Soft actuators are ideal candidates for wearable biomedical devices, their inherent compliance, robustness, lightweight and the possibility to be washable take advantage over rigid actuators. Thus, a soft pneumatic fabric-polymer bending actuator as a base component for a robotic device for lymphedema treatment is reported in this work. The actuator is composed of two mechanical elements, one made of fabric and the other one made of a hyperelastic polymer which is stuck on the fabric element. The fabric element is designed and fabricated with a curved shape longer than the polymer element, that is a hyperelastic beam. To assemble both elements, the fabric element was folded before sticking in order to match the length of the polymer beam. Once the air is pumped into the fabric, it bends towards its original curved shape. Once the air is removed, the hyperelastic beam allows the actuator to recover its initial position. This actuator is capable of exerting compression and lateral force on a human arm mimicking manual lymphatic drainage. A mathematical model is presented which is in good agreement with the experimental data, it could serve to predict the actuator motion. An end-tip free bending displacement of about 2.2 cm and a bending force of about 0.35 N were achieved at 12.5 kPa. A proof-of-concept system for lymphedema treatment is presented as well.

In this paper, a closed-loop strategy for controlling the transient regime of Marangoni flows and thus to selectively manipulate and separate micro-particles is reported. Marangoni flows were generated by an infrared laser as a heat source. Simulations of the transient regime of Marangoni flows were performed with COMSOL Multiphysics to analyze the temperature field and velocity profile. The convection cell dynamic growth was controlled with the laser beam exposure time. Then, selected particles, glass beads ranging from 150 up to 212 μm, were dragged by small convection flows without reaching undesired particles. The closed-loop control improved the manipulation speed and precision in comparison to manual manipulation.

Laser induced convection flows is a new and promising method to achieve better manipulation of mesoscale objects (above 1 mum and below 500 mum) in a liquid medium. The temperature gradient created by laser absorption generates natural and thermocapillary (or Marangoni) convection flows. These flows are used to perform the manipulation itself. In this paper, we demonstrate for the first time that large and heavy particles can be dragged using the Marangoni convection flows. Experiments based on these phenomena show that fast and accurate underwater micromanipulation of particles up to 280 mum is possible using only a convergent 1480 nm laser beam.