Force measurement study of engineered collagen-chitosan scaffold using Atomic Force Microscopy

The structure and properties of scaffold are important in cell-based tissue engineering, especially the mechanical property. Here, we quantify the dynamic oscillatory mechanical behavior of two kinds of porous collagen/chitosan scaffolds. The Young´s Modulus were measured in PBS using Atomic Force Microscopy (AFM)-based nano-indentation in response to an imposed oscillatory deformation as a function of force, which can be converted to Young´s Modulus. Collagen/chitosan scaffolds with different ratio (8:2 and 7:3, V/V), which already showed good properties for cell culture, were tested. The Young´s Modulus of collagen/chitosan scaffold with ratio 7:3 is bigger than that of 8:2, which is consistent with our expectation. Force curves were obtained first from indentation, and then Young´s Modulus was determined using a proper Hertz contact mathematical model. Meanwhile, the mechanical properties of mice pancreas and heart were obtained as controls. The results indicated that AFM-based nano-indentation is a good method for the mechanical property testing of porous scaffold.