Detailed Profiling of Protein Corona Formed by Polydopamine Nanoparticles in Human Plasma

The term protein corona (PC) indicates proteins adsorbed onto the surface of nanostructures exposed to biological media such as blood or serum. The analysis of the composition, evolution, and effect of the PC complexed with nanomaterials gained attention in recent years due to the importance of these parameters in determining the biological fate of nanostructures. In particular, the PC represents the first component of a nanomaterial interfacing with biological structures, dictating parameters such as nanoparticle internalization, immune response, bioavailability, and even toxicity. Polydopamine nanoparticles (PDNPs), obtained through the polymerization of dopamine, are "smart" materials characterized by high biocompatibility, high antioxidant capacities, high tunability and surface reactivity, biodegradability, and the ability to act as photothermal conversion agents when irradiated with a near-infrared (NIR) light source. Despite many interesting applications of PDNPs are currently described in the scientific literature, there is still no comprehensive analysis of the phenomenon of PC formation consequent to the exposure of these nanomaterials to biological media. Moreover, to date, the investigation of the effects of light irradiation of photothermally active nanomaterials on the composition and evolution of the associated PC has been extremely limited. With this work, we aim to provide for the first time an analysis of the phenomenon of PC formation associated with PDNPs, before and after NIR light stimulation. We characterized the PC formed following exposure to human plasma and analyzed the effects of several parameters on the overall PC composition and quantity, such as the PDNP size, presence of a surface functionalization, exposure time, and irradiation with an NIR laser, demonstrating that these parameters play a pivotal role in the resulting PC composition. Eventually, we showed that PDNPs exposed to human plasma have significantly different properties with respect to bare PDNPs, showing higher internalization rates in human glioblastoma cells, a higher light absorption value, and enhanced photothermal conversion abilities.