Izdelava in vrednotenje elektrostatsko sukanih polimernih vlaken za zdravljenje kroničnih ran

Vrhovnik, Lea (author), Zupančič, Špela (mentor), Kogermann, Karin (co-mentor)

Rana je opredeljena kot poškodba ali motnja anatomske strukture ali funkcije kože. Kadar se rane ne zacelijo oziroma se ne zacelijo pravočasno in urejeno, jih imenujemo kronične rane. Obloge za rane so bistvenega pomena za celjenje ran, saj rane ščitijo pred zunanjimi vplivi ter sočasno pospešujejo celjenje. Vlaknene polimerne obloge predstavljajo velik potencial za izboljšano celjenje ran in so najpogosteje izdelane z elektrostatskim sukanjem. Pri razvoju nanovlaken in mikrovlaken je potrebno upoštevati lastnosti polimerov, saj le-te zagotavljajo različne mehanske lastnosti in stopnje razgradnje oblog za rane ter interakcije med celicami in materialom obloge, kar povzroči določene odzive tkiva. Namen magistrske naloge je bil razumeti vpliv različnih polimerov na mehanske lastnosti polimernih oblog za rane, pridobljenih z metodo elektrostatskega sukanja, ter obnašanje le-teh v biorelevantnih vodnih pogojih. V nalogi smo primerjali dva različna hidrofobna polimera, poli (ε-kaprolakton) (PCL) in poli (L-laktid-ko-ε-kaprolakton) (PLC). Polimera smo raztopili v ustreznem organskem topilu in iz njunih raztopin izdelali vlakna z metodo elektrostatskega sukanja pod enakimi okoljskimi pogoji. Nato smo ovrednotili različne lastnosti vlaknenih membran, kot so morfologija vlaken, mehanske lastnosti in obnašanje vlaknenih membran v biorelevantnih vodnih pogojih. Optimizacija formulacijskih in procesnih parametrov elektrostatskega sukanja je omogočila pridobitev vlaken iz obeh polimerov. Odvisno od polimera sta vlakneni membrani pokazali različni morfologiji vlaken. Premer vlaken polimera PCL je v poprečju meril 500 nm, premer vlaken polimera PLC pa 2 μm. Vlakna polimera PLC so bila homogena, vlakna polimera PCL pa nehomogena in so vsebovala nekaj morfoloških napak. Vlakna polimera PLC so v vodnem okolju nabreknila, membrana vlaken pa se je skrčila, medtem ko vlakna polimera PCL niso kazala večjih sprememb. Razgradnja obeh vlaknenih membran v vodnem okolju je bila podobna po izgubi mase. Razlike so se pokazale v mehanskih lastnostih vlaknenih membran, in sicer je bil Youngov modul višji pri membranah vlaken polimera PLC kot pri PCL, medtem ko je bila natezna trdnost podobna za obe polimerni membrani. Raztezek ob pretrganju pa je bil znatno večji pri vlaknenih membranah polimera PLC. Glede na rezultate lahko sklepamo, da je obnašanje elektrostatsko sukanih vlaknenih membran v veliki meri odvisno od uporabljenega polimera kot tudi od strukture membrane vlaken.

• Language: Slovenian
• Keywords: Obloge za rane, nanovlakna, elektrostatsko sukanje, poli (ε-kaprolakton) in poli (L-laktid-ko-ε-kaprolakton).
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2023
• PID: 20.500.12556/RUL-147258
• Publication date in RUL: 28.06.2023

Secondary language

• Language: English
• Title: Formulation and characterization of electrospun polymer fiber mats for chronic wound healing

Abstract

A wound is defined as damage or disruption of the skin in its anatomical structure or function. When wounds fail to heal and repair properly in a timely manner, they are referred to as chronic wounds. Wound dressings are essential for wound healing as they protect wounds from external hazards and accelerate healing. Fibrous polymeric wound dressings present a promising potential for improved wound healing. They are most commonly produced by electrospinning. In the development of nanofibers and microfibers, polymer characteristics should be considered, since they offer a variety of mechanical properties, degradation rates, and cell-material interactions. The aim of this thesis was to understand the effects of different polymers on the relevant properties of electrospun fiber mats to be used as wound dressings and their behaviour in biorelevant aqueous conditions. We compared two different hydrophobic polymers, poly(ε-caprolactone) (PCL) and poly(L-lactide-co-ε-caprolactone) (PLC). The polymers were dissolved in a suitable organic solvent and electrospun under the same environmental conditions. Various relevant properties of the fiber mats were evaluated, such as the morphology, mechanical properties and their behaviour in biorelevant aqueous conditions. In order to obtain fibers from both polymers, we optimized the formulation and process parameters of electrospinning. Depending on the polymer, the electrospun mats showed different fiber morphologies. The mean fiber diameter for PCL was 500 nm, and for PLC 2 μm, even though they were both prepared from 9% (w/w) solution in the same solvent. PLC fibers were homogeneous, while PCL fibers were inhomogeneous with some defects. The behaviour in aqueous conditions and the degradation of the fiber mats were different depending on the polymer. PLC fibers swelled and fiber mats shrunk after being in aqueous conditions, while PCL fibers and fiber mats obtained its shape and size. The mechanical properties of the fiber mats showed differences. Young’s modulus and elongation at break was higher for PLC fiber mats, while the tensile strength was similar for both polymer mats. Based on results, we can conclude that the behaviour of electrospun fiber mats strongly depends on the polymer used as well as on the structure of the fiber mats.

• Keywords: Wound dressing, nanofibers, electrospinning, poly(ε-caprolactone) and poly(L-lactide-co-ε-caprolactone).