The objective of this study was to characterize influence of different cooling and heating rates on gelation of fish gelatin (FG)-gum arabic (GA) complex coacervate phase using rheological measurements. For the coacervate phase prepared at 10°C, the gelling temperature, melting temperature, gel strength, and stress relaxation decreased with increasing cooling or heating rate, however, no gelation was observed at the highest cooling rate of 0.05°C/min. Similar trends were obtained for the coacervates phase prepared at 30°C, but the gelation did not occur at a cooling rate of 0.033 or 0.05°C/min. The results indicated that rheological properties of FG-GA coacervate gels were highly dependent to the cooling process, where more thermos-stable and stronger gels formed at slower cooling. This was probably because of higher degree of molecular rearrangements, more hydrogen bindings, and formation of greater junction zones into the gel network at slower cooling rates. However, all of the FG-GA coacervate gels obtained at different cooling rates were classified as a weak physical gel.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.05.096 | DOI Listing |
J Am Chem Soc
January 2025
Institute of Advanced Materials (INAM), Universitat Jaume I, Castelló de la Plana 12071, Spain.
Phase-separated coacervates can enhance reaction kinetics and guide multilevel self-assembly, mimicking early cellular evolution. In this work, we introduce "reactive" complex coacervates that undergo chemically triggered self-immolative transformations, directing the self-assembly of the reaction products within their matrix. These self-assemblies then evolve to show life-like properties such as budding and membrane formation.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Center for Sustainable Materials (SusMat), School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Complex coacervation is a form of liquid-liquid phase separation, whereby two types of macromolecules, usually bearing opposite net charges, self-assemble into dense microdroplets driven by weak molecular interactions. Peptide-based coacervates have recently emerged as promising carriers to deliver large macromolecules (nucleic acids, proteins and complex thereof) inside cells. Thus, it is essential to understand their assembly/disassembly mechanisms at the molecular level in order to tune the thermodynamics of coacervates formation and the kinetics of cargo release upon entering the cell.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Université Le Havre Normandie, Normandie Univ, URCOM, UR 3221, Le Havre F-76600, France. Electronic address:
In this study, fungal chitosan (FC) and gum Arabic (GA) were combined to develop non-animal complex coacervates for encapsulation. Optimal coacervate formation occurred at pH 5 with a 1:4 (FC:GA) weight ratio. Innovative complementary approaches, including rheology coupled with phase-contrast microscopy, revealed that FC-GA coacervates could withstand high shear rates, reverting to their original structure afterward, making them suitable for industrial applications.
View Article and Find Full Text PDFProtein Sci
February 2025
Department of Cell Biology and Genetics, Texas A&M Health Science Center, Texas A&M University, Bryan, Texas, USA.
The Drosophila intrinsically disordered protein Ultrabithorax (Ubx) undergoes a series of phase transitions, beginning with noncovalent interactions between apparently randomly organized monomers, and evolving over time to form increasingly ordered coacervates. This assembly process ends when specific dityrosine covalent bonds lock the monomers in place, forming macroscale materials. Inspired by this hierarchical, multistep assembly process, we analyzed the impact of protein concentration, assembly time, and subphase composition on the early, noncovalent stages of Ubx assembly, which are extremely sensitive to their environment.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Peking University, school of materials science and engineering, CHINA.
Dynamic liquid-liquid phase separation (LLPS) of intrinsically disordered proteins (IDPs) and associated assembly and disassembly of biomolecular condensates play crucial roles in cellular organization and metabolic networks. These processes are often regulated by supramolecular interactions. However, the complex and disordered structures of IDPs, coupled with their rapid conformational fluctuations, pose significant challenges for reconstructing supramolecularly-regulated dynamic LLPS systems and quantitatively illustrating variations in molecular interactions.
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