Incorporation of extracellular matrix (ECM) components into bioinks can enhance biological functionality but often compromises print fidelity and structural stability. This study developed a dual-stage calcium chloride (CaCl₂) crosslinking strategy to incorporate Wharton’s jelly-derived ECM (WJ-ECM) into a gelatin-alginate bioink for bioprinted scaffold fabrication. A baseline formulation (BGA) and a WJ-ECM-supplemented formulation (BGAE, 1 mg/mL) were pre-crosslinked with 14 mM CaCl₂ prior to extrusion, followed by secondary crosslinking in 0.5 M CaCl₂ post-printing. Both formulations exhibited comparable viscosity (20–180 kcP) and high print fidelity (Pr = 0.99 ± 0.01 for BGA; 0.95 ± 0.01 for BGAE), with scaffolds displaying well-defined architecture and over 84% of pores within the target range (160–270 µm). FTIR analysis confirmed WJ-ECM incorporation without detectable alteration of the primary matrix structure. Both scaffolds were non-cytotoxic and supported fibroblast viability; BGAE constructs showed greater cell coverage over 14 days when surface-seeded and more stable fluorescence intensity through 28 days when encapsulated. In a murine thermal burn model, BGAE-treated wounds demonstrated more advanced re-epithelialization and more continuous epidermal coverage at day 14 compared to controls. These findings indicate that dual-stage crosslinking enables WJ-ECM integration while preserving printability, offering a practical platform for bioactive skin tissue engineering applications.

Bioink is a fundamental component of three-dimensional (3D) printing technology, exerting a direct influence on the overall quality, precision, and structural integrity of printed biological constructs. Among various factors influencing printing outcomes, printability is a key determinant for success, as it impacts the precision of printed structures, the consistency of filament formation, and the ability to maintain the correct shape throughout the printing process. The printability of bioink is influenced not only by its composition but also by external conditions, particularly the storage temperature. Therefore, evaluating the impact of storage temperature on bioink printability is essential. This paper presents the evaluation of the effects of three different storage temperature conditions on the printability of gelatin-alginate B-GA bioink over a period of 21 days. These conditions included freezing at -20 ± 1°C, refrigeration at 4 ± 1°C and storage at room temperature of 25 ± 2°C. The printability was assessed by examining various parameters, including the state of the bioink, the ability to form continuous filaments, the uniformity factor (U), the diffusion rate (Df) and the effectiveness of pore formation (Pr). The results showed that the printability of B-GA bioink remained stable during the first 14 days under all three tested storage conditions. However, after 21 days, a significant decline in printability was observed in the cases of freezing and room temperature conditions, proven by the decrease in Pr values of 0.8469 ± 0.0056 and 0.8630 ± 0.0074, respectively. In contrast, refrigeration at 4 ± 1°C allowed the B-GA bioink to retain its printability consistently throughout the entire 21-day period, with a Pr value of 0.908 ± 0.0227. Therefore, in the test, storing B-GA bioink at 4 ± 1°C was the most effective condition for preserving its printability over 21 days.

Several previous studies in the field of assisted reproduction have focused on the use of blood gel derivatives, such as platelet-rich fibrin (PRF), as a treatment for endometrial rehabilitation. However, the ability to release growth factors and the gel form of this product led to the evolution of platelet lysates. In this study, blood gel derivatives, including PRF lysate, which was in liquid form, and PRF gel, were collected and evaluated for growth factors. It was shown to be effective in endometrial wound healing and regeneration in mouse injured uterine tissue models through structure and function (pinopode expression, embryo implantation) evaluation. The results demonstrated that the concentrations of growth factors, including PDGF-AB and VEGF-A, were higher in the PRF lysate compared to the PRF gel (p < 0.05). PRF lysate could release these growth factors for 8 days. Furthermore, both PRF gel and PRF lysate restored the morphology of injured endometrial tissues in terms of luminal and glandular epithelia, as well as uterine gland secretory activity. However, the presence of pinopodes and embryonic implantation were only observed in the PRF lysate group. It can be concluded that PRF lysate promotes wound healing in mouse injured tissue models in vitro, which can act as healing products in tissue repair.