Fig 1.
(A) AMB-PEG reaction scheme. The NHS ester on MS(PEG)4 reacts with the primary amine (–NH2) group on AMB at a 1:1 molar ratio, generating conjugated AMB-PEG via amide bond formation. (B) Solubility of AMB-PEG at varying AMB:PEG molar ratios. AMB-PEG mixtures and unreacted AMB were prepared in DMSO, incubated for 2 hours and then (i) dispersed to a final concentration of 2 mM in PBS-EDTA, containing 10% DMSO by volume. (ii) The mixtures were then centrifuged to facilitate the observation of insoluble precipitates. Higher molar ratios yielded a suspension of yellow particles that precipitated upon centrifugation, similar to what was observed with unconjugated AMB.