Article
Chemistry, Physical
Aditya N. Singh, Arun Yethiraj
Summary: Research has shown that interactions between peptides rich in arginine and tyrosine are energetically driven, correlated with the number of pi-cation bonds, and exhibit similarities with LLPS. These peptides do not undergo coacervation like complexation, but rather exhibit phase separation similar to neutral polyion pairs.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Polymer Science
Sojeong Kim, Won Bo Lee, Nicolas R. de Souza, Soo-Hyung Choi
Summary: The segmental dynamics of complex coacervates were studied using quasi-elastic neutron scattering. It was found that the number of mobile chain segments and their dynamics increase with salt concentration in ammonium-based coacervates, whereas guanidinium-based coacervates show slow and comparable segmental relaxation regardless of salt concentration, possibly due to non-electrostatic interactions. The combination of chemical structure, salt concentration, and temperature plays a significant role in determining polymer chain dynamics influenced by the strength of ionic bonding.
Article
Biochemistry & Molecular Biology
Jin Zhou, Yuting Wan, Martien A. Cohen Stuart, Mingwei Wang, Junyou Wang
Summary: Protein-polyelectrolyte coacervation is regulated by factors such as pH, ionic strength, and the properties of the polymers involved. Moderate pH and ionic strength are essential for the formation of coacervate droplets. Excess polyelectrolytes are often needed for full complexation, and polymers with longer chains or primary amine groups and a branched structure have a stronger electrostatic interaction with proteins. Nevertheless, coacervates do not disrupt the protein structure and activity, indicating their safe encapsulation. The principles revealed in this study can guide the development of other protein-based coacervations.
Article
Chemistry, Multidisciplinary
Carolina Paganini, Umberto Capasso Palmiero, Sabrina Picciotto, Alessandro Molinelli, Ilaria Porello, Giorgia Adamo, Mauro Manno, Antonella Bongiovanni, Paolo Arosio
Summary: Programmable coacervates based on zwitterionic polymers are designed as dynamic materials for ion exchange bioseparation. These materials offer a new purification method for efficient and gentle separation of nanoparticles, with great potential for various applications.
Article
Chemistry, Physical
Jin Zhou, Ying Cai, Yuting Wan, Bohang Wu, Jinbo Liu, Xinxin Zhang, Weiwei Hu, Martien A. Cohen Stuart, Junyou Wang
Summary: This study presents a sequential coacervation process for efficiently isolating and purifying proteins with different isoelectric points (pIs) from a mixed solution. By introducing a suitable polyelectrolyte at the appropriate pH and ionic strength, selective complex coacervation can be achieved, enabling the separation of proteins with high purity.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Chemistry, Applied
Jiabao Zheng, Qing Gao, Ge Ge, Jihong Wu, Chuan-he Tang, Mouming Zhao, Weizheng Sun
Summary: Sodium chloride was found to regulate the phase transition of beta-CG/LYS complexes, affecting the zeta-potential of the biomacromolecules and leading to a significant exothermic enthalpy change as the main driving force behind complex formation. The study also demonstrated dynamic protein exchange in coacervate droplets, similar to that in polyelectrolyte-based complex coacervates.
FOOD HYDROCOLLOIDS
(2022)
Article
Chemistry, Multidisciplinary
Hang Zhai, Tatyana Bendikov, Assaf Gal
Summary: The formation of intricate biosilica nanostructures in simple organisms is far superior to current synthetic manufacturing. A biomimetic polycation-polyanion system was used to study polymer-induced silicification. It was found that the polymer phase separation process, rather than silica-polymer interactions, controls silica precipitation. Ionic strength can be used to tune the morphology and structure of the precipitates. The results highlight the importance of hydrated polymer condensates in this process and pave the way for developing nanoscale bioinspired silica morphologies based on liquid-liquid phase separation chemistry.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Multidisciplinary Sciences
Avigail Baruch Leshem, Sian Sloan-Dennison, Tlalit Massarano, Shavit Ben-David, Duncan Graham, Karen Faulds, Hugo E. Gottlieb, Jordan H. Chill, Ayala Lampel
Summary: Inspired by the role of intracellular liquid-liquid phase separation (LLPS) in the formation of membraneless organelles, researchers have developed dynamic compartments formed by LLPS of intrinsically disordered proteins (IDPs) or short peptides. However, the molecular mechanisms underlying the formation of biomolecular condensates have not been fully understood. In this study, the authors demonstrate that the LLPS propensity, dynamics, and encapsulation efficiency of designed peptide condensates can be tuned by subtle changes to the peptide composition. This sequence-structure-function correlation could pave the way for the future development of compartments for various applications.
