Effect of surface functionality of silica nanoparticles on cellular uptake and cytotoxicity

Mesoporous silica nanoparticles (MCM-41) with different surface chemistry were used as carrier system to study its influence on drug delivery and anticancer activity of curcumin (CUR). CUR was encapsulated in pristine MCM-41 (hydrophilic and negatively charged), amino functionalized MCM-41 (MCM-41-NH2 which is hydrophilic and positively charged), and methyl functionalized MCM-41 (MCM-41-CH3 which is hydrophobic and negatively charged) and evaluated for in vitro release and cell cytotoxicity in human squamous cell carcinoma cell line (SCC25). Various techniques were employed to evaluate the performance of these materials on cellular uptake and anticancer activity in the SCC25 cell line. Both positively and negatively charged surfaces demonstrated enhanced drug release and anticancer activity compared to pure CUR. Positively charged nanoparticles showed higher cell uptake compared to negatively charged nanoparticles owing to its electrostatic interaction with cells. However, hydrophobic surface modified nanoparticles (MCM-41-CH3) showed no improvement in drug release and anticancer activity due to its poor wetting effect. Cell cycle analysis and cell apoptosis studies revealed different pathway mechanisms followed by the positively and negatively charged nanoparticles but exhibiting similar anticancer activity in SCC25 cells.