Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging
Christopher J. Serpell, Reida N. Rutte, Kalotina Geraki, Elzbieta Pach, Markus Martincic, Magdalena Kierkowicz, Sonia De Munari, Kim Wals, Ritu Raj, Belén Ballesteros, Gerard Tobias, Daniel C. Anthony & Benjamin G. Davis. Nature Communications 7, Article number: 13118 (2016). doi:10.1038/ncomms13118
The desire to study biology in situ has been aided by many imaging techniques. Among these, X-ray fluorescence (XRF) mapping permits observation of elemental distributions in a multichannel manner. However, XRF imaging is underused, in part, because of the difficulty in interpreting maps without an underlying cellular ‘blueprint’; this could be supplied using contrast agents. Carbon nanotubes (CNTs) can be filled with a wide range of inorganic materials, and thus can be used as ‘contrast agents’ if biologically absent elements are encapsulated. Here we show that sealed single-walled CNTs filled with lead, barium and even krypton can be produced, and externally decorated with peptides to provide affinity for sub-cellular targets. The agents are able to highlight specific organelles in multiplexed XRF mapping, and are, in principle, a general and versatile tool for this, and other modes of biological imaging.