Biological activity of a chitosan-carboxymethylcellulose-zinc oxide and calcium carbonate in 3D scaffolds stabilized by physical links for bone tissue engineering.

Today, regenerative osteogenesis represents a clinical need, due to the incidence of bone defects that involve groups of pathologies ranging from congenital anomalies to traumatic injuries, as well as problems presented surgically. This is why the design of a polymeric biomaterial (scaffold) of chitosan, carboxymethylcellulose, zinc oxide, and calcium carbonate with similar characteristics in terms of composition and bone structure offers high potential to help address this health problem. The technique for obtaining the scaffolds of this research was to develop a physical hydrogel to have the biofunctionality of the active groups of the polymer chains used, then make use of the lyophilization process to obtain three-dimensional (3D) porous scaffolds. The physicochemical and biological properties of the scaffolds were evaluated. The scaffolds presented morphology with pore size and interconnectivity that favor the need for cell proliferation and viability. The biocompatibility tests confirm that the designed scaffolds do not present cytotoxicity and the analyzes with alizarin red staining show calcium deposits in the materials with CaCO3 and ZnO. Osteoinduction assays to osteogenic lineage using runt-related transcription factor type 2 (RUNX2) and collagen type 1 (COL-1) antibodies allowed expression in differentiated cells. Therefore, the calcium carbonate-containing scaffolds stabilized by physical bonds have characteristics of being non-cytotoxic, bioactive, and osteoinductive, which motivate their use in future tests to evaluate their demeanor with rat models for bone engineering studies.

In Vitro and In Vivo Evaluation of a Polycaprolactone (PCL)/Polylactic-Co-Glycolic Acid (PLGA) (80:20) Scaffold for Improved Treatment of Chondral (Cartilage) Injuries.

Articular cartilage is a specialized tissue that provides a smooth surface for joint movement and load transmission. Unfortunately, it has limited regenerative capacity. Tissue engineering, combining different cell types, scaffolds, growth factors, and physical stimulation has become an alternative for repairing and regenerating articular cartilage. Dental Follicle Mesenchymal Stem Cells (DFMSCs) are attractive candidates for cartilage tissue engineering because of their ability to differentiate into chondrocytes, on the other hand, the polymers blend like Polycaprolactone (PCL) and Poly Lactic-co-Glycolic Acid (PLGA) have shown promise given their mechanical properties and biocompatibility. In this work, the physicochemical properties of polymer blends were evaluated by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) and were positive for both techniques. The DFMSCs demonstrated stemness by flow cytometry. The scaffold showed to be a non-toxic effect when we evaluated it with Alamar blue, and the samples were analyzed using SEM and phalloidin staining to evaluate cell adhesion to the scaffold. The synthesis of glycosaminoglycans was positive on the construct in vitro. Finally, the PCL/PLGA scaffold showed a better repair capacity than two commercial compounds, when tested in a chondral defect rat model. These results suggest that the PCL/PLGA (80:20) scaffold may be suitable for applications in the tissue engineering of articular hyaline cartilage.