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Opis: Chronic wounds do not heal within a reasonable time frame due to hypoxia and bacterial inflammation, creating an urgent need for advanced biomaterials to address these challenges. In this study, oxygen-generating, antibacterial xanthan gum-polylactic acid (XA/PLA) aerogels loaded with dexamethasone were developed for the first time for potential wound healing applications. The aerogels contained sodium percarbonate and calcium peroxide as oxygen-releasing agents, providing sustained oxygen release for up to 48 h. The aerogels had a highly porous structure with a high specific surface area (up to 396 ± 8 m2/g) and revealed high liquid absorption capacity in simulated body fluid, absorbing up to 67 times their original weight and remaining stable for 72 h. The in vitro release tests showed controlled profiles of dexamethasone over 24 h. The antibacterial tests demonstrated strong antibacterial activity against Escherichia coli (an up to 15.92 mm inhibition zone diameter) and Staphylococcus aureus (up to a 31.07 mm inhibition zone diameter). The in vitro biocompatibility assays revealed good cytocompatibility with mouse fibroblast cells (NIH/3T3), with a cell viability of >90%. Hemocompatibility tests showed no hemolytic activity with human blood (lysis rate <2%). Overall, these results emphasise the versatility of the XA/PLA aerogels and their potential for the treatment of chronic wounds.
Ključne besede: wound healing, aerogels, xanthan gum
Objavljeno v DKUM: 08.12.2025; Ogledov: 0; Prenosov: 1
Celotno besedilo (10,31 MB)

Opis: Magistrsko delo se osredotoča na razvoj in validacijo HPLC metode za določanje sorodnih substanc v raztopini klorheksidin diglukonata z uporabo pristopa Analytical Quality by Design (AQbD). Izhodišče raziskave je bila uradna metoda Evropske farmakopeje, ki uporablja kolono Luna C18 (25 cm × 4,6 mm, 5 μm) in gradientno ločbo s trifluoroocetno kislino v vodi in acetonitrilu. Metoda se je v praksi izkazala za neustrezno, saj ni zagotovila zadovoljive ločljivosti med nečistotama B in N ter O in I. Poleg tega kaže občutljivost na serijske razlike kolon, z sorazmerno dolgim časom kromatografije. Kot nadaljnji korak smo preučili revidirano različico metode, ki temelji na koloni Kinetex C18 (5 μm) in spremenjenem gradientu. Ta je izboljšala ločitev kritičnih parov nečistot, vendar podaljšala že sicer predolg čas analize. Za optimmizacijo revidirane metode smo uporabili programsko opremo LabSolutions MD (Shimadzu), ki temelji na načelih AQbD. Z načrtovanjem eksperimentov (DoE) in simulacijami kromatogramov smo sistematično analizirali vpliv pretoka in temperature kolone na ločljivost. S pomočjo orodij programa kot sta: analiza variance ANOVA ter matematična analiza modela, smo lahko časovno učinkovito in kvalitetno interpretirali rezultate eksperimentov. Podatke smo statistično obdelali ter opredelili robustno območje metode. Rezultati so pokazali, da kombinacija izbranih pogojev (pretok 1,5 mL/min, temperatura 25 °C) omogoča več 30-odstotno skrajšanje časa kromatografije glede na revidirano metodo, ob ohranjeni ustrezni ločljivosti vseh vrhov. Delna validacija je potrdila ponovljivost sistema in metode, linearno odzivnost, specifičnost ter robustnost. Magistrsko delo potrjuje, da kombinacija AQbD pristopa z uporabo programske opreme LabSolutions MD predstavlja zanesljivo in učinkovito orodje za razvoj HPLC metod.
Ključne besede: Razvoj metode, AQbD, Klorheksidin diglukonat, LabSolutions MD
Objavljeno v DKUM: 11.09.2025; Ogledov: 0; Prenosov: 28
Celotno besedilo (7,90 MB)

