Chitosan-Calcium-Simvastatin Scaffold as an Inductive Cell-Free Platform

Abstract

The development of biomaterials based on the combination of biopolymers with bioactive compounds to develop delivery systems capable of modulating dentin regeneration mediated by resident cells is the goal of current biology-based strategies for regenerative dentistry. In this article, the bioactive potential of a simvastatin (SV)–releasing chitosan-calcium-hydroxide (CH-Ca) scaffold was assessed. After the incorporation of SV into CH-Ca, characterization of the scaffold was performed. Dental pulp cells (DPCs) were seeded onto scaffolds for the assessment of cytocompatibility, and odontoblastic differentiation was evaluated in a microenvironment surrounded by dentin. Thereafter, the cell-free scaffold was adapted to dentin discs positioned in artificial pulp chambers in direct contact with a 3-dimensional (3D) culture of DPCs, and the system was sealed to simulate internal pressure at 20 cm/H2O. In vivo experiments with cell-free scaffolds were performed in rats’ calvaria defects. Fourier-transform infrared spectroscopy spectra proved incorporation of Ca and SV into the scaffold structure. Ca and SV were released upon immersion in a neutral environment. Viable DPCs were able to spread and proliferate on the scaffold over 14 d. Odontoblastic differentiation occurred in the DPC/scaffold constructs in contact with dentin, in which SV supplementation promoted odontoblastic marker overexpression and enhanced mineralized matrix deposition. The chemoattractant potential of the CH-Ca scaffold was improved by SV, with numerous viable and dentin sialoprotein–positive cells from the 3D culture being observed on its surface. Cells at 3D culture featured increased gene expression of odontoblastic markers in contact with the SV-enriched CH-Ca scaffold. CH-Ca-SV led to intense mineralization in vivo, presenting mineralization foci inside its structure. In conclusion, the CH-Ca-SV scaffold induces differentiation of DPCs into a highly mineralizing phenotype in the presence of dentin, creating a microenvironment capable of attracting pulp cells to its surface and inducing the overexpression of odontoblastic markers in a cell-homing strategy.

Creating a Microenvironment to Give Wings to Dental Pulp Regeneration—Bioactive Scaffolds

“…The 50 mm diameter polydioxanone fibers containing VEGF exhibited a good angiogenic effect [ 173 ]. Another example of the synergistic effect of this material with some bioactive factors is chitosan and its derivatives scaffolds; they were loaded with simvastatin, displaying the ability to improve the odontogenic differentiation and mineralization of DPSCs [ 174 , 175 , 176 ]. Regarding chemical binding, chitosan-loaded calcium ions through coordination bond is a good example; they continued to release calcium ions for 21 days, displaying potential applications in dental tissue engineering [ 177 ].…”

A critical analysis of research methods and biological experimental models to study pulp regeneration

“…This increase in rigidity induces overexpression (>100-fold) of DSPP and DMP-1 genes in DPSC (Lu et al, 2015). Likewise, the incorporation of 1 µM simvastatin into a chitosan/calcium hydroxide scaffold, through DPSC using an artificial pulp chamber assay, has been able to increase cell migration and the expression of alkaline phosphatase (ALP), DSPP, and DMP-1 using an artificial pulp chamber assay (Soares et al, 2021). Scaffolds can be further personalized via additive manufacturing technologies (3D printing).…”

Mineral‐induced bubbling effect and biomineralization as strategies to create highly porous and bioactive scaffolds for dentin tissue engineering

“…The macro‐porous structure obtained after freeze‐drying allowed cells from surrounding in vitro 3D‐matrices and in vivo tissues to easily infiltrate and spread inside and throughout the scaffold structure, denoting its potential as an inductive cell‐homing platform 4 . Furthermore, calcium was complexed to chitosan, creating the chitosan‐calcium (CHCa) scaffold, which also acted as a calcium‐release system capable of increasing the odontogenic potential of human dental pulp cells (HDPCs) by increasing the deposition of mineralized tissue 15,16 …”

“…4 Furthermore, calcium was complexed to chitosan, creating the chitosan-calcium (CH Ca) scaffold, which also acted as a calcium-release system capable of increasing the odontogenic potential of human dental pulp cells (HDPCs) by increasing the deposition of mineralized tissue. 15,16 Based on the results obtained by our group, we hypothesized that other mineral phases could also promote the bubbling effect, generating a conductive surface that would favor tissue formation and growth. In this context, calcium phosphates have been extensively studied as biomaterials for their favorable characteristics such as biocompatibility, bioactivity, the absence of toxicity, variable degradation rates, and osteoconductivity.…”