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The development of bioinks incorporating extracellular matrix (ECM) has attracted significant interest for creating three‐dimensional (3D)‐printed structures that simulate natural skin, aiming to facilitate profound wound healing. In our study, we utilized the potential of human placenta, renowned for its abundant structural proteins and growth factors essential for wound recovery, as a basis for an ECM‐based bioink. Different concentrations (1.5%, 3% and 5% w/v) of decellularized/solubilized placental ECM were integrated into silk fibroin/alginate to generate a printable bioink. The biocompatibility of the printed hydrogels was studied in vitro. Our refined ECM‐based bioink at a 5% w/v concentration was administered to full‐thickness wounds in a mouse model. The ECM‐based frameworks, due to their distinct structure, created a non‐cytotoxic environment conducive to in vitro cell adhesion, infiltration, and proliferation. Crucially, they did not provoke an adverse immune reaction in the host. Implanting the 3D‐printed ECM scaffold into deep wounds resulted in increased formation of granulation tissue, angiogenesis, and re‐epithelialization compared to scaffolds lacking ECM and untreated wounds. Our findings decisively demonstrate that the 5% ECM 3D scaffold promotes regeneration of deep wounds in vivo, creating a skin substitute with cellular organization closely resembling normal skin. This advancement sets the stage for future clinical exploration and holds tremendous promise for advancing wound healing therapies. [ABSTRACT FROM AUTHOR]

The liver is one of the vital organs in the body, and the gold standard of treatment for liver function impairment is liver transplantation, which poses many challenges. The specific three‐dimensional (3D) structure of liver, which significantly impacts the growth and function of its cells, has made biofabrication with the 3D printing of scaffolds suitable for this approach. In this study, to investigate the effect of scaffold geometry on the performance of HepG2 cells, poly‐lactic acid (PLA) polymer was used as the input of the fused deposition modeling (FDM) 3D‐printing machine. Samples with simple square and bioinspired hexagonal cross‐sectional designs were printed. One percent and 2% of gelatin coating were applied to the 3D printed PLA to improve the wettability and surface properties of the scaffold. Scanning electron microscopy pictures were used to analyze the structural properties of PLA–Gel hybrid scaffolds, energy dispersive spectroscopy to investigate the presence of gelatin, water contact angle measurement for wettability, and weight loss for degradation. In vitro tests were performed by culturing HepG2 cells on the scaffold to evaluate the cell adhesion, viability, cytotoxicity, and specific liver functions. Then, high‐precision scaffolds were printed and the presence of gelatin was detected. Also, the effect of geometry on cell function was confirmed in viability, adhesion, and functional tests. The albumin and urea production of the Hexagonal PLA scaffold was about 1.22 ± 0.02‐fold higher than the square design in 3 days. This study will hopefully advance our understanding of liver tissue engineering toward a promising perspective for liver regeneration. [ABSTRACT FROM AUTHOR]

Background: Several factors like three‐dimensional microstructure, growth factors, cytokines, cell–cell communication, and coculture with functional cells can affect the stem cells behavior and differentiation. The purpose of this study was to investigate the potential of decellularized placental sponge as adipose‐derived mesenchymal stem cells (AD‐MSCs) and macrophage coculture systems, and guiding the osteogenic differentiation of stem cells. Methods: The decellularized placental sponge (DPS) was fabricated, and its mechanical characteristics were evaluated using degradation assay, swelling rate, and pore size determination. Its structure was also investigated using hematoxylin and eosin staining and scanning electron microscopy. Mouse peritoneal macrophages and AD‐MSCs were isolated and characterized. The differentiation potential of AD‐MSCs co‐cultured with macrophages was evaluated by RT‐qPCR of osteogenic genes on the surface of DPS. The in vivo biocompatibility of DPS was determined by subcutaneous implantation of scaffold and histological evaluations of the implanted site. Results: The DPS had 67% porosity with an average pore size of 238 μm. The in vitro degradation assay showed around 25% weight loss during 30 days in PBS. The swelling rate was around 50% during 72 h. The coculture of AD‐MSCs/macrophages on the DPS showed a significant upregulation of four differentiation osteogenic lineage genes in AD‐MSCs on days 14 and 21 and a significantly higher mineralization rate than the groups without DPS. Subcutaneous implantation of DPS showed in vivo biocompatibility of scaffold during 28 days follow‐up. Conclusions: Our findings suggest the decellularized placental sponge as an excellent bone substitute providing a naturally derived matrix substrate with biostructure close to the natural bone that guided differentiation of stem cells toward bone cells and a promising coculture substrate for crosstalk of macrophage and mesenchymal stem cells in vitro. [ABSTRACT FROM AUTHOR]

Spermatogenesis is a process in which animals generate spermatozoa from spermatogonial stem cells (SSCs). Successful in vitro differentiation of SSCs towards spermatids holds a significant promise for regeneration of impaired spermatogenesis. The present study aims to evaluate the efficiency of a 3D culture containing naringenin on proliferation and differentiation potentials of mouse SSCs. In this study, multi‐walled carbon nanotubes (MWCNTs) were incorporated into poly(l‐lactic acid) (PLLA) fibers via electrospinning technique. The fibrous PLLA/MWCNTs were studied by Fourier‐transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), water contact angle measurements, electrical conductivity, and mechanical properties. Next, the SSCs were seeded into the PLLA/MWCNTs scaffolds and exhibited preferable survival and differentiation efficiency to subsequent cell lines. To shed more light on this matter, the immunocytochemistry, reverse‐transcription polymerase chain reaction (RT‐PCR), and qRT‐PCR results showed that the aforementioned cells on the 3D fabrics overexpressed the C‐kit and SYCP3 proteins. In addition, the reactive oxygen species (ROS) measurement data demonstrated that naringenin, an effective antioxidant, plays an important role in in vitro spermatogenesis. Taken together, the results of this study revealed the synergistic effects of 3D scaffolds and naringenin for efficient spermatogenesis in laboratories. [ABSTRACT FROM AUTHOR]