were in case of the PCL/fibroin of 8.13±6.45 µm2. The total porosity reduced gradually with the addition of the fillers, resulting in the lowest value in case of the layered scaffolds (from 94.2 to 68.5%). The tensile strength of the electrospun scaffolds improved with the addition of the antibiotic and in case of the layered structure, resulting in the maximum value of 260.33±60.53 cN/mm2. These results suggest that the nature of the filler affects its miscibility with the polymer and electrospinning jet stretching and both porosity and tensile strength are affected by the scaffolds composition and layered structure. In this way by variating the composition and physical structure, scaffolds can be designed according to requirements in tissue therapy and repair.

Melt electrospinning and its application in tissue engineering research is part of the Croatian Science Foundation project concerning the development of electrospun scaffolds suitable for skin and ocular cells culture. The melt electrospinning process is free of organic solvents thus avoiding toxicity problems when developing medical products. Another important aspect is certainly the micro fibrous structure that is produced by melt electrospinning, thus very much favourable for the cells in-depth penetration in the scaffolds. The “Spraybase” melt electrospinning device used in this project combines electrospinning and 3D printing principles for the production of custom tailored scaffolds with target defined topography. The “Spraybase” device involves several steps in the production of the melt electrospun scaffolds: 1) 3D design and model generation of the scaffolds geometry, 2) polymer selection (in this project polycaprolactone or polylactid), 3) temperature, electrical voltage, pressure and head to collector distance set up and 4) electrospinning. The process involves the formation of the melt jet though polymer melting, as the polymer is pushed by the pressure in the head, the jet starts to form at the tip of the nozzle and stretches by the electrical voltage. The geometry of the scaffold is formed by the movement of the collector in the X and Y axis according to the 3D model. The thickness of the scaffold results from the head movement in the Z direction. The micro fibers are positioned in compliance with the designed patterns.

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 applications. In this work, tissue engineering scaffolds composed of polycaprolactone (PCL) and silk fibroin (SF) were prepared by electrospinning technique. Morphology, chemical composition, thermal properties, thermal stability and hydrophobicity 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 water contact angle analysis. Electrospinning resulted in uniform fibers morphology, with thinner fibers in case of the PCL/SF scaffolds and a homogeneous SF distribution throughout the fibers. The FTIR results showed that the silk fibroin was successfully introduced to the PCL scaffolds. The hydrophilicity of the PCL modified scaffolds was enhanced. Results obtained with DSC analysis showed that with addition of the silk fibroin, glass transition temperature of the PCL increases, while the melting temperature and degree of crystallinity decreases, because of the less organized crystal structure with addition of silk fibroin. The thermal stability of the PCL/SF scaffolds also decreased with the addition of the SF.

