Hydrothermal Fabrication of Highly Porous Titanium Bio-Scaffold with a Load-Bearable Property

Abstract

Porous titanium (P_Ti) is considered as an effective material for bone scaffold to achieve a stiffness reduction. Herein, biomimetic (bio-)scaffolds were made of sintered P_Ti, which used NaCl as the space holder and had it removed via the hydrothermal method. X-ray diffraction results showed that the subsequent sintering temperature of 1000 °C was the optimized temperature for preparing P_Ti. The compressive strength of P_Ti was measured using a compression test, which revealed an excellent load-bearing ability of above 70 MPa for that with an addition of 50 wt % NaCl (P_Ti_50). The nano-hardness of P_Ti, tested upon their solid surface, was presumably consistent with the density of pores vis-à-vis the addition of NaCl. Overall, a load-bearable P_Ti with a highly porous structure (e.g., P_Ti_50 with a porosity of 43.91% and a pore size around 340 μm) and considerable compressive strength could be obtained through the current process. Cell proliferation (MTS) and lactate dehydrogenase (LDH) assays showed that all P_Ti samples exhibited high cell affinity and low cell mortality, indicating good biocompatibility. Among them, P_Ti_50 showed relatively good in-cell morphology and viability, and is thus promising as a load-bearable bio-scaffold.

Keywords: biomimetic scaffold; cell affinity; load bearable; porous titanium.

Figure 1

Fabrication processes. (a) Hydrothermal route; (b) spacer removal; (c) sintering; and (d) bio-assessments.

Figure 2

The ICP-MS measurements and XRD patterns of porous Ti samples. (a) ICP-MS spectrum for Na; (b) results of simulation and extreme solution test; (c) XRD patterns of pure Ti sintered at 900–1100 °C; and (d) XRD patterns of samples with various NaCl concentrations sintered at 1000 °C.

Figure 3

SEM images of (a) Ti_1000_0; (b) Ti_1000_10; (c) Ti_1000_30; (d) Ti_1000_50; and (e) Ti_1000_70; (f) Corresponding pore sizes.

Figure 4

Quality and compressive strength of porous Ti samples. (a) Porosity; (b) compressive strength; (c) nano-hardness; and (d) nanomechanical strength.

Figure 5

Optical microscopy images for live/dead staining protocol on surfaces of (a-i) Ti_1000_0; (a-ii) Ti_1000_10; (a-iii) Ti_1000_30; (a-iv) Ti_1000_50; and (a-v) Ti_1000_70; (b) Summary of cell viability for these surfaces. (c) Results of the cell proliferation MTS assay; (d) Effects of lactate dehydrogenase LDH in early stage for Ti_1000_0, Ti_1000_10, Ti_1000_30, Ti_1000_50, and Ti_1000_70. No significant differences in LDH level on surfaces were found between samples.

Figure 6

Porous Ti-based scaffold with high biocompatibility.