APATITE FORMATION ON ORGANIC POLYMERS BY A BIOMIMETIC PROCESS

Organic polymer substrates were placed on granular particles of a CaO, SiO2-based glass soaked in a simulated body fluid (SBF) with ion conce ntrations nearly equal to those of human blood plasma, and then soaked in a solution highly supersaturated with respect to the apatite, e.g. , that with ion concentrations 1.5 times those of SBF. During the firs t treatment, apatite nuclei were formed on the polymers by catalytic e ffect of a silicate ion dissolved from the glass particles and attache d on the polymers. During the second treatment, the apatite nuclei gre w spontaneously to form a dense and uniform bonelike apatite layer on any kind of polymers in any shapes including fine fiber fabric. The in duction period for the apatite nucleation in the first treatment was a lmost 6 h for most of the examined polymers previously treated with ox ygen glow discharge. The thickness of the apatite layer increased in p roportion to the time of the second treatment at a rate of 1.7 and 7.0 mu m/day at 36.5 and 60 degrees C, respectively. The adhesive strengt hs of the apatite layer to the polymers were about 10 MPa at maximum f or polymers treated with oxygen glow discharge. Thus formed apatite la yer bonded to living bone directly. This type of apatite-polymer compo sites are expected to be useful for repairing living hard and soft tis sues.