Polydopamine Nanoparticle‐Sensitized Photoporation Delivers Macromolecules in Monocytes and Macrophages with Minimal Impact on Cell Homeostasis

Pivotal in inflammation and tissue homeostasis, monocytes and macrophages have become attractive therapeutic targets for modulating the tumor microenvironment. Enhancing their potency often requires genetic modification. This is traditionally achieved using viral transduction, but vector development is expensive, and safety concerns hinder its clinical implementation. Photoporation is an emerging alternative non-viral delivery method that is based on laser irradiation of sensitizing nanoparticles. The resulting photothermal effects induce transient membrane permeabilization, allowing the influx of external molecules into the cell. In this study, the applicability of polydopamine nanoparticle (PDNP)-sensitized photoporation to monocyte and macrophage cell lines for the delivery of model macromolecules (FITC-dextran 500 kDa and eGFP-mRNA), with physicochemical properties resembling those of clinically relevant macromolecules, is investigated. Moreover, a direct comparison is made to a state-of-the-art electroporation platform. Several PDNP sizes, PDNP concentrations, and laser fluences are tested to identify optimal delivery conditions. Once optimized, it is found that, for similar transfection yields, neither technique strongly affects canonical cell surface markers and secreted cytokines. However, unlike photoporation, electroporation affects cell proliferation and morphology considerably. Thus, these findings confirm that PDNP-sensitized photoporation is a gentle intracellular delivery technology for monocytes and macrophages, making it a promising approach for therapeutic applications.