Self-assembled rosette nanotubes encapsulate and slowly release dexamethasone

Rosette nanotubes (RNTs) are novel, self-assembled, biomimetic, synthetic drug delivery materials suitable for numerous medical applications. Because of their amphiphilic character and hollow architecture, RNTs can be used to encapsulate and deliver hydrophobic drugs otherwise difficult to deliver in biological systems. Another advantage of using RNTs for drug delivery is their biocompatibility, low cytotoxicity, and their ability to engender a favorable, biologically-inspired environment for cell adhesion and growth. In this study, a method to incorporate dexamethasone (DEX, an inflammatory and a bone growth promoting steroid) into RNTs was developed. The drug-loaded RNTs were characterized using diffusion ordered nuclear magnetic resonance spectroscopy (DOSY NMR) and UV-Vis spectroscopy. Results showed for the first time that DEX can be easily and quickly encapsulated into RNTs and released to promote osteoblast (bone-forming cell) functions over long periods of time. As a result, RNTs are presented as a novel material for the targeted delivery of hydrophobic drugs otherwise difficult to deliver.