Morphology-engineered spiky-fibrous hollow silica nanoparticles for enhanced drug loading and controlled release

Spiky nanoparticles have attracted considerable interest for drug delivery owing to their high surface area and favorable interfacial properties; however, their synthesis often involves harsh conditions that limit biomedical applicability. Here, we report a mild and facile synthetic strategy for spiky-fibrous silica-shelled hollow silica (HSN@S-SiO 2 ) nanoparticles using polystyrene spheres as sacrificial cores. By varying the tetraethyl orthosilicate (TEOS) volume, the shell thickness, pore structure, and surface morphology were precisely tuned. Among the investigated conditions, nanoparticles synthesized with 19 μL TEOS exhibited a well-defined spiky-fibrous morphology and the highest specific surface area, whereas those prepared with higher TEOS volumes formed thicker shells with reduced surface area. Drug-loading and release studies demonstrated that thicker shells effectively suppressed the initial burst release, while the optimized spiky-fibrous architecture enabled high drug-loading capacity and sustained release behavior. These results demonstrate that morphology-controlled HSN@S-SiO 2 nanoparticles can be produced via a safer and less harsh approach, offering a promising silica-based platform for delayed drug-delivery applications.