Affecting over 10 million people worldwide, corneal scarring and fibrosis due to trauma or surgery is the second leading cause of blindness after glaucoma. As a result of scarring or fibrosis, corneal haze clouds the endothelium of the tissue, decreasing transparency necessary for proper function of the eye. Polyethylenimine-Conjugated Gold Nanoparticles (PEI2-GNPs) offer a new mode of delivery in gene therapy to promote wound healing and reduce corneal haze . The gene therapy introduces BMP7, a protein coding gene that functions to promote epithelial cell growth in the stroma. Branched polyethylenimine (PEI2) is conjugated (bonded at the p orbitals with alternating double and single bonds) to gold nanoparticles to aid in the transfection of the plasmid DNA expressing the gene BMP7 during recombination . The use of gold nanoparticles as a gene delivery vector is advantageous due to its properties of stability, non-immunogenicity, high surface area for plasmid application, and nontoxicity.
PEI2-GNPs function as a stable and controlled administrator of BMP7 to promote wound healing of corneal scarring and fibrosis in lateral gene transfer. The gold nanoparticles offer a non-toxic delivery vector that can be regulated through passive, photothermal, or targeted distribution of a gene.
This approach poses fewer risks concerning cytotoxicity and unpredictable immune responses as compared to virus based delivery. By administering genes, biomolecules, or drugs through nanoparticles, delivery can be targeted by specific ligands, diffused to a specified section of tissues, or activated when exposed to light radiation. Gold nanoparticles with diameters of over 50nm have also shown to promote the tissue’s faster internalization of biomolecules. The high bioavailability of gold nanoparticles makes them an effective and viable source of vector delivery in gene therapy.
In the activation of BMP7 the proteins pSmad-1/5/8 are increased in concentration as well as the inhibitory protein Smad6. The effect of the suppression of TGFβ, a key protein in regulating cellular function, due to an increased Smad6 proteins has yet to be explored with regards to cell differentiation and proliferation.