Formvar film

High-resolution TEM imaging and energy-dispersive X-ray spectroscopy (EDX) elemental analysis were performed on a Tecnai G2 F20 Transmission Electron Microscope (FEI, Eindhoven, The Netherlands) operated at 200 kV. Briefly, 400 mesh copper grids (Formvar film, ProSciTech) were glow discharged and IAPP (25 μM), GQDs (500 μg/mL) or GQDs pre-incubated with IAPP, which were dissolved/suspended in Milli-Q water for 24 h, were placed onto the grids. Negative staining by 1 % uranyl acetate was performed before imaging. Images were recorded using an UltraScan 1000 P 2k CCD camera (Gatan, California, USA) and Gatand Digital Micrograph 3.9.5 software.

Carbon-coated copper grids (400 mesh, formvar film, ProSciTech) were glow-discharged for 15 s prior to deposition of samples (5 μL). After 70 s of absorption, excess sample was drawn off using filter paper and grids washed 1× with 10 μL MilliQ water. For negative staining, grids were exposed to 5 μL of 1% uranyl acetate (UA) for 30 s, with excess stain drawn off as previously and grids allowed to air-dry. The samples were imaged on a Tecnai G2 F20 transmission electron microscope (FEI, 200 kV) with UltraScan 1000 P 2k CCD camera (Gatan) and Gatan Digital Micrograph 3.9.5 software utilized for the acquisition and processing of images. ImageJ (FIJI) was used to extract features such as fibril length and thickness.

For this measurement, 5 μL of the L/R-SiO₂ (0.2 mg/mL) was allowed to interact with IAPP monomers (5 μL of 50 μM; freshly dissolved in water, termed as ‘0 h IAPP’ from here onwards), oligomers/protofibrils (1 h into fibrillization, termed as ‘1 h IAPP’), and fibrils (48 h into fibrillization, termed as ‘48 h IAPP’) for 24 h of incubation. The samples were then pipetted onto 15 s glow-discharged 400 mesh copper grids (Formvar film, ProSciTech) for 60 s of adsorption. Excess samples were drawn off by filter paper and the grids were washed using 10 μL of Milli-Q water, with excess drawn off. The grids were then negatively stained with 5 μL of 1% uranyl acetate (UA) for 30 s with excess stain drawn off and air-dried. Samples were characterized on a Tecnai G2 F20 transmission electron microscope (FEI, Eindhoven, The Netherlands) operated at a voltage of 200 kV. Images were recorded using an UltraScan 1000 P 2k CCD camera (Gatan, California, USA) and Gatan Digital Micrograph 3.9.5 software.