This technique uses multimodal nonlinear optical microscopy with the image contrast of second harmonic generation (SHG)coherent anti-Stokes Raman scattering (CARS). By analyzing the nonlinear signals on images, it can be used to characterizequantify the structural variation in the collagen scaffolds processed with different crosslinking methods. The correlation between signalsmechanical properties can then be derived. Additionally, comparative analysis of these two signals can be used to monitor the structural (triple-helix) change of collagen molecules during the crosslinking processes.