Table 1.
Physicochemical features of plain and functionalized MSNs
| Type of particle | Hydrodynamic size (nm) in HEPES buffer (pH 7.2)
|
Hydrodynamic size (nm) in HO2
|
Net surface charge/zeta potential (mV) in HEPES buffer (pH 7.2) | Total mass loss (wt%) | FA content (wt%) | Fluorescence intensity (au) at λ=521 nm in HEPES buffer (pH 7.2) | ||
|---|---|---|---|---|---|---|---|---|
| Size (nm ± SD) | PDI | Size (nm ± SD) | PDI | |||||
| MSN | >1,000 | 1 | 384±6.9 | 0.22 | 0.8 | 12 | NA | 944 |
| PEI-MSN ± SD | 478±12 | 0.36 | ND | 52 | 28 | NA | 436 | |
| PEG-MSN | >1,000 | 1 | 474±12 | 0.26 | −2.1 | 15 | NA | 308 |
| PEG-PEI-MSN | 472±5.8 | 0.25 | ND | 10 | 35 | NA | 206 | |
| FA-MSN | >1,000 | 1 | 424±6.7 | 0.24 | −0.3 | 14 | 0.04 | 721 |
| FA-PEI-MSN | 410±1.9 | 0.21 | ND | 40 | 34 | 0.06 | 292 | |
| FA-PEG-MSN | >1,000 | 1 | 382±30 | 0.19 | −0.9 | 21 | 0.13 | 511 |
| FA-PEG-PEI-MSN | 496±3.0 | 0.26 | ND | 26 | 34 | 0.05 | 215 | |
Abbreviations: MSN, mesoporous silica nanoparticle; HEPES, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; FA, folic acid; au, arbitrary units; PDI, polydispersity index; NA, not applicable; PEI, poly(ethylene imine); ND, not determined; PEG, poly(ethylene glycol); SD, standard deviation.