Hollow and porous hydroxyapatite microspheres prepared with an O/W emulsion by spray freezing method.
Microspheres with hollow and/or porous structures have been widely used in various applications. A new method of spraying and freezing emulsions was developed to prepare hollow HA (hydroxyapatite) microspheres with interconnected pores by using PVA (polyvinyl alcohol) as emulsifiers and binders. The relationships between viscosity and shear time or rates were tested and the dispersing stability of oil in water (O/W) emulsions was characterized with comparison to suspensions without the addition of oil phase. The effects of solid loadings of HA and the volume ratio between oil and water on the morphologies of microspheres were investigated. Hollow HA microspheres with particle diameter of ~20μm and pore size of ~0.6μm were successfully obtained by spray freezing method. Besides, drying and sintering processes were crucial to the formation of hollow and porous structures, respectively. The gentamicin loading and releasing of HA porous microspheres with different hollow volumes were tested.
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China.
Qiyao
Q
Xiao
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China.
Kechao
K
Zhou
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China.
Chao
C
Chen
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China.
Mingxiang
M
Jiang
Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK.
Yan
Y
Zhang
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China.
Hang
H
Luo
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, China. Electronic address: dzhang@csu.edu.cn.
Dou
D
Zhang
D017886:Durapatite / Q000737:chemistry*; D045703:Emulsifying Agents / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry*; D005615:Freezing; D005839:Gentamicins / Q000737:chemistry* / Q000378:metabolism; D008863:Microspheres; D011142:Polyvinyl Alcohol / Q000737:chemistry; D016062:Porosity
D045703:Emulsifying Agents; D004655:Emulsions; D005839:Gentamicins; D011142:Polyvinyl Alcohol; D017886:Durapatite
Emulsions; HA microspheres; Hollow structures; Porous structures