Nanographene oxide as a switch for CW/pulsed NIR laser triggered drug release from liposomes

- Nanographene oxide (nGO) with ~ 40 nm was integrated into the large size (~ 800 nm) liposomes
- nGOs could act as a light activable switch to trigger the drug release from liposomes
- NIR light triggered, on-demand drug release from nGO-liposomes was achieved by a femtosecond pulsed laser and/or continuous wave (CW) laser
- Femtosecond pulsed laser irradiation resulted in larger drug release compared to CW laser irradiation

The application of pulsed and continuous wave (CW) lasers in nanomedicine has increased significantly over the last decade. Near infrared (NIR) lasers can be used for the precise control of drug release at the target site in a non-invasive manner. In this study, we have prepared nanographene oxide (nGO, size ~ 40 nm) integrated liposomes (size ~ 900 nm). The nGOs were not simply adsorbed onto the liposome surface but was embedded inside the liposomes as characterized by cryo-TEM, selected area electron diffraction (SAED), and fluorescence quenching studies. The embedded nGOs could act as a molecular switch for NIR light controlled drug release from the liposomes. Calcein was encapsulated into the liposome as a model drug to evaluate the efficiency of light controlled release. An on-demand pulsatile drug release was achieved by irradiation of CW/pulsed NIR lasers into the nGO-liposome suspension. Triggering with a pulsed laser resulted in larger release of calcein with a minimal temperature increase (~ 2 °C) of the liposome solution, compared to lower release rate and a significant temperature increase (~ 8 °C) by a CW laser with the same light energy, suggesting two separate mechanisms and different potential applications depending on the laser type.

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