2-(Dimethylamino)ethyl Methacrylate/(2-Hydroxyethyl) Methacrylate/α-Tricalcium Phosphate Cryogels for Bone Repair, Preparation and Evaluation of the Biological Response of Human Trabecular Bone-Derived Cells and Mesenchymal Stem Cells

Tiago Volkmer,Luis Rodríguez-Lorenzo,Elena Burguera,Luis Santos,Francisco Blanco,Joana Magalhães,Vania Sousa,Julio Román

doi:10.3390/polym6102510

Abstract

The aim of this work is to evaluate the potential of cryogels to be used as scaffolds in tissue engineering. Scaffolds based on the α-tricalcium phosphate reinforced PDMAEMA (Poly(dimethyl aminoethyl methacrylate))/PHEMA (poly(hydroxyethyl methacrylate)) system were prepared and human trabecular bone-derived cells (HTBs) and bone marrow derived-mesenchymal stem cells (BM-MSCs) cultured on them. Several features, such as porosity, pore shape, molecular weight between crosslinks and mesh size, are studied. The most suitable PDMAEMA/PHEMA ratio for cell proliferation has been assessed and the viability, adhesion, proliferation and expression of osteoblastic biochemical markers are evaluated. The PDMAEMA/PHEMA ratio influences the scaffolds porosity. Values between 53% ± 5.7% for a greater content in PHEMA and 75% ± 5.5% for a greater content in PDMAEMA have been obtained. The polymer ratio also modifies the pore shape. A greater content in PDMAEMA leads also to bigger network mesh size. Each of the compositions were non-cytotoxic, the seeded cells remained viable for both BM-MSCs and HTBs. Thus, and based on the structural analysis, specimens with a greater content in PDMAEMA seem to provide a better structural environment for their use as scaffolds for tissue engineering. The α-tricalcium phosphate incorporation into the composition seems to favor the expression of the osteogenic phenotype.

Highlights

Cryogels have considerable potential for applications as scaffolds for tissue engineering since they may provide with the necessary support for cells to proliferate and maintain their differentiated function [1,2]
The most suitable ratio of DMAEMA/HEMA and the consequences of introducing α-tricalcium phosphate will be evaluated based on the resulting structural features and on the response of cultured human trabecular bone-derived cells and human mesenchymal stem cells
Methacrylate MAEMA/PHEMA reinforced with α-tricalcium phosphate can be prepared by cryopolymerization

Summary

Introduction

Cryogels have considerable potential for applications as scaffolds for tissue engineering since they may provide with the necessary support for cells to proliferate and maintain their differentiated function [1,2]. Cryotopic gelation is a specific type of gelation that takes place upon cryogenic treatment of initial systems potentially capable of forming a gel [3]. The cryogel structure is mainly controlled by the freezing conditions because the formed solvent crystals acts as the porogenic factor [4]. After melting the solvent crystals, a system of large interconnected pores is formed. The formation of interconnections occurs when ice crystals from the solvent grow enough to connect with another ice crystal [5]. Concomitant with the solvent crystallization, there is an increase in the monomers concentration in the remaining liquid solvent that leads to the polymerization, by a phenomenon called cryoconcentration

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