Fabrication of Biodegradable Mg Alloy Bone Scaffold Through Electrical Discharge µ-Drilling Route

Abstract

Magnesium alloys based materials are gaining popularity for bone tissue engineering as they are biocompatible, bioresorbable and shows high osteoblast activities in biological environment. In present work, perforated structures are produced using electrical discharge drilling (EDD), with an attempt to fabricate Mg alloy based biodegradable scaffold for bone tissue engineering. Using appropriate EDD parameters and tubular electrode of diameter 300 µm, micro holes of diameter 408 µm are produced in ZM21 alloy and two different types of perforated structures are obtained with porosity of 22% and 34%. These two perforated structures are compared with solid sample in terms of apatite formation, weight gain and loss of load bearing capacity after immersion in simulated body fluid (SBF) media. After 21 days of immersion test in SBF media, apatite formation in perforated structure with interconnected holes (porosity 34%) is highest, resulting into highest weight gain of 6.23%, for this sample, whereas, solid sample shows negligible weight gain of 0.58%. The loss in mechanical load bearing capacity is found lowest at 5.58% in scaffold having interconnected holes (with porosity 34%). Thus, interconnected perforated Mg alloy structures having well defined micro pores and pore density can be designed and fabricated for biodegradable scaffold application.