Chemical and Biomolecular Engineering - Research Publications

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    Synthetic peptide branched polymers for antibacterial and biomedical applications
    Shabani, S ; Hadjigol, S ; Li, W ; Si, Z ; Pranantyo, D ; Chan-Park, MB ; O’Brien-Simpson, NM ; Qiao, GG (Springer Science and Business Media LLC, )
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    Controlling the Supramolecular Architecture Enables High Lithium Cationic Conductivity and High Electrochemical Stability for Solid Polymer Electrolytes
    Xie, K ; Fu, Q ; Chen, F ; Zhu, H ; Wang, X ; Huang, G ; Zhan, H ; Liang, Q ; Doherty, CM ; Wang, D ; Qiao, GG ; Li, D (WILEY-V C H VERLAG GMBH, 2024-01-01)
    Solid polymer electrolytes (SPEs) are long sought after for versatile applications due to their low cost, light weight, flexibility, ease of scale‐up, and low interfacial impedance. However, obtaining SPEs with high Li+ conductivity (σ+) and high voltage stability to avoid concentrated polarization and premature capacity loss has proven challenging. Here a stretchable dry‐SPE is reported with a semi‐interpenetrating, supermolecular architecture consisting of a cross‐linked polyethylene oxide (PEO) tetra‐network and an alternating copolymer poly(ethylene oxide‐alt‐butylene terephthalate). Such a unique supermolecular architecture suppresses the formation of Li+/PEO intermolecular complex and enhances the oxidation stability of PEO‐based electrolyte, thus maintaining high chain segmental motion even with high salt loading (up to 50 wt%) and achieving a wide electrochemical stability window of 5.3 V. These merits enable the simultaneous accomplishment of high ionic conductivity and high Li+ transference number (t+) to enhance the energy efficiency of energy storage device, and electrochemical stability.
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    Divide and Conquer: A Novel Dual-Layered Hydrogel for Atmospheric Moisture Harvesting
    Feng, A ; Onggowarsito, C ; Mao, S ; Qiao, GG ; Fu, Q (WILEY-V C H VERLAG GMBH, 2023-07-21)
    Atmospheric water harvesting (AWH) has been recognized as a next-generation technology to alleviate water shortages in arid areas. However, the current AWH materials suffer from insufficient water adsorption capacity and high-water retention, which hinder the practical application of AWH materials. In this study, we developed a novel dual-layered hydrogel (DLH) composed of a light-to-heat conversion layer (LHL) containing novel polydopamine-manganese nanoparticles (PDA-Mn NPs) and a water adsorption layer (WAL) made of 2-(acryloyloxyethyl) trimethylammonium chloride (AEtMA). The WAL has a strong ability to adsorb water molecules in the air and has a high-water storage capacity, and the PDA-Mn NPs embedded in the LHL have excellent photothermal conversion efficiency, leading to light-induced autonomous water release. As a result, the DLH displays a high-water adsorption capacity of 7.73 g g-1 under optimal conditions and could near-quantitatively release captured water within 4 h sunlight exposure. Coupled with its low cost, we believed that the DLH will be one of the promising AWH materials for practical applications.
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    An Atom-Economic Enzymatic Cascade Catalysis for High-Throughput RAFT Synthesis of Ultrahigh Molecular Weight Polymers
    Li, R ; Zhang, S ; Li, Q ; Qiao, GG ; An, Z (WILEY-V C H VERLAG GMBH, 2022-11-14)
    High-throughput synthesis of well-defined, ultrahigh molecular weight (UHMW) polymers by green approaches is highly desirable but remains unexplored. We report the creation of an atom-economic enzymatic cascade catalysis, consisting of formate oxidase (FOx) and horseradish peroxidase (HRP), that enables high-throughput reversible addition-fragmentation chain transfer (RAFT) synthesis of UHMW polymers at volumes down to 50 μL. FOx transforms formic acid, a C1 substrate, and oxygen to CO2 and H2 O2 , respectively. CO2 can escape from solution while H2 O2 is harnessed in situ by HRP to generate radicals from acetylacetone for RAFT polymerization, leaving no waste accumulation in solution. Oxygen-tolerant RAFT polymerization using enzymatic cascade redox cycles was successfully performed in vials and 96-well plates to produce libraries of well-defined UHMW polymers, and represents the first example of high-throughput synthesis method of such materials at extremely low volumes.
