Glycosylation-driven interactions of nanoparticles with the extracellular matrix: Implications for inflammation and drug delivery.

Cationic nanoparticles (NPs) are emerging as promising carriers for intra-articular drug delivery, particularly for osteoarthritis (OA) where treatment options are limited. However, the clinical translation is challenged by an incomplete understanding of NP interactions within pathological environments. While the influence of the protein coronas on NP behavior has been extensively studied, the specific role of glycoproteins in the extracellular matrix (ECM) remains underexplored, representing a significant knowledge gap. This study investigates how glycosylation-driven interactions between polymeric NPs and enzyme-degraded cartilage biomolecules such as glycosaminoglycans (GAGs) affect NP-ECM aggregate formation and subsequent inflammatory responses. Using an ex vivo model of cartilage degradation induced by catabolic enzymes- hyaluronidase, ADAMTS5 and collagenase- a novel model system was developed to specifically study the behavior of small (<10 nm) and large (∼270 nm) cationic NPs in glycoprotein-enriched environments. Atomic force microscopy and dynamic light scattering revealed distinct mesh-like structures formed by the NP aggregates following different enzymatic treatments, confirming the adsorption of glycosylated fragments onto the particles. While total protein content showed minimal differences between NP samples, smaller NPs demonstrated a prominent association with GAGs such as hyaluronic acid and aggrecan, as demonstrated by circular dichroism. These ECM-NP interactions significantly influenced the immunological response, as evidenced by differential cytokine production from macrophages exposed to the aggregates. Our findings underscore the crucial, yet underappreciated, role of glycoproteins in determining NP behavior in pathological environments. Accounting for glycoprotein interactions into the design of nanomaterial and drug delivery systems could significantly improve therapeutic outcomes by enhanced targeting precision, optimized delivery, and effectively modulating immune responses in OA and other complex diseases.