We herein demonstrate the outstanding protein-repelling characteristic of starlike micelles and polymersomes manufactured from amphiphilic block copolymers made by poly(butylene oxide) (PBO) hydrophobic segments and polyglycidol (PGL) hydrophilic outer shells. Although positively charged proteins (herein modeled by lysozyme) may adsorb onto the surface of micelles and polymersomes where the assemblies are stabilized by short PGL chains (degree of polymerization smaller then 15), the protein adsorption vanishes when the degree of polymerization of the hydrophilic segment (PGL) is higher than ~ 20, regardless the morphology. This has been probed by using three different model proteins which are remarkable different concerning molecular weight, size and zeta potential (bovine serum albumin -BSA, lysozyme and immunoglobulin G -IgG). Indeed, the adsorption of the most abundant plasma protein (herein modeled as BSA) is circumvented even by using very short PGL shells due to the highly negative zeta potential of the produced assemblies which presumably promotes protein-nanoparticle electrostatic repulsion. The highly negative zeta potential, on the other hand, enables lysozyme adsorption and the phenomenon is governed by electrostatic forces as evidenced by isothermal titration calorimetry.Nevertheless, the protein coating can be circumvented by slightly increasing the degree of polymerization of the hydrophilic segment. Notably, the PGL length required to circumvent protein fouling is significantly smaller than the one required for PEO. This feature and the safety concerns regarding the synthetic procedures on the preparation of poly(ethylene oxide)-based amphiphilic copolymers might make polyglycidol a promising alternative towards the production of non-fouling particles.

No abstract

This contribution fills the need for quantitative mechanistic and kinetic information for epoxide polymerizations catalyzed by tBuP4 phosphazene base.

2,5-Diketopiperazines (DKPs) are the smallest cyclic dipeptides found in nature with various attractive properties. In this study, we have demonstrated the successful modification of proline-based DKPs using anionic ring-opening polymerization (AROP) as a direct approach. Four different proline-based DKPs with various side chains and increasing steric hindrance were used as initiating species for the polymerization of 1,2-epoxybutane or ethoxyethyl glycidyl ether in the presence of t-BuP 4 phosphazene base. The addition of a Lewis acid, tri-isobutyl aluminum, to the reaction mixture strongly decreased the occurrence of side reactions. Impact of the DKP side-chain functionalities on molar mass control and dispersity was successfully evidenced.