Synthesis And Application Of Spiral-containing Block Copolymer Polyisonitrile

In this paper, two series of diblock copolymers, poly(y-benzyl L-glutamate)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PBLG-PPI) and PPI-PCL were designed and synthesized. The polymers were full characterized and their applications on biological field were studied. The details are shown as follow: Biocompatible hybrid rod-rod diblock copolymers, (PBLG-PPI), with individual chirality were synthesized via the sequential copolymerization of γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and phenyl isocyanide (PI) derivative monomers with chiral menthyl pendants (L- or D-PI) by using Ni(cod)(bpy) complex as catalyst in one-pot. Circular dichroism (CD) spectra and transmission electron microscopy (TEM) images distinctly revealed the right- or left-handed helical structures of copolymers dried from 1,1,2,2-tetrachloroethane. Deprotection of benzyl groups could afford poly(L-glutamic acid) (PLGA) incorporated biocompatible amphiphilic diblock copolymers (PLGA-PPI). Chiral rhodamine chromophore, RhB(D), encapsulated nanospheres formed by cosolvent-induced aggregation and enantioselective complexation could be further efficiently internalized into living cells and directly monitored by confocal microscope over time. The present contribution will be useful for developing novel rod-rod biocompatible hybrid block copolymers with a controlled helicity both in solution and solid states, and may also provide unique chiral materials for potential bio-medical applications. In this part, a stimuli-responsive RhB incorporated bifunctional initiator was synthesized. Moreover, a series of biocompatible hydrophilic diblock copolymers, amphiphilic helical PPI(-RhB)-PCL diblock copolymers, have been prepared through one-pot approach based on distinct mechanism. Subsequent studies on co-solvent self-assembly show the nanomicelle with helical PPI shell and biodegradable PCL core. As the results, similar to the ability of peptide to cross plasma membranes, the nanomicelles with helical PPI-shell can penetrates the cells effectively. Thus the drugs encapsulated by the nanomicelles were easy to enter into the cell. Besides, the RhB can emitted a strong fluorescence in the acidic Hela cell, the progress can be tracked by confocal microscopy.