The ERASMUS Programme (EuRopean Community Action Scheme for the Mobility of University Students) is a European Union (EU) student exchange programme established in 1987. International Relations Office at University of Zagreb Faculty of Textile Technology (IRO TTF) was founded in 2007. The first Head, and ERASMUS coordinator was professor Ana Marija Grancarić (2007-2013). In 2009, when Croatia approached EU integration, the University of Zagreb signed ERASMUS, and made the Higher Education (HE) student exchange possible. By signing a bilateral agreement with L'Ecole Nationales Superiure des Artes et Industries Textiles (ENSAIT), Roubaix, France, TTF was one of the first faculties in Croatia with ERASMUS HE student exchange. In the academic year of 2009/2010 TTF had three incoming students for study (SMS) ; in 2011/2012 nine SMS ; in 2012/13 six SMS and 1 student mobility for traineeship (SMT), and in 2013/14 eight SMS and 3 SMTs, all from ENSAIT. In 2013/14 three TTF students were at ENSAIT as SMS. With the academic year 2013/14 the old ERASMUS Programme ended, and a new ERASMUS+ Programme that combines all EU's current schemes for education, training, youth and sport, started, and will end in 2020/2021. The next Head of TTF IRO and ERASMUS+ coordinator became assist. prof. Anita Tarbuk (2013-2017). The current TTF ERASMUS+ coordinator is Emilija Zdraveva, PhD. Within the ERASMUS+ Programme TTF signed 31 bilateral agreements, among which were ones with four French universities: from 2014/15 ENSAIT, Roubaix ; and Universite de Haute Alsace, Ecole Nationale Supérieure d'Ingénieurs Sud Alsace (ENSISA), Mulhouse ; from 2015/16 Institut Textile et Chimique de Lyon (ITECH), Lyon ; and from 2017/18 L’Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Lille. Whithin this E+ SMS in 2014/15 five ENSAIT students were at TTF, and 3 TTF students were in Roubaix. One TTF student as E+ SMT did internship in Elie Saab company, Paris, France. Whithin this E+ SMS in 2015/16 six ENSAIT students were at TTF, and 3 TTF students were in Roubaix. In 2016/17 one TTF student as E+ SMT did internship in Decathlon AddLab, Lille, France ; and 2 students from ITECH, Lyon were at TTF as E+ SMS. The staff E+ mobility from ITECH, Lyon was achieved in this year as well. In 2017/18 two TTF students were at ENSAIT as E+ SMS, one was at ITECH, Lyon as E+ SMT, and one E+ SMS from ENSAIT, and one E+ SMT from ENSCL, Lille were at TTF. A. Tarbuk was at ITECH as E+ TM. Currently, 2 E+ SMS students from ITECH, one from ENSCL and one from ENSISA are at TTF, and in the next semester of 2018/2019, 4 students will come from ENSAIT.

Tensile response of a given material is recorded by the standard test in which the stress caused by the mechanical loading is evenly distributed in the test specimen. Textile materials are flexible and unable to withstand any in-plane compression. Compressive cut off can be viewed as the first source of the nonlinearity in textile deformation. This paper brings the study in which these nonlinear phenomena are illustrated on the case of the out-of-centre tensile load in the modified standard tension test, where the force is applied to the specimen via the rigid crossbar. If the negative stress of bending part surpasses the average tensile stress, compressive cut off takes place and the static conditions must be satisfied in the new situation of a reduced specimen.

Elektroispredeni materijali koji se primjenjuju za pasivnu pohranu toplinske energije izrađuju se na bazi materijala sa promjenom stanja (engl. phase change materials - PCMs). U ovom radu dan je kratki osvrt na istraživanje vezano uz razvoj ovakvih materijala na bazi biljnih ulja i polikaprolaktona.

Tissue engineering provides great opportunities in the development of artificial organs, especially biological regenerative materials, such as cartilage, bone and skin. Designing the appropriate biodegradable and biocompatible materials and investigation of their biochemical and physical properties as well as cell growth factors, makes it possible to generate substitutes that can restore or substantially improve the function of damaged tissues. In this paper, the effect of different topographies of electrospun Polycaprolactone fibrous carrier on the incorporation and cell growth was investigated. Polymer carriers with different structure and porosity, have been prepared by electrospinning of PCL/CEFUROXIM® (CFU) solution at the 3D printed collectors. Polymer solution was prepared with different concentrations of antibiotic CFU, 15 and 20 %wt., which is used for local eye infection treatment. Fibrous morphology was followed by scanning electron microscopy (SEM), while the incorporation of cells in the polymer carrier was identified by Fourier transformation infrared spectroscopy (ATR-FTIR). Melting (Tm) and crystallization (Tc) temperatures of PCL/CFU as well as degree of crystallinity were determined by differential scanning calorimetry (DSC), while thermal stability of material was obtained by thermogravimetry (TG). Results of PCL/CFU carrier microstructure were correlated with transformation temperatures and antibiotic concentrations as well as cell growth.

