Nitinol actuated soft structures towards transnasal drug delivery: a pilot cadaver study Sudden hearing loss can be treated noninvasively by administering drugs to the middle ear (xe2x89x881 ml) via the eustachian tube. The nasopharyngeal cavity requires high dexterity manipulation as it is restricted by the nasal vestibule, and precise drug delivery through the small cavity can allow previously unreachable areas to be reconsidered for localized delivery. Nitinol has shape memory capabilities and can be used for distal actuation accessed from small lumen and a tortuous path. The drug delivery device (DDD) is a soft and needlesized (2 mm) and comprises of Nitinol, ribbon spring, and a drug delivery tube. By controlling the input voltage to the Nitinol, bending of the device at different angles could be achieved, and the ribbon spring works antagonistically to the Nitinol to revert to the initial position once deactivated. The actuation of the device and its corresponding bending are calculated in vitro and found to have a bending angle ranging between 36.2 and 66.8xc2xb0 for applied voltages of 1.2xe2x80x932.0 V, with surface temperature of 45.6xe2x80x93154 xc2xb0C. The DDD is able to actuate 200 cycles with xe2x89x8891xe2x80x9376% retention of bending performance, with a temperature increase of xe2x89x888.5xe2x80x939% when 1.2xe2x80x932.0 V is applied. Addition of soft insulating material shows xe2x89x8834xe2x80x9362% reduction in the surface temperature in the first cycle and xe2x89x8837xe2x80x9359% over 200 cycles when actuated at 1.2xe2x80x932.0 V. The active steering and navigation capabilities of the DDD are demonstrated in simulated environments (based on the eustachian tube dimensions of adult and infant). Preclinical testing in human cadavers is demonstrated and suggests the developed DDD controlled by varying the input voltages for bending, and mechanically varied drug delivery may be a feasible option for localized drug delivery in eustachian tube.

Actuation and stiffening in fluiddriven soft robots using lowmeltingpoint material Soft material robots offer a number of advantages over traditional rigid robots in applications including humanrobot interaction, rehabilitation and surgery. These robots can navigate around obstacles, elongate, squeeze through narrow openings or be squeezed  and they are considered to be inherently safe. The ability to stiffen compliant soft actuators has been achieved by embedding various mechanisms that are generally decoupled from the actuation principle. Miniaturisation becomes challenging due to space limitations which can in turn result in diminution of stiffening effects. Here, we propose to hydraulically actuate soft manipulators with lowmeltingpoint material and, at the same time, be able to switch between a soft and stiff state. Instead of allocating an additional stiffening chamber within the soft robot, one chamber only is used for actuation and stiffening. Low Melting Point Alloy is integrated into the actuation chamber of a singlecompartment soft robotic manipulator and the interfaced robotic syringe pump. Temperature change is enabled through embedded nichrome wires. Our experimental results show higher stiffness factors, from 9xe2x80x9312 opposing the motion of curvature, than those previously found for jamming mechanisms incorporated in separate additional chambers, in the range of 2xe2x80x938 for the same motion.