Size-Dependent Cellular Uptake of DNA Functionalized Gold Nanoparticles.

The extensive use of gold nanoparticles (AuNPs) in nanomedicine, especially for intracellular imaging, photothermal therapy, and drug delivery, has necessitated the study of how functionalized AuNPs engage with living biological interfaces like the mammalian cell. Nanoparticle size, shape, surface charge, and surface functionality can affect the accumulation of functionalized AuNPs in cells. Confocal microscopy, flow cytometry, and inductively coupled plasma mass spectrometry demonstrate that CaSki cells, a human cervical cancer cell line, internalize AuNPs functionalized with hairpin, single stranded, and double stranded DNA differently. Surface charge and DNA conformation are shown to have no effect on the cell-nanoparticle interaction. CaSki cells accumulate small DNA-AuNPs in greater quantities than large DNA-AuNPs, demonstrating that size is the major contributor to cellular uptake properties. These data suggest that DNA-AuNPs can be easily tailored through modulation of size to design functional AuNPs with optimal cellular uptake properties and enhanced performance in nanomedicine applications.