1. 3D printed fibroblast-laden alginate-cellulose scaffolds support extracellular matrix formation and angiogenic growth factor secretionJernej Vajda, Dragana Bjelić, Boštjan Vihar, Matej Vesenjak, Polona Dobnik-Dubrovski, Lidija Gradišnik, Monika Belak, Uroš Maver, Marko Milojević, 2025, original scientific article Abstract: Effective microvascular tissue engineering requires fibroblasts that remain phenotypically stable and secrete extracellular matrix (ECM) proteins and growth factors relevant for vascularization. This study evaluated 3D printed hydrogels based on sodium alginate (ALG) and carboxymethyl cellulose (CMC) to assess their ability to sustain fibroblast phenotype, ECM deposition, and angiogenic growth factor secretion during long-term culture. Seven formulations – including one with nanofibrillated cellulose – were compared by encapsulating fibroblasts and crosslinking with CaCl₂ or SrCl₂. All scaffolds were printable and exhibited comparable degradation profiles. Mechanical testing indicated stable compressive response, with Sr2+-crosslinked hydrogels generally showing higher apparent compressive modulus, while Ca2+-crosslinked scaffolds supported slightly higher cell viability. Encapsulated fibroblasts retained their phenotype for 30 days, evidenced by steadily increasing collagen I/III and fibronectin deposition, alongside sustained expression of specific fibroblast markers. After 30 days, all groups produced comparable levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2), with one formulation yielding a significantly higher FGF-2 output. This multiparametric study demonstrates that scaffold composition and crosslinker chemistry influence fibroblast phenotype maintenance, ECM deposition, and growth factor secretion. To our knowledge, this is the first systematic, 30-day screening of ALG-CMC hydrogels – tuned by polymer content, NFC addition, and Ca2+/Sr2+ crosslinking – specifically for their ability to sustain fibroblast phenotype, extracellular matrix deposition, and growth factor secretion, providing design considerations to guide bioink development for microvascular models.
Keywords: 3D bioprinting, alginate, cellulose, skin fibroblast, microvasculature, angiogenesis
Published in DKUM: 18.12.2025; Views: 0; Downloads: 2
 Full text (10,79 MB)
This document has many files! More... |
2. Fusion behavior of pure magnesium during selective laser meltingSnehashis Pal, Matjaž Finšgar, Jernej Vajda, Uroš Maver, Tomaž Brajlih, Nenad Gubeljak, Hanuma Reddy Tiyyagura, Igor Drstvenšek, 2025, original scientific article Abstract: This study examined the melting behavior and flowability of pure magnesium during selective laser melting. The potential to increase product density was also investigated. Various combinations of manufacturing parameters were considered. The laser power was gradually increased in different machine runs, with different scanning speeds for each run to vary the energy density (ED). The laser power ranged from 10 W to 75 W, and the scanning speed ranged from 100 mm/s to 800 mm/s. Lower laser powers resulted in poor melting, while higher laser powers produced better melting, with significant differences even when the ED was the same. High EDs between 3.50 J/mm² and 4.30 J/mm² led to a lack of melting at low laser power and to an unstable melt pool with significant spattering at high laser power. In contrast, moderate EDs in the range of 1.40 J/mm² to 2.90 J/mm² resulted in better density at high laser power. Higher scanning speeds helped to avoid the formation of a dense smog cloud and provided sufficient energy in a short time with the aid of higher laser power. Therefore, increasing both laser power and scanning speed improved melting performance and increased product density. The relative product density ranged from 80 % to 96.5 %. Reducing the layer thickness from 50 µm to 25 µm at a laser power of 40 W resulted in the formation of a well-formed melt pool in some areas and significant melt spattering in others, which led to a deterioration in density.
