Preparation of Nano-Sized Collagen I and Collagen II Particles

This pilot study describes a new method to prepare nano-sized collagen type I and collagen type II particles by using a high-voltage electrostatic field system. Observations from transmission electron microscopy showed that, the nano-sized collagen II particles with a range of 150 nm in diameter could be produced with a good spherical shape under the experimental setting of 2.7~4.5 kVcm^-1, under 23degC and a moderate concentration of collagen II solution at 0.2 mg/ml. When the treatment temperature increased to 30degC or higher, collagen II began to lose the tendency to individually separated spherical shaped nano-sized particles, instead, the fibrillogenesis of collagen II occurred by the spontaneous reconstitution of collagen II and then formed collagen II fibrils. More strict experimental settings were necessary for preparing nano-sized collagen I particles, that are, lower temperature setting (under 7degC environment), lower collagen concentration (0.1 mg/ml) and lower applied voltage (2.5 kVcm^-1). Moreover, these prepared nano-sized collagen I particles exhibited smaller size in diameter (100 nm) but poorer sphericity than collagen II particles. They often aggregated together and exhibited an irregular outer shape.