Intracellular delivery of BSA by phosphonate@silica nanoparticles

Intracellular protein (BSA) delivery by a phosphonate@mesoporous silica nanoparticle vehicle, PMSN, with high load capacity for the relatively large test protein BSA, is described. Wide pore (11.6 nm) PMSN nanoparticles were synthesised and loaded with a BSA cargo to give BSA^#@PMSN*, where # and * signify Fluorescein and Rhodamine fluorescent labels respectively. Internalisation of BSA^#@PMSN*s by HeLa cells was analysed from confocal microscopy and TEM images after dose and time dependent treatments. No evidence of cytotoxicity was observed after 24 h and in contrast to PMSN* no significant loss of BSA^#@PMSN* was observed after 3 h incubation of the loaded cells in DMEM. Receptor blocking experiments showed caveolar uptake of PMSN* and folate receptor mediated uptake of BSA^#@PMSN*s.