Bone-like apatite layer formation on hydroxyapatite prepared by spark plasma sintering (SPS)

Area of Science:

• Biomaterials Science
• Materials Engineering
• Biomineralization

Background:

• Hydroxyapatite (HA) is a key biomaterial for bone regeneration.
• Spark plasma sintering (SPS) offers a method for fabricating dense HA ceramics.
• Understanding apatite layer formation on HA in simulated body fluid (SBF) is crucial for assessing biocompatibility.

Purpose of the Study:

• To fabricate dense hydroxyapatite (HA) compacts using spark plasma sintering (SPS).
• To investigate the formation and characteristics of a bone-like apatite layer on SPS-consolidated HA in simulated body fluid (SBF).
• To elucidate the mechanism of apatite layer formation on HA surfaces immersed in SBF.

Main Methods:

• Fabrication of HA compacts via spark plasma sintering (SPS) using spray-dried HA powders.
• Immersion of HA compacts in simulated body fluid (SBF) for up to 28 days.
• Analysis of structural changes using scanning electron microscopy (SEM), grazing incidence X-ray diffraction (GIXD), and X-ray photoelectron spectroscopy (XPS).

Main Results:

• Dense HA compacts with superior mechanical properties were successfully fabricated by SPS.
• A microcrystalline carbonate-containing hydroxyapatite layer formed on HA surfaces after 24 hours of SBF immersion.
• Structural analysis confirmed the formation of a bone-like apatite layer.

Conclusions:

• SPS is an effective method for producing high-quality HA bioceramics.
• The formation of a carbonate-containing HA layer in SBF is attributed to ion exchange and favorable nucleation conditions.
• The observed apatite layer formation enhances the potential biocompatibility of HA implants.