Impressão 3D de blocos de biomaterial compósito de PLGA e beta-TCP visando aplicações médicas em enxertos e implantes

Abstract

Musculoskeletal disorders are the most common causes of reduced quality of life in the world. In some situations, very large flaws in the bones prevent them from regenerating naturally, requiring the use of a bone substitute. In this sense, solutions have been proposed using intelligent materials for making scaffolds. In this work, a composite biomaterial of beta-tricalcium phosphate (beta-TCP), a bioactive, osteoconductive ceramic, with a good balance between absorption, degradation and formation of the new bone; and poly (lactic-co-glycolic acid) copolymer (PLGA), a biocompatible, bioabsorbable, biodegradable, non-toxic synthetic polyester, moldable and with good mechanical properties, was developed. This composite was used as an input for 3D printing, a technique that allows the creation of structured three-dimensional scaffolds with controlled porosity and customizable shape. The beta-TCP particles obtained had a diameter between 421 and 785 nm. Through the images of the cryogenic fracture of the printed piece of PLGA/beta-TCP, beta-TCP particles were observed on the polymeric matrix with the formation of dispersed agglomerates in a standard way on the sample. The thermal analysis of the printed biocomposite block provided a real percentage of the ceramic mass of 32.3% and the X-ray tomography showed a value of 30.6%, showing that the composite shows little variation in its proportion. Tomography also showed that the pore volume in the printed piece of PLGA/beta-TCP was 13.8%, a value that can be easily adjusted during 3D printing according to the implant application. Printed specimens were obtained and these presented tensile strength of 27 ± 2 MPa, compressive strength of 39 ± 1 MPa, and elastic modulus of 1.58 ± 0.05 GPa, which correspond to lower mechanical properties than cortical bone, but similar to the trabecular bone and other polymeric implants on the market. The torsion resistance showed a value of 1.70 ± 0.15 Nm, which is superior to the cortical bone. In the in vitro cytotoxicity assay, the biocomposite did not show any toxic effect. Based on the results, it was possible to print successfully the product of PLGA/beta-TCP in the form of blocks, wedges, cylinders and meshes was obtained, with adequate structural and mechanical properties to be applied as a bone implant with an adjustable size and porosity as needed.