Designing DNA Origami for Force-mediated Release of Molecular Cargo

Iowa State University, Ames IA

Investigators

Abstract

This award to Iowa State University is supporting research that will design, build and test a nanosized container made using a technique called DNA origami. This nanosized container can release molecules in response to small forces exerted within tissues. Forces play an important role in biology. During tissue development and disease, cells exert forces on the extracellular matrix (ECM), the protein web that surrounds cells. These forces both create tissue structure and communicate information to other cells. Small forces occurring during tissue injury can damage the ECM. The project will connect the nanosized container to the ECM through specific DNA sequences that bind to strands of the protein web that constitute the ECM. These DNA sequences will connect both the container lid and container edge to the ECM through a mechanical lock. When forces are exerted on strands of the web, this mechanical lock will open and molecules in the DNA origami container will leak out, conveying a signal to surrounding cells. The DNA origami container can be filled with a wide array of different molecules that can instruct cells in the vicinity to perform certain functions. Both graduate and undergraduate students will be trained in the engineering design rules associated with creating nanosized DNA structures. In order to enhance public knowledge in the area of DNA nanotechnology, demonstrations and hands-on activities based on fundamental principles of DNA origami design will be created to transmit this understanding to audiences of a variety of ages. Thia project seeks to support research that will develop a mechanically actuatable DNA origami structure that is able to release molecular cargo in response to cellular level forces exerted on the ECM. Tasks in these studies are to: 1) select ECM binding aptamers that are uniquely sensitive to ECM fibril structure and composition, 2) uncover the design constraints of force-mediated rupture of aptamer-linked DNA sequences and 3) build DNA origami boxes and characterize force-mediated cargo release. This work is built upon novel strategies to select for DNA aptamers that bind fibrillar ECM proteins with high affinity. DNA aptamers provide the ability to mechanically link the DNA origami to the ECM. Furthermore, these DNA aptamers are extensions of double-stranded DNA origami locks containing complementary DNA sequences that rupture at defined forces depending on the specific application. Mechanically inducible molecular cargo release will be useful in numerous applications including drug delivery during fibrosis progression, injury during mechanical lung ventilation used to treat respiratory illness or decompression sickness. Furthermore, mechanically inducible molecular cargo release will allow for the control of tissue engineered systems including organoid systems where cell contractile forces are exerted and communicate signals important to tissue structure and function. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.