Cytotoxicity and cellular uptake of red-emitting organic-inorganic hybrid nanoparticles

Highly luminescent and stable hybrids composite Eu(TTA-TESP)3(P(Oct)3)@mSiO2 [europium (III); 4,4,4-trifluoro-1-(thiophen-2-yl)− 2-(3-(triethoxysilyl)propyl) butane-1,3-dione = TTA-TESP; trioctylphosphine = (P(Oct)3); mesoporous silica = mSiO2]; were prepared. Eu(III) and P(Oct)3 molecules reacted to TTA-TESP grafted mSiO2 through strong covalent bonding inside the cavity/mesopores of mSiO2. Photoluminescence (PL) curves of emission spectra and excitation spectrum depending on different concentrations show typical characteristic with a maximum emission peaks at 621 nm which is related to 5D0→7F2 transition of Eu(III) complexes with strong red emission. The cytotoxic effects depending on concentrations and incubation times of Eu(TTA-TESP)3(P(Oct)3)3@mSiO2 were confirmed to be practically non-toxic in terms of cytotoxicity in HepG2 cells. From the in-vivo results, Eu(TTA-TESP)3(P(Oct)3)3 @mSiO2 particles mainly accumulated in the liver, and the fluorescence signal in the heart, spleen, kidney, lung, and pancreas was weak. The result suggests that the synthesized Eu(TTA-TESP)3(P(Oct)3)3@mSiO2 particles can be used as a imaging agent for the liver through intravascular injection.