Liquid phase electron microscopy
LPEM provides real-time direct information of nanoscale processes such as self-assembly, nucleation and growth and particle-particle interactions. Continued development of this technology is essential for providing information on the currently unknown processes which govern material formation. This includes innovations liquid cells, sample preparation, data acquisition and data processing. With these advancements we aim to visualize the dynamic processes which govern material formation.
A Rizvi, et al. Observation of Liquid–Liquid-Phase Separation and Vesicle Spreading during Supported Bilayer Formation via Liquid-Phase Transmission Electron Microscopy. Nano Letters. 2021
H Wu, et al. Studying Reaction Mechanisms in Solution Using a Distributed Electron Microscopy Method. ACS Nano. 2021
W Gibson, JP Patterson. Liquid Phase Electron Microscopy Provides Opportunities in Polymer Synthesis and Manufacturing. Macromolecules. 2021
JT can Ommen, et al. Liquid Phase Transmission Electron Microscopy with Flow and Temperature Control. Journal of Materials Chemistry C. 2020
A Ianiro, et al. Liquid-liquid phase separation during amphiphilic self-assembly. Nat Chem. 2019
Doxil, liposome encapsulated cancer drug
Cryo-electron microscopy
CryoEM provides high resolution two and three dimensional structural information on materials in liquids. Using time resolved sampling it is possible to trap transient structures for high resolution inspection and accurately map out the structural landscapes of materials as they form. We aim to combine this information with the direct kinetic information from LPEM to provide combined data-sets with quantitative information on how and why materials form.
PJ Hurst, et al. Visualizing Teixobactin Supramolecular Assemblies and Cell Wall Damage in B. Subtilis Using Cryoem. ACS Omega. 2021
MA Moradi, et al. Spontaneous organization of supracolloids into three-dimensional structured materials. Nature Materials. 2021
PJ Hurst, et al. Ring-opening polymerization-induced crystallization-driven self-assembly of poly-L-lactide-block-polyethylene glycol block copolymers (ROPI-CDSA). Nature Communications. 2020
AF Ogata, et al. Revealing Nonclassical Nucleation Pathways Using Cryogenic Electron Microscopy. ACS Symposium Series. 2020
AF Ogata, et al. Direct Observation of Amorphous Precursor Phases in the Nucleation of Protein-Metal-Organic-Frameworks. Journal of American Chemical Society. 2020
Liquid–liquid phase separation
Liquid–liquid phase separation of macromolecules is an important process in many biological and synthetic systems. The process results in the formation of coacervates that act as membraneless compartments for storage and concentrated polymer precursors to solid phase materials. For example, Spider silks is formed through a coacervate intermediate which enables the spinning of these high performance materials. The Patterson Lab studies the liquid-liquid phase separation of block copolymers and its role in controlling self-assembly processes. We have demonstrated that coacervates can serve as precursors to self-assembled nanoparticles, microparticles, microporous membrane and nanoporous fibers.
A Rizvi, et al. Observation of Liquid–Liquid-Phase Separation and Vesicle Spreading during Supported Bilayer Formation via Liquid-Phase Transmission Electron Microscopy. Nano Letters. 2021
A Rizvi, et al. Nonionic Block Copolymer Coacervates. Macromolecules. 2020
A Ianiro, et al. Liquid-liquid phase separation during amphiphilic self-assembly. Nat Chem. 2019
Ring Opening Polymerization-Induced Crystallization-Driven Self-Assembly
The properties and performance of self-assembled block copolymers are intrinsically linked to both their molecular and hierarchical structure. However, facilitating independent control over these variables using scalable one-pot chemistry remains a key challenge. To address this issue, we recently developed ring opening polymerization-induced crystallization-driven self-assembly (ROPI-CDSA) of poly-L-lactide-block-polyethylene glycol block copolymers into 1D, 2D and 3D nanostructures. Through a multifaceted analysis using cryo-transmission electron microscopy, wide-angle x-ray scattering, Fourier transform infrared spectroscopy, and turbidity studies, we have determined that self-assembly occurs via unimer growth or particle aggregation depending on the structure of the block copolymer (see inset). A key feature of ROPI-CDSA is that the polymerization time is much shorter than the self-assembly relaxation time, resulting in a non-equilibrium self-assembly process. We are currently researching how varying the rate of polymerization affects the self-assembly process and are developing new protocols to extend ROPI-CDSA to a wide range of polylactones, the most well-known class of biocompatible polymers.
PJ Hurst, AA Graham, JP Patterson. Gaining Structural Control by Modification of Polymerization Rate in Ring-Opening Polymerization-Induced Crystallization-Driven Self-Assembly. ACS Polymers. 2022
PJ Hurst, et al. Ring-opening polymerization-induced crystallization-driven self-assembly of poly-L-lactide-block-polyethylene glycol block copolymers (ROPI-CDSA). Nature Communications. 2020
protein-mof crystal growth
The encapsulation of proteins within metal-organic frameworks (MOFs) to form composites known as p-MOFs is an emerging technology in the biochemical industry for bio-sensing, biopharmaceuticals and bio-catalysis. A key advantage of p-MOFs is that they can be synthesized by simply mixing the metal, ligand and enzyme at room temperature in aqueous solutions, a process analogous to biomineralization. Post encapsulation the proteins can display chemical and thermal stabilities. Utilizing advanced electron microscopy and complementary characterization techniques, we investigate the nucleation and growth mechanisms of p-MOFs. Ultimately this project aims to build a link between the formation pathway and the final p-MOF crystals. This will enable an informed synthesis to finely tune p-MOF size, encapsulation efficiency, and catalytic activity.
GD Palma, S Geels, BP Carpenter, R Talosig, C Chen, F Marangoni, and JP Patterson. Cyclodextrin metal-organic framework-based protein biocomposites. Biomaterials Science. 2022
BP Carpenter, R Talosig, JT Mulvey, JG Merhan, J Esquivel, B Rose, AF Ogata, DA Fishman, and JP Patterson.Role of Molecular Modification and Protein Folding in the Nucleation and Growth of Protein–Metal–Organic Frameworks. Chemistry of Materials. 2022
AF Ogata, et al. Direct Observation of Amorphous Precursor Phases in the Nucleation of Protein-Metal-Organic-Frameworks. Journal of American Chemical Society. 2020
Materials Research Science and Engineering Center(MRSEC)
The Materials Research Science and Engineering Center (MRSEC) at the University of California, Irvine (UCI) builds on UCI’s strengths in multidisciplinary science and engineering research, experiential learning, world-class facilities, and commitment to diversity. The primary mission of the Center is to establish foundational knowledge in materials science and engineering of new classes of materials offering unique and broad functionality via an interplay among design, simulation, synthesis, and advanced characterization.
IRVINE MATERIALS RESEARCH INSTITUTE
The UC Irvine Materials Research Institute (IMRI) is among the world’s leading centers for the characterization of materials. It serves as an interdisciplinary nexus for the research and development of engineered and natural materials, systems and devices. The institute supports the highest-performance transmission electron microscopes available today, offering researchers a powerful tool for looking at the structure of matter – from millimeter to subatomic length scales – and revealing the functional properties of materials.
