Magnet-Like Motion\nof Marine Polysaccharides by Remote\nControl of Chitosan/Fucoidan Nanoparticles for Targeted Movements\nand Manipulation

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