Characterization of collagen response to bone fracture healing using polarization-SHG.

In this study, we extend on the three parameter analysis approach of utilizing a noninvasive dual-liquid-crystal-based polarization-resolved second harmonic generation (SHG) microscopy to facilitate the quantitative characterization of collagen types I and II in fracture healing tissues. The SHG images under various linear and circular polarization states are analyzed and quantified in terms of the peptide pitch angle (PA), SHG-circular dichroism (CD), and anisotropy parameter (AP). The results show that the collagen PA has a value of 49.