Magneto-fluorescent superparamagnetic Fe3O4@SiO2@alginate/carbon quantum dots nanohybrid for drug delivery

Magneto-fluorescent nanohybrids are promising candidates for the application in drug delivery systems with simultaneous bioimaging. In this research, Fe3O4@SiO2 superparamagnetic nanoparticles were synthesized through the co-precipitation method to be used as a platform in drug delivery systems. The core/shell nanoparticles were coated with alginate (Fe3O4@SiO2@al). N-doped carbon quantum dots (CQDs) were also synthesized by the hydrothermal method and were used in a nanohybrid with the alginate-coated Fe3O4@SiO2 nanoparticles. The synthesized nanohybrid was used for drug loading and release experiments. Phase analysis, chemical bondings, magnetic properties, drug release characteristics, and particles' size and morphology were studied by XRD, FTIR, VSM, UV–Vis, AFM, TEM, and FESEM techniques, respectively. TEM studies showed the successful synthesis of Fe3O4@SiO2 nanoparticles with a mean particle size of around 20 nm. The Fe3O4@SiO2@al/CQDs nanoparticles showed a saturation magnetization of 42.46 emu/g. The N-doped CQDs have fluorescence emission by excitation in the range of 210–400 nm. The synthesized nanohybrid exhibited 81% drug loading, and a 25% and 38% drug release within 48 h at a pH of 7.4 and 5.5, respectively. The higher rate of drug release in a simulated tumor environment compared to normal tissues makes multifunctional magneto-fluorescent Fe3O4@SiO2@al/CQDs nanohybrid a promising candidate for simultaneous drug delivery and bioimaging.