Preparation of Magnetic Natural Polyelectrolyte-coated Nanoparticles and Their Application to Magnet-Induced Injectable Gels

With an aim to prepare a magnet-induced injectable gel composing of magnetic nanocores with biodegradable polyelectrolytes outside, the magnetite nanoparticles were synthesized by the co-precipitation of ferric chloride and sodium bisulfate under an ultrasonic stir, and the magnetic particles were then encapsulated with layer-by-layer deposition of the opposite charged polymers-alginic acid (AA) (or dextran sulfate, DS) and chitosan (methylated chitosan, MCS or low-molecular-weight chitosan, LMCS) in sequence The composite nanoparticles can be dispersed in water, and are also biocompatible and biodegradable TEM photographs have shown that the nanoparticles can be dispersed in aqueous solution, displaying tens to hundreds nanometers in diameter based on various polymer coating layers. DS and LMCS particles pair showed well dispersion and high absolute value of zeta potentials. Magnetic-induced gel-forming tests showed the gel morphology can be controlled by blending different ratios ofcationic and anionic nanoparticles.