Surface Chemistry\nInduced IgG Unfolding and Modulation\nof Immune Responses

Immunoglobulin G (IgG) comprises a significant portion\nof the protein\ncorona that forms on biomaterial surfaces and holds a pivotal role\nin modulating host immune responses. To shed light on the important\nrelationship between biomaterial surface functionality, IgG adsorption,\nand innate immune responses, we prepared, using plasma deposition,\nfour surface coatings with specific chemistries, wettability, and\ncharge. We found that nitrogen-containing coatings such as these deposited\nfrom allylamine (AM) and 2-methyl-2-oxazoline (POX) cause the greatest\nIgG unfolding, while hydrophilic acrylic acid (AC) surfaces allowed\nfor the retention of the protein structure. Structural changes in\nIgG significantly modulated macrophage attachment, migration, polarization,\nand the expression of pro- and anti-inflammatory cytokines. Unfolded\nIgG on the POX and AM surfaces enhanced macrophage attachment, migration,\nextracellular trap release, and pro-inflammatory factors production\nsuch as IL-6 and TNF-α. Retention of IgG structure on the AC\nsurface downregulated inflammatory responses. The findings of this\nstudy demonstrate that the retention of protein structure is an essential\nfactor that must be taken into consideration when designing biomaterial\nsurfaces. Our study indicates that using hydrophilic surface coatings\ncould be a promising strategy for designing immune-modulatory biomaterials\nfor clinical applications.