Facile Fabrication of AIE-Active Fluorescent Polymeric Nanoparticles with Ultra-Low Critical Micelle Concentration Based on Ce(IV) Redox Polymerization for Biological Imaging Applications

Abstract

Fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) property have received increasing attention and possess promising biomedical application potential in the recent years. Many efforts have been devoted to the fabrication methodologies of FPNs and significant advance has been achieved. In this contribution, a novel strategy for the fabrication of AIE-active amphiphilic copolymers is reported for the first time based on the Ce(IV) redox polymerization. As an example, ene group containing AIE-active dye (named as Phe-alc) is directly grafted onto a water soluble polymer polyethylene glycol (PEG) in H O/THF system under low temperature. Thus-obtained amphiphilic fluorescent polymers will self-assemble into FPNs with ultra-low critical micelle concentration, ultra-brightness, and great water dispersibility. Biological evaluation results suggest that the PEG-poly(Phe-alc) possess excellent biocompatibility and can be used for tracing their behavior in cells using confocal laser scanning microscope. These features make PEG-poly(Phe-alc) FPNs promising candidates for many biomedical applications, such as cell imaging, drug delivery vehicles, and targeted tracing. More importantly, many other functional groups can also be incorporated into these AIE-active FPNs through the redox polymerization. Therefore, the redox polymerization should be a facile and effective strategy for fabrication of AIE-active FPNs.

Aggregation-Induced Emission: A Trailblazing Journey to the Field of Biomedicine

“…(vi) Polymer AIEgen dots. The sixth category involves the introduction of small-molecule AIEgens into the backbone or side-chains of synthetic polymers to yield AIE polymers, which are subjected to molecular assembly to form polymer AIEgen dots (Figure F). − Due to the steric hindrance imposed by the backbone and side chains, the intramolecular motions are easily dampened to induce enhanced emission. In view of the tunable structures, compositions, and morphology as well as diverse modifications, this type of probes is also regarded as a useful tool for various biomedical applications.…”

Progress and Trends in AIE-Based Bioprobes: A Brief Overview

“…Besides the AIE dots where the AIEgens are physically encased by polymeric matrices, AIE NPs with the AIE motifs covalently bonded to the polymer chains have also been frequently reported in the past few years. − The AIE-chitosan bioconjugate 34 is such an example. As discussed in Section , the spontaneously formed aggregates of 34 in cell culture media were microsized and nonuniform.…”

“…Directly attaching AIEgens to biocompatible polymers yields the polymeric AIEgens first, and then the AIE NPs could be easily generated by virtue of the NP synthesis methodologies. Another method to afford covalently bound AIE polymers which could form NPs under proper conditions is to in situ polymerize the AIEgens into polymer chains. − Wei’s group contributes most to this subject. They have developed a large quantity of AIE NPs with various polymerizable AIEgens and diverse polymerization methods including free radical polymerization, , reversible addition–fragmentation chain transfer polymerization, , emulsion polymerization, , ring-opening polymerization, , and redox polymerization .…”

Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications

“…Graphene oxide (GO-OH)/Ce(IV)/HNO 3 redox initiating system (at 30°C) as described by Ma et al [126], Copyright 2013. Adapted with permission from Elsevier Ltd. possibility to functionalize highly interesting graphene surfaces [127][128][129][130].…”