Keywords: magnesium, melt pool, laser power, scanning speed, layer thickness, support structure, laser powder bed fusion
Published in DKUM: 09.12.2025; Views: 0; Downloads: 6
Full text (3,08 MB)
This document has many files! More... |
3. Fusion behavior of pure magnesium during selective laser meltingSnehashis Pal, Matjaž Finšgar, Jernej Vajda, Uroš Maver, Tomaž Brajlih, Nenad Gubeljak, Hanuma Reddy Tiyyagura, Igor Drstvenšek, 2025, original scientific article Abstract: This study examined the melting behavior and flowability of pure magnesium during selective laser melting. The potential to increase product density was also investigated. Various combinations of manufacturing parameters were considered. The laser power was gradually increased in different machine runs, with different scanning speeds for each run to vary the energy density (ED). The laser power ranged from 10 W to 75 W, and the scanning speed ranged from 100 mm/s to 800 mm/s. Lower laser powers resulted in poor melting, while higher laser powers produced better melting, with significant differences even when the ED was the same. High EDs between 3.50 J/mm² and 4.30 J/mm² led to a lack of melting at low laser power and to an unstable melt pool with significant spattering at high laser power. In contrast, moderate EDs in the range of 1.40 J/mm² to 2.90 J/mm² resulted in better density at high laser power. Higher scanning speeds helped to avoid the formation of a dense smog cloud and provided sufficient energy in a short time with the aid of higher laser power. Therefore, increasing both laser power and scanning speed improved melting performance and increased product density. The relative product density ranged from 80 % to 96.5 %. Reducing the layer thickness from 50 µm to 25 µm at a laser power of 40 W resulted in the formation of a well-formed melt pool in some areas and significant melt spattering in others, which led to a deterioration in density.
Keywords: magnesium, melt pool, laser power, scanning speed, layer thickness, support structure, laser powder bed fusion
Published in DKUM: 09.12.2025; Views: 0; Downloads: 0 |
4. Upcycling wool and feather waste into nanofibers via eco-friendly hydrothermally assisted isolation of keratin : a promising approach to tunable functionalitiesSimona Strnad, Miša Žnidarič, Mojca Škerget, Maja Čolnik, Lidija Gradišnik, Uroš Maver, Lidija Fras Zemljič, 2025, original scientific article Abstract: Hydrothermal degradation processes are a particularly promising eco-friendly approach to keratin isolation from biomass. They, however, result in products with a broad molecular weight distribution, which can be particularly unfavorable for fiber production. In this study, we aimed to determine whether hydrothermally degraded feather and wool waste is suitable to produce nanofibers that retain the key functional properties of keratin, such as antioxidant activity and biocompatibility. Keratin/PEO blends were used for needleless electrospinning of nanofibers cross-linked with two different cross-linkers, ethylene glycol diglycidyl ether (EGDE) and pentaerythritol triacrylate (PETA), to improve their stability to water. The surface tension, pH, turbidity, zeta potential, and protein concentration of the keratin extract solutions were analyzed. The morphology of the produced nanofibers was analyzed using a scanning electron microscope, the surface chemical structure by attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR analysis), and the cross-linking success by water contact angle measurements. The antioxidant capacity and the biocompatibility of the nanofiber mats with skin cells were investigated using a 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) vitality test, respectively. The results showed that despite the unfavorable starting materials with a wide molecular mass range from 3 to 15 kDa and low average molecular weights keratin products obtained by a green hydrothermal extraction process can be used to produce nanofibers with excellent antioxidant properties and skin cell biocompatibility. The cross-linking of the nanofibers resulted in hydrophobic nanofiber surfaces; however, it impaired their biocompatibility with skin cells compared to noncross-linked nanofibers.