Elektroispredanje je tehnika proizvodnje fine vlaknaste strukture promjera pora raspona od 2 nm do nekoliko mikrometara iz polimernih otopina ili talina, koja imaju manji promjer pora i veću specifičnu površinu u odnosu na materijale dobivene konvencionalnim postupcima izrade tekstila. Jedno od područja primjene vlaknastih struktura dobivenih elektroispredanjem je tkivno inženjerstvo. Strategija tkivnog inženjerstva temelji se na regeneraciji oštećenih tkiva na način da se biopsijom stanice uzimaju iz pacijenta, potom se izoliraju i zasijavaju na 3D nosač. Kao materijal za izradu nosača koriste se različiti prirodni i umjetni polimeri. Osnovni problem u tkivnom inženjerstvu je slaba infiltracija stanica u mrežu vlakana. U ovom radu je za elektroispredanje nosača različite geometrije korišten polikaprolakton (PCL). Nosači su elektroispredani na kolektorima izrađenim 3D printanjem iz fotoreaktivne prozirne smole na bazi estera metakrilne kiseline i foto-inicijatora. 3D printani kolektori su različite geometrije, u cilju dobivanja elektroispredenih vlaknastih nosača specifične topografije, na kojima bi zasijane ljudske stanice rasle i migrirale prema obliku površine nosača stvarajući tkivo određene 3D mikrogeometrije. Morfologija vlakana određena je SEM analizom, raspodjela veličina promjera pora BET metodom, a interakcije na površini metodom mjerenja kontaktnog kuta s vodom. Primjenom SEM analize vidljivo je da je ostvarena željena porozna struktura PCL nosača elektroispredenih na 3D printanim kolektorima ciljane geometrije. Dobivena je dvostruka (nano/mikro) porozna struktura koja omogućuje zasijavanje i pričvršćivanje stanica, te prijenos nutrijenata i kisika što je važno za razvoj stanica. Mjerenjem kontaktnog kuta s vodom elektroispredeni PCL nosači su pokazali vrlo slabe interakcije s vodom. Rezultati BET analize pokazali su da 3D struktura nosača rezultira i s više od 4 puta većom specifičnom površinom. Veća specifična površina je vrlo pogodna za adheziju tj. veći broj mjesta za vezivanje stanica, rast, diferencijaciju i proliferaciju zasijanih stanica.

This paper focuses on the fabrication and characterization of electrospun thermoregulating fabrics incorporating phase change materials (PCM). The influence of the PCM content on the electrospun fibers morphology, thermal stability, phase change sustainability and heat storing was examined. The fibers showed cylindrical shapes and rough surfaces. The 14 % surfactant resulted in beads disappearance for both 30 and 50 wt% PCM. The PCM amount did not affected too much materials’ temperature weight loss. Higher encapsulation efficiency above 30 % was calculated for the PCM 50 wt%. These fabrics are good candidates for protective clothing as can regulate the temperature near the human skin and are lightweight, thus improving body comfort.

In the standard test of textile flexibility it is usual to express the test result as the length of the cantilever specimen at which the deflected line reaches the prescribed slope. Along with the mass per unit area this provides an insight to bending stiffness of the fabric, or inversely its flexibility. However the computation of bending deformation is governed by the equation in which curvature as the measure of deformation is related to the bending moment and stiffness. The data on stiffness is not acquired directly from the test, so in this study an attempt is taken to recalculate the test measurement into the computational stiffness. To this end, a model of the test is adopted in which the shape of the bent specimen is approximated by the hyperbolic cosine curve, or the catenary. This allows for an easy and efficient derivation of the approximate formulae for bending stiffness.

Osviještenost o zaštiti okoliša postaje sve veća, a u tom smislu znanost o materijalima je sve više posvećena razvoju biokompozita koji u postupku odlaganja doprinose smanjenju onečišćenja okoliša zbog biorazgradivosti. Uspješno pripremljeni biokompoziti na bazi polietilen oksida(PEO) i otpadne biomase tj. ri žinih ljuski imaju široku primjenu obzirom na termoizolacijska svojstva punila. U ovom radu pokazalo se da povećanjem količine punila opada vlačna čvrstoća ili naprezanje biokompozita kod maksimalne vlačne sile, dok smanjenjem veličine punila raste vlačna čvrstoća, kao i maksimalna vlačna sila, što je rezultat veće homogenizacije tj. veće adhezije punila s matricom.

