3D Bioprinting of Polycaprolactone-Based Scaffolds for Pulp-Dentin Regeneration: Investigation of Physicochemical and Biological Behavior.

In this study, two structurally different scaffolds, a polycaprolactone (PCL)/45S5 Bioglass (BG) composite and PCL/hyaluronic acid (HyA) were fabricated by 3D printing technology and were evaluated for the regeneration of dentin and pulp tissues, respectively. Their physicochemical characterization was performed by field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), contact angle, and compressive strength tests. The results indicated that the presence of BG in the PCL/BG scaffolds promoted the mechanical properties, surface roughness, and bioactivity. Besides, a surface treatment of the PCL scaffold with HyA considerably increased the hydrophilicity of the scaffolds which led to an enhancement in cell adhesion. Furthermore, the gene expression results showed a significant increase in expression of odontogenic markers, e.g., dentin sialophosphoprotein (DSPP), osteocalcin (OCN), and dentin matrix protein 1 (DMP-1) in the presence of both PCL/BG and PCL/HyA scaffolds. Moreover, to examine the feasibility of the idea for pulp-dentin complex regeneration, a bilayer PCL/BG-PCL/HyA scaffold was successfully fabricated and characterized by FESEM. Based on these results, it can be concluded that PCL/BG and PCL/HyA scaffolds have great potential for promoting hDPSC adhesion and odontogenic differentiation.

Synthesis, physicochemical, rheological and in-vitro characterization of double-crosslinked hyaluronic acid hydrogels containing dexamethasone and PLGA/dexamethasone nanoparticles as hybrid systems for specific medical applications.

Injectable hydrogels and biodegradable nanoparticles are using in tissue engineering applications and drug delivery systems. To improve physiochemical properties of biomaterials and to develop their applications, hybrid systems consist of hydrogels, and biodegradable nanoparticles were synthesized. In this study, hybrid systems based on double crosslinked hyaluronic acid and PLGA/Dexamethasone sodium phosphate (PLGADEX) nanoparticles are designed and synthesized in several steps. At the first step, poly(l-lactide-co-glycolide) (PLGA) in a ratio of LLA:GA = 85:15 mol% was synthesized via ring-opening polymerization. Then, PLGADEX nanoparticles were synthesized in different ratios using the partially modified emulsification-diffusion method and fully characterized, and desirable nanoparticle was selected (PLGADEX20). At the second step, a double cross-linked hyaluronic acid (XHA) was prepared by mixing various ratios of amino-hyaluronic acid and aldehyde-hyaluronic acid in the presence of genipin. Finally, by mixing of various ratios of PLGADEX20 and Dexamethasone sodium phosphate (DEX) with different ratios of XHA, hybrid systems were prepared. Based on the characterization of hybrid samples and the release studies, hydrogels containing nanoparticles showed a controlled drug release, while the best sample with 3% of optimized nanoparticle was chosen. According to physiochemical and biological properties, these hybrid systems can be good candidates for anti-adhesion barriers, wound dressings, and novel drug delivery systems.