Fabrication of SnO2/porous silica/polyethyleneimine nanoparticles for pH-responsive drug delivery

To create novel nanocarriers for achieving excellent drug delivery performance, pH-responsive fluorescent porous silica (PS) nanocarriers were developed by encapsulating SnO 2 nanoparticles and coating polyethyleneimine (PEI) layer. SnO 2 /porous silica (SnO 2 /PS) nanoparticles have an average diameter of 80   nm and center-radial large pore channels. The large channels endow them high surface area with a Brunauer–Emmett–Teller (BET) area of 939   m 2   g −   1 . Aspirin was used as test drug to evaluate the releasing behavior of SnO 2 /porous silica/polyethyleneimine (SnO 2 /PS/PEI) nanoparticles. Results indicated that aspirin can be successfully incorporated into the SnO 2 /PS/PEI nanoparticles and the SnO 2 /PS/PEI nanoparticles displayed excellent pH-responsive release. The release rate in pH   7.4 buffer is higher than that in pH   5.5 buffer, which attributed to the PEI structure change in varied pH buffer. In addition, the SnO 2 /PS/PEI nanoparticles presented novel drug-dependent fluorescence, which could be used to trace the drug release.