Amphiphilic (di-)gradient copoly(2-oxazoline)s are potent amyloid fibril formation inhibitors

Effect of polymer architecture on the properties and in vitro cytotoxicity of drug formulation: A case study with mono- and di-gradient amphiphilic poly(2-Oxazoline)s

Due to the straightforward single-step synthesis, amphiphilic gradient copoly(2-oxazoline)s are becoming more popular alternative to their block analogue for the development of next-generation drug delivery systems. Here, we investigated the influence of polymer architecture on the physiochemical and biological assessment of nanoformulations formed by the self-assembly of gradient copoly(2-oxazoline)s. Two different architectures were synthesized: hydrophilic-grad-hydrophobic (mono-gradient) and hydrophobic-grad-hydrophilic-grad-hydrophobic (di-gradient) which contained a hydrophilic monomer, 2-ethyl-2-oxazoline (EtOx) and a hydrophobic monomer, 2-phenyl-2-oxazoline (PhOx). Di-gradient copolymers self-assembled in the presence of a hydrophobic model drug, curcumin and formed monodispersed or slightly polydispersed nanoparticle solution. On the other hand, mono-gradient copolymers formed polydispersed nanoparticle solutions. Di-gradient copolymer was slightly more efficient to solubilize curcumin. Mono-gradient copolymer nanoparticle showed faster monomer chain exchange kinetics and comparatively less stability in the presence of serum albumin. At longer incubation times, faster drug release was observed from the mono-gradient copolymer nanoformulations. Cytotoxicity of free curcumin and curcumin loaded nanoparticles in cancer cell of U87 MG (human glioblastoma cell) was dose and time-dependent, whereby the significant cell death occurred after 48 h. Curcumin-loaded mono-gradient copolymer nanoparticles inhibited U87MG cancel cell growth to a large extent compared to the di-gradient copolymer nanoparticles.

Dissimilar effects of the hydrophilic carbon dots on the amyloid aggregation of two model proteins and the mechanism discussion

Many proteins could aggregate into amyloid fibrils under certain conditions. However, the aggregation process and morphology of the fibrils may be significantly different because of the distinct protein structure. In this article, the hydrophilic carbon dots (Lys-CA-CDs) were prepared using lysine (Lys) and citric acid (CA) as reactant under the assistance of a microwave. The dissimilar modulation effect of Lys-CA-CDs on the aggregation process of distinct structure protein was further investigated, where bovine serum albumin (BSA) and hen egg white lysozyme (HEWL) were chosen as model proteins. All results showed that Lys-CA-CDs displayed the contrary influence on the aggregation process of BSA and HEWL. Lys-CA-CDs could induce BSA to aggregate into more wormlike fibrils and inhibit the aggregation of HEWL into hair-like fibrils. The influence on the aggregation process of BSA may be assigned to the increased concentration of BSA around the Lys-CA-CDs caused by their interaction. However, inserting of Lys-CA-CDs into the inner structure of HEWL led to the change of protein secondary structure. The change of secondary structure further made it difficult for HEWL to aggregate into fibrils and Lys-CA-CDs showed the inhibition effect on HEWL aggregation.