Using magnetic mesoporous silica nanoparticles armed with EpCAM aptamer as an efficient platform for specific delivery of 5-fluorouracil to colorectal cancer cells.

Theranostic nanoparticles with both imaging and therapeutic capacities are highly promising in successful diagnosis and treatment of advanced cancers. Here, we developed magnetic mesoporous silica nanoparticles (MSNs) loaded with 5-fluorouracil (5-FU) and surface-decorated with polyethylene glycol (PEG), and epithelial cell adhesion molecule (EpCAM) aptamer (Apt) for controlled release of 5-FU and targeted treatment of colorectal cancer (CRC) both and . In this system, Au NPs are conjugated onto the exterior surface of MSNs as a gatekeeper for intelligent release of the anti-cancer drug at acidic conditions. Nanocarriers were prepared with a final size diameter of 78 nm, the surface area and pore size of SPION-MSNs were calculated as 636 mg, and 3 nm based on the BET analysis. The release of 5-FU from nanocarriers was pH-dependent, with an initial rapid release (within 6 h) followed by a sustained release for 96 h at pH 5.4. Tracking the cellular uptake by flow cytometry technique illustrated more efficient and higher uptake of targeted nanocarriers in HT-29 cells compared with non-targeted formula. results demonstrated that nanocarriers inhibited the growth of cancer cells apoptosis induction. Furthermore, the targeted NPs could significantly reduce tumor growth in immunocompromised C57BL/6 mice bearing HT-29 tumors, similar to those injected with free 5-FU, while inducing less side effects. These findings suggest that application of Apt-PEG-Au-NPs@5-FU represents a promising theranostic platform for EpCAM-positive CRC cells, although further experiments are required before it can be practiced in the clinic.