NATURE COMMUNICATIONS
(2023)
Article
Biochemistry & Molecular Biology
Pratik Mullick, Antonio Trovato
Summary: The formation of droplets of bio-molecular condensates through liquid-liquid phase separation (LLPS) is crucial for maintaining cellular homeostasis. This study develops a predictor for LLPS that combines the ability to form pi-pi interactions and the propensity to stabilize the beta-pairing interaction mode. The results show improved performance and suggest that increasing the main chain conformational entropy of the beta-pairing maintained droplet state enhances the likelihood of phase separation. Interestingly, the entropic stabilization of the droplet state appears to proceed differently depending on the proportion of droplet-driving proteins present in the positive set.
Article
Chemistry, Multidisciplinary
Aoon Rizvi, Justin T. Mulvey, Joseph P. Patterson
Summary: The study investigates the formation of block-copolymer-supported bilayers using LP-TEM, revealing two formation pathways involving liquid droplets or vesicles as intermediates. The results suggest that bilayer assembly methods via liquid droplet intermediates are beneficial for forming pristine supported bilayers, and supported bilayers inside liquid cells may be useful for imaging membrane interactions with proteins and nanoparticles in the future.
Review
Chemistry, Multidisciplinary
Xiao Xiao, Liyan Jia, Jianbin Huang, Yiyang Lin, Yan Qiao
Summary: Coacervation, or liquid-liquid phase separation, is a crucial phenomenon for molecular assembly and has various applications in the fields of biomolecule extraction and drug delivery.
CHEMISTRY-AN ASIAN JOURNAL
(2022)
Article
Chemistry, Physical
Anna Bratek-Skicki, Margot Van Nerom, Dominique Maes, Peter Tompa
Summary: Biomolecular condensates are membraneless organelles formed through liquid-liquid phase separation that can concentrate a variety of molecules in cells. They are highly dynamic and play crucial roles in cellular organization and physiology, with links to diseases like neurodegenerative disorders and cancer. This review discusses the mechanisms, dynamics, and evolution of these biological colloids, particularly focusing on their surface properties and interactions with other cellular components. Experimental approaches for characterizing the formation, interactions, and functions of these cellular colloidal organelles are also summarized.
ADVANCES IN COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Max Renner-Rao, Franziska Jehle, Tobias Priemel, Emilie Duthoo, Peter Fratzl, Luca Bertinetti, Matthew J. Harrington
Summary: This study investigates the structure and formation process of mussel plaque, a bioinspired underwater glue composed of proteins, using 3D electron microscopic imaging. The study reveals that micro-and nanopores form spontaneously during the secretion of protein-filled secretory vesicles. Researchers also discovered that each vesicle contains a fluid condensate consisting of histidine and/or DOPA-rich proteins, which are likely the required ingredients for building the plaque. By rupturing vesicles under specific buffering conditions, controlled phase separation of different proteins occurs, resulting in the formation of a porous microplaque with fluid condensates within the pores. The results suggest that combining phase separation with tunable cross-linking kinetics could be effective for microfabricating hierarchically porous materials via self-assembly.
Article
Chemistry, Physical
Tea-Yon Kim, Eui Hyun Suh, Eric Firestone, Austin L. Raithel, Chunqiang Q. Xu, Xianglin Ke, Dong-Jin Yun, Jaeyoung Jang, John McCracken, Thomas W. Hamann
Summary: Transition-metal complexes with excellent charge transport properties in solid films show promise for modern electronics. In this study, the effect of 4-tert-butylpyridine (TBP) on the charge transport mechanism and film properties of [Cu(dmbpy)(2)](2+/+) (dmbpy = 6,6'-dimethyl-2,2'-bipyridine)-based molecular solids was investigated. The addition of TBP increases film conductivity and changes the transport mechanism from hopping to band-like transport through ligand-exchange reactions. These findings enhance our understanding of molecular metal complex solids and enable optoelectronic applications.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Shi Yang, Han Yu, Xiuli Xu, Ting Yang, Yue Wei, Rui Zan, Xiaonong Zhang, Qingming Ma, Ho Cheung Shum, Yang Song
Summary: This article presents the synthesis of a peptide-based RNA sensor by connecting aggregation-induced emission luminogen (AIEgen) tetraphenylethylene (TPE) to tandem peptide repeats of (RRASL)n (n = 1, 2, 3). The conjugation of TPE promotes liquid-liquid phase separation of the peptide repeats, with significantly decreased minimum coacervation concentration (MCC) compared to the untagged counterparts. Furthermore, the luminescence of TPE-(RRASL)n is greatly enhanced with increasing RNA concentration, attributed to the constricted rotation of the TPE moiety within the droplet phase formed by peptide/RNA coacervates. In addition, TPE-(RRASL)n can efficiently penetrate human gallbladder carcinoma cells, translocate into the nucleus, and colocalize with intracellular RNA, highlighting its potential as a droplet-based biosensor for intracellular RNA imaging.