Out-of-Equilibrium bio-based polymeric complex fluids (OutBioPoly)

Complex fluids play an emerging role in fundamental research and have wide-ranging medical and industrial uses, ranging from biological fluids and drug delivery to food, textile, and personal care products. Complex fluids manifest non-Newtonian rheological behavior, changing their structures and properties due to shearinduced supramolecular transitions, leading to large changes (shear-thinning or shear-thickening) in bulk viscosity. This project focus on an innovative high-throughput thermomechanical approach to induce supramolecular transitions in polymeric bio-based complex fluids, specifically, biopolymers in natural solvents. High shear rates will promote the formation of out-of-equilibrium structures. The aims are to understand the supramolecular transition mechanism, improve thermomechanical processes for regenerating materials, and ultimately produce materials with interesting properties for future applications. These materials may have novel applications ranging from shear-thickening bulletproof jackets or heat-resistant materials for aerospace to self-healing membranes.

Published works

Insights into the Hierarchical Assembly of a Chemically Diverse Peptide Hydrogel Derived from Human Semenogelin IA peptide corresponding to a 13-residue segment of the human protein semenogelin I has been shown to generate a hydrogel consisting of amyloid-like fibrils. The relative chemical diversity (compared to synthetic de novo sequences) with 11 distinct amino acids makes this peptide (P0) an ideal candidate for investigating the role of individual residues in gelation. Herein, the N-terminal residues have been sequentially removed to furnish a series of truncated peptides, P1–P10, ranging from 12 to 3 residues in length. FTIR spectroscopy investigations reveal that P0–P6 forms a β-sheet secondary structure while shorter sequences do not self-assemble. Site-specific isotope labeling of the amide backbone of P0–P2 with the IR-sensitive vibrational probe 13C═O yields FTIR spectra indicative of the initial formation of a kinetic product that slowly transforms into a structurally different thermodynamic product. The effects of the isotopic labels on the IR spectra facilitate the assignment of parallel and antiparallel structures, which are sometimes coexistent. Additional IR studies of three PheCN-labeled P0 sequences are consistent with an H-bonded β-sheet amide core, spanning the 7 central residues. The macromolecular assembly of peptides that form β-sheets was assessed by cryo-TEM, SAXS/WAXS, and rheology. Cryo-TEM images of peptides P1–P6 display μm-long nanofibrils. Peptides P0–P3 generate homogeneous hydrogels composed of colloidally stable nanofibrils, and P4–P6 undergo phase separation due to the accumulation of attractive interfibrillar interactions. Three amino acid residues, Ser39, Phe40, and Gln43, were identified to be of particular interest in the truncated peptide series as the removal of any one of them, as the sequence shortens, leads to a major change in material properties.

Talk 

Gentile L., "Cellulose-based active materials: from semidilute unentangled solutions to films  project" ECIS2024 38th Conference of the European Colloid & Interface Society- September 1-6, 2024 - Copenhagen (Denmark)

Instrumentation 

Electrospinning/Electrospraying Multi-Nozzle system

Equipped with: 

Single High Voltage Power Supply Unit: 0-30kVolt

Syringe Heater

EFA150 Fume hood 

Optical Microscope with polarizers

Equipped with: 

63x

Under Delivery From Leica

Microfluidics Devices

Double pumps 

Herringbone Mixer Chip