Optimisation of Dyes@SWCNT Raman Nanoprobes

Abstract

Single-Walled Carbon Nanotubes (SCWNTs) have attracted a lot of attention in biomedical fields. Their easily functionalised surface and ability to encapsulate different materials make them interesting not only for imaging, but also for other applications, such as drug delivery and cell targeting. This work concerns specifically the use of SWCNTs to fabricate Raman nanoprobes for bio-imaging. These nanoprobes are composed of dyes encapsulated inside the SWCNTs and the nanotubes are grafted with anti-bodies functionalized on the outer surface.First, we aim to optimize the encapsulation process so that the dye/SWCNTs nanohybrid gives a strong, uniform and reproductible signal that is easily detectable by Raman imaging. This is done by varying the parameters of the liquid-phase encapsulation process and crosschecking the results by Raman imaging. We also work to optimize the stability of the nanohybrid in biological media. This parameter is important to determine the best conditions for antibody attachment and cell/tissue interactions. Using different biological buffers, we study the dispersion of the assemblies with Dynamic Light Scattering (DLS) and their stability with Electrophoretic Light Scattering (ELS). The results of the analysis on the nanohybrids show an average hydrodynamic radius of 160 nm and a Zeta potential at -45 mV in aqueous media, proving that the stability of the short nanohybrids in water is favourable to the development of nanoprobes.