Block Copolymer-Encapsulated CaWO4 Nanoparticles: Synthesis, Formulation, and Characterization

We envision that CaWO4 (CWO) nanocrystals have the potential for use in biomedical imaging and therapy because of the unique ways this material interacts with high-energy radiation. These applications, however, require development of nanoparticle (NP) formulations that are suitable for in vivo applications; primarily, the formulated nanoparticles should be sufficiently small, chemically and biologically inert, and stable against aggregation under physiological conditions. The present study demonstrates one such method of formulation, in which CWO nanoparticles are encapsulated in bioinert block copolymer (BCP) micelles. For this demonstration, we prepared three different CWO nanocrystal samples having different sizes (3, 10, and 70 nm in diameter) and shapes (elongated vs truncated rhombic). Depending on the specific synthesis method used, the as-synthesized CWO NPs contain different surfactant materials (citric acid or cetyltrimethylammonium bromide or a mixture of oleic acid and oleylamine) in the coati...