| AVS 54th International Symposium | |
| Biomaterial Interfaces | Thursday Sessions |
| Session BI-ThP |
| Session: | Biomaterial Interfaces Poster Session |
| Presenter: | N. Farkas, National Institute of Standards and Technology |
| Authors: | N. Farkas, National Institute of Standards and Technology J.A. Dagata, National Institute of Standards and Technology K.F. Pirollo, Georgetown University Medical Center E.H. Chang, Georgetown University Medical Center |
| Correspondent: | Click to Email |
Colloidal systems composed of nanoparticles must be charge stabilized in order to prevent aggregation. In many applications of nanotechnology it is necessary to immobilize nanoparticles intact and dispersed on a substrate so that high-resolution imaging and characterization can be carried out. An essential first step in sample preparation therefore involves appropriately matching the zeta potential of nanoparticles in solution to the zeta potential of the substrate surface and adjusting the pH and ionic strength of the solution environment. Here we report a method for preparing patterned substrates with regions of optimally tuned surface zeta potential by combining fluid scanning probe microscopy and a recently reported surface zeta potential apparatus [P. J. Sides et al., Langmuir 22 (2006) 9765]. Specifically, we vary the zeta potential of a poly-L-lysine substrate over a range of approximately -60 mV < ζ < + 100 mV by exposure to UV/ozone and control nanoparticle adsorption from effectively zero to full monolayer coverage. Exposure through a mask produces local regions with positive and negative surface charge resulting in selective adsorption of nanoparticles. We demonstrate attachment, followed by particle size distribution, and zeta potential measurements, for hard and soft nanoparticles including 10- to 80-nm diameter gold nanoparticles and 30- to 80-nm diameter liposomes.