When Interfaces Decide: Stimulus-Driven Corona-Controlled Transport in Mesoporous Silica Nanocarriers

Molecular transport in mesoporous carriers is often treated as passive diffusion through fixed pore networks, even though polymer-coated systems can dynamically reconfigure interfacial permeability. Here, rice-husk-derived mesoporous silica nanoparticles were converted into a stimulus-responsive, corona-regulated urea carrier through functionalization with a dual thermo- and pH-responsive chitosan-graft-poly(N isopropylacrylamide) corona, yielding MSN@CP nanocarriers. The polymer corona increases urea loading to 67.4% and effectively suppresses the burst release observed for bare mesoporous silica nanoparticles. Urea release was quantified over 14 days under soil-relevant conditions spanning pH 5.5-8.5 and temperatures from 10-40 °C, revealing pronounced stimulus dependence. Cumulative release reaches approximately 81-89% at 40 °C, with the highest release at pH 5.5, while remaining limited to approximately 39-44% at 10 °C. Weibull analysis captures the full release profiles with high fidelity and revealed systematic changes in curve shape that reflect stimulus-regulated corona permeability. Independent interfacial and colloidal measurements including dynamic light scattering, zeta potential, and pendant drop tensiometry, consistently indicate temperature- and pH-driven corona restructuring that tracked the observed transport regimes. Together, these results establish an interface-centered framework for corona-controlled transport in mesoporous nanocarriers and demonstrate a waste-derived platform capable of adaptive urea release under variable pH and temperature conditions.