7. C-dots synthesis, characterization, and calculation of binding to phosphory-Tyrosine

The mixture of soybean and ethylenediamine (1:4) (Sigma Aldrich^®) with water were heated at 200 ^oC for 5h. After centrifuge, the supernatant was collected by evaporating the water in vacuo using rotavap, followed by wash with methanol. The final solid product was obtained by heating in oven at 80^oC for 24 h.

A SmartSPM 100 scanning probe microscope (AIST-NT) in non-contact mode was used to characterize the morphology and particle size of the carbon dots using high accuracy HA-NC “etalon” probes (cantilever frequency 140 kHz) at a scan rate of 1 Hz. The functional groups distributed on the surface of c-dots were characterized using a FTIR spectrometer. The FTIR absorbance was recorded in the range of 400 cm⁻¹ to 4000 cm^-1. Calculation of C-dots binding to phosphory-Tyrosine was performed as described in details in supplemental methods (32).