Dean of Engineering Brown University Providence, Rhode Island, United States
Introduction: Nanoparticles with targeting ability hold promise in payload delivery to target cells with reduced off-target side effects. Optimal interaction between targeting ligand and cell receptor reciprocates in maximum cellular internalization. Targeting ligand density and presentation on the nanoparticle surface often holds the key to the said optimal interaction. However, control in targeting ligand design parameters on nanoparticle surfaces presents a significant challenge, considering most of the existing nanoparticle fabrication methodologies. Here, we evaluated how the density and presentation of targeting ligands dictate the cellular uptake of nanoparticles. To do so, we used a DNA scaffolded PLGA nanoparticle system to achieve efficient and tunable ligand conjugation.
Materials and
Methods: We have designed a DNA scaffolded nanoparticle decorated with the small molecule ACUPA on the surface through complementary DNA hybridization. The particles are designed to utilize the high specificity of ACUPA targeting the prostate-specific membrane antigen (PSMA). Our DNA-scaffolded nanoparticle fabrication strategy provides a controlled method to manage the density and presentation style of targeting ligands. The density and presentation of PSMA targeting ligand ACUPA was precisely tuned on the DNA scaffolded nanoparticle surface and their impact on cellular uptake was evaluated.
Results, Conclusions, and Discussions: Our data shows that matching the number of the targeting ligands (ACUPA) and the number of surface receptors (PSMA), occupying the same surface area, on a prostate cancer cell line is critical for maximum uptake. Furthermore, DNA hybridization mediated targeting chain rigidity of the DNA scaffolded nanoparticle offered ~3 times higher cellular uptake compared to ACUPA-terminated PLGA nanoparticle. Our findings also indicated a ~3.7-fold reduction in the cellular uptake for the DNA hybridization of the non-targeting chain. We showed that nanoparticle uptake is energy-dependent and follows a clathrin-mediated pathway. Finally, we validated the preferential tumor targeting of the nanoparticles in a bilateral tumor xenograft model. Our work reveals that maximum uptake requires rigid presentation of the targeting strands that are surrounded by flexible non-targeting strands. Those properties are important for maximizing the interaction between the targeting ligand and the receptor and subsequently minimize the overall energy upon such interaction. Overall, the presented data supports the further utilization of our DNA scaffolded nanoparticles as a platform that provides precise surface control of the number, and the presentation style of different targeting ligands that can be used for various therapeutic applications. The knowledge of cell receptor density can be translatable into corresponding targeting nanoparticles with precise control in design through this strategy. This controlled strategy can effectively be generalized for efficient targeting of immune cells for potential remedies to diseases beyond cancer. We believe that this study would be of great interest to investigators and practitioners in nanomedicine, materials science, biomedical engineering, and nanotechnology.
Acknowledgements (Optional): We acknowledge financial support from F. Hoffmann-La Roche AG (MBTDSIO44) and the Helen Diller Family Comprehensive Cancer Center Support Grant of the National Institutes of Health (P30CA82103).
