Magnet-Like Motion of Marine Polysaccharides by Remote Control of Chitosan/Fucoidan Nanoparticles for Targeted Movements and Manipulation

The controllable motion of materials in response to external stimuli has profoundly impacted various applications such as robots, sensors, self-adaptive devices, and targeted therapy. However, remote control of unmodified materials by external signals is still rare. In this work, the controlled motion of marine polysaccharides in tetrachloromethane is found when fingers wearing nitrile gloves touch on or move around the plastic tube, similar to magnet field-driven iron powders. The effects of several key parameters on the magnet-like motion of chitosan are investigated, including solvents, concentrations, molecular weight, and containers. By adjusting these parameters, the formation and degree of magnet-like motion can be significantly tuned. In addition to chitosan, the controllable motion of fucoidan and the chitosan/fucoidan mixture is also detected. Further investigation sheds light on the mechanism of this motion, which is proven to be the force of static electricity. Based on this, chitosan/fucoidan nanoparticles are successfully prepared and manipulated by remote control. Thus, this work offers a facile approach for obtaining controllable motion of marine polysaccharides, opening doors to precise manipulation of nonmagnetic nanomaterials by remote control and holding great potential in nanomedicine, sensors, robotics, etc.