This new rROPISA process was then readily applied to the synthesis of fluorescent, degradable, polymer prodrug nanoparticles to confer therapeutic and imaging properties for potential theranostic applications. To fluorescently label nanoparticles, we chose to covalently link the fluorescent dye to the copolymer backbone instead of simply encapsulating it during the self-assembly process . This approach usually avoids dye leakage from nanoparticles and misinterpretation of fluorescence images with regards to nanoparticle localization. We selected a commercially available rhodamine B-functionalized methacrylate monomer (RhoMA) for RAFT-mediated copolymerization (f RhoMA = 0.1 mol %) with OEGMA to fluorescently label the solvophilic block. After purification to remove unreacted RhoMA and OEGMA, the resulting P(OEGMA 24 -co-RhoMA) macro-CTA exhibited strong purple color and well-defined characteristics (M n = 8900, Ð = 1.08, Table ). It was then chain-extended under rROPISA conditions identical to those of C0, to produce fluorescent and degradable drug-free nanoparticles (C0-Rho). After purification, they exhibited strong purple color with a fluorescent