Parameters affecting intracellular delivery of molecules using laser-activated carbon nanoparticles.

Previous studies showed that carbon nanoparticles exposed to nanosecond laser pulses cause intracellular uptake of molecules. In this study, prostate cancer cells incubated with carbon-black (CB) nanoparticles and fluorescent marker compounds were exposed to 10ns laser pulses at 1064nm wavelength, after which intracellular uptake was measured by flow cytometry. Calcein and dextran (150kDa) were delivered into >50% of cells, whereas larger dextrans (≤2000kDa) were taken up by ~10% of cells. Under all conditions studied, cell viability loss was minimal. Uptake also increased with increasing laser power, increasing CB nanoparticle concentration, increasing CB nanoparticle size and decreasing laser wavelength. CB nanoparticles enabled uptake better than gold nanoparticles or multi-walled carbon nanotubes under the conditions studied. Proof-of-principle experiments showed intracellular uptake by cells in vivo. We conclude that intracellular uptake of molecules using laser-activated CB nanoparticles provides a promising approach to deliver molecules into cells. FROM THE CLINICAL EDITOR: Delivery of drugs using nanoparticles as carriers is promising. The authors in this study investigated the use of laser-activated carbon nanoparticles to increase the cellular uptake of payloads in various parameters. The positive data generated should provide further platform for a new approach for intracellular delivery of molecules.

Delivery of molecules into cells using carbon nanoparticles activated by femtosecond laser pulses.

A major barrier to drug and gene delivery is crossing the cell's plasma membrane. Physical forces applied to cells via electroporation, ultrasound and laser irradiation generate nanoscale holes in the plasma membrane for direct delivery of drugs into the cytoplasm. Inspired by previous work showing that laser excitation of carbon nanoparticles can drive the carbon-steam reaction to generate highly controlled shock waves, we show that carbon black nanoparticles activated by femtosecond laser pulses can facilitate the delivery of small molecules, proteins and DNA into two types of cells. Our initial results suggest that interaction between the laser energy and carbon black nanoparticles may generate photoacoustic forces by chemical reaction to create transient holes in the membrane for intracellular delivery.