Development of Measurement System for Diameter and Refractive Index of Silk Fibroin Filament Based on Scattered Light Pattern

Abstract

When a cylindrical transparent filament such as a silk fibroin one is irradiated by a laser beam, a scattering intensity pattern appears on a plane perpendicular to the filament. Its diameter and refractive index are determinable by measuring this intensity pattern. On the basis of this principle, I have developed an automated measurement system for the pattern. Using the system, I have examined to determine the parameters for the sample filaments of the silk fibroin peeled from cocoons. As a result, the theoretical intensity patterns were corresponded well to the experimentally measured ones. Furthermore, it revealed that the refractive indices and diameters of the filaments were reasonably determined.