Keywords: waste chicken feathers, wool, keratin nanofibers, greene xtraction process, subcritical water, hydrothermal isolation process, electrospinning, cross-linking
Published in DKUM: 28.11.2025; Views: 0; Downloads: 5
Full text (6,51 MB)
This document has many files! More... |
5. Izolacija in priprava celičnih linij ledvic z namenom razvoja novih in vitro modelov nefrotoksičnostiTadej Petreski, 2025, doctoral dissertation Abstract: Ledvice so ključne za številne homeostatske mehanizme in so odgovorne za velik delež izločanja snovi iz telesa, zaradi česar so posebej dovzetne za delovanje nefrotoksičnih spojin. Med različnimi vrstami ledvičnih celic so proksimalne tubulne epitelijske celice (PTEC), ki sodelujejo pri tubularni sekreciji snovi, najbolj izpostavljene in zato ključnega pomena za razumevanje nefrotoksičnosti ter interakcij med zdravili v predkliničnih raziskavah. Omejena razpoložljivost in funkcionalna variabilnost komercialno dostopnih PTEC predstavlja ozko grlo pri teh raziskavah, zato je razvoj zanesljivih protokolov za njihovo izolacijo ključna za nadaljnji razvoj področja.
V tej disertaciji sta predstavljena dva optimizirana protokola za izolacijo primarnih PTEC iz rutinskih biopsij ledvičnega tkiva, pridobljenih od 13 bolnikov. Rezultat tega sta dve celični liniji, poimenovani MFUM-RPTEC-1 in MFUM-RPTEC-2. Obe celični liniji izražata za PTEC celice ključne označevalce, vključno s SGLT2, MRP4, OAT1, OAT3, OCT2, P-gp, MATE1, N-kadherinom, ZO-1 in CK-18. Ob gojenju na Transwell ploščah so celice pokazale ustrezno polarizacijo, saj so bili transportni proteini lokalizirani na predvideni (apikalni ali bazolateralni) strani, kar je bilo potrjeno tudi s konfokalno mikroskopijo.
Potencial ustvarjenih celičnih linij za uporabo v predkliničnih raziskavah smo preverjali s pripravo enostavnega in vitro modela za raziskovanje nefrotoksičnosti in interakcij med izbranimi zdravili. Celice so ohranile svojo viabilnost tudi po izpostavitvi nefrotoksičnim spojinam, kot so ciklosporin, omeprazol in njuni kombinaciji, kar dokazuje potencial celičnih linij za nadaljnji razvoj orodij in vzpostavitev raziskav na področju farmakologije ledvic.
Keywords: proksimalne tubulne epitelijske celice, ledvična biopsija, izolacija celic, nefrotoksičnost, in vitro model
Published in DKUM: 05.11.2025; Views: 0; Downloads: 12
Full text (2,96 MB) |
6. Effect of phenolic anchor groups on enzymatic polymerization of coniferyl alcohol at cellulosic interfacesThomas Elschner, Jakob Schönrich, Matej Bračič, Tina Maver, Uroš Maver, Steffen Fischer, 2025, original scientific article Abstract: The chemical recalcitrance of lignin limits the industrial processing of biomass, which could be addressed by so-called designer lignins. Dehydrogenation polymers (DHPs) formed by artificial lignification of monolignols, enable studies on structure-property relationships independently of genetic information. Thin films of phenolic acid esters of cellulose were prepared and used for quartz crystal microbalance with dissipation monitoring (QCM-D) experiments to investigate surface polymerization in real-time. The phenolic anchor groups significantly influenced lignification speed, deposited mass, and rigidity of resulting DHP layers. Linkage types in the lignin structure were quantified by HSQC NMR spectroscopy. Polymerization efficiency was increased in the order ferulate < p-coumarate < caffeate. Among the tested anchors, protocatechuate groups were excellently performing the reaction, while vanillate and p-hydroxybenzoate led to minimal deposition of DHPs. Lignification behavior could be correlated with radical stability of phenolic anchor groups and the formation of benzodioxane structures of caffeate moieties. The presence of caffeate units that undergo trapping reaction, prevents cross-linking of cell wall components and enhances digestibility. Moreover, the benzodioxane motif increased rigidity and linearity of lignin, which is advantageous for material science applications, e.g. for bio-based carbon fibers.
