Berlin 2008 – scientific programme
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BP: Fachverband Biologische Physik
BP 9: Membranes and Interfaces
BP 9.2: Talk
Tuesday, February 26, 2008, 10:45–11:00, PC 203
Local Heating of Phospholipid Bilayers with Gold Nanoparticles — •Alexander S. Urban1, Margaret R. Horton2, Srujan K. Dondapati1, Tapan K. Sau1, Thomas A. Klar1, Joachim O. Rädler2, and Jochen Feldmann1 — 1Photonics and Optoelectronics Group, Ludwig-Maximilians-Universität München — 2Soft Condensed Matter Group , Ludwig-Maximilians-Universität München
We examine the possibility of increasing the membrane permeability for drugs and large bio-molecules by exploiting light-induced local heating of phospholipid bilayers containing gold nanoparticles. Giant unilamellar vesicles (GUVs) provide model systems for cellular membranes. They were prepared from 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine via the electroformation method. Nanoparticles were made in various shapes (rods, spheres, cubes), sizes (20-100 nm) and with different surfactants, the latter playing an important role in the vesicle adhesion efficiency. Cetyl trimethylammonium bromide forms bilayers around the gold and was readily incorporated into GUV membranes. Too high a concentration of gold nanoparticles resulted in vesicle rupture due to osmotic stress. Furthermore, we investigated the heating of the GUV-gold complexes by illumination with laser light near the plasmon resonance. Increasing the laser intensity led to rupturing of the bilayers. The intensity required for rupture was highly dependent on nanoparticle size and the number of gold nanoparticles in close proximity. This model system is also being used to quantitatively study the transport of biologically active molecules across the lipid membrane through specific and local cell heating.