Because it contains a very high diversity of proteins, natural cuticle also occurs in different thicknesses and degrees of rigidity or flexibility, depending on where it occurs in the insect's body. The researchers found that, by controlling water content during fabrication of Shrilk, they could reproduce these wide variations in stiffness of natural insect cuticle, resulting in a range of materials from highly elastic to highly rigid.
The chitin component of natural cuticle can be difficult to work with because of its low solubility. Chitosan, a more soluble, highly deacetylated form of chitin, is already approved for use in wound dressings by the US Food and Drug Administration. Fibroin from silk is also widely used in surgical sutures. This combination of attributes, in addition to its biocompatibility, means that applications for Shrilk could include suturing wounds that must bear high loads, such as for hernia repair, or as a scaffold for tissue regeneration. Other applications as a cheap, environmentally safe alternative to plastic include packaging that degrades quickly. The fact that the new material is as tough and strong as aluminum suggests that it might have applications in industrial or transportation applications as well.
Chitosan/silk combinations have been attempted before for medical applications that require both high strength and biocompatibility, but the strength of the combined materials was disappointing. One possibility for this is the fact that previous combinations were disorganized conglomerates that did not reproduce the laminar structure of chitin and protein layers found in natural insect cuticle.