(520d) Mechanical Evaluation of Silk Fibroin Collected from Plodia Interpunctella: An Alternative Source of Silk for Biomedical Applications

Silk fibroin is a natural biopolymer used for tissue engineering and regenerative medicine applications (1). Most silk fibroins used in biomedical applications are from a single source of silk fibroin protein- Bombyx mori cocoons- where the silk cocoon is processed into a regenerated silk solution (2). However, natural silk fibroins are produced across most of the 160,000 lepidopteran species as well as various other arthropod species and used as a versatile multifunctional biopolymer. The silk fiber structure is comprised of two major components, fibroin and sericin. Amazing, these proteins are not structurally similar across silk producing species, displaying a wide array of physical and chemical properties based on several physiological triggers and hypothesized use. Since cocoon silk from the domesticated Bombyx mori silkworm has been explored almost exclusively as a biomaterial, the biomaterials community has not leveraged the available natural biodiversity of silk and thus we aim to explore alternative sources for silk fibroin protein for use in biomedical applications. An alternative silk producing model lepidopteran, the Indian meal moth, Plodia interpunctella (IMM) was chosen given that it is a readily accessible organism. IMM is easily reared with a short life cycle and minimal cost. Recent advances and the new availability of partial genomic sequences for important silk genes as well as an alternative mode of silk production (sheeting) has made this species attractive. To properly scale up silk production, we examine silk production, including fibroin composition, as a function of environmental culture conditions such as population density, food quantity, and temperature, with the goal of leveraging the unique physical and chemical properties to expand the array of silk fibroin-based tunable biomaterials available for tissue engineering. Preliminary data shows population density is the major factor in silk sheeting and that individual larvae lay silk in a directed manner. Future work will look to scale production of IMM silk, determine suitable biomedical applications, and explore how fibroin modifications can be leveraged within IMM to create diverse biopolymers that are superior to the native structure.

1. Stoppel WL, Raia N, Kimmerling E, Wang S, Ghezzi CE, Kaplan DL. 2.12 Silk Biomaterials ☆. In: Ducheyne P, editor. Comprehensive Biomaterials II. Oxford: Elsevier; 2017. p. 253-78.
2. Rockwood DN, Preda RC, Yucel T, Wang X, Lovett ML, Kaplan DL. Materials fabrication from Bombyx mori silk fibroin. Nat Protoc. 2011;6(10):1612-31. PubMed PMID: 21959241.