Visualization of the nanoscale assembly of type I collagen on PLA by AFM

Collagen adsorption and the morphology of its assemblies at polymer surface play an important role in improving the biocompatibility of materials. In this study, the nanoscale organization of type I collagen on Polylactide (PLA) was observed directly by high-resolution atomic force microscopy. The results show that the supramolecular structure of adsorbed collagen was affected by the concentration of collagen solution, appropriate pH and electrolyte composition of the buffer. On PLA substrate, network structures formed in high humidity atmosphere. In addition, collagen formed well-oriented nano-patterns at nearly neutral pH and appropriate electrolyte composition. Particularly, the typical 65 nm D-periodicity of collagen fibers was observed in the presence of potassium ions. Our investigation provides useful insights into the regulation of collagen assembly by substrates and environmental conditions, which is important for understanding the mechanism of collagen adsorption and assembly on polymer surfaces. It also offers a potential way to create surfaces of bio-functioned and nano-patterned materials for biotechnological and biomedical applications.