Chemical and Biomolecular Engineering - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 18
-
ItemNo Preview AvailableSite‐Selective Coordination Assembly of Dynamic Metal‐Phenolic Networks(Wiley, 2022-08-22)Abstract Coordination states of metal‐organic materials are known to dictate their physicochemical properties and applications in various fields. However, understanding and controlling coordination sites in metal‐organic systems is challenging. Herein, we report the synthesis of site‐selective coordinated metal‐phenolic networks (MPNs) using flavonoids as coordination modulators. The site‐selective coordination was systematically investigated experimentally and computationally using ligands with one, two, and multiple different coordination sites. Tuning the multimodal Fe coordination with catechol, carbonyl, and hydroxyl groups within the MPNs enabled the facile engineering of diverse physicochemical properties including size, selective permeability (20–2000 kDa), and pH‐dependent degradability. This study expands our understanding of metal‐phenolic chemistry and provides new routes for the rational design of structurally tailorable coordination‐based materials.
-
ItemHighly Stable and Active Flexible Electrocatalysts Derived from Lotus Fibers(WILEY-V C H VERLAG GMBH, 2023-03)Abstract The stability and activity of electrocatalysts are fundamental in energy‐related applications (e.g., hydrogen generation and energy storage). Electrocatalysts degrade over time when the active centers are not strongly anchored to the support. However, if the active centers are too strongly anchored, the activity of the electrocatalysts decreases due to reduced accessibility to reactants. Herein, a strategy is presented to balance the stability and activity of different active materials using a natural and flexible support material that can be woven and carbonized. Lotus fibers, which have surface hydroxyl and phenolic groups, high mechanical strength, and a mesoscale porosity post‐pyrolysis, are used to load diverse functional metal‐containing materials such as metal–organic frameworks, 2D materials, metal sulfide nanoparticles, metal ions, and high‐entropy alloys. After pyrolysis, the electrocatalysts display flexibility, high catalytic performance, and long‐term stability, outperforming commercial benchmarks (e.g., Pt/C) in specific scenarios for water splitting, liquid batteries, and flexible electronics.
-
ItemSite-Selective Coordination Assembly of Dynamic Metal-Phenolic Networks(WILEY-V C H VERLAG GMBH, 2022-08-22)Coordination states of metal-organic materials are known to dictate their physicochemical properties and applications in various fields. However, understanding and controlling coordination sites in metal-organic systems is challenging. Herein, we report the synthesis of site-selective coordinated metal-phenolic networks (MPNs) using flavonoids as coordination modulators. The site-selective coordination was systematically investigated experimentally and computationally using ligands with one, two, and multiple different coordination sites. Tuning the multimodal Fe coordination with catechol, carbonyl, and hydroxyl groups within the MPNs enabled the facile engineering of diverse physicochemical properties including size, selective permeability (20-2000 kDa), and pH-dependent degradability. This study expands our understanding of metal-phenolic chemistry and provides new routes for the rational design of structurally tailorable coordination-based materials.
-
ItemExploiting Molecular Dynamics in Composite Coatings to Design Robust Super-Repellent Surfaces(WILEY, 2022-02)Fluorinated motifs are promising for the engineering of repellent coatings, however, a fundamental understanding of how to effectively bind these motifs to various substrates is required to improve their stability in different use scenarios. Herein, the binding of fluorinated polyhedral oligomeric silsesquioxanes (POSS) using a cyanoacrylate glue (binder) is computationally and experimentally evaluated. The composite POSS-binder coatings display ultralow surface energy (≈10 mJ m-2 ), while still having large surface adhesions to substrates (300-400 nN), highlighting that super-repellent coatings (contact angles >150°) can be readily generated with this composite approach. Importantly, the coatings show super-repellency to both corrosive liquids (e.g., 98 wt% H2 SO4 ) and ultralow surface tension liquids (e.g., alcohols), with ultralow roll-off angles (<5°), and tunable resistance to liquid penetration. Additionally, these coatings demonstrate the potential in effective cargo loading and robust self-cleaning properties, where experimental datasets are correlated with both relevant theoretical predictions and systematic all-atom molecular dynamics simulations of the repellent coatings. This work not only holds promise for chemical shielding, heat transfer, and liquid manipulations but offers a facile yet robust pathway for engineering advanced coatings by effectively combining components for their mutually desired properties.
-
ItemAssembly of Bioactive Nanoparticles via Metal-Phenolic Complexation(Wiley, 2022)The integration of bioactive materials (e.g., proteins and genes) into nanoparticles holds promise in fields ranging from catalysis to biomedicine. However, it is challenging to develop a simple and broadly applicable nanoparticle platform that can readily incorporate distinct biomacromolecules without affecting their intrinsic activity. Herein, a metal-phenolic assembly approach is presented whereby diverse functional nanoparticles can be readily assembled in water by combining various synthetic and natural building blocks, including poly(ethylene glycol), phenolic ligands, metal ions, and bioactive macromolecules. The assembly process is primarily mediated by metal-phenolic complexes through coordination and hydrophobic interactions, which yields uniform and spherical nanoparticles (mostly <200 nm), while preserving the function of the incorporated biomacromolecules (siRNA and five different proteins used). The functionality of the assembled nanoparticles is demonstrated through cancer cell apoptosis, RNA degradation, catalysis, and gene downregulation studies. Furthermore, the resulting nanoparticles can be used as building blocks for the secondary engineering of superstructures via templating and cross-linking with metal ions. The bioactivity and versatility of the platform can potentially be used for the streamlined and rational design of future bioactive materials.