Different methods were used to investigate water vapour resistance and water vapour permeability on several bovine leathers to be used for making professional footwear. The Permetest instrument determined water vapour resistance while water vapour permeability was determined by a standard method, according to HRN EN ISO 20344:2012. Samples of box calf leather and nappa leather, whose raw material is equal, were technologically processed in a similar manner (hydrophobisized, combination tanned and polyurethane finish of the face of the leather) have the highest water vapour resistance. In the case of identical processing a sample of less thick suede has lower water vapour resistance in relation to thicker suede. Water vapour permeability is largely dependent on the processing of the face of the leather. Suede samples have high values of water vapour permeability in comparison to samples of box calf and nappa leather, independent on thickness and processing which is associated with the permeable structure of their buffed face.

Nanovlakna i proizvodnja nanovlaknastih materijala, poglavito tehnikom elektroipsrednja, zauzimaju vrlo važno mjesto u znanstvenom svijetu obzirom na jedinstvena svojstva tj. raznovrsna područja primjene. Općenito, područje funkcionalnog tekstila je područje gdje se nanovlaknasti materijali mogu primijeniti i kod izrade cipela. U ovom radu dan je kratki pregled područja primjene nanovlakana kod izrade cipela što uključuje piezo-električne materijale i materijale s kontroliranim prijenosom vlage. Na kraju dan je i primjer komercijalnog proizvoda s ugrađenim nanovlaknima. Iako je broj istraživanja ovih materijala kod izrade cipela nešto skromniji u odnosu na istraživanja vezana uz odjeću to svakako ne umanjuje njihov značaj.

The study focuses on the design and evaluation of electrospun dual function scaffolds with the ability to heal inflammation in skin and eye tissues and to provide topographical cues for cells penetration into the scaffolds depth. For this purpose scaffolds were loaded with antibiotic and electrospun on 3D printed collectors with purpose made geometry.

Elektroispredeni materijali nalaze primjenu kao sustavi za prijenos lijekova. U ovom radu uspješno je pripremljen elektroispredeni polikaprolakton (PCL) s dodatkom antibiotika, Cefuroxim (CF). Ispitivanjem morfoloških karakteristika utvrđeno je da s povećanjem koncentracije punila ili CF-a dolazi do smanjenja promjera PCL vlakana i promjera deformacija, dok su promjene kod površine pora neznatne. Ukupna poroznost materijala se također smanjuje, a maksimalna izračunata vrijednost iznosila je 76% kod PCL-a sa najmanjom koncentracijom antibiotika.

This paper work is based on a brief discussion of a recent project proposal, approved by the Croatian Science Foundation. The project proposal focuses on the application of the technique of electrospinning in the development of scaffold prototype to be used for in vitro culture of ocular and skin cells. A brief review was also conducted on recent studies focusing on the usage of electrospinning combined with other advanced techniques for the fabrication of materials used for biomedical applications. The project itself has proposed scaffolds fabrication combining both solution and melt electrospinning.

Polycaprolactone/CNT nanocomposites were prepared by laboratory Brabender mixer, with different content of CNT: 0.05, 0.1, 0.2, 0.5 % mas. . Morphological structure of investigated samples was obtained by Field-Emission Scanning Electron Microscope (FE-SEM). Glass transition temperatures, melting and crystallization temperatures were followed by Differential Scanning Calorimetry (DSC). Viscoelastic properties were obtained by Dynamic–mechanical analysis (DMA), while tensile strength and Young modulus were determined by Zwick Universal mechanical testing machine. PCL/CNT nanocomposites showed better final properties in relation to neat PCL.

