Adsorption Of Collagen On PLA Surface Using Quartz Crystal Microbalance

Collagen is a kind of important structural protein of the extracellular matrix. Quartz crystal microbalance (QCM) is a sensitive mass sensor with good surface selectivity and real-time monitoring advantages. It is widely used in biochemistry, medicine and chemical industry. In this work, biodegradable and absorbable material poly-lactic acid (PLA) is selected as adsorption substrate to investigate the adsorption behavior of collagen using quartz crystal microbalance and atomic force microscopy (AFM). Factors such as buffer pH, ionic strength, collagen concentration and temperature were investigated. The process of collagen adsorbed on PLA surface was studied. The frequency change caused by water, buffer ions and collagen molecules were distinguished. The adsorption amount of collagen first increases and then decreases with the increasing ionic strength. The adsorption amount varies with the pH. Atomic force microscopy images show that fibrillar structures of different collagen sources were completely different. The results also show that with the increasing concentration of collagen, the adsorption amount and initial adsorption rate on PLA surface increases correspondingly. The adsorption was significantly influenced by temperature changes in the buffer, indicating that the collagen is a kind of temperature-sensitive material. Langmuir model and Freundlich model were applied to fit the experimental data respectively. The isotherm equations were abstained. The kinetic experimental data were correlated with the Lagergren pseudo-first order kinetic model and the Lagergren pseudo-second order kinetic model. The results of this work will conduce to the development of new biofunctional materials. The study method used in this work can provide reference in protein adsorption.