Hydrolyzed Poly(2‐plenyl‐2‐oxazoline)s in Aqueous Media and Biological Fluids

Abstract

Hydrolyzed poly(2‐phenyl‐2‐oxazoline)s (PPhOx) are synthesized by partial hydrolysis of PPhOx in order to produce self‐assembling copolymers with chargeable and hydrophobic units. The resulting poly(ethylene imine‐co‐2‐phenyl‐2‐oxazoline) [P(EI‐co‐PhOx)] amphiphilic copolymers contain phenyl‐oxazoline and ethylene imine segments in a random sequence and their chemical structure is confirmed by 1H NMR and attenuated total reflection‐Fourier transform infrared spectroscopy. Static and dynamic light scattering experiments show that in aqueous solutions the random copolymers associate into aggregates of sizes in the range between 50 and 200 nm depending on the solution conditions and hydrophobic content. The positive charge of the nanoaggregates that is caused by protonation of the amine nitrogen is confirmed by zeta potential measurements. Self‐assembly in phosphate buffered saline results in large aggregates. The aggregates are proved to interact with fetal bovine serum proteins. This investigation shows that hydrolyzed phenyl oxazoline‐based copolymers provide stable amphiphilic nanoparticles able to interact with biological macromolecules for biotechnological and pharmaceutical applications.

Association and Internal Morphology of Self-Assembled HPPhOx/BSA Hybrid Nanoparticles in Aqueous Solutions

“…The extracted forward scattering from the hierarchical levels a and b follow these trends (Table ). In the absence of salt, R g, a is higher than the values obtained by LS of our previous work ( R g ≈ 40 nm). This possibly comes from the different concentration regime we test in SANS in comparison with LS.…”

“…It has to be mentioned that in PPrOx–PEI thermoresponsive copolymers, the formation of globular aggregates with significant positive ζ potential occurred above the transition temperature, i.e., at 37 °C . In HPPhOx, formation of aggregates with positive surface charge occurs at room temperature . This is possibly caused by the comparably higher content of EI units in HPPhOx and the hydrophobicity of PhOx, which in our case, although it does not induce thermoresponsive behavior, it can effectively drive self-association at room temperature in contrast with PrOx.…”

“…HPPhOx synthesis and solution properties have been described in detail elsewhere . HPPhOx with M n = 2.03 × 10 3 g mol –1 , M w / M n = 1.13 (PPhOx precursor), and 67% molar content in PhOx was utilized for the present studies.…”

“…In our previous work, we have synthesized and characterized partially hydrolyzed poly­(2-phenyl-2-oxazoline) (HPPhOx), leading to amphiphilic charged random copolymers. These macromolecules contain hydrophobic (PhOx) and hydrophilic ethylenimine (EI) units in a random sequence.…”

Selective Partial Hydrolysis of 2-isopropyl-2-oxazoline Copolymers towards Decreasing the Ability to Crystallize

“…To obtain ethyleneimine units in the poly(2-oxazoline) chain, hydrolysis is necessary. Acidic and basic hydrolysis conditions, leading to full or partial cleavage of the bond between backbone and substituent (side groups), were studied for many POxs [13,[30][31][32][33][34][35][36][37][38].…”