Preliminary study of bovine-derived bone filler in bioresorbable polymeric 3D-printed scaffold for maxillary bone regeneration
PEDRAZA R. 1, DI MARO M. 2, FAGA M. 2, DURACCIO D. 2, MALUCELLI G. 3, MOSCA BALMA A. 1, ROATO I. 1, MUSSANO F. 1
1 Department of Surgical Science, C.I.R. Dental School, Università di Torino, Torino, Italy; 2 Institute of Sciences and Technologies for Sustainable Energy and Mobility, National Council of Research, Torino, Italy; 3 Department of Applied Science and Technology, Politecnico di Torino, and local INSTM Unit, Alessandria, Italy
OBJECTIVE: Maxillary surgery is a very invasive approach. To minimize collateral effects and optimize results, 3D-printed scaffolds are a possible solution. In this work we have tested adipose stem cells (ASC) and periodontal ligament stem cells (PDLSC) on a 3D-printed composite material customizable scaffold made of polycaprolactone (PCL) matrix and bovine-derived mineral bone (BMB) filler for maxillary bone regeneration.
MATERIALS AND METHODS: Three different types of materials were compared: neat PCL, PCL/BMB 70/30 w/w and neat BMB. PCL/BMB 70/30 w/w was prepared by mixing milled BMB and PCL powders using dry technique. PCL/BMB 70/30 w/w and neat PCL were 3D-printed with standard parameters in order to create support scaffolds for ASC52 hTert cells and human primary PDLSCs. CellTiter-Glo kit was used for cell viability test to analyze the scaffold colonization and cells proliferation at 3, 7 and 14 days. All materials were subjected to an osteogenic stimulation in culture medium, to observe their osteoconductive behavior and evaluate which material promotes the most the differentiation in vitro. The osteogenic culture was carried out for 2 months and the gene expression was evaluated with Real-Time PCR, focusing on the expression of ALP, RUNX2, COLL1, and OCN. SEM analysis was used for observing the formation of new tissue and EDX analysis for quantifying the deposition of calcified nuclei within collagenic matrix (CaO, Na2O, P2O3).
RESULTS: All the materials allowed the adhesion and proliferation of both cell types. In particular, ASCs showed a relevant affinity for neat PCL in the long term. The cell proliferation was the highest on neat PCL and differs from the other two materials in a statistically relevant way. Also PDLSCs’ adhesion and proliferation were observed for every composition, with remarkable proliferation rate on BMB. Neat BMB showed a statistically significant difference with PCL (p = 0.0001) and with PCL/SB (p = 0.0001) only at the 7th day. Real-Time PCR, instead, indicated a clear difference between two cells populations. COLL1 gene was widely expressed in all substrates by both cell types; OCN gene expression of PDLSCs, instead, differed significantly from the one of ASCs. This resulted in an enhanced calcification of the collagen matrix by the PDLSCs compared to ASCs, as also confirmed by SEM-EDX analysis.
CONCLUSIONS: The composite material PCL/BMB showed a biocompatible and improved osteoinductive behavior compared to the one of neat PCL. This result represents a relevant starting point for a customizable, resistant and osteoconductive material for tissues regeneration. Future experiments will be focus on biomechanical tests at different filler concentrations.
