Rattle-Structured Upconversion Nanoparticles for Near-IR-Induced Suppression of Alzheimer's β-Amyloid Aggregation

NIR-light-induced suppression of Aβaggregation using upconversion nanoparticles (UCNPs) was reported. UCNPs were prepared by thermal decomposition process as previously reported and added in a mixture of Igepal Co-520 and cyclohexane followed by stirring for 3 h. Then, ammonium hydroxide solution was added dropwise into the solution and stirred for 0.5 h. After that, TEOS was added into the mixture and stirred for 6 h. A mixture of BTEB and APTES was added and stirred for another 18 h. By the addition of methanol, UCNP@OS particles were precipitated and collected by centrifugation. UCNP@ROS was mixed with 1 mL of RB solution in DMF and stirred for 12 h in the dark. RB-loaded UCNP@ROS nanoparticles were collected by centrifugation and washed with ethanol and PBS for several times. The RB loading capacity of UCNP@ROS was measured by the RB absorption at 563 nm. The solution was centrifuged and the supernatant was extracted to determine leaked RB in solution from RB-loaded UCNP@ROS by measuring absorption spectra. The RB/UCNP@ROS effectively inhibited the self-assembly of β to aggregates under 980 nm NIR light. It is found that found that RB/UCNP@ROS is not only biocompatible but also effective in suppressing the Aβ-induced cytotoxicity under NIR light.