PROGRAMMING SILK: CUSTOMIZING ITS PROPERTIES

Spider silk is a remarkable natural material, exhibiting an incredible range of strength and elasticity. Silk-weaving spiders can actually choose from a wide array of silks (such as dragline, capture-spiral, and egg cocoon silk), each having its own unique physical profile and genetic origin. However, one thing that’s common to all silk is that their genes are comprised of highly-repetitive modules. By comparing and the contribution of each type of module to the silk fiber’s physical properties, we can begin to understand how to create a collection of silk modules to build our own gene!

By genetically engineering the repetitive modules, and stringing them together in defined orders and ratios, we can customize the physical properties of the resulting silk fibers. Given the diversity that naturally exists across different types of silk, we can potentially assemble a massive library of silk proteins with an impressive range of strength and elasticity for a variety of applications. We plan on optimizing the compatibility of the iterative capped assembly (ICA) technique for the iGEM competition, creating a standardized method of assembling any highly-repetitive gene fragment in an efficient, user-definable manner. Having a library of silk gene blocks to choose from, and an optimized protocol for assembling them, we can optimize the selection and production of programmable silk with customizable properties.

Our platform for synthesizing silk is a scalable, eco-friendly solution to the needs of booming industries such as medicine and fashion. Silk is a popular material for tailoring fine garments, and the ability to modify silk to meet any specification would be an extremely useful tool for textile companies. Silk is also of great interest within the medical field since it does not elicit a strong immune response, and is biodegradable. Consequently, it has been investigated as a material for use in sutures, grafts, and implants. These surgical procedures require materials with very specific properties, and the ability to easily modify silk would transform the medical field.

Working with silk on the genetic level gives us the freedom to modify the properties of silk fibers. But why stop there? What if we could functionalize the silk by fusing it to other genes that encode for fluorescent or therapeutic compounds?