Back to Bombyx

Silk Worms are Back! Bombyx mori is the domesticated silk worm bred for silk production.

Introduction
Silk is an interesting biomaterial, that can be easily sterilized with alcohol, to make gels, to print, etc...

Obtaining Silk Protein
What is used as biomaterials is the fibroin part of the silk thread and cocoon. (See image to the right, from Professor Norihisa Kato's lab, Hiroshima University). The dissolution conditions seem to be different between the domesticated Bombyx, and other wild strains. Step-by-step documentation from HTGAA 2015 from silklab
 * 1) Degumming or removal of sericin - 5g/L sodium carbonate, pH, T, 1h (for Bombyx).
 * 2) Dissolution of fibroin

This review paper from 2008 is a nice resource.

LiBr or not
Lithium Bromide (LiBr), while one can source it online, as a non-institutional person, still can be hard to find. Brief summary of reading some papers is that LiBr is the best for degummed fibers of silk cocoons, where nearly 100% can be solubilized in LiBr, compared to 30% in CaCl2, or 50% NaSCN (sodium thiocyanate) (numbers taken from Addis and Raina 2013). A Researchgate thread mentioned "2.5wt% silk fibroin in 28% ammonium aqueous solution by magnetic stirring."

Sourcing
CH IN
 * Swiss Silk
 * Department of Sericulture Government of Karnataka
 * Silkworm Seed Production Centre, Government Office Bengaluru, Karnataka
 * National Silkworm Seed Organization, Agricultural Seed Store, Bengaluru, Karnataka
 * Silk Worm Breeding Unit, Bengaluru, Karnataka
 * Sri Lingeshwara Silk Worm Seed Product, Kamenahalli, Karnataka

About the Silk Worm

 * Microscopic Studies of Bombyx mori David Walker, UK

Material Properties and Methods

 * Polyol-Silk Bioink Formulations as Two-Part Room-Temperature Curable Materials for 3D Printing ACS Biomater. Sci. Eng., 2015, 1 (9), pp 780–788 DOI: 10.1021/acsbiomaterials.5b00160: The researchers combined silk proteins, which are biocompatible, and glycerol, a non-toxic sugar alcohol commonly found in food and pharmaceutical products. The resulting ink was clear, flexible, stable in water, and didn’t require any processing methods.
 * Pdf of Materials fabrication from Bombyx mori silk fibroin, Nat Protoc. 2011 Sep 22;6(10):1612-31. doi: 10.1038/nprot.2011.379.
 * HTGAA 2015 Lucern documentation on bioprinting

Molecular Biology

 * SilkDB a draft genome sequence for the silkworm B. mori, by the Beijing Genomics Institute (BGI)
 * SilkDB for the silkworm, Bombyx mori from Scripps and, genomic data including functional annotation of genes, gene products and chromosomal mapping, extensive biological information such as microarray expression data, ESTs and corresponding references
 * WildSilkbase BLAST searchable catalogue of expressed sequence tags (ESTs) generated from several tissues of wild silkmoths at different developmental stages, Center for DNA Fingerprinting and Diagnosis, Hydrabad India
 * Insect Proteome Database, Silkworm
 * Table 2.2 Genomics and Functional Genomics Resources Molecular Biology and Genetics of the Lepidoptera edited by Marian R. Goldsmith, Frantisek Marec, CRC Press ISBN 1420060201, 9781420060201.
 * Key enzymes and proteins of crop insects as candidate for RNAi based gene silencing Kola et al. Department of Biotechnology, Directorate of Rice Research, ICAR-Indian Institute of Rice Research, Hyderabad, India. Front. Physiol., 22 April 2015 | https://doi.org/10.3389/fphys.2015.00119