Abstract
Purpose: :
To develop a new efficient method of drug delivery into the subretinal space, the subretinal injection of antibody conjugated gold nanoparticles was studied in a rabbit model.
Methods: :
Gold nanoparticles (about 15 nm of diameter) were created using citrate reduction methods. Goat serum IgG was conjugated with gold nanoparticles electrostatically. The goat IgG conjugated gold nanoparticles were injected into the subretinal space of Dutch-belted pigmented rabbits. As a control, the buffer with the same amount of goat IgG was injected similarly. The animal protocol was approved by IACUC. After the injection, fundus photographs were taken at 1 week, 1 month, 2, and 3 months. Then, the eyes were removed and processed for immunohistochemistry and transmission electron microscopy (TEM). The immunohistochemistry detected localization of the goat IgG in the retina.
Results: :
Fundus photographs showed pigmented changes in the injected area of goat IgG conjugated gold nanoparticles after 1 month. By histology, only a few layers of the outer nuclear layer were remained in the injected area at 1 week after the injection. In the control eyes, mild pigmented changes were observed in the injected area by fundus photography. By histology the similar loss of the outer nuclear layer was observed in the control eyes. By immunohisotochemistry, more positive reactions were detected in the photoreceptor layer of the eyes in which goat IgG conjugated gold nanoparticles were injected than those in which the buffer with goat IgG was injected. By TEM the injected gold nanoparticels were observed in the RPE cells and photoreceptor cells in the injected area.
Conclusions: :
Subretinal delivery of goat IgG was successfully achieved by this method. However, the pigmented changes in the injected area and the rapid disappearance of delivered IgG should be solved.