Tunable and Regenerative DNA Zipper Based Spring

Abstract

We report a DNA zipper based actuator device termed ‘DNA- spring’ with tunable and repeated cycles of extension and contraction ability. DNA zipper is a double-stranded DNA system engineered to open upon its specific interaction with appropriately designed single strand DNA (ssDNA), opening of the zipper is driven by binding energy differences between the DNA strands. The zipper system is incorporated with defined modifications to function like a spring, capable of delivering ∼9 pN force over a distance of ∼13 nm, producing ∼116 kJ/mol of work. The spring described here consists of four DNA oligonucleotides totaling 244 bases that utilize ssDNA to trigger its extension and contraction. Time-lapse fluorescence and fluorescent DNA gel electrophoresis analysis is utilized to evaluate and confirm the spring action. A second zipper incorporated into the spring provides the ability to couple/decouple to an object/substrate. Such devices would have wide application, including for conditionally triggered molecular delivery systems and as actuators in nano-devices.