-
ItemLuminescent Metal-Phenolic Networks for Multicolor Particle Labeling(WILEY-V C H VERLAG GMBH, 2021-11-15)The development of fluorescence labeling techniques has attracted widespread interest in various fields, including biomedical science as it can facilitate high-resolution imaging and the spatiotemporal understanding of various biological processes. We report a supramolecular fluorescence labeling strategy using luminescent metal-phenolic networks (MPNs) constructed from metal ions, phenolic ligands, and common and commercially available dyes. The rapid labeling process (<5 min) produces ultrathin coatings (≈10 nm) on diverse particles (e.g., organic, inorganic, and biological entities) with customized luminescence (e.g., red, blue, multichromatic, and white light) simply through the selection of fluorophores. The fluorescent coatings are stable at pH values from 1 to 8 and in complex biological media owing to the dominant π interactions between the dyes and MPNs. These coatings exhibit negligible cytotoxicity and their strong fluorescence is retained even when internalized into intracellular compartments. This strategy is expected to provide a versatile approach for fluorescence labeling with potential in diverse fields across the physical and life sciences.
-
ItemEngineered Coatings via the Assembly of Amino‐Quinone Networks(Wiley, 2021-02)Abstract Engineering coatings with precise physicochemical properties allows for control over the interface of a material and its interactions with the surrounding environment. However, assembling coatings with well‐defined properties on different material classes remains a challenge. Herein, we report a co‐assembly strategy to precisely control the structure and properties (e.g., thickness, adhesion, wettability, and zeta potential) of coatings on various materials (27 substrates examined) using quinone and polyamine building blocks. By increasing the length of the amine building blocks from small molecule diamines to branched amine polymers, we tune the properties of the films, including the thickness (from ca. 5 to ca. 50 nm), interfacial adhesion (0.05 to 5.54 nN), water contact angle (130 to 40°), and zeta potential (−42 to 28 mV). The films can be post‐functionalized through the in situ formation of diverse nanostructures, including nanoparticles, nanorods, and nanocrystals. Our approach provides a platform for the rational design of engineered, substrate‐independent coatings for various applications.
-
ItemFluorinated Metal-Organic Coatings with Selective Wettability(AMER CHEMICAL SOC, 2021-07-07)Surface chemistry is a major factor that determines the wettability of materials, and devising broadly applicable coating strategies that afford tunable and selective surface properties required for next-generation materials remains a challenge. Herein, we report fluorinated metal-organic coatings that display water-wetting and oil-repelling characteristics, a wetting phenomenon different from responsive wetting induced by external stimuli. We demonstrate this selective wettability with a library of metal-organic coatings using catechol-based coordination and silanization (both fluorinated and fluorine-free), enabling sensing through interfacial reconfigurations in both gaseous and liquid environments, and establish a correlation between the coating wettability and polarity of the liquids. This selective wetting performance is substrate-independent, spontaneous, durable, and reversible and occurs over a range of polar and nonpolar liquids (60 studied). These results provide insight into advanced liquid-solid interactions and a pathway toward tuning interfacial affinities and realizing robust, selective superwettability according to the surrounding conditions.
-
ItemExploiting Supramolecular Dynamics in Metal-Phenolic Networks to Generate Metal-Oxide and Metal-Carbon Networks(WILEY-V C H VERLAG GMBH, 2021-06-21)Supramolecular complexation is a powerful strategy for engineering materials in bulk and at interfaces. Metal-phenolic networks (MPNs), which are assembled through supramolecular complexes, have emerged as suitable candidates for surface and particle engineering owing to their diverse properties. Herein, we examine the supramolecular dynamics of MPNs during thermal transformation processes. Changes in the local supramolecular network including enlarged pores, ordered aromatic packing, and metal relocation arise from thermal treatment in air or an inert atmosphere, enabling the engineering of metal-oxide networks (MONs) and metal-carbon networks, respectively. Furthermore, by integrating photo-responsive motifs (i.e., TiO2 ) and silanization, the MONs are endowed with reversible superhydrophobic (>150°) and superhydrophilic (≈0°) properties. By highlighting the thermodynamics of MPNs and their transformation into diverse materials, this work offers a versatile pathway for advanced materials engineering.
-
ItemMetal–Phenolic Networks as Tunable Buffering Systems(American Chemical Society (ACS), 2021)The buffering effects displayed by pH‐responsive polymers have recently gained attention in diverse fields such as nanomedicine and water treatment. However, creating libraries of modular and versatile polymers that can be readily integrated within existing materials remains challenging, hence restricting applications inspired by their buffering capacity. Herein, we propose the use of metal–phenolic networks (MPNs) as tunable buffering systems and through mechanistic studies show that their buffering effects are driven by pH‐responsive, multivalent metal–phenolic coordination. Owing to such supramolecular interactions, MPNs exhibit ~2‐fold and 3‐fold higher buffering capacity than polyelectrolyte complexes and commercial buffer solutions, respectively. We demonstrate that the MPN buffering effects are retained after deposition onto solid supports, thereby allowing stabilization of aqueous environmental pH for 1 week. Moreover, by using different metals and ligands for the films, the endosomal escape capabilities of coated nanoparticles can be tuned, where higher buffering capacity leads to greater endosomal escape. This study forms a fundamental basis for developing future metal–organic buffering materials.