Computational study on optical properties of the collagen

Some report showed that the dermis exhibits strong scattering in the blue light region. It is hypothesized that this scattering is caused by collagen, although the exact mechanism remains unclear. Additionally, the dependency of this scattering varies according to the measurement conditions, as reported in various studies.

In our research, we calculated the wavelength dependency of the refractive index of collagen molecules using first-principles calculations based on quantum mechanics. Subsequently, we computed the scattering characteristics of collagen fibers using the discrete dipole approximation method.

DFT calculations show the refractive index 1.50 at 700 nm wavelength. This value is good agreement with experimentally obtained value. By varying the distance between collagen fibers, we observed changes in their scattering properties. Specifically, the scattering in the blue spectrum was strongest when the distance between the fibers was greater. This indicates that, at the same density, better dispersion results in stronger blue scattering.