摘要
Advent of additive manufacturing in biomedical field has nurtured fabrication of complex,customizable and reproducible orthopaedic implants.Layer-by-layer deposition of biodegradable polymer employed in development of porous orthopaedic screws promises gradual dissolution and complete metabolic resorption thereby overcoming the limitations of conventional metallic screws.In the present study,screws with different pore sizes(916×918μm to 254×146μm)were 3D printed at 200μm layer height by varying printing parameters such as print speed,fill density and travel speed to augment the bone ingrowth.Micro-CT analysis and scanning electron micrographs of screws with 45%fill density confirmed porous interconnections(40.1%)and optimal pore size(259×207×200μm)without compromising the mechanical strength(24.58±1.36 MPa).Due to the open pore structure,the 3D printed screws showed increased weight gain due to the deposition of calcium when incubated in simulated body fluid.Osteoblast-like cells attached on screw and infiltrated into the pores over 14 days of in vitro culture.Further,the screws also supported greater human mesenchymal stem cell adhesion,proliferation and mineralized matrix synthesis over a period of 21 days in vitro culture as compared to non-porous screws.These porous screws showed significantly increased vascularization in a rat subcutaneous implantation as compared to control screws.Porous screws produced by additive manufacturing may promote better osteointegration due to enhanced mineralization and vascularization.
基金
funding from the Indo-US Science and Technology Forum-JC-26-2014.Dr.Kumbar acknowledges funding from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health-R01EB020640 and the Connecticut Regenerative Medicine Research Fund(15-RMBUCHC-08)
First Author is thankful to the Council of Scientific and Industrial Research for senior research fellowship(09/1095(0022)/18-EMR-I)
Government of India.Third Author would like to thank Innovation in Science Pursuit for Inspired Research(INSPIRE),DST,India for Junior Research Fellowship(IF150843).