Addition of CNTs in the PCL (polycaprolactone) improves thermal and mechanical properties of PCL. That’s why in most cases CNTs are added to biodegradable PCL and such nanocomposite has a significant application for prosthetic leg. Investigated PCL/MWCNT nanocomposites were prepared by Brabender mixer as well as by dissolution in THF. The content of nanofiller was 1, 2 , 3 and 5 % wt. The infulence of MWCNT on the thermal stability and crystallinity was determined by simultaneous thermal analyzer (STA). Microstructure was performed by Field- Emission Scanning Electron Microscope (FE-SEM). Mechanical and Dynamic–mechanical properties were followed by Zwick Universal Mechanical Testing Machine and Dynamic-mechanical Analyzer (DMA). Results showed incresing crystallinity and better final properties with incresing MWCNT content in biodegradable PCL matrix.

Thermo-regulating through a phase change material (PCM) offers an effective approach to improve the thermal comfort feature of fabrics. Recently, electrospinning has been recognized as an alternative way of encapsulating phase change materials. This paper discusses the development of electrospun nanofibrous materials with a heat storing ability based on polycaprolactone (PCL), owing to its low melting point as an advantage in practical applications. TA low molecular weight PCL was encapsulated in nanofibers through electrospinning its blend with polyvinilidene fluoride (PVDF). The as prepared nanofibrous materials, with different polymers weight ratios, were evaluated for their heat storing performance, temperature decomposition and mechanical behavior. The heat managing function of the nanofibres has been clearly demonstrated with an efficient encapsulation of almost 50 % PCL in the fibres, meanwhile the cast films with same polymer composition only showed 29 %. Further, the electrospun materials performed with greater structure stability and improved mechanical stiffness after exposure to a temperature higher than the melting point of PCL, compared to control samples. On the other hand the heat treatment of the cast films resulted in greater separation or porous structure during PCL solid-liquid phase transition.

Electrospinning is the process of nanofibers formation under electrical field, where polymer solution or melt is being stretched by electrostatic forces. Nanometer dimension TiO2 nanoparticles have been recently proposed as attractive filler materials for biodegradable polymer matrices as it enhances cell attachment and proliferation on the composite surfaces. The degradation process extends into the polymer matrices through the diffusion of the reactive oxygen species. Resistance to UV light is an important factor for outdoor applications of polymeric materials. In this study polycaprolactone was electrospun into fibres with the addition of nano- and micro- TiO2 as well as TiO2 nanotubes. The photodegradation behavior of the electrospun PCL and PCL/TiO2 micro- and nano-composites fibers was investigated. The addition of micro TiO2 particles in the PCL slightly increased Tg of TiO2 while the addition of nano TiO2 (nTiO2) and Ti nanotubes (TiNT) did not affect on the Tg prior to UV irradiation. After UV irradiation, the Tg of the electrospun PCL/TiNT composite fibres was moved to a higher temperature. This behaviour could be explained by the lower mobility of the amorphous phase of PCL. TGA results showed that the slight improvement of thermal stability of electrospun PCL/ TiO2 composites fibres was obtained with the addition of micro- and nanoparticles of TiO2 as well as with TiNT. The results obtained from the SEM analysis suggests that the mTiO2 acts as a photocatalyst. This result suggests that in air any alkyl radicals will react with oxygen and formed hydroperoxides which can contribute to auto-catalytic reaction.TiO2 fillers in irradiated PCL/TiO2 composite led to the changes of some characteristic functional groups of PCL that was probably due to the photocatalytic activity of the TiO2 particles which accelerates the process of composite degradation.

Nanofibers being the main unit of electrospun materials have paid attention in the last decades as their potential applications are increasing each day. In this work single and blend polymers solutions were prepared from polyurethane (PU), poly(ethylene oxide) (PEO) and (PU/PEO). The solutions were electrospun into porous microstructures and evaluated with regard to their fiber diameter and pore area distribution using SEM analysis. The mean fiber diameter and pore area decreased for almost 200 nm and 4 µm2 respectively, for both dual polymer electrospun systems, influenced by the water extracted amount of the water soluble PEO. Statistically the difference showed significance, but an inverse effect for the pore area as expected was not reached due to wet fibers agglutination.

