Skip to main content
. 2014 Apr 29;9(4):e95406. doi: 10.1371/journal.pone.0095406

Figure 1. Reaction with PEG polymers and fluorochrome and DOTA bearing peptides yields PEG-like Nanoprobes (PN’s).

Figure 1

A) Syntheses of PEG-like Nanoprobe (PN’s). The peptide (DOTA)Lys-Cys(Fluor.), with an N-terminal DOTA, a variable fluorochrome (Fluor.) attached to the cysteine side chain, and a single primary amine, reacts with the NHS ester of a variable PEG. In the conventional PEGylations of proteins or nanoparticles, multiple PEG’s provide a PEG bearing surface. This approach yields materials with a PEG to protein ratio or with a PEG surface density. B) Synthesis of the PN denoted PN(783)4.3. A 5 kDa PEG is reacted with the (DOTA)Lys-Cys(IR-783) peptide. The diameter (by FPLC) is 4.3 nm and the absorption maximum is 783 nm, hence PN(783)4.3. C) A 30 kDa PEG is reacted with the (DOTA)Lys-Cys(Cy3) peptide. The diameter is 10.0 nm and an absorption maximum is 545 nm, hence, PN(545)10.0. A list of PN’s and their properties is given in Table 1.