Fig. 2. (A) SEM image of the commercial PS-COOH (the inset is the local enlarged image of PS-COOH), (B) SEM image of the commercial PS-PEG-NH2 (the inset is the local enlarged image of PS-PEG-NH2), (C) fluorescence image of PS-PEG-Pep under a dark field and (D) zeta potential of PS-COOH (a), PS-PEG-NH2 (b) and PS-PEG-Pep-COOH (c).
