pH Switchable Nanoassembly for Imaging a Broad Range of Malignant Tumors

Abstract

Polymer-based fluorescent nanomaterials have proven to universally image various tumors based on their extremely sharp responsiveness to pH change. Such a property has never been realized in supramolecular systems. We herein design a small molecule (DPP-thiophene-4) that is composed of a diketopyrrolopyrrole (DPP) core and two alkyl chains terminated with quaternary ammonium. DPP-thiophene-4 can self-assemble into a nonfluorescent nanoassembly when the pH is >7.0 but reversibly disassembles back to fluorescent monomers when the pH is <6.8. Meanwhile, its fluorescence emission increases by 10-fold within a 0.2 pH unit change. Such a fluorogenic nanoassembly can precisely differentiate a number of malignant tumors among normal tissues in vivo due to the slight acidity within tumor microenvironments. Further the nanoassembly shows satisfactory biocompatibility and an effective clearance from the body. Overall, this supramolecular fluorogenic nanoassembly exhibits an immense potential for realizing broad range tumor diagnosis.

Functional biomimetic nanoparticles for drug delivery and theranostic applications in cancer treatment

“…Among the various types of stimuli, pH-responsive systems have been widely employed to design sensitive nanosystems for drug delivery in cancer therapy [27].…”

Fluorescent‐functionalized graphene oxide for selective labeling of tumor cells

“…Conversely, fluorescence intensities of both donor and acceptor were decreased in a significant amount when intracellular pH was raised from 5.0 to 9.0. Again, with amine functionality where agglomeration in basic media is overcome by generating ammonium ion through the reduction of pH (acidic condition lead to charge separation due to repulsion of same charged species), whereas reverse phenomena occurs in sulfonated functionality in this study (aggregation at acidic pH from dispersed phase in basic condition) leading to a unique model as shown in Fig. G.…”

Ultra‐pH‐Sensitive Small Molecule Probe Showing a Ratiometric Fluorescence Color Change

“…reported a small molecule consisting of a protonatable diketopyrrolopyrrole (DPP) core and two alkyl chains terminated with a hydrophilic quaternary ammonium. It showed 10‐fold fluorescence intensity on‐off within a 0.2 pH unit change between 6.8–7.0 with the aid of hydrophobicity‐driven cooperative self‐assembly behavior . Nevertheless, such on‐off signal can be easily interfered by surrounding environments and detection condition such as the excitation power of the instruments, background fluorescence, and concentration of the fluorophores .…”