Potential of Mesoporous Silica Nanoparticles As Small Molecule Delivery Platform Against Pathogenic Bacteria

Nanoparticles are increasingly being used in an array of applications such as pharmaceuticals, environmental protection, and electronics due to their unique characteristics such as the ability to exhibit technologically important size-dependent properties such as quantum confinement effect in semiconductor particles, surface plasmon resonance in some metal particles and superparamagnetism in magnetic materials. Mesoporous silica nanoparticles (MSNs) in particular are being researched extensively as potential cargo delivery systems due to their large surface area to volume ratio, tunable pore size, large pore volume, and the range of possible surface functionalization options they have. They are emerging as promising candidates for delivery of therapeutic small molecules against antibiotic resistant pathogenic bacteria of Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. In this study, we present findings on the use of engineered MSNs loaded with gentamicin small molecule. The MSNs were synthesized using surfactant templating approach and surface functionalized with polyethyleneimine (PEI) to permeabilize the outer membrane (OM) of bacteria and facilitate antibiotic uptake. The nanoparticles were characterized using dynamic light scattering (DLS), zeta potential measurements and transmission electron microscopy (TEM). The amount of gentamicin loaded into the nanoparticle and release rates were quantified using Nanodrop spectrophotometer based on UV-Vis absorption. The findings show that MSNs can slowly release gentamicin and kill E. coli K12 T7 cells in vitro according to both colony formation and kinetic of killing assays. Together, the findings show that, MSN is a viable antibiotic small molecule delivery platform which can be explored for complex in vivo applications.