Virus-inspired Ganoderma lucidum polysaccharide-functionalized adjuvant with pseudo-zwitterionic interface for potentiated nasal immunization

Intranasal vaccination is promising against respiratory infections but hindered by the mucus barrier. To overcome the adhesion-penetration dilemma, we developed a virus-inspired hybrid nanoparticle (GHNP) by functionalizing a cationic polymer/lipid core (HNP) with Ganoderma lucidum polysaccharide (GLP). By tuning the surface modification density of GLP, GHNP achieved balanced mucosal interaction and penetration, with an optimal GLP-to-HNP mass ratio of 1:24. The optimized GHNP(1/24) (∼104 nm, +27 mV) markedly enhanced mucus penetration via its virus-mimetic pseudo-zwitterionic interface. This led to improved antigen uptake under mucin barrier conditions by 79-fold in dendritic cells and 25-fold in macrophages. In a murine intranasal immunization model, the intrinsic immunostimulatory activity of GLP, mediated through TLR2/4 activation, further potentiated the immune response, eliciting robust mucosal and systemic immune responses. Specifically, GHNP(1/24) elevated bronchoalveolar sIgA 1.5-fold and serum IgG 1.6-fold compared to antigen alone, while maintaining a balanced IgG1/IgG2a profile. This work establishes a modular platform that bridges structural biomimetics and carbohydrate immunoengineering, offering a tunable, dual-functional strategy for advanced mucosal vaccine design that surpasses the capabilities of traditional delivery systems which often address either adhesion or immunostimulation alone.