by Keyword: Phase-separation

Seuma M, Bolognesi B, (2022). Understanding and evolving prions by yeast multiplexed assays Current Opinion In Genetics & Development 75, 101941

Yeast genetics made it possible to derive the first fundamental insights into prion composition, conformation, and propagation. Fast-forward 30 years and the same model organism is now proving an extremely powerful tool to comprehensively explore the impact of mutations in prion sequences on their function, toxicity, and physical properties. Here, we provide an overview of novel multiplexed strategies where deep mutagenesis is combined to a range of tailored selection assays in yeast, which are particularly amenable for investigating prions and prion-like sequences. By mimicking evolution in a flask, these multiplexed approaches are revealing mechanistic insights on the consequences of prion self-assembly, while also reporting on the structure prion sequences adopt in vivo.Copyright © 2022 Elsevier Ltd. All rights reserved.

JTD Keywords: aggregation, appearance, domains, inheritance, mutations, nucleation, physical basis, propagation, protein, Phase-separation

Sole-Marti, X, Vilella, T, Labay, C, Tampieri, F, Ginebra, MP, Canal, C, (2022). Thermosensitive hydrogels to deliver reactive species generated by cold atmospheric plasma: a case study with methylcellulose Biomaterials Science 10, 3845-3855

Hydrogels have been recently proposed as suitable materials to generate reactive oxygen and nitrogen species (RONS) upon gas-plasma treatment, and postulated as promising alternatives to conventional cancer therapies. Acting as delivery vehicles that allow a controlled release of RONS to the diseased site, plasma-treated hydrogels can overcome some of the limitations presented by plasma-treated liquids in in vivo therapies. In this work, we optimized the composition of a methylcellulose (MC) hydrogel to confer it with the ability to form a gel at physiological temperatures while remaining in the liquid phase at room temperature to allow gas-plasma treatment with suitable formation of plasma-generated RONS. MC hydrogels demonstrated the capacity for generation, prolonged storage and release of RONS. This release induced cytotoxic effects on the osteosarcoma cancer cell line MG-63, reducing its cell viability in a dose-response manner. These promising results postulate plasma-treated thermosensitive hydrogels as good candidates to provide local anticancer therapies.

JTD Keywords: Cellulose, Phase-separation, Stability, Substituent, Thermoreversible gelation

Zeinali, Reza, del Valle, Luis J., Franco, Lourdes, Yousef, Ibraheem, Rintjema, Jeroen, Alemán, Carlos, Bravo, Fernando, Kleij, Arjan W., Puiggalí, Jordi, (2022). Biobased Terpene Derivatives: Stiff and Biocompatible Compounds to Tune Biodegradability and Properties of Poly(butylene succinate) Polymers 14, 161

Different copolymers incorporating terpene oxide units (e.g., limonene oxide) have been evaluated considering thermal properties, degradability, and biocompatibility. Thus, polycarbonates and polyesters derived from aromatic, monocyclic and bicyclic anhydrides have been considered. Furthermore, ring substitution with myrcene terpene has been evaluated. All polymers were amorphous when evaluated directly from synthesis. However, spherulites could be observed after the slow evaporation of diluted chloroform solutions of polylimonene carbonate, with all isopropene units possessing an R configuration. This feature was surprising considering the reported information that suggested only the racemic polymer was able to crystallize. All polymers were thermally stable and showed a dependence of the maximum degradation rate temperature (from 242 °C to 342 °C) with the type of terpene oxide. The graduation of glass transition temperatures (from 44 °C to 172 °C) was also observed, being higher than those corresponding to the unsubstituted polymers. The chain stiffness of the studied polymers hindered both hydrolytic and enzymatic degradation while a higher rate was detected when an oxidative medium was assayed (e.g., weight losses around 12% after 21 days of exposure). All samples were biocompatible according to the adhesion and proliferation tests performed with fibroblast cells. Hydrophobic and mechanically consistent films (i.e., contact angles between 90° and 110°) were obtained after the evaporation of chloroform from the solutions, having different ratios of the studied biobased polyterpenes and poly(butylene succinate) (PBS). The blend films were comparable in tensile modulus and tensile strength with the pure PBS (e.g., values of 330 MPa and 7 MPa were determined for samples incorporating 30 wt.% of poly(PA-LO), the copolyester derived from limonene oxide and phthalic anhydride. Blends were degradable, biocompatible and appropriate to produce oriented-pore and random-pore scaffolds via a thermally-induced phase separation (TIPS) method and using 1,4-dioxane as solvent. The best results were attained with the blend composed of 70 wt.% PBS and 30 wt.% poly(PA-LO). In summary, the studied biobased terpene derivatives showed promising properties to be used in a blended form for biomedical applications such as scaffolds for tissue engineering.

JTD Keywords: alternating copolymerization, biobased materials, biodegradability, composites, crystallization, cyclohexene oxide, induced phase-separation, limonene oxide, mechanical-properties, polyesters, scaffolds, spherulites, terpene derivatives, thermal properties, thermally-induced phase separation, Acetone, Bio-based, Bio-based materials, Biobased materials, Biocompatibility, Biodegradability, Butenes, Cell culture, Chlorine compounds, Degradation, Evaporation, Glass transition, Limonene oxide, Monoterpenes, Phase separation, Poly (butylenes succinate), Polybutylene succinate, Property, Ring-opening copolymerization, Scaffolds, Spheru-lites, Tensile strength, Terpene derivatives, Thermal properties, Thermally induced phase separation, Thermally-induced phase separation, Thermally?induced phase separation, Thermodynamic properties, Thermogravimetric analysis