Universal computing by DNA origami robots in a living animal

Biological systems are collections of discrete molecular objects that move around and collide with each other. Cells carry out elaborate processes by precisely controlling these collisions, but developing artificial machines that can interface with and control such interactions remains a significant challenge. DNA is a natural substrate for computing and has been used to implement a diverse set of mathematical problems1-3, logic circuits4-6 and robotics7-9. The molecule also naturally interfaces with living systems, and different forms of DNA-based biocomputing have previously been demonstrated10-13. Here we show that DNA origami14-16 can be used to fabricate nanoscale robots that are capable of dynamically interacting with each other17-18 in a living animal. The interactions generate logical outputs, which are relayed to switch molecular payloads on or off. As a proof-of-principle, we use the system to create architectures that emulate various logic gates (AND, OR, XOR, NAND, NOT, CNOT, and a half adder). Following an ex vivo prototyping phase, we successfully employed the DNA origami robots in living cockroaches (Blaberus discoidalis) to control a molecule that targets the cells of the animal

Novel assembly properties of recombinant spider dragline silk proteins

NMR show the crystalline regions to consist of pleated �-sheets of polyalanine stretches that give strength to the thread [5, 6], and the predominant secondary struc-and Biochemistry ture of the amorphous matrix is the glycine-rich 31-helix, Technische Universität München providing elasticity [7]. Freshly secreted silk proteins are 85747 Garching stored at high concentrations [8] as a liquid crystalline Germany spinning dope [9, 10] that is altered by changes in ionic 2Department of Zoology composition, pH (from pH 6.9 to 6.3) [11, 12], and wate