Uptake and Release of Double‐Walled Carbon Nanotubes by Mammalian Cells

Abstract

Efforts to develop carbon nanotubes (CNTs) as nano‐vehicles for precise and controlled drug and gene delivery, as well as markers for in vivo biomedical imaging, are currently hampered by uncertainties with regard to their cellular uptake, their fate in the body, and their safety. All of these processes are likely to be affected by the purity of CNT preparation, as well as the size and concentration of CNTs used, parameters that are often poorly controlled in biological experiments. It is demonstrated herein that under the experimental conditions of standard transfection methods, DWNTs are taken up by cultured cells but are then released after 24 h with no discernable stress response. The results support the potential therapeutic use of CNTs in many biomedical settings, such as cancer therapy.

Design of double-walled carbon nanotubes for biomedical applications

“…A strong, locally confined Raman signal was detected within the whole cell, confirming successful DWNT uptake and possible localization within endosomes, as also reported in previous work by our group, which has looked at the intracellular distribution of functionalized DWNTs in greater detail [19,20]. An important factor for the design of DWNTs as a nano-vector is that they do not significantly modify the cell environment, so that perturbations due to the payload can be detected.…”

Drug loading, dispersion stability, and therapeutic efficacy in targeted drug delivery with carbon nanotubes

“…The drug would then translocate to the cell nucleus to exert its cytotoxic action; interference with DNA replication [26]. The exact uptake mechanism and fate of CNTs inside cells is currently further investigated in our laboratory and will be published separately [27,28]. It is important to note that a small amount of doxorubicin has been found to detach from its CNT carrier extracellularly during incubation in cellular growth medium ( Figure 6) and can potentially diffuse through the cell membrane on its own.…”

Properties of Carbon Nanotubes

“…This may have some very positive effects that could be used for biomedical applications [235], but this may also lead to some adverse effects such as toxicity [236]. After describing how the functionalization of CNTs can modify their interactions with biological systems and in particular make them potentially exhibit some (at least partial) biodegradation, we will briefly review both the toxicity issue and the biomedical applications currently in development.…”