Rhodamine based pH-sensitive “intelligent” polymers as lysosome targeting probes and their imaging applications in vivo

Abstract

Two rhodamine-based polymers (P-1 and P-2) were prepared via free radical polymerization, which could serve as lysosome targeting probes with prominent pH sensitivity. The polymers exhibited suitable water solubility and the content of rhodamine in them was determined through ¹H NMR and ultraviolet-visible absorption spectroscopy. Both P-1 and P-2 have excellent selectivity, membrane permeability and low cytotoxicity. Confocal microscopy was used to investigate the intracellular distribution of lysosomes and visualize pH-responsive changes in the liver of zebrafish. Moreover, fluorescence imaging of nude mice of P-1 and P-2 displayed a chance for the visualization of cancerous tissue in vivo by sensing the tumor acidic microenvironments.