Opis: Namen diplomskega dela je bil sintetizirati polisaharidne aerogele na osnovi škroba z dodatkom hitozana ter preučiti vpliv dodatka hitozana na njihove termične in strukturne lastnosti. Polisaharidni aerogeli so izjemno lahki in porozni materiali, ki so se zaradi svoje biokompatibilnosti in biorazgradljivosti v zadnjem desetletju izkazali kot obetavni kandidati za razvoj novih metod v biomedicinskih aplikacijah. V eksperimentalnem delu smo s sol-gel sintezo pripravili škrobno-hitozanske aerogele pri različnih koncentracijah obeh polimerov, ki smo jih nato posušili s superkritičnim ogljikovim dioksidom. Sušenje smo izvedli pri 40 °C in 120 bar na polindustrijski napravi za superkritično sušenje UHDE. Lastnosti škrobno-hitozanskih aerogelov smo karakterizirali z metodami plinske adsorpcije, vrstične elektronske mikroskopije (SEM), Fourierjeve transformacijske infrardeče spektroskopije (FTIR), termogravimetrične analize (TGA) in diferencialne vrstične kalorimetrije (DSC). Nazadnje smo z izvedbo testov nabrekanja in stabilnosti preučili njihovo obnašanje v vodnem mediju. Rezultati so pokazali, da se je hitozan uspešno vgradil v strukturo škrobnih aerogelov ter izboljšal njihove strukturne in termične lastnosti.
Ključne besede: Aerogeli, polisaharidi, škrob, hitozan, superkritični fluidi, sol-gel sinteza
Objavljeno v DKUM: 24.09.2024; Ogledov: 0; Prenosov: 46
Celotno besedilo (5,38 MB)

Opis: Developing double porous biodegradable and biocompatible scafolds that can incorporate and release drugs in a controlled manner holds immense potential in regenerative medicine. This study presents a synthesis method for preparing a macro-mesoporous scafold, where poly(lactic acid) adds to the macroporous region and mechanical properties, and ethyl cellulose adds to the surface area (182 m2 /g). High surface area enables the incorporation of model drug indomethacin with an entrapment efciency of 17.0% and its later controlled release profle. The resulting scafold has desirable mechanical properties in the range of a natural trabecular bone with a compressive modulus of 22.4 MPa. The material is stable in the simulated body fuids for 120 days before the slow degradation starts. In vitro studies demonstrate the material’s ability to support bone cell adhesion, proliferation, and diferentiation, promoting osteogenic activity. Overall, the unique combination of poly(lactic acid) and ethyl cellulose produces advanced materials with tailored macro and mesopore properties, remarkable mechanical properties, optimal degradation rate, and drug delivery potential, making it a promising candidate for bone scafolds in regenerative medicine and tissue engineering
Ključne besede: bio composite, polymer-matrix composites (PMCs), polymers, porosity/voids, secondary ion mass spectrometry
Objavljeno v DKUM: 23.08.2024; Ogledov: 130; Prenosov: 11
Celotno besedilo (2,87 MB)

Opis: Access to conjugated porous polymers via synthetically sustainable and straightforward routes is highly desirable, as many polymer systems exhibit high performance but require arduous synthetic protocols that rarely pave the way to commercial reality. In this article, we describe an easily fabricated series of novel highly porous poly(Schiff bases) that feature an aliphatic conjugated backbone obtained with low synthetic complexity from simple reagents such as glyoxal and hydrazine monohydrate in water. The effective synthesis enables the preparation of three different functional scaffolds, i.e., aerogels, polyHIPEs (polymerized HIPEs), and even carbon foams from aliphatic poly(azine) (PAZ) networks. The reported synthetic approach is compared to the literature using ″green chemistry metrics″, such as the E-factor and synthetic complexity (SC) index, and shows dramatic improvements. An E-factor of up to 0.27 for aerogels or 80 for polyHIPEs and an SC index of 2.7 are much lower than those for poly(arylene)-based conjugated analogues, indicating good scalability, sustainability, and low cost. PAZ materials feature impressive red/near IR-shifted optical absorption band edges, with an electrochemical band gap of 1.45 eV. Aliphatic PAZ scaffolds are characterized by high flexibility compared to aromatic analogues and do not fail at compressive loads of up to 70%. Finally, carbonization at 500 °C leads to highly porous carbonaceous scaffolds with a high N content of up to 29 wt % (21 mmol of nitrogen per gram carbon material).
Objavljeno v DKUM: 13.03.2024; Ogledov: 696; Prenosov: 24
Celotno besedilo (11,24 MB)
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