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Renewable and degradable materials, formed using biopolymers as material precursors, are sought after in pharmaceutical, biomedical, and industrial fields. Silk-based biomaterials, primarily derived from the silk fibroin protein of the Bombyx mori (B. mori) silkworm, have advantageous mechanical properties, biocompatibility, and commercial availability. Recent efforts aim to expand the range of achievable silk-based biomaterial properties via alternative sources of silk proteins with different sequences and structures. These structural distinctions drive differences in physical and chemical properties of silk fibers, primarily due to the varying degree of crystallinity in the polymers. For the development of alternative silk-based materials, silk from Plodia interpunctella (P. interpunctella), a small agricultural pest that infests and damages food products via silk production, is evaluated. Early investigations have highlighted differences between P. interpunctella and B. mori silk fibroin proteins, however P. interpunctella silk still largely lacks characterization and optimization on both the silk fiber and bulk material level. This work evaluates the structural, thermal, mechanical, and cell-material properties of non-degummed and degummed P. interpunctella silk as a raw material for biomaterial fabrication and discusses the benefits and limitations of these proteins as new biopolymers. Observed properties are used to identify links between silk fibroin protein sequence and fiber function in addition to forming hypotheses in how P. interpunctella silk-based biomaterials will perform in comparison to other natural biopolymers. Future work aims to develop methods to process P. interpunctella silk into material formats, utilizing the material characteristics determined here as a baseline for shifts in material performance. 

Silk fibers are produced by a wide variety of insects. The silkworm Bombyx mori (Bombyx) was domesticated because the physical properties of its silk fibers were amenable to the production of fine textiles. Subsequently, engineers have regenerated silk fibroin to form biomaterials. The monocular focus on Bombyx silk has underutilized the expanse of diverse silk proteins produced by more than 100,000 other arthropods. This vast array of silk fibers could be utilized for biomedical engineering challenges if sufficient rearing and purification processes are developed. Herein, we show that the moth, Plodia interpunctella (Plodia), represents an alternative silk source that is easily reared in highly regulated culture environments allowing for greater consistency in the silk produced. We controlled the temperature, resource availability (larvae/gram diet), and population density (larvae/mL) with the goal of increasing silk fiber production and improving homogeneity in Plodia silk proteins. We determined that higher temperatures accelerated insect growth and reduced life cycle length. Furthermore, we established initial protocols for the production of Plodia silk with optimal silk production occurring at 24 °C, with a resource availability of 10 larvae/gram and a population density of 0.72 larvae/mL. Population density was shown to be the most prominent driving force of Plodia silk mat formation among the three parameters assessed. Future work will need to link gene expression, protein production and purification, and resulting mechanical properties as a function of environmental cues to further transition Plodia silk into regenerated silk fibroin biomaterials.