Bottom-up fabrication of redispersible β-1,3-1,6-glucan nanoparticle powders with enhanced aqueous solubility and improved macrophage responsiveness.

β-1,3-1,6-Glucans exhibit immunological activities, but their poor aqueous dispersibility and aggregation limit their use in aqueous formulations. Here, we developed a bottom-up alkali-neutralization renaturation strategy to prepare redispersible β-1,3-1,6-glucan nanoparticle (r-glucan NP) powders. Native triple-helical glucan was dissociated in alkali, reassembled by neutralization, purified, and lyophilized. The resulting powders retained high molecular weight and local triple-helical features while showing only a small apparent long-range ordered-domain contribution in the dried state. After redispersion, r-glucan NPs maintained nanoscale particle size and achieved apparent aqueous glucan concentrations up to approximately 250 mM without visible precipitation before the solubility plateau. Freeze-drying/redispersion did not substantially impair hydrophobic guest encapsulation or apparent carrier-associated curcumin retention in PBS. Compared with sonicated t-glucan, which showed similar apparent aqueous solubilization but lower molecular weight and residual insoluble material, r-glucan NPs induced higher TNF-α secretion in J774A.1 macrophages withoAut detectable cytotoxicity under the tested conditions. IL-6 increased over time, whereas IL-10 did not show a significant increase. These findings indicate that bottom-up structural reassembly enables highly water-dispersible β-glucan nanoparticle powders while preserving key molecular and local conformational features, and that improved aqueous solubilization alone did not reproduce the macrophage responsiveness of r-glucan NPs under the present experimental conditions.