Purpose  Calcium phosphate nanoparticles (CaP-NPs) are an ideal tool for transfection due to their outstanding biocompatibility and easy degradability. After transfection, the particles dissolve into calcium and phosphate, and it has been shown that the light increase of intracellular Ca²⁺-levels does not affect cell viability . The aim of this study was to compare the transfection efficiency of different CaP-based NPs in corneal endothelial cells.
Methods  CaP-NPs functionalized with pcDNA3-EGFP (triple-shell, CaP/DNA/CaP/DNA) and stabilized by different amounts of poly(ethylenimine) (PEI) were prepared. Polyfect^®-pcDNA3-EGFP-complexes served as positive control. The transfection of human and murine corneal endothelial cells (suspensions and donor tissue) was optimized by varying the concentrations of CaP-NPs and duration of transfection. The transfection efficiency was analyzed by EGFP-expression detected by flow cytometry and fluorescence microscopy. To evaluate the toxicity of the system, the cell vitality was detected by TUNEL staining.
Results  Coating with PEI significantly increased the transfection efficiency of CaP-NPs,EGFP expression increased up to 50% in corneal endothelial cells. The EGFP expression in tissues remained considerably stable as corneal endothelial cells exhibit minimal proliferative capacity and very low apoptosis transfected with CaP-NPs.
Conclusions  CaP-NPs are suitable tools for the transfection of corneal endothelial cells, the transfection efficiency significantly increased once the NPs are coated with PEI. With CaP-NPs merely inducing little apoptosis, they may offer an alternative to viral vectors which is not safe for patient use.