Titanium dioxide (TiO2) nanoparticles have shown success as photosensitizers in the form of light-based cancer therapy called Cerenkov radiation induced therapy (CRIT). While TiO2 nanoparticles have been reported to be an effective therapeutic agent, there has been little work to control their functionalization and stability in aqueous suspension. In this work, the controlled coating of 25 nm diameter TiO2 nanoparticles with the glycoprotein transferrin (Tf) for application in CRIT was demonstrated using an electrospray system. Monodisperse nanoscale droplets containing TiO2 and Tf were dried during flight, coating the proteins on the surface of the metal oxide nanoparticles. Real-time scanning mobility particle sizing, dynamic light scattering, and transmission electron microscopy show efficient control of the Tf coating thickness when varying the droplet size and the ratio of Tf to TiO2 in the electrospray precursor suspension. Further, the functionality of Tf-coated TiO2 nanoparticles was demonstrated, and these particles were found to have enhanced targeting activity of Tf to the Tf receptor after electrospray processing. The electrospray-coated Tf/TiO2 particles were also found to be more effective at killing the multiple myeloma cell line MM1.S than that of nanoparticles prepared by other reported functionalization methods. In summary, this investigation not only provides a single-step functionalization technique for nanomaterials used in Cerenkov radiation induced therapy but also elucidates an electrospray coating technique for nanomaterials that can be used for a wide range of drug design and delivery purposes.
Keywords: Cerenkov radiation induced therapy; electrospray; functionalization; multiple myeloma; titanium dioxide; transferrin.