Cucurbituril/hydroxyapatite based nanoparticles for potential use in theranostic applications

We present the engineering of cucurbituril/hydroxyapatite based theranostic nanoparticles with a high aspect ratio and a needle shaped morphology. These particles with varying sizes, surface charges and tunable degradation profiles manifested the advantages of the presence of cucurbituril with respect to drug loading, encapsulation efficacy and release kinetics. In vitro release profiles with two model drugs, Doxorubicin hydrochloride (Dox, hydrophilic) and Nile Red dye (NR, hydrophobic), were evaluated. It was ascertained that hydrophilic Dox was released at a faster rate compared to hydrophobic NR over similar time periods. The concomitant presence of samarium (Sm3+) and CB[7] confers theranostic potential to the synthesized nanoparticles. Cellular toxicity effects systematically assessed using MTT and live/dead assay protocols indicate inappreciable toxicity. The nanoparticles further reveal excellent blood compatibility and cellular internalization properties as visualized by fluorescence microscopy. Particles excited at 300 nm revealed Dox emission in the green channel (470 nm) as well as Sm3+ emission in the red channel (590 nm). These studies unravel the potential of these nanoparticles for effective theranostic applications.