Hydrogels (gels) are attractive tools for tissue engineering and regenerative medicine due to their potential for drug delivery and ECM-like composition. In this study, we use rheology to characterize GelMA/alginate gels loaded with human platelet lysate (PL). We then characterize these gels from a physicochemical perspective and evaluate their ability to transport PL proteins, their pore size, and their rate of degradation. Finally, their biocompatibility is evaluated. We describe how alginate changes the mechanical behavior of the gels from elastic to viscoelastic after ionic (calcium-mediated) crosslinking. In addition, we report the release of ~90% of PL proteins from the gels and relate it to the degradation profile of the gels. Finally, we evaluated the biocompatibility of the gels. Thus, the developed gels represent attractive substrates for both cell studies and as bioactive materials.

Human platelet lysate (HPL), rich in growth factors, is increasingly recognized for its potential in tissue engineering and regenerative medicine. However, its use in liquid or gel form is constrained by limited stability and handling difficulties. This study aimed to develop dry and porous aerogels from HPL hydrogel using an environmentally friendly supercritical CO₂-based shaping process, specifically tailored for tissue engineering applications. The aerogels produced retained their three-dimensional structure and demonstrated significant mechanical robustness and enhanced manageability. Impressively, they exhibited high water absorption capacity, absorbing 87% of their weight in water within 120 min. Furthermore, the growth factors released by these aerogels showed a sustained and favourable biological response in vitro. They maintained the cellular metabolic activity of fibroblasts (BALB-3T3) at levels akin to conventional culture conditions, even after prolonged storage, and facilitated the migration of human umbilical vein endothelial cells (HUVECs). Additionally, the aerogels themselves supported the adhesion and proliferation of murine fibroblasts (BALB-3T3). Beyond serving as excellent matrices for cell culture, these aerogels function as efficient systems for the delivery of growth factors. Their multifunctional capabilities position them as promising candidates for various tissue regeneration strategies. Importantly, the developed aerogels can be stored conveniently and are considered ready to use, enhancing their practicality and applicability in regenerative medicine.

Human Platelet lysate, a hemoderivative product rich in growth factors, holds significant promise in tissue engineering and regenerative medicine. However, its practical utility in liquid or gel form is hampered by challenges such as limited stability and handling difficulties. This study aimed to engineer dry and porous aerogels from platelet lysate hydrogel using an environmen-tally friendly supercritical CO2-based shaping process customized for tissue engineering appli-cations. The resulting aerogels demonstrated remarkable mechanical robustness and improved manageability. Notably, they exhibited a high-water absorption capacity. Moreover, these aer-ogels exhibited a sustained and favourable biological response in-vitro. They demonstrated the ability to release functional growth factors, sustaining cellular metabolic activity similar to that of conventional culture conditions, even after prolonged storage. Furthermore, they supported the adhesion and proliferation of murine fibroblasts (BALB-3T3) and the migration of Human Um-bilical Vein Endothelial Cells (HUVEC). In addition to serving as excellent matrices for cell culture, these proposed aerogels also function as efficient growth factor delivery systems. This multi-functional capability positions them as promising candidates for various tissue regeneration strategies. Importantly, the elaborated aerogels can be conveniently stored and considered as ready-to-use products, enhancing their practicality and applicability in regenerative medicine