Keywords: artificial lignin, dehydrogenation polymerization, phenolic cellulose esters, QCM-D, thin films
Published in DKUM: 15.09.2025; Views: 0; Downloads: 5
Full text (1,95 MB)
This document has many files! More... |
7. Urinary catheters : state of the art and future perspectives – a narrative reviewKristijan Skok, Uroš Bele, Špela Pintar, Zdenka Peršin Fratnik, Katja Kuzmič, Matej Bračič, Lidija Fras Zemljič, Uroš Maver, 2025, review article Abstract: Catheter associated urinary tract infection (CAUTI) is the most frequent healthcare associated infection, arising from microbial adhesion to catheter surfaces, biofilm development, and the growing problem of antimicrobial resistance. Many publications have addressed CAUTI epidemiology, biofilm biology, or biomaterials for catheters in isolation, yet there is little literature that connects these areas into a coherent translational perspective. This review seeks to fill that gap by combining an overview of biofilm pathophysiology with recent advances in material based innovations for catheter design, including nanostructured and responsive coatings, sensor enabled systems, additive manufacturing, and three dimensional printing. Established approaches such as hydrophilic or antimicrobial impregnated catheters are considered alongside bio inspired surface textures, zwitterionic polymers, and multifunctional hydrogels. Each strategy is evaluated in terms of maturity, clinical applicability, and barriers to translation, with a focus on shifting from antibiotic dependent treatment toward prevention of biofilm formation. By bringing together knowledge from microbiology, engineering, and clinical urology, the review outlines pathways for developing the next generation of catheters that improve outcomes and reduce infection rates.
Keywords: urinary catheters, urinary tract infection, antibiotic resistance, nanotechnology, biomedical engineering
Published in DKUM: 15.09.2025; Views: 0; Downloads: 4
Full text (8,64 MB)
This document has many files! More... |
8. |
9. Uporaba nanotomografijev biomedicinski znanosti in mediciniJernej Vajda, Marko Milojević, Uroš Maver, Boštjan Vihar, 2025, review article Keywords: Computed tomography, CT, Microtomography, Micro-CT, Nanotomography, Nano-CT, Biomedical imaging
Published in DKUM: 30.07.2025; Views: 0; Downloads: 10
Full text (330,58 KB)
This document has many files! More...
This document is also a collection of 1 document! |
10. Substrate-dependent variability in viability and angiogenicmarker expression among three endothelial cell subtypes : insights for artificial tissue vascularizationJernej Vajda, Boštjan Vihar, Marko Milojević, Dragana Bjelić, Amadeja Brečko, Uroš Maver, 2025, original scientific article Abstract: issue engineering faces the challenge of achieving effective vascularization within tissue constructs for sustained viability andoptimal function. The success of tissue-engineered constructs depends on selecting an optimal angiogenesis-stimulating ECMsubstitute material. This study compares four substrates made from three different biomacromolecules—fibrin, fibronectin,non-crosslinked, and crosslinked gelatin, and their effect on endothelial cells. Acknowledging the diverse range of endothelialcells that play a role in (micro)vascularization, human endothelial primary cells, human umbilical vein endothelial cells, andhuman microvascular endothelial cells are subjected to these materials for evaluation. Biocompatibility is assessed by measuringcell viability (Live/Dead assay), metabolic activity (alamarBlue assay), morphology (actin staining), phenotype expression(immunocytochemistry), and the production of von Willebrand factor, which promotes angiogenesis by promoting cell adhesionand migration. The results show that the use of biomaterials as culturing substrates significantly impacts the viability andmorphology of the cells. While the expression of angiogenic markers is shown to rely more on the cell lineage, the use of differentsubstrates has an impact on the expression timeline. Thus, combining cells and biomaterials in a favorable manner can be usedas a powerful tool for controlled vascularization in vitro, which requires the systematic assembly of different stimuli.
Keywords: biomacromolecules, endothelial cell types, materials, microvascularization, vascularization
Published in DKUM: 22.07.2025; Views: 0; Downloads: 21
Full text (10,47 MB)
This document has many files! More... |
