Bioactivity and Antibacterial Behaviors of Nanostructured Lithium-Doped Hydroxyapatite for Bone Scaffold Application.

Pardis Keikhosravani,Ali Fallah,Ziba Dargahi,Majid Kavanlouei,Younes Beygi-Khosrowshahi,Pooriya Khademi-Azandehi,Hossein Maleki-Ghaleh,M Hossein Siadati,Mahdi Bodaghi,Amir Kahaie Khosrowshahi

doi:10.3390/ijms22179214

Abstract

The material for bone scaffold replacement should be biocompatible and antibacterial to prevent scaffold-associated infection. We biofunctionalized the hydroxyapatite (HA) properties by doping it with lithium (Li). The HA and 4 Li-doped HA (0.5, 1.0, 2.0, 4.0 wt.%) samples were investigated to find the most suitable Li content for both aspects. The synthesized nanoparticles, by the mechanical alloying method, were cold-pressed uniaxially and then sintered for 2 h at 1250 °C. Characterization using field-emission scanning electron microscopy (FE-SEM) revealed particle sizes in the range of 60 to 120 nm. The XRD analysis proved the formation of HA and Li-doped HA nanoparticles with crystal sizes ranging from 59 to 89 nm. The bioactivity of samples was investigated in simulated body fluid (SBF), and the growth of apatite formed on surfaces was evaluated using SEM and EDS. Cellular behavior was estimated by MG63 osteoblast-like cells. The results of apatite growth and cell analysis showed that 1.0 wt.% Li doping was optimal to maximize the bioactivity of HA. Antibacterial characteristics against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were performed by colony-forming unit (CFU) tests. The results showed that Li in the structure of HA increases its antibacterial properties. HA biofunctionalized by Li doping can be considered a suitable option for the fabrication of bone scaffolds due to its antibacterial and unique bioactivity properties.

Highlights

Bioceramic scaffolds have been broadly employed for the treatment of hard tissues such as bones, joints, and teeth, owing to their outstanding chemical stability and nontoxicity [1,2]
Based on the obtained data, the crystallinity increased from 95% to 98% upon adding Li up to 1.0 wt.%
This can be attributed to the formation of Ca10 Li(PO4 )7 phase, and the placement of Li+ in the HA structure [8,43]

Summary

Introduction

Bioceramic scaffolds have been broadly employed for the treatment of hard tissues such as bones, joints, and teeth, owing to their outstanding chemical stability and nontoxicity [1,2]. The bioactive materials enable the formation of layers such as bone apatite on the HA surface resulting in strong interfacial bonding [15,16]. Metal dopants such as Li, Zn, Mn, Si, Mg, and Sr cause enhancement of osteogenesis, the proliferation of osteoblast, and neovascularization. The addition of these dopants to the calcium phosphate structure improves bone healing [17,18]. Various studies have shown that Li+ can increase the effect of HA on osteoblast proliferation [26]

Methods

Discussion

Conclusion