Photoporation Using Carbon Nanotubes for Intracellular Delivery of Molecules and Its Relationship to Photoacoustic Pressure

Abstract

Exposure of carbon-black (CB) nanoparticles to near-infrared nanosecond-pulsed laser energy can cause efficient intracellular delivery of molecules by photoporation. Here, cellular bioeffects of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) are compared to those of CB nanoparticles. In DU145 prostate-cancer cells, photoporation using CB nanoparticles transitions from (i) cells with molecular uptake to (ii) nonviable cells to (iii) fragmented cells with increasing laser fluence, as seen previously. In contrast, photoporation with MWCNTs causes uptake and, at higher fluence, fragmentation, but does not generate nonviable cells, and SWCNTs show little evidence of bioeffects, except at extreme laser conditions, which generate nonviable cells and fragmentation, but no significant uptake. These different behaviors cannot be explained by photoacoustic pressure output from the particles. All particle types emit a single, ≈100 ns, mostly positive-pressure pulse that increases in amplitude with laser fluence. Different particle types emit different peak pressures, which are highest for SWCNTs, followed by CB nanoparticles and then MWCNTs, which does not correlate with cellular bioeffects between different particle types. This study concludes that cellular bioeffects depend strongly on the type of carbon nanoparticle used during photoporation and that photoacoustic pressure is unlikely to play a direct mechanistic role in the observed bioeffects.

Serum Protects Cells and Increases Intracellular Delivery of Molecules by Nanoparticle-Mediated Photoporation

“…However, the uptake generally increases, peaks and then falls as the parameters are varied, because viability loss sets in at more aggressive conditions. 11 , 13 , 14 , 18 , 59 This trend in the prior literature is consistent with the findings in the present study after photoporation without serum or other additives (eg, Figure 1 , with no FBS). However, when we included protein and polymer additives in this study, we saw a different result: increasing laser fluence increased uptake, which then plateaued without decreasing at more aggressive conditions because viability loss did not set in.…”

“…Previous studies had shown no difference between the effects of photoporation on uptake or viability by adding CB nanoparticles immediately before laser exposure or adding the CB nanoparticles many hours earlier. 14 This indicates that the FBS’ ability to change bio-effects should be unrelated to endocytosis of CB nanoparticles by cells. Other studies examining damaging effects of agitated and aerated bioreactors showed FBS concentration–dependent viability protection and faster growth of mammalian cells.…”

“… 11–13 Additional nanoparticle materials such as nanotubes, gold and others have also been used in the context of photothermal ablation, imaging and drug delivery, however with varied efficiencies. 14–16 …”

Vapor nanobubble-mediated photoporation constitutes a versatile intracellular delivery technology

“…Although not proven, membrane disruption and intracellular delivery was attributed to bubble formation following the carbon-steam reaction. In a recent study from the Prausnitz group, carbon nanotubes (single-walled and multi-walled) were evaluated as nanosensitizers of which it was noticed that they had a different photoporation behavior compared to the previously studied carbon black NPs [39]. With increasing laser fluence, intracellular delivery, cell toxicity and cell fragmentation increased for carbon black NPs.…”