Morphosynthesis of Zn-Substituted Stoichiometric and Carbonate Hydroxyapatite Nanoparticles and Their Cytotoxicity in Fibroblasts

Hydroxyapatite (Ca10(PO4)3(OH)2) (HAp) is crystallographically and chemically similar to the human hard tissues and has been widely researched. The naturally formed HAp has some impurities of some ions, which provides the biocompatibility as well as the nanosized morphologies in the tissues. In this study, the morphosynthesis of zinc-substituted stoichiometric and carbonate hydroxyapatite (Zn:HAp and Zn:CAp) nanoparticles was investigated from the reagents of CaCl2, ZnCl2, and K2HPO4. The initial (Ca + Zn)/P ratios of 1.67 and 2.00 were adjusted by the initial ZnCl2 amount at the Zn/(Ca + Zn) concentration of 0.0−10 mol%. The crystalline sizes of the nanoparticles decreased with increasing the Zn ion amount, suggesting that the Zn substitution significantly suppressed the crystal growth. TEM images of the nanoparticles indicated that all the crystalline sizes are less than 100 nm and the needle-like shapes were significantly changed to spherical shapes with increasing the Zn ion substitution to resultantly exhibit the higher surface areas as well as the nanoparticle aggregation states. Furthermore, all the nanoparticle films electrically plated on a silicone substrate give no cytotoxicity, and the Zn:CAp nanoparticle films significantly provided the bioactive properties for fibroblast ingrowth, suggesting the effect of Zn and carbonate ions on the cytocompatibility

水酸アパタイトナノ粒子膜の調製と生物医学的応用のための細胞親和性の評価に関する研究

国立大学法人長岡技術科学大

Hydroxyapatite Nanoparticle Coating on Polymer for Constructing Effective Biointeractive Interfaces

Bone is an organic-inorganic composite with the ability to regenerate itself. Thus, several studies based on artificial organic-inorganic interface sciences have been tried to develop capable materials for effective regenerative bone tissues. Hydroxyapatite nanoparticles (HAp NPs) have extensively been researched in bone tissue engineering due to the compositional and shape similarity to the mineral bone and excellent biocompatibility. However, HAp alone has low mechanical strength, which limits its applications. Therefore, HAp NPs have been deposited on the biocompatible polymer matrix, obtaining composites with the enhanced mechanical, thermal, and rheological properties and with higher biocompatibility and bioactivity. For developing new biomedical applications, polymer-HAp interfacial interactions that provide biofusion should be investigated. This paper reviewed common coating techniques for obtaining HAp NPs/polymer fusion interfaces as well as in vitro studies of interfacial interactions with proteins and cells, demonstrating better biocompatibility. Studies based on interfacial interactions between biomolecules and HAp NPs were highlighted, and how these interactions can be affected by specific protein preadsorption was also summarized

Drug Molecular Immobilization and Photofunctionalization of Calcium Phosphates for Exploring Theranostic Functions

Theranostics (bifunction of therapeutics and diagnostics) has attracted increasing attention due to its efficiency that can reduce the physical and financial burden on patients. One of the promising materials for theranostics is calcium phosphate (CP) and it is biocompatible and can be functionalized not only with drug molecules but also with rare earth ions to show photoluminescence that is necessary for the diagnostic purpose. Such the CP-based hybrids are formed in vivo by interacting between functional groups of organic molecules and inorganic ions. It is of great importance to elucidate the interaction of CP with the photofunctional species and the drug molecules to clarify the relationship between the existing state and function. Well-designed photofunctional CPs will contribute to biomedical fields as highly-functional ormultifunctional theranostic materials at the nanoscales. In this review, we describe the hybridization between CPs and heterogeneous species, mainly focusing on europium(III) ion and methylene blue molecule as the representative photofunctional species for theranostics applications

Investigation of Inclusion States of Silicate and Carbonate Ions in Hydroxyapatite Particles Prepared under the Presence of Sodium Silicate

Biological hydroxyapatite (HA) contains the different minor ions which favour its bio-reactivity in vivo. In this study, the preparation of HA particles containing both silicate and carbonate ions under the presence of sodium silicate was investigated, and the physicochemical properties were evaluated according to the contents and states of silicate and carbonate ions. The increment in the silicate ion reduced the crystallinity and expanded the crystalline size along with a-axis. Solid-state 29Si–NMR spectra indicated the increase in the adsorption of oligomeric silicate species on the HA particle surfaces in addition to the substitution state of silicate ions, suggesting the occurrence of the surface coating of silicates on the surfaces. The possible states of carbonate and silicate ions at the HA surfaces will provide the bioactivity

Investigation of Inclusion States of Silicate and Carbonate Ions in Hydroxyapatite Particles Prepared under the Presence of Sodium Silicate

Biological hydroxyapatite (HA) contains the different minor ions which favour its bio-reactivity in vivo. In this study, the preparation of HA particles containing both silicate and carbonate ions under the presence of sodium silicate was investigated, and the physicochemical properties were evaluated according to the contents and states of silicate and carbonate ions. The increment in the silicate ion reduced the crystallinity and expanded the crystalline size along with a-axis. Solid-state 29Si–NMR spectra indicated the increase in the adsorption of oligomeric silicate species on the HA particle surfaces in addition to the substitution state of silicate ions, suggesting the occurrence of the surface coating of silicates on the surfaces. The possible states of carbonate and silicate ions at the HA surfaces will provide the bioactivity