Development of novel bionanocomposites for musculoskeletal reconstruction applications

Abstract

With an increase in the aging population worldwide, a surge in demand for joint replacement has been observed. It has been anticipated that by 2030, the demand for primary total hip joint replacement (THR) will increase by 171% for patients less than 65 years of age. Although THR is considered to be the most efficacious surgical intervention in load-bearing orthopedic applications, its overall success is constrained by unavoidable clinical issues such as osteolysis and aseptic loosening resulting in implant failure. In this context, Ultra-high molecular weight polyethylene (UHMWPE) has been playing a significant role as an acetabular liner over the last six decades due to its attractive mechano-chemical, tribological, and biocompatibility properties. Yet, the challenges posed by UHMWPE, particularly those associated with its in vivo wear and oxidation, need to be addressed. A substantial part of this dissertation will explore the science behind the processibility, physicomechanical properties, and biocompatibility of the new generation modified graphene oxide reinforced HDPE/UHMWPE (HUmGO) nanocomposite for acetabular liner applications. Overall, the HUmGO proved to be a promising biomaterial when benchmarked against commercially available medical-grade UHMWPE and XL-UHMWPE and also with Trident®X3® (Stryker, orthopedics) implant in terms of the manufacturing, following dimensions, and properties. On the other hand, another aspect to be considered for THR success is the physical interlocking between the reamed acetabulum and the metal-backed (especially Ti-6Al-4V) acetabular assembly. The bioinertness of the Ti-6Al-4V-backed acetabular shell interferes with implant-bone bonding; hence, a bioactive material-coated acetabular shell is used. Even though hydroxyapatite (HA)-coated Ti-6Al-4V shells are used in clinical settings, due to cell-mediated resorption and lack of suitable properties, there is a constant need to introduce stable and adherent new generation coating material for bioinert Ti-6Al-4V acetabular shell. This dissertation will also discuss the deposition of an adherent pDOPA co-doped Barium Titanium reinforced (BT) functionalized PVDF nanocomposite coating on Ti-6Al-4V with desired physicochemical and cytocompatibility properties for acetabular shell applications concerning better osseointegration. Herein, the fundamental aspects of cell-material interactions have been correlated with the substrate functionalities. Taken together, our observations indicate that osteoblast functionality can be tailored by providing a cell-instructive surface modification to the acetabular components. Summarizing, this dissertation will broadly revolve around the development of novel for the acetabular components with the view to eliminate long-standing clinical issues of osteolysis and aseptic loosening, resulting in a shorter implant lifespan. On fundamental aspects, this dissertation will also provide qualitative and quantitative insights into the process-structure-properties of these new generation bionanocomposites.