Maldi tof

As described in Table 1, high purity of CPT were synthesized by AnyGen (Gwangju, Korea) using solid-phase peptide synthesis. The purity and molecular masses of the peptides were determined using high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) (Shimadzu, Kyoto, Japan).

To demonstrate that corona formation is a time-resolved process, both aminated and pristine nanodiamonds (500 μg mL⁻¹) were incubated with FN9-10 (250 μg mL⁻¹) and BSA (Sigma Aldrich, USA) (2 mg mL⁻¹). After 5 min, 30 min and 120 min of incubation samples were collected and centrifuged at 15 000g and 4 °C for 15 min, and then washed with deionized water. This process was repeated three times to remove unbound proteins from the surface of nanodiamonds. The pellets obtained were dispersed in 100 μL of deionized water. 0.7 μL of this dispersion was aliquoted and transferred to a MALDI-TOF plate. This was allowed to air dry before adding a sinapic acid matrix (Sigma Aldrich, USA). Measurements were performed using MALDI-TOF (AXIMA Performance, SHIMADZU, Japan) with a 355 nm Nb:YAG laser operating in linear mode with a 120 kV acceleration voltage and a laser repetition rate of 15. For each spectrum, 1000 laser shots were performed. MALDI-TOF enabled the identification of proteins by peptide mass fingerprinting (PMF) and will allow the differentiation of the specific protein bound to the nanodiamond surface.