Designing a quantifiable detection method for the optimization of gold nanoparticle based gene therapy

Gold nanoparticles (GNPs) are becoming an increasingly prominent biomedical tool. GNPs are biocompatible and can carry high payloads and a wide array of biological materials, making them an ideal delivery vector for various therapeutics, such as gene therapy. However, one major obstacle to clinical application is endosomal entrapment and subsequent degradation of the nanoparticle-therapy complex. Coating GNPs with an endosomal escape agent can serve as an effective approach to overcome this challenge. This study explores the probability of different types of coated GNPs to perform endosomal escape. We used a novel, multi-modal approach applying fluorescent confocal microscopy, as well as sophisticated image analysis, to provide a quantitative and uniform method that can denote endosomal escape efficacy. Our findings can ultimately advance understanding of endosomal escape abilities of various GNP coatings and promote their application for gene therapy.