A facile aqueous production of bisphosphonated-polyelectrolyte functionalized magnetite nanoparticles for pH-specific targeting of acidic-bone cells

Bone malignancy treatment is being hindered due to the insufficient selectivity of therapeutic nanoparticles towards malignant bone sites. Polyelectrolyte functionalized magnetic nanoparticles having dually specific pH-sensing ability and bisphosphonate moieties, can be an effective solution for selective targeting of bone malignancies. First, polyelectrolyte was prepared via N-carboxycitraconyzation of chitosan (NCCS) followed by successive functionalization with alendronic acid (AL) and fluorescein isothiocyanate (FITC). Then, Fe3O4-NCCS-FITC-AL nanoparticles were synthesized by a facile one-step microwave-assisted aqueous method via in situ surface functionalization. The formation, crystal structure, and surface conjugation of Fe3O4 nanoparticles with polyelectrolytic stabilizer were confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analyses. Synthesized Fe3O4-NCCS-FITC-AL nanoparticles were superparamagnetic, colloidally stable and highly hemocompatible under physiological conditions. Moreover, at pH 5.0, Fe3O4-NCCS-FITC-AL nanoparticles formed a precipitate due to inversion of their surface charge. This pH-dependent charge-inversion drastically changed the interactions with erythrocytes and bones. Selective membranolysis of erythrocytes occurred at pH 5.0. The designed nanoparticles showed enough potential for selective targeting of pathological bone sites in early-stage magnetofluorescent imaging and as a therapeutics carrier to treat malignant bone diseases.

Automated summary

Bone malignancy treatment can benefit from the use of functionalized magnetic nanoparticles with pH-sensing ability and bisphosphonate moieties. Researchers have successfully synthesized Fe3O4-NCCS-FITC-AL nanoparticles that are superparamagnetic, colloidally stable, and compatible with blood. These nanoparticles exhibit selective membranolysis of erythrocytes at pH 5.0, making them a potential tool for targeted imaging and therapy of malignant bone diseases.