Intraocular Biocompatibility of Gold-Nanoparticles

Intraocular Biocompatibility of Gold-Nanoparticles

Background: The present study is to assess the in vitro biocompatibility of colloidal gold nanoparticles (CGN) and to describe the effect of CGN over the normal electrical activity of the retina on an in vivo rat model.

Material and Methods: Retinal pigment epithelium cells (ARPE- 19) were cultured to confluence. Three wells were incubated with a mixture of CGN conjugated to goat anti-mouse IgG and three were incubated with culture media as a control. After 2 days, media was aspirated and incubated again with 4,5-dimethylthiazol- 2-yl-2,5-diphenyltetrazolium bromide for 2 hrs. The absorbance of each well was measured by spectrophotometry at a 540 nm wavelength, subtracting the background measurement at 670 nm. A total of 16 eyes of eight brown Norway rats were used, being divided in two groups of eight eyes each; Right eyes received an intravitreal injection of 1μM/5μL CGN suspension at baseline. An electroretinogram (ERG) was done at baseline and then again after six weeks. A two-sample t-test was used as statistical method.

Results: Absorbance signal for the CGN Group was 89.06% with respect to the reference values of 100% for untreated controls. There was no statistical difference between groups (p=0.1). The ERG yielded no statistically significant difference between groups at any time point for any of the five steps of the ERG.

Conclusion: The in vitro viability of ARPE-19 cells seems not to be affected by addition of 5 nm CGN to the culture, with no significant morphological changes. The normal electrical activity of the retina seems not be disturbed by the intravitreal injection of CNG.