A linear-dendron-like polyampholyte was synthesized via the combination of ring-opening polymerization (ROP)

divergent synthesis procedure and click chemistry.First

azide-terminated poly(-benzyl-L-glutamate) (PBLG-N3) and the second generation PAMAM (D2) with alkyne focal group and four terminal primary amine groups were synthesized by the ROP of -benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and divergent synthesis procedure

respectively.Subsequently

PBLG-N3 was click conjugated with alkyne focal group of D2 to generate primary amine-terminated linear-dendron-like PBLG-b-D2

which was then used as the microinitiator for the ROP of -benzyloxycarbonyl-L-lysine N-carboxyanhydride (ZLL-NCA) to produce the linear-dendron-like copolymer PBLG-b-D2-(PZLL)4.The targeted linear-dendron-like polyampholyte

PLGA50-b-D2-(PLL9)4

where PLGA is poly(L-glutamic acid) and PLL is poly(L-lysine)

was obtained by the hydrolysis of protecting benzyl and benzyloxycarbonyl groups of PBLG and PZLL

respectively.The molecular structures of the intermediates and the final polyampholyte were characterized by 1H-NMR

Fourier transform-infrared spectroscopy (FTIR) and gel permeation chromatograph (GPC).The physical properties and pH-responsive behavior in aqueous solution were investigated via potentiometric and conductometric titration

1H-NMR

zeta potential measurement

laser light scattering (LLS)

scanning electron microscopy (SEM) and circular dichroism spectroscopy (CD).The results show that PLGA50-b-D2-(PLL9)4 can self-assemble into schizophrenic micelles which can be reversibly produced as a function of pH in pure water

i.e.

it can self-assemble into spherical micelles with PLGA-core at acidic pH and rod-like micelles with PLL-core at alkaline pH

accompanied with the coil-to-helix conformational transition of PLGA and PLL.The linear-dendron-like asymmetrical topological structure is believed to play an impotent role in the morphology formation of self-assembly nanostructures.