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    Star-Peptide Polymers are Multi-Drug-Resistant Gram-Positive Bacteria Killers
    Li, W ; Hadjigol, S ; Mazo, AR ; Holden, J ; Lenzo, J ; Shirbin, SJ ; Barlow, A ; Shabani, S ; Huang, T ; Reynolds, EC ; Qiao, GG ; O'Brien-Simpson, NM (AMER CHEMICAL SOC, 2022-06-08)
    Antibiotic resistance in bacteria, especially Gram-positive bacteria like Staphylococcus aureus, is gaining considerable momentum worldwide and unless checked will pose a global health crisis. With few new antibiotics coming on the market, there is a need for novel antimicrobial materials that target and kill multi-drug-resistant (MDR) Gram-positive pathogens like methicillin-resistant Staphylococcus aureus (MRSA). In this study, using a novel mixed-bacteria antimicrobial assay, we show that the star-peptide polymers preferentially target and kill Gram-positive pathogens including MRSA. A major effect on the activity of the star-peptide polymer was structure, with an eight-armed structure inducing the greatest bactericidal activity. The different star-peptide polymer structures were found to induce different mechanisms of bacterial death both in vitro and in vivo. These results highlight the potential utility of peptide/polymers to fabricate materials for therapeutic development against MDR Gram-positive bacterial infections.
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    Thin film composite membranes for postcombustion carbon capture: Polymers and beyond
    Liu, M ; Nothling, MDD ; Zhang, S ; Fu, Q ; Qiao, GGG (PERGAMON-ELSEVIER SCIENCE LTD, 2022-03)
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    Evaporation reduction and salinity control in microalgae production ponds using chemical monolayers
    Poddar, N ; Scofield, J ; Shi, S ; Prime, EL ; Kentish, SE ; Qiao, GG ; Martin, GJO (ELSEVIER, 2022-07)
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    Ultrasonics in polymer science: applications and challenges
    Kumar, ARSS ; Padmakumar, A ; Kalita, U ; Samanta, S ; Baral, A ; Singha, NK ; Ashokkumar, M ; Qiao, GG (PERGAMON-ELSEVIER SCIENCE LTD, 2023-07)
    Ultrasonic waves in a liquid media generate both chemical and mechanistic effects that are actively used to perform chemical reactions, polymer synthesis, nanoparticle synthesis, colloids, food processing and so on. The application of sonochemistry in polymer science has been an interesting topic of research in the recent years. Ultrasonication acts as an external stimulus to initiate free radical polymerization (FRP) by the homolysis of the solvent, thereby generating radicals. The recent utilization of high frequency ultrasound (>100 KHz) for polymer synthesis has evoked new interest in the use of sonochemistry in the field of polymer chemistry, especially in chain growth polymerization reactions including reversible-deactivation radical polymerization (RDRP) techniques and novel applications. This review presents the principles of sonochemisty and the fundamental aspects governing the cavitation process and the radical generation process. A historical overview of the development of ultrasound-assisted polymerization with a focus on chain-growth polymerizations operating under pseudo-“living” conditions including nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP) and reversible addition–fragmentation chain transfer (RAFT) polymerization is provided. The utilization of ultrasound in polymer applications such as hydrogels, biomedical nanostructures, drug delivery, nanocomposite synthesis is also discussed. Unlike conventional FRP, ultrasound-initiated polymerization does not involve any external toxic chemical initiators, adds temporal control to the polymerization process, offers excellent control over the molecular weight and the microstructure of the final polymers, etc. The ultrasound assisted polymerization is a novel, clean and green technology, which can be investigated further by coupling with thermo-, mechano- or photochemical stimuli or flow chemistry. It has the potential to be scaled up into an industrial process.
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    High chain-end fidelity in sono-RAFT polymerization
    Padmakumar, AK ; Kumar, ARSS ; Allison-Logan, S ; Ashokkumar, M ; Singha, NK ; Qiao, GG (Royal Society of Chemistry, 2022-10-15)
    The chain-end fidelity of polymers synthesized via the sono-RAFT technique in an aqueous medium was investigated by performing chain extension studies and preparation of multi-block copolymers. Sono-RAFT polymerization of N,N-dimethylacrylamide (DMA), 2-hydroxyethyl acrylate (HEA) and N-acryloyl morpholine (NAM) exhibited higher conversion values, low dispersity and excellent chain-end fidelity. MALDI-TOF analysis indicated that the fraction of dead chains observed was almost negligible indicating high livingness of the polymer end groups. The sono-RAFT technique was compared to the photo-iniferter method by performing chain extension experiments. Polymers prepared via sono-RAFT were identical to those prepared via the photo-iniferter RAFT method in terms of livingness, and the polymer reached very high conversion within a fraction of the time compared to the latter method. An icosapenta block copolymer (25 blocks) was synthesized at room temperature within 46 h. The resulting block copolymer displayed a controlled molecular weight and a final dispersity of 1.39.