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, izvirni znanstveni članek Opis: 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. Ključne besede: 3D bioprinting, alginate, cellulose, skin fibroblast, microvasculature, angiogenesis Objavljeno v DKUM: 18.12.2025; Ogledov: 0; Prenosov: 2
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3. Is tissue augmentation a reality in biosurgery? An experimental study of endothelial cell invasion into tissue fillerTomaž Velnar, Vladimir Smrkolj, Marjan Rupnik, Lidija Gradišnik, 2013, izvirni znanstveni članek Opis: New therapeutic approaches for wound treatment are evolving. Non healing wounds in oncology and after trauma may be cured by a novel technique of tissue augmentation with soft tissue fillers. The principle resides in filling the wound with collagen filler in order to seal the defect and promote healing. Successful angiogenesis forms the basis of tissue filler survival and determines the outcome of the healing process. During this study, basic data about endothelial cell invasion into collagen-made substratum was collected that could be used for neoangiogenesis studies in tissue augmentation techniques for large wound defect treatment. In the in vitro assay, the human umbilical vein endothelial cells (HUVEC) grow into a three-dimensional framework of collagenous tissue fillers, forming the basic step for angiogenesis. After heparins were used as chemotactic agents, a typical bell-shaped relationship between chemotaxis and agent concentrations was found. Significant cell infiltration was present in the assays with chemotactic agents. These observations support the potential for tissue augmentation with soft tissue fillers that could be used in acute and chronic non healing traumatic and oncology wounds after extensive surgical resections and radiotherapy. Ključne besede: angiogenesis, cell invasion, tissue augmentation, tissue filler, wound healing Objavljeno v DKUM: 10.07.2015; Ogledov: 1535; Prenosov: 107
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