Boron Nitride Nanotubes are Noncytotoxic and can be Functionalized for Interaction with Proteins and Cells

Carbon nanotubes (CNTs) have been widely explored for use in biological applications including biosensing,1 imaging,2 intracellular delivery,3,4 and cancer cell targeting.5 However, their inherent cytotoxicity has imposed limitations on their use as biological probes and in therapeutic composites.6-9 The cytotoxicity of CNTs can be reduced by surface functionalization,5,10-12 but the pos-sibility of in situ desorption brings considerable risk to their use in living organisms. Here we report that boron nitride nanotubes (BNNTs), isosteres of CNTs with unique physical properties, are inherently noncytotoxic. Furthermore, BNNTs can be surface functionalized with biological epitopes that mediate protein and cell binding. Finally, we show that BNNTs can deliver DNA oligomers to the interior of cells with no apparent toxicity. This work suggests that BNNTs may be superior to CNTs for use as biological probes and in biomaterials