Structural transitions and encapsulation selectivity of thermoresponsive polyelectrolyte complex micelles

摘要: Polyelectrolyte complex (PEC) micelles are formed by mixing a block copolymer composed of neutral and charged block, with an oppositely polymer. The have PEC core, capable encapsulating molecules like nucleic acids or proteins, while the block(s) forms corona that offers protection can prevent cargo from being degraded under physiological conditions. This work explores using thermosensitive polymer, poly(N-isopropyl acrylamide) (pNIPAM), as primary corona-forming how be leveraged in context drug delivery. pNIPAM has lower critical solubility temperature (LCST), above which hydrophilic to hydrophobic transition occurs. We characterizing diblock pNIPAM–b-poly(acrylic acid) (1) poly(lysine) (2) poly(ethylene glycol)-b-poly(lysine) dynamic light scattering, small angle X-ray absorbance fluorescence spectroscopy, transmission electron microscopy. Our results indicate creates worm-like micelles, same spherical micelles. At temperatures 35 °C, acid), lose their structure, retain but both aggregate into larger assemblies. Lastly, we evaluate ability these encapsulate release model therapeutics, cationic monoion, methylene blue polyion, polylysine conjugated rhodamine. find is not encapsulated micelle, instead exhibits counterion-like behaviour upon polyelectrolyte formation. Conversely, measurements rhodamine-labelled show quenching indicating polyion encapsulated. By quenched unlabelled systems immune molecular exchange environment remains trapped micellar cores. Measurement micelle LCST, decreases no substantial for either system. However, increase LCST its persistence after cooling may offer additional protective triggered temperature.