2.3. Synthesis of PB@PDA nanocomposites (PBPs)

Briefly, PB (1 mg), EDC (0.1 mg), and NHS (0.12 mg) were dissolved in 2 mL deionized water in a plastic centrifuge tube under dark conditions for 12 h. After centrifugation, activated PBs was obtained. Then, dopamine hydrochloride (1.5 mg) was added to the above suspended solution (1 mL deionized water) under oscillating conditions, which was kept overnight. Then, the resulting products were collected by the same method as that for the PBs.