Self-sacrificing template synthesis of ultralight porous hydroxyapatite microtube-based ceramics for hemoglobin adsorption

Abstract

Strong and porous hydroxyapatite ceramics are highly desired for biomedical materials. However, 1D hydroxyapatite crystals with enhanced bioactivity, densification, and sinterability are limited in practical application for self-agglomeration and unfavorable 3D morphology. Herein, a sacrificed template approach is developed to prepare ultralight porous hydroxyapatite microtube-based ceramics (HMTC). First, hydroxyapatite microtubes (HMTs) are self-assembled proceeding from nanowires to microtubes through a solvothermal reaction. Then, HMTs are shaped into 3D columns by using chitosan aerogel as a template and sintered at 1300 °C to obtain ultralight porous ceramics. The chitosan template considerably contributes to constructing the macro-meso-microporous architecture of HMTC, thereby benefiting the loading capacity, biomolecule migration, cell proliferation, and other biomedical applications. HMTC exhibits ultralight weight but excellent compressive resistance to bear objects weighing hundreds of times more. HMTC exhibits a high adsorption capacity (311 mg g−1) towards bovine hemoglobin (BHb) at the pH near pI by the driving force of ionic interaction and hydrophobic interaction. The adsorption kinetics and fixed-bed adsorption confirm that the physisorption process is controlled by the intraparticle diffusion of BHb. The excellent protein adsorption performance and good recyclability demonstrate the biological availability of HMTC.