TUNING THE MORPHOLOGY OF BLOCK COPOLYMER-BASED pH-TRIGGERED NANOPLATFORMS AS DRIVEN BY CHANGES IN MOLECULAR WEIGHT AND PROTOCOL OF MANUFACTURING

The ability to tune size and morphology of self-assemblies is particularly relevant in the development of delivery systems. By tailoring such structural parameters, one can provide larger cargo spaces or produce nanocarriers that can be loaded with hydrophilic and hydrophobic molecules, and starting ideally from the same polymer building unit. We herein demonstrate that the morphology of block copolymer-based pH-triggered nanoplatforms produced from poly(2-methyl-2-oxazoline)m-b-poly[2-(diisopropylamino)-ethyl methacrylate]n (PMeOxm-b-PDPAn) is remarkably influenced by the overall molecular weight of the block copolymer and by the method of manufacturing. Polymersomes were produced by nanoprecipitation using a block copolymer of relatively low molecular weight (Mn ~ 10 kg.mol-1) nevertheless, this method conducted to the formation of core-shell nanoparticles when block copolymers of higher molecular weight were used despite the high hydrophobic weight ratio (wPDPA > 0.70), thus suggesting that the fast (few seconds) self-assembly procedure is controlled by kinetics rather than thermodynamics. We further demonstrated the formation of vesicular structures using longer chains via the solvent-switch approach when the “switching” to the bad solvent is performed in a time scale of a few hours (approximately 3 hs). Accordingly, using fairly simple approaches one can tailor the morphology of the block copolymers self-assemblies thus producing structurally different pH-triggered nanoplatforms via a kinetic or thermodynamically-controlled process.