title: Lysozyme loading and release from Se doped hydroxyapatite nanoparticles.
abstract: Element-substituted hydroxyapatite (HA) based nanocomposites have become a promising therapeutic material for improving bone defect repair. Selenium substituted HA nanoparticles can both induce apoptosis of bone tumor cells and enhance osteointegration. However, the effect of selenite ions on the proteins in combination with the HA nanoparticles remains to be elucidated. Here, we investigated the influence of selenium doping concentration on the loading and release of lysozyme (LSM) as a model protein drug. The selenium substituted HA-LSM composites with different doping concentrations were synthesized and characterized. The subsequent delivery of lysozyme was studied in a phosphate buffer solution (PBS). We found that selenium substituted HA-LSM composites with Se:P=10% showed the highest amount of lysozyme loading (41.7%), whereas the amount of lysozyme loaded in undoped HA nanoparticles was the lowest (34.1%). The doped selenium interacts with lysozyme molecules, which leads to the increase of β-sheet and unordered, and the decrease of self-association, α-helix and β-turns in protein structures. Moreover, selenium addition significantly slows the protein release from HA-LSM composites. The composites with Se:P=10% release lysozyme at the slightly slower rate among the samples with different Se doping concentrations. It also shows that the released lysozyme retains most of its enzymatic activity.
authors.affiliation: Medical Science College of China Three Gorges University, Yichang, China. Electronic address: juddy0921@163.com.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Hao
authors.affiliation: Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Shengmin
authors.initials: S
authors.lastname: Zhang
mesh_terms: D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D017886:Durapatite / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D009113:Muramidase / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D053758:Nanoparticles / Q000737:chemistry*; D012643:Selenium / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D003692:Delayed-Action Preparations; D017886:Durapatite; D009113:Muramidase; D012643:Selenium
keywords: Hydroxyapatite; Lysozyme; Nanoparticle; Protein release; Selenium