Ultra soft magnetic drive superelastic robot navigation software for DNA delivery cells confined space
In recent years, small robot shown great potential applications in the biomedical field, such as disease diagnosis, drug delivery and surgery. Such mm to micron-order small-sized robot can move within a limited space, and reaches the deep tissue. Currently, most small robot hard material, usually less than its flexibility, mobility difficulties and irregularities in confined spaces, and its high mechanical strength is likely to cause additional damage to biological tissue. Inspired by nature soft organisms, such as soft caterpillar, octopus and earthworms, scientists have developed software robots to improve the adaptability of the work environment. Electroactive polymer, shape memory material, thermal response and hydrogel elastomer material or the like is used to construct the software robot. Among these materials, because of the hydrogel on adjustable mechanical strength responsiveness and sensitivity to external stimuli received extensive attention. deoxyribonucleic acid (DNA) As life genetic molecules, biological macromolecules is programmable, in recent years new beginning for the manufacture of biological materials, particularly DNA hydrogel material booming ( Progress in Polymer Science , 2019, 101163). DNA hydrogels low mechanical strength (modulus of elasticity is typically less than 1000 Pa), especially suitable for building software robot. 
Recently, School of Chemical Engineering and Technology Professor Yang Dayong Task Force constructed based on DNA software robot DNA hydrogel material [ 123]. The mechanical properties of both software robot super soft super-elastic, the cells can be delivered to the limited space in the driven magnetic navigation. They use rolling circle amplification (RCA) synthetic DNA hydrogels (Figure 1). Between the long-chain DNA is wound to form a dynamic physical crosslinks, DNA-modified magnetic nanoparticles as the permanent crosslinking points together to build a unique dual network hydrogel. This elastic modulus is less than the magnetic DNA hydrogels 1 Pa, the performance of the soft characteristic surplus; 13 times and may be stretched, exhibit elastic properties surplus. Based on the unique properties of the hydrogel, they designed a software robot DNA having a shape adaptive. In the magnetic drive, the DNA may be moved by the robot is smaller than the volume of their narrow passage, it may be irregularly shaped into the groove space, even a complex path to complete the task of running the maze. More importantly, DNA showed a hydrogel comprising a three-dimensional porous structure and good biocompatibility can be used as a three-dimensional cell culture carrier material, in the magnetic navigation driven to deliver cells to the confined space, and does not affect cell activity. The DNA software robot could be used for diagnosis and treatment, implantable biomedical important related fields such as medical devices and minimally invasive surgery.
FIG. 1: DNA Molecular Design Schematic software robot.