Formation of bone-like apatite on poly(L-lactic acid) fibers by a biomimetic process

Bone-like apatite coating on poly(L-lactic acid) (PLLA) fibers was formed b y immersing the fibers in a modified simulated body fluid (SBF) at 37 degre esC and pH 7.3 after hydrolysis of the fibers in water. The ion concentrati ons in SBF were nearly 1.5 times of those in the human blood plasma. The ap atite was characterized by scanning electron microscopy (SEM) with energy d ispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thin-film X-ray diffraction, and Fourier transform infrared spectroscopy. After 15 days of incubation in SBF, an apatite layer with about 5-6 mum thi ckness was formed on the surface of the fibers. This apatite had a Ca/P rat io similar to that of natural bone. The mass of apatite coated PLLA fibers increased with extending the incubation time. After 20 days incubation, the fibers increased their mass by 25.8 +/- 2.1%. The apatite coating had no s ignificant effect on the tensile properties of PLLA fibers. In this article , the bone-like apatite coating on three-dimensional PLLA braids was also s tudied. The motivation for this apatite coating was that it might demonstra te enhanced osteoconductivity in the future studies when they serve as biod egradable scaffolds in tissue engineering. (C) 2001 John Wiley & Sons, Inc.