Real-Time QCM-D Monitoring of Deposition of Gold Nanorods on a Supported Lipid Bilayer as a Model Cell Membrane

Abstract

Gold nanorods (GNRs) exhibit promising potentials in therapeutics and diagnostics. A quartz crystal microbalance with dissipation (QCM-D) monitoring was used to study the influence of size and solution chemistry on the deposition of GNRs on a model cell membrane. Supported lipid bilayers (SLBs) comprising zwitterionic 1,2-dioleoyl-snglycero- 3-phosphocholine were used as the model cell membrane. QCM-D results showed that the deposition mass of GNRs on SLBs increased with increasing GNR concentration from 1 to 50 mu M. The GNRs with smaller size exhibited a higher deposition mass in comparison with the larger one when they had a similar zeta potential. Additionally, pH also influenced the deposition behavior of GNRs on SLBs because of the change in their electrostatic interaction. Under neutral pH conditions, the deposition masses of GNRs on SLBs increased with increasing concentrations of NaCl, which is probably attributed to the reduced electrostatic repulsive force. However, the deposition mass of GNRs decreased over a range of CaCl2 concentration from 0.5 to 10 mM. In this case, the GNR aggregation and electrostatic repulsion between GNRs and SLBs may occur due to the charge reversal of SLBs. The deposition kinetic showed that the final deposition mass was positively correlated with the initial deposition rate. Furthermore, a possible mechanism was proposed. This study provides a good understanding of the deposition of GNRs with cell membranes.