Fig. 3. (a) Schematic representation of the influence of spacer PEG chain length on the conjugation efficiency (CE%) and ligand availability (%) of PLGA–PEG NPs. Shorter PEG chains (PEG1k) are expected to achieve better CE% and imager availability due to improved maleimide and ligand free motion, and reduced flexibility and entanglement of PEG chains. (b) Quantification of ligand number/NP by qPAINT with increasing maleimide content (10–30%) and varying spacer PEG chain length (PEG5k – blank, PEG1k – lined). Standard deviation bars are given for each formulation.
