Impact of ionizable groups in star polymer nanoparticles on NLRP3 inflammasome activation†

The advent of cancer nanovaccines (N.V.s) has transformed immunotherapy by using nanoparticles as biologic delivery vehicles or vaccine adjuvants. However, challenges remain due to nanoparticle-immune cell interactions. Investigating nanoparticle (N.P.) physicochemical effects on the innate immune system is crucial for safe biomaterials design. The NLRP3 inflammasome, a key innate immunity component, is implicated in many inflammatory disorders. Various nanoparticle-associated molecular patterns (NAMPs) trigger NLRP3 activation, but the combined effect of these NAMPs in a single N.P. platform is not well understood. Star polymer nanocarriers were chosen to study the impact of combined hydrophobic and ionizable groups on NLRP3 activation. Star polymers offer stable self-assembly, high drug/gene encapsulation, and enhanced cellular internalization. We designed 4-arm star random copolymers with constant hydrophobic moiety and varied ionizable groups to evaluate their NLRP3 activation in macrophages. The study revealed differences in cytokine release and cell death linked to ionizable groups, providing insights for selecting safe, immunomodulatory biomaterials.