Modulating the Physicochemical Properties of Mesoporous Strontium Silicate Nanostructures Using a Design-of-Experiments Approach

Mesoporous silicate nanoparticles are known for their pore size, pore volume, high surface area, and tunable surface properties and, as a result, have found application in medicine, healthcare, advanced materials, and devices. Furthermore, tailoring the silicate domain with certain metals has advanced the tissue engineering properties by moderating the cellular function at the molecular level for therapeutic response. However, limited efforts have been made to explore systemic synthesis protocols that could change structure or shape of mesoporous metal silicate nanostructures as the change in shape has inherent potential to tailor biological response. Here, we have focused on using Design of Experiments (DoE) to optimize reaction conditions for the synthesis of mesoporous strontium silicate nanostructures (MPSrSiO2 NSs) (nanoparticles—NPs and nanorods—NRs) with different physicochemical properties. The conditions allowed a change in shape from NPs to NRs by tailoring the concentration of liquid ammonia (liq. NH3, NH4OH, 82.7 mM to 248.2 mM) during the pre-synthesis incubation state. The MPSrSiO2 NPs had a significantly higher zeta potential compared to NPs (p = 0.0061). Also, NPs possessed significantly higher surface area (p = 0.0306), pore diameter (p = 0.0003), and pore volume (p = 0.0004) than NRs. In addition, the optimized reaction conditions allowed modulation of the physicochemical properties such as surface area, surface charge, amount of metal, pore diameter, pore volume, tailored degradation profile and release profile of loaded drug (gentamicin). Finally, the protocol has the advantage of allowing incorporation of other metals such as cerium, rhodium, and ruthenium independently and/or in combination.