In this report, we designed a system to release cargo from MSN using dextran as a gatekeeper. The engineered silica has a pH-dependent surface charge, allowing cargo to be loaded at high pH and released at lower pH. However, previous designs only worked at very low pH (3), making them unsuitable for applications like cancer therapy. Therefore, we addressed this using a combination of carboxylic acid and propylamine groups, switching charges at a more relevant pH. Dextran was then attached to block the pores at high pH, preventing cargo release. Finally, lowering the pH triggered dextran detachment and cargo release, demonstrating a promising system for controlled cargo delivery.