Cora 5001

The optical properties of GQDs were characterized by Horiba Duetta. The time-resolved PL spectra were characterized with a Horiba FluoroMax. Raman spectra were performed by an Anton Paar Cora 5001 with 532 nm. FT-IR spectra were obtained by using a Thermo Scientific iS50. XPS spectra were assessed utilizing a Thermo ESCALAB 250Xi spectrometer. AFM images was recorded with ScanAsyst air mode using Nanoscope V Multimode 8 (Bruker).

PL and UV-vis absorption spectra were characterized by Horiba Duetta. The time-resolved PL spectra were obtained with a Horiba FluoroMax with a 455 nm laser. A transmission electron microscopy (TEM) image was performed by using a Japan Hitachi HT7700. The Raman spectrum was achieved by an Anton-Paar Cora 5001 with 785 nm of laser wavelength. The Fourier transform infrared (FT-IR) spectrum was characterized with a Thermo Scientific iS50 FT-IR. The X-ray photoelectron spectroscopy (XPS) spectrum was acquired using a Thermo ESCALAB 250Xi spectrometer. Dynamic light scattering (DLS) is a powerful tool used to monitor particle size evolutions. Aβ_1–42 peptides were mixed with 6 mg/mL N-CDs incubated for 24 h at 37 °C and then the size distribution was measured by a ZetasizerNano ZS nanoparticle size analyzer (Malvern Instruments Ltd., Malvern, UK). Aβ_1–42 solutions incubated with PBS were also utilized as controls. After measuring the effect of N-CDs on Aβ_1–42 fibrosis by ThT and DLS as shown previously, the morphologies of the Aβ_1–42 aggregates incubated with or without N-CDs were observed and visualized by TEM (Japan Hitachi HT7700, Japan, Tokyo).