Manufacture of titanium alloy materials with bioactive sandblasted surfaces and evaluation of osseointegration properties

Abstract

Titanium alloys are some of the most important orthopedic implant materials currently available. However, their lack of bioactivity and osteoinductivity limits their osseointegration properties, resulting in suboptimal osseointegration between titanium alloy materials and bone interfaces. In this study, we used a novel sandblasting surface modification process to manufacture titanium alloy materials with bioactive sandblasted surfaces and systematically characterized their surface morphology and physicochemical properties. We also analyzed and evaluated the osseointegration between titanium alloy materials with bioactive sandblasted surfaces and bone interfaces by in vitro experiments with co-culture of osteoblasts and in vivo experiments with a rabbit model. In our in vitro experiments, the proliferation, differentiation, and mineralization of the osteoblasts on the surfaces of the materials with bioactive sandblasted surfaces were better than those in the control group. In addition, our in vivo experiments showed that the titanium alloy materials with bioactive sandblasted surfaces were able to promote the growth of trabecular bone on their surfaces compared to controls. These results indicate that the novel titanium alloy material with bioactive sandblasted surface has satisfactory bioactivity and osteoinductivity and exhibit good osseointegration properties, resulting in improved osseointegration between the material and bone interface. This work lays a foundation for subsequent clinical application research into titanium alloy materials with bioactive sandblasted surfaces.

Keywords: bioactive sandblasted surface; biomaterial; osseointegration; surface modification; titanium alloy.

FIGURE 1

In vitro experiment specimens from the (A) smooth titanium alloy group and (B) sandblasted titanium alloy group. In vivo experiment specimens from the (C) smooth titanium alloy group and (D) sandblasted titanium alloy group.

FIGURE 2

The surfaces of the specimens from the (A) smooth titanium alloy group and (B) sandblasted titanium alloy group under SEM. EDS detection results. (C) detection area of smooth titanium alloy group; (D) detection area of sandblasted titanium alloy group; (E) EDS detection results of smooth titanium alloy group; (F) EDS detection results of sandblasted titanium alloy group.

FIGURE 3

AFM topographical images of (A) smooth titanium alloy group and (B) sandblasted titanium alloy group, with the range of 15 μm × 15 μm. (C) Roughness values (Rq and Ra) of smooth titanium alloy group and sandblasted titanium alloy group, with the range of 15 μm × 15 μm ^* p < 0.05.

FIGURE 4

Analysis results of (A) XPS and (B) XRD. The detection results of contact angle from (C) the smooth titanium alloy group and (D) sandblasted titanium alloy group. (E) Analysis of contact angle between smooth group and sandblasted group. ^* p < 0.05.

FIGURE 5

(A) Primary cultured osteoblasts in the field of vision under an inverted microscope. (B) Primary cultured osteoblasts identification results in the field of vision under an inverted microscope at 200 times magnification.

FIGURE 6

(A) CCK-8 test results of the smooth titanium alloy group and sandblasted titanium alloy group at the three incubation time points of 1d, 4d, and 7d. (B) The results of ALP activity detection at the two incubation time points of 7d and 14d. The mRNA relative expression levels of the four osteogenesis-related genes at the two incubation time points of 7d and 14d. (C) ALP; (D) RUNX2; (E) Col1α1; (F) OCN; GAPDH as the house-keeping gene. ^* p < 0.05.

FIGURE 7

The results of immunocytochemical staining of type I collagen secretion at the two incubation time points of 7d and 14d.

FIGURE 8

The cell growth detection results under SEM at the two incubation time points of 7d and 14d.

FIGURE 9

The process of animal model preparation: (A) Skin preparation; (B) Incision; (C) Exposure for this surgery; (D) Removal of bone cortex; (E) Implantation of the sample; and (F) Sew up the incision.

FIGURE 10

HE staining results.

FIGURE 11

Micro-CT detection of osseointegration (A) The results of Micro-CT detection of osseointegration at the two time points of 8 weeks and 12 weeks; (B) Analysis of newly-formed bone volume fraction at the two time points of 8 weeks and 12 weeks.

FIGURE 12

Hard tissue section detection of osseointegration (A) The results of hard tissue section detection of osseointegration at the two time points of 8 weeks and 12 weeks; (B) Analysis of area of newly-formed trabecular bone at the two time points of 8 weeks and 12 weeks. ^* p < 0.05.