Hybrid Magnetic Polymer Nanoparticle Synthesis

Hybrid magnetic polymer nanoparticles were synthesized by the “oil-in-water” microemulsion method followed by solvent evaporation based on the method previously described by us with modifications [40 (link),41 (link),42 (link)]. A total of 12 mg PLGA (RG 858 S, lactide/glycolide 85:15, MW 190–240 kDa, Sigma, Darmstadt, Germany), 100 µL of oleate-stabilized magnetite, and 250 µg IR775 (Sigma, Darmstadt, Germany) in 300 µL of dichloromethane were added to 3 mL of 3% aqueous PVA (Mowiol 4-88, Sigma, Darmstadt, Germany) supplemented with chitosan oligosaccharide lactate with a final concentration of 1 g/L (5 kDa, Sigma, Darmstadt, Germany). The mixture was treated with ultrasound for 1 min. After solvent evaporation, the particles were washed thrice with centrifugation for 5 min at 5000× g and finally resuspended in 10 mM HEPES (pH 7.0).