Calculation of conjugation efficiency (%), number of ligands by qPAINT and ligand availability (%) for PLGA–PEG NPs with varying maleimide content and spacer PEG lengthsa.
| Maleimide content (%) | Spacer PEG chain length (kDa) | |||||
|---|---|---|---|---|---|---|
| Conjugation efficiency (%) | Quantified ligands (qPAINT) | Ligand availability (%) | ||||
| 5 | 1 | 5 | 1 | 5 | 1 | |
| 10 | 25 | 38 | 6 | 42 | 8 | 21 |
| 20 | 21 | 35 | 8 | 54 | 6 | 15 |
| 30 | 31 | 70 | 31 | 79 | 2 | 5 |
a
PLGA–PEG NPs with increasing maleimide content (10–30%) and varying spacer PEG chain length (PEG5k and PEG1k). The conjugation efficiency (%) was calculated using spectrophotometry, the number of accessible ligands by qPAINT and the ligand availability (%) by considering the number of available ligands out of the theoretical expected number of ligands. For calculations of CE% and ligand availability see ESI Experimental section and Table S2 in ESI.