3D printed hydroxyapatite – Zn2+ functionalized starch composite bone grafts for orthopedic and dental applications. (September 2022)

• Record Type: Journal Article
• Authors: Bhattacharjee, Arjak; Bose, Susmita
• Is Part Of: Materials & design. Volume 221(2022)
• Publication Date: 2022-09
• Subjects: Hydroxyapatite (HA) bone graft -- Extrusion -- Starch functionalization -- antibacterial study -- Osteoblast cell -- 3D Printing; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.110903
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Zinc functionalized starch is used as a novel binder for 3D printing of hydroxyapatite-polymer bone grafts. The grafts show mechanical strength like cancellous bone without any post-processing or sintering. A unique univariate multi-objective optimization is utilized to predict the best compositions. Zinc functionalization results in improved mechanical and biological properties. Zinc functionalization leads to enhanced in vitro stability of the grafts. Abstract: Hydroxyapatite (HA) – polymer composite based 3D printed bone grafts require extensive mechanical and biological property optimization for specific clinical needs. This fuels the need to develop innovative methods of optimization. Using an in-house extrusion-based 3D printer, we show the feasibility of fabricating hydroxyapatite- Zn 2+ functionalized starch composites as artificial bone graft substitutes. The experimental procedure for this purpose is fortified with a univariate multi-objective optimization strategy to predict the best composition. The compressive strength of the grafts improves up to ∼ 4 folds by parametric optimization and Zn 2+ functionalization, without any post-processing. These grafts maintain mechanical integrity and strength during 6 weeks of dissolution study in simulated body fluid (SBF), while the non -functionalized starch-HA grafts fully degrade within a week. The Zn 2+ functionalization results in up to ∼ 79% antibacterial efficacy against S. aureus . Osteoblast cell viability increases ∼ 1.6 folds on these graft surfaces on day 11. Our innovative methods of optimization are expected to reduce the experiment time, cost, and chance of human error in 3D printing. This study redefines the importance of understanding composition and process dependence for making a functionalized 3D printed bone graft for repairing low load-bearing defects such as craniomaxillofacial bone.