Textile based 3d constructs targetting flat bone

Abstract

Over the years, tissue engineering has been consistently advancing with the prospects of new therapies targeting the regeneration of damage tissues. Bone tissue engineering is particularly challenging with autografts still being considered as the “gold standard” despite the related complications such as donor site morbidity, insufficient quantities, and restrictions in graft shape. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding options for restoring the form and function of injured bone. Bone tissue engineering using scaffolds is a promising strategy in order to overcome bone grafts obstacles, by improving cell adhesion to scaffolds and restoring bone shape and function. Thus textile-based scaffolds have been recently proposed for bone tissue engineering since they present high reproducibility, precision and superior control over the design. In this work, a three dimensional (3D) textile made of two weft-knitted silk fibroin fabric layers spaced by a monofilament of polyethylene terephthalate (PET) was modified with calcium phosphates aiming the creation of a osteoinductive, hierarchically patterned scaffold to meet the specific requirements of flat bone for craniofacial applications. Three different approaches were used, namely calcium nitrate tetrahydrate/diammonium hydrogen phosphate, brushite, and hydroxyapatite powder in a sodium alginate solution, to impregnate calcium phosphates in the 3D constructs. Among these, the Hap/alginate was proven to be the most effective. The developed composites were characterized in terms of morphology, mechanical properties (flexural and tensile strength and Young’s modulus) and Fourier transform infrared spectroscopy (FTIR). FTIR analysis allowed to confirm the presence of the calcium phosphates inside the fabric. Despite the low strength, flexural modulus of selected composite was similar to the spongy bone flexural modulus described in the literature. There is often a great level of discrepancy between the ideal characteristics of bone substitutes and good and viable reproducibility that can be overcome.

Date of Award	3 May 2017
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Sanjukta Deb (Supervisor) & Ana Leite Oliveira (Co-Supervisor)