Functionalization of Ti-40Nb implant material with strontium by reactive sputtering

Abstract

BackgroundSurface functionalization of orthopedic implants with pharmaceutically active agents is a modern approach to enhance osseointegration in systemically altered bone. A local release of strontium, a verified bone building therapeutic agent, at the fracture site would diminish side effects, which could occur otherwise by oral administration. Strontium surface functionalization of specially designed titanium-niobium (Ti-40Nb) implant alloy would provide an advanced implant system that is mechanically adapted to altered bone with the ability to stimulate bone formation.MethodsStrontium-containing coatings were prepared by reactive sputtering of strontium chloride (SrCl2) in a self-constructed capacitively coupled radio frequency (RF) plasma reactor. Film morphology, structure and composition were investigated by scanning electron microscopy (SEM), time of flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). High-resolution transmission electron microscopy (HR-TEM) was used for the investigation of thickness and growth direction of the product layer. TEM lamellae were prepared using the focused ion beam (FIB) technique. Bioactivity of the surface coatings was tested by cultivation of primary human osteoblasts and subsequent analysis of cell morphology, viability, proliferation and differentiation. The results are correlated with the amount of strontium that is released from the coating in biomedical buffer solution, quantified by inductively coupled plasma mass spectrometry (ICP-MS).ResultsDense coatings, consisting of SrOxCly, of more than 100 nm thickness and columnar structure, were prepared. TEM images of cross sections clearly show an incoherent but well-structured interface between coating and substrate without any cracks. Sr2+ is released from the SrOxCly coating into physiological solution as proven by ICP-MS analysis. Cell culture studies showed excellent biocompatibility of the functionalized alloy.ConclusionsTi-40Nb alloy, a potential orthopedic implant material for osteoporosis patients, could be successfully plasma coated with a dense SrOxCly film. The material performed well in in vitro tests. Nevertheless, the Sr2+ release must be optimized in future work to meet the requirements of an effective drug delivery system.Electronic supplementary materialThe online version of this article (10.1186/s40824-017-0104-8) contains supplementary material, which is available to authorized users.

The Effect of Antibacterial-Osteogenic Surface Modification on the Osseointegration of Titanium Implants: A Static and Dynamic Strategy

“…Cell adhesion also plays a crucial role in the process of osseointegration. The main purpose is promoting the adhesion of osteoblasts associated with osseointegration, such as with BMSCs and the osteoblast-like cell line MC3T3 and HOB. , The surface morphology of Ti can be changed by preparing rough porous structures to create adhesion surfaces for BMSCs and MC3T3 cells, , and biologically active adhesion peptide sequences, such as RGD, , GFOGER, and FHRRIKA, can be loaded onto the Ti surface to improve the adhesion, proliferation, and viability of osteogenic-associated cells, and ultimately, promote the osseointegration of peri-implant osteoblasts.…”

Mass Spectrometry Imaging of Biomaterials

“…Another research was carried out using strontium surface functionalization of specially designed titanium-niobium (Ti- 40 Nb) implant to accelerate bone growth by stimulating the osteoblasts and, at the same time, to inhibit the osteoclasts, which are responsible for bone resorption [ 68 ]. This remodeling process accelerated by the biomaterial may provide an advanced implant system that is mechanically adapted to the altered bone with the ability to stimulate bone formation.…”

“…It is an important aim to develop advanced metallic implants that are mechanically adapted to the weakened bone structure and ensure fast bone integration by modified surface characteristics. ToF-SIMS analysis of the Ti- 40 Nb surface after the release experiment revealed traces of residual strontium [68].…”

“…The following supporting information can be downloaded at: , Table S1: A tabulation of the main aspects of articles discussed in this review [ 17 , 38 , 40 , 46 , 49 , 50 , 51 , 52 , 58 , 62 , 63 , 64 , 65 , 68 , 69 , 70 , 72 , 78 , 83 , 88 , 93 , 96 , 98 , 99 , 100 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 110 , 111 ].…”

Properties improvement of titanium alloys scaffolds in bone tissue engineering: a literature review

“…Metal ions, such as copper, silver, magnesium, strontium, etc., can promote osteogenesis and avoid certain toxicities by being carried with a slow-released coating film (76)(77)(78)(79). Van Hengel et al (80) indicated that the synergistic antibacterial effect could prevent infections by antibioticresistant bacteria.…”