Fig. 4.

(A) Truncating labeling radius by modulating the diffusion coefficient. (B) 2D DOSY NMR of a mixture of PEG3-PhN₃ (3) and PEG24-PhN₃ (5). Analysis of cross-peaks in the DOSY spectra reveals that the PEG24 analog has a ∼1.6-fold reduced diffusion coefficient relative to PEG3. (C) STED image of BSA labeling on the surface of a coverslip with extended linker azide probe (5) reveals a labeling radius of 80 ± 28 nm. (D) Targeted cell-surface EGFR interactome labeling using PEG24 PhN₃ (5) reveals smaller clusters in the diffusion reduced labeling (scale bar, 0.5 µm). (E) TMT-based proteomics for PEG3 PhN₃-based µMap. (F) TMT-based proteomics for PEG24 PhN₃-based µMap. (G) Range of labeling radii measured across PLPs analyzed in this manuscript. These mean FWHM values (averages of 100 measurements) were calculated from clusters observed on BSA-coated coverslips.