Alemdar, C., Gundogdu, D., Karauzum, A., Turan, C., Seza, E. G., Güray, N. T., et al. (2025). Poly (2-oxazoline) based polymersomes and their hollow multilayer capsules as nano-and micro-reactors for enzymatic reactions. European Polymer Journal, 114174. DOI: 10.1016/j.eurpolymj.2025.114174  

This study reports on preparation of poly(2-oxazoline) based nano-/micro-reactors for enzymatic reactions. Nanoreactors were fabricated through self-assembly of amphiphilic poly(2-isopropyl-2-oxazoline)-b-poly(2-phenyl-2-oxazoline)-b-poly(2-isopropyl-2-oxazoline) (PiPOX-b-PPhOX-b-PiPOX) into polymersomes in the presence of glucose oxidase (GOx). The polymersomes with temperature-sensitive PiPOX inner core and outer corona, along with a PPhOX membrane effectively encapsulated GOx and the polymersome membrane had sufficient permeability to allow diffusion of the substrate into the inner core. GOx-loaded polymersomes (polymersome-GOx) were then used as building blocks to prepare hollow capsules through layer-by-layer (LbL) technique using Tannic Acid (TA) as the counter-part. The effect of pH and temperature-induced conformational rearrangement on enzymatic reactions in polymersomes and hollow capsules was comparatively evaluated. Polymersomes responded faster to changes in temperature and pH. The enzymatic reaction rate was higher at pH 5.5 compared to pH 7.4, with a slightly more pronounced difference in the capsules as the reaction proceeded. Increasing the temperature from 25 °C to 37 °C led to increased reaction rates in both, especially at pH 5.5, but with a slightly larger increase in the polymersomes. Cytotoxicity tests on HeLa cells showed no significant reduction in cell viability with the hollow capsules while a significant decrease in viability was observed with the highest concentration of polymersome-GOx.
Overall, this study generated fundamental insights into the effect of pH and temperature on enzymatic reactions in stimuli-responsive poly(2-oxazoline)-based polymersomes and their LbL capsules.