ABSTRACT
The so-called bioactive ceramics have been attractive because they spontaneously bond to living bone. Organic-inorganic hybrids consisting of organic polymers and the essential constituents of the bioactive ceramics, i.e., silanol (Si-OH) group and calcium ions (Ca(2+)), are useful as novel bone substitutes, owing to bioactivity and high flexibility. In the present study, organic-inorganic hybrids are synthesized from chitin by modification with glycidoxypropyltrimethoxysilane (GPS) and calcium chloride (CaCl(2)). Their apatite-forming ability is examined in a simulated body fluid (SBF). The prepared hybrids form apatite on their surfaces in SBF within 7 days.
Subject(s)
Bone Substitutes/chemistry , Bone Substitutes/chemical synthesis , Calcium Chloride/chemistry , Chitin/analogs & derivatives , Nanostructures/chemistry , Silanes/chemistry , Apatites/chemical synthesis , Apatites/chemistry , Body Fluids , Ceramics/chemical synthesis , Ceramics/chemistry , Chitin/chemistry , In Vitro Techniques , Materials Testing , Microscopy, Electron, Scanning , Silanes/chemical synthesis , Spectroscopy, Fourier Transform Infrared , Surface PropertiesABSTRACT
Organic-inorganic composites, prepared from bone-bonding bioactive ceramics and organic polymers, are useful for novel bone substitutes having mechanical properties analogous to natural bone. We synthesized composites from cellulose and carbonate hydroxyapatite (CHAp) in situ through mechanochemical reaction. They contained B-type CHAp analogous to bone apatite. They showed a bending strengths of 10-13 MPa and Young's modulus of 1.5-2.2 GPa. We predicted their microstructure by comparing the measured density with the theoretical one. Cellulose was assumed to be distributed in the pore of CHAp at low cellulose content, and in grain boundaries of CHAp at high cellulose content. The composites formed calcium phosphate on their surfaces in simulated body fluid, meaning that they have a potential to be bioactive.
Subject(s)
Bone Substitutes/chemical synthesis , Cellulose/chemistry , Hydroxyapatites/chemistry , Biomechanical Phenomena , Bone Substitutes/chemistry , Humans , Hydroxyapatites/analysis , Materials Testing , X-Ray DiffractionABSTRACT
Apatite formation in the living body is an essential requirement for artificial materials to exhibit bone-bonding bioactivity. It has been recently revealed that sulfonic groups trigger apatite nucleation in a body environment. Organic-inorganic hybrids consisting of organic polymers and the sulfonic groups are therefore expected to be useful for preparation of novel bone-repairing materials exhibiting flexibility as well as bioactivity. In the present study, organic-inorganic hybrids were prepared from hydroxyethylmethacrylate (HEMA) in the presence of vinylsulfonic acid sodium salt (VSAS) and calcium chloride (CaCl(2)). The bioactivities of the hybrids were assessed in vitro by examining the apatite formation in simulated body fluid (SBF, Kokubo solution). The hybrids deposited on the apatite after soaking in SBF within 7 days. Tensile strength measurements showed a tendency to increase with increases in VSAS and CaCl(2) content. It was assumed that this phenomenon was attributed to the formation of cross-linking in the hybrids.