Shape memory thin film actuator for holding a fine blood vessel

In this paper, we describe a shape memory alloy (SMA) thin film actuator which can hold a fine blood vessel for a pulsation monitor. The device has a function of two-step actuation with integrated micro-heaters which can heat up the SMA locally. The TiNiCu ternary SMA thin film was deposited onto a sacrificial copper substrate by flash evaporation method. Phase transformation temperatures can be controlled to be higher than human body temperature for secure actuation by timed operation of a shutter during flash evaporation of a series of pellets. The actuator holds the vessel securely by the first actuation, and allows continuous monitoring after microsurgery. After using, it can release the blood vessel easily by the second actuation and is removed completely without any additional surgical invasions. The micro-heaters can heat up the SMA actuator over 65 °C locally within 10 s when it was heated by an electric current of 10 mA.