Nanomechanical mapping of PLA hydroxyapatite composite scaffolds links surface homogeneity to stem cell differentiation.

Polymer composite scaffolds hold promise in bone tissue engineering due to their biocompatibility, mechanical properties, and reproducibility. Among these materials, polylactic acid (PLA), a biodegradable plastics has gained attention for its processability characteristics. However, a deeper understanding of how PLA scaffold surface properties influence cell behavior is enssential for advancing its applications. In this study, 3D-printed PLA scaffolds containing hydroxyapatite (HA) were analyzed using atomic force microscopy and nanomechanical mapping. The addition of HA significantly increased key surface properties compared to unmodified PLA scaffols. Notably, the HA-modified scaffold demonstrated Gaussian distribution of stiffness and adhesive forces, in contrast to the bimodal properties observed in the unmodified PLA scaffolds. Human adipose-derived mesenchymal stem cell (hADMSC) seeded on the 3D-printed PLA scaffolds blended with 10% HA (P10) exhibited strong attachment. After four weeks, osteogenic differentiation of hADMSCs was detected, with calcium deposition reaching 6.76% ± 0.12. These results suggest that specific ranges of stiffness and adhesive forces of the composite scaffold can support cell attachement, and mineralization. The study highlights that tailoring suface properties of composite scaffolds is crucial for modulating cellular interactions, thus advancing the development of effective bone replacement materials.

Entropically Toughened Robust Biodegradable Polymer Blends and Composites for Bone Tissue Engineering.

Biodegradable polymers and composites are promising candidates for biomedical implants in tissue engineering. However, state-of-the-art composite scaffolds suffer from a strength-toughness dilemma due to poor interfacial adhesion and filler dispersion. In this work, we propose a facile and scalable strategy to fabricate strong and tough biocomposite scaffolds through interfacial toughening. The immiscible biopolymer matrix is compatible by the direct incorporation of a third polymer. Densely entangled polymer chains lead to massive crazes and global shear yields under tension. Weak chemical interaction and high-shear melt processing create nanoscale dispersion of nanofillers within the matrix. The resultant ternary blends and composites exhibit an 11-fold increase in toughness without compromising stiffness and strength. At 70% porosity, three-dimensional (3D)-printed composite scaffolds demonstrate high compressive properties comparable to those of cancellous bones. In vitro cell culture on the scaffolds demonstrates not only good cell viability but also effective osteogenic differentiation of human mesenchymal stem cells. Our findings present a widely applicable strategy to develop high-performance biocomposite materials for tissue regeneration.

Perfusion decellularization of porcine esophagus: Study of two processing factors affecting the folded mucosal structure of the esophageal scaffold.

Acellular scaffolds from decellularized donor organs are showing promising clinical results in tissue and organ repair and regeneration. A successful decellularization process is determined by (a) its capability to decellularize complete organs of large animals, (b) retention of the extracellular matrix (ECM) structures and morphologies, and (c) minimal loss of ECM proteins. In this study, porcine esophagi were perfused in full thickness with 0.25% w/v sodium dodecyl sulfate at perfusion rates 0.1-0.2 ml/min for up to 5 days. Decellularized tissues were characterized for their residual DNA, histological staining for their matrix structures, immunohistochemical staining for collagen type IV and laminin, and scanning electron microscopy for structural integrity. Our results showed that full thickness esophageal tissues treated using the horizontal perfusion setup were decellularized with good structural and biochemical integrity in the ECM. Residual DNA content in decellularized tissues was found to be 36 ± 12 ng/mg of tissues (n = 6) which was significantly lower than that of native tissues (p = .00022). Our study showed that the organ must be decellularized in full thickness and perfusion pressure must be controlled to minimize radial expansion. These factors were found to be critical in preserving the folded mucosa in the decellularized tissues.