Identification and classification of silks using infrared spectroscopy

Area of Science:

• Biochemistry
• Materials Science
• Spectroscopy

Background:

• Lepidopteran silks exhibit significant diversity in structure, properties, and industrial applications.
• Understanding this biochemical diversity is crucial for exploring silk's potential.

Purpose of the Study:

• To develop and apply an infrared (IR) spectroscopy-based method for identifying and screening lepidopteran silks.
• To classify silks based on their biochemical composition and spectral properties.

Main Methods:

• Collected and analyzed over 1214 IR spectra from native silk feedstock and cocoons of 35 different species.
• Utilized multivariate analysis to group silks into distinct hierarchies and classifications.
• Quantified relative content of key silk components like sericin, calcium oxalate, and beta-sheets.

Main Results:

• The IR spectral analysis successfully grouped silks, aligning with current phylogenetic data and taxonomies.
• Identified the domesticated mulberry silkmoth (Bombyx mori) as a spectral outlier among silkmoths.
• Discovered high beta-sheet content in Epiphora bauhiniae silk, exceeding previously reported levels for wild silks.

Conclusions:

• Infrared spectroscopy offers a novel and effective approach for determining cocoon chemical composition.
• This method provides a new biological and material classification system for lepidopteran silks.
• The findings highlight the unique spectral characteristics of Bombyx mori and Epiphora bauhiniae silks, expanding our understanding of silk diversity.