Fabricating Triple-Sensitive Polymer Nano-Aggregates via an Aqueous Iminoboronate Multicomponent Reaction

A triple-sensitive polymer of poly(ethylene glycol)-iminoboronate nitrobenzyl ethanediol chelate (PEG-INEC) is efficiently fabricated via the convenient aqueous iminoboronate multi-component reaction (MCR) of methoxypolyethylene glycol amine (mPEG-NH2), 2-formylphenylboronic acid (FPBA), and bis(2-nitrophenyl) ethanediol (BNPE, a photo-cleavable nitrobenzyl alcohol derivate). The aqueous MCR synthetic procedure is followed using H-1 NMR and turbidity analysis. It is shown that polymer nano-aggregates of PEG-INEC in aqueous solution can be dissociated through the stimuli responsive reactions of the hydrophobic iminoboronate nitrobenzyl ethanediol chelates (INECs) when exposed to UV light, acid, and H2O2, respectively. Furthermore, upon the stimulation of combined triggers, the dissociation of polymer nano-aggregates can be accelerated to different extents, resulting in the synergistic release of encapsulated hydrophobic molecules in water. The proposed facile and general method is quite desirable and of great importance in practical applications like drug and gene delivery.