Zbog izuzetnih svojstava poput velike specifične površine, velike poroznosti i povezanosti pora, mogućnosti kontrole promjera vlakana u postupku elektroispredanja, elektroispredeni materijali nalaze primjenu u mnogim područjima među kojima je i područje pohrane energije na bazi materijala s promjenom agregatnog stanja. U radu su pripremljeni elektroispredeni materijali iz emulzije na bazi vodotopivog polimera i mješavine biljnih ulja. Materijali su pokazali pouzdanost u pohrani i oslobađanju toplinske energije uz najveću entalpiju od 80 J/g, te deformacije po duljini vlakna, u obliku grudica, kod najveće dodane količine materijala s promjenom agregatnog stanja. Ovakvi materijali se mogu potencijalno koristiti kod izrade zaštitne odjeće s mogučnošću regulacije temperature.

The aim of the study was to investigate the impact of electrospun polyurethane and polycaprolactone nanoscaffolds, before and after hydrolytic surface modification, on viability and differentiation of cultured human eye epithelial cells, in comparison with natural scaffolds. The scaffolds used were: amniotic membrane, fibrin, polyurethane (PU) and polycaprolactone (PCL) nanoscaffolds, with or without prior NaOH treatment. Human placenta was taken at elective caesarean delivery. Fibrin scaffolds were prepared from commercial fibrin glue kits. Nanoscaffolds were fabricated by electrospinning. Limbal cells were isolated from surpluses of human cadaveric cornea and seeded on feeder 3T3 cells. Scaffolds morphological characterization was performed using scanning electron microscopy. Human limbal cells were identified by immunofluorescence confocal laser scanning microscope, using markers for limbal stem cells p63 and differentiated cells of the cornea CK3. There was statistically significant difference in viability of cells cultured on plastic and cells cultured on all other scaffolds. Cells grown on fibrin and amnion showed higher viability compared to the electrospun nanoscaffolds. On the other hand, electrospun PU, PCL and electrospun PCL treated with NaOH had more than 80% of limbal cells positive for stem cell marker p63. SEM photographs of all tested scaffolds showed good colony spreading of seeded limbal cells. Although compared to natural carriers, the higher porosity and larger surface of nanoscaffolds and their NaOH treated versions, promised superior cell attachment and spreading, this was not the case. They showed lower cell viability compared to fibrin and plastic. On the contrary, high percentages of p63 positive cells on these scaffolds still makes them good candidates as efficient delivery systems for therapeutic purposes. Modifications in nanoscaffold surface properties should be more thoroughly tested to achieve higher level of viability and proliferation.

Aim was to investigate the impact of synthetic electrospun polyurethane and polycaprolactone nanoscaffolds, before and after hydrolytic surface modification, on viability and differentiation of cultured human eye epithelial cells, in comparison with natural scaffolds: fibrin and human amniotic membrane. Human placenta was taken at elective caesarean delivery. Fibrin scaffolds were prepared from commercial fibrin glue kits. Nanoscaffolds were fabricated by electrospinning. Limbal cells were isolated from surpluses of human cadaveric cornea and seeded on feeder 3T3 cells. The scaffolds used for viability testing and immunofluorescence analysis were: amniotic membrane, fibrin, polyurethane (PU) and polycaprolactone (PCL) nanoscaffolds, with or without prior NaOH treatment. SEM photographs of all tested scaffolds showed good colony spreading of seeded limbal cells. In regard to viability performance there was statistically significant difference between cells with highest viability cultured on tissue culture plastic and cells cultured on all other scaffolds. On the other hand, electrospun PU, PCL and electrospun PCL treated with NaOH had more than 80% of limbal cells positive for stem cell marker p63 compared to only 27%of p63 positive cells on fibrin. Natural scaffolds, fibrin and amniotic membrane, showed better cell viability compared to electrospun scaffolds. On contrary, high percentages of p63 positive cells on these scaffolds still makes them good candidates as efficient delivery systems for therapeutic purposes.