Real-Time Near-Infrared Confocal Imaging of Bacterial Cell Division in the Presence of Single-Walled Carbon Nanotubes

Abstract

The chemical and optical properties of single-walled carbon nanotubes (SWCNTs) have inspired the development of a plethora of different applications in the field of cell nanobiotechnology. However, most studies to date have focused on interfacing SWCNTs with cells of eukaryotic organisms. The work herein presented introduces a first comprehensive study focusing on the interaction of fluorescent SWCNTs with bacterial cells. We established wrappings that facilitate nanoparticle uptake over the bacterial cell wall, which represents a first important step towards the expansion of nanomaterials’ application in the broad field of microbiology. We employed a custom-built, spinning disc confocal microscope to image near-infrared (NIR) SWCNT fluorescence within the cells. By performing in situ cell growth and nanoparticle tracking we investigated the fate of internalized SWCNTs upon multiple cell division events. Real-time monitoring of cell growth revealed that the indefinitely photostable NIR fluorescence is inherited by daughter cells. The imparted NIR fluorescence thus offers an unprecedented avenue for quantitative and continuous imaging of nanobioengineered cells across multiple generations. Above and beyond bacterial nanobionics, this technique creates new opportunities for imaging subcellular targeting and trafficking of NIR-fluorescent probes in the field of drug delivery and biosensing.