- Chemical and Biomolecular Engineering - Research Publications
Chemical and Biomolecular Engineering - Research Publications
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ItemAntifogging Surface Facilitated by Nanoscale Coatings with Controllable Hydrophobicity and Cross-Linking DensityNam, E ; Wong, EHH ; Tan, S ; Fu, Q ; Blencowe, A ; Qiao, GG (WILEY-V C H VERLAG GMBH, 2017-01)
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ItemBlood-Catalyzed RAFT PolymerizationReyhani, A ; Nothling, MD ; Ranji-Burachaloo, H ; McKenzie, TG ; Fu, Q ; Tan, S ; Bryant, G ; Qiao, GG (WILEY-V C H VERLAG GMBH, 2018-08-06)The use of hemoglobin (Hb) contained within red blood cells to drive a controlled radical polymerization via a reversible addition-fragmentation chain transfer (RAFT) process is reported for the first time. No pre-treatment of the Hb or cells was required prior to their use as polymerization catalysts, indicating the potential for synthetic engineering in complex biological microenvironments without the need for ex vivo techniques. Owing to the naturally occurring prevalence of the reagents employed in the catalytic system (Hb and hydrogen peroxide), this approach may facilitate the development of new strategies for in vivo cell engineering with synthetic macromolecules.
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ItemA novel solid state photocatalyst for living radical polymerization under UV irradiationFu, Q ; McKenzie, TG ; Ren, JM ; Tan, S ; Nam, E ; Qiao, GG (Nature Publishing Group: Open Access Journals - Option C, 2016-02-11)This study presents the development of a novel solid state photocatalyst for the photoinduced controlled radical polymerization of methacrylates under mild UV irradiation (λmax ≈ 365 nm) in the absence of conventional photoinitiators, metal-catalysts or dye sensitizers. The photocatalyst design was based on our previous finding that organic amines can act in a synergistic photochemical reaction with thiocarbonylthio compounds to afford well controlled polymethacrylates under UV irradiation. Therefore, in the current contribution an amine-rich polymer was covalently grafted onto a solid substrate, thus creating a heterogeneous catalyst that would allow for facile removal, recovery and recyclability when employed for such photopolymerization reactions. Importantly, the polymethacrylates synthesized using the solid state photocatalyst (ssPC) show similarly excellent chemical and structural integrity as those catalysed by free amines. Moreover, the ssPC could be readily recovered and re-used, with multiple cycles of polymerization showing minimal effect on the integrity of the catalyst. Finally, the ssPC was employed in various photo-"click" reactions, permitting high yielding conjugations under photochemical control.
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ItemPhotocontrolled Cargo Release from Dual Cross-Linked Polymer ParticlesTan, S ; Cui, J ; Fu, Q ; Nam, E ; Ladewig, K ; Ren, JM ; Wong, EHH ; Caruso, F ; Blencowe, A ; Qiao, GG (AMER CHEMICAL SOC, 2016-03-09)Burst release of a payload from polymeric particles upon photoirradiation was engineered by altering the cross-linking density. This was achieved via a dual cross-linking concept whereby noncovalent cross-linking was provided by cyclodextrin host-guest interactions, and irreversible covalent cross-linking was mediated by continuous assembly of polymers (CAP). The dual cross-linked particles (DCPs) were efficiently infiltrated (∼80-93%) by the biomacromolecule dextran (molecular weight up to 500 kDa) to provide high loadings (70-75%). Upon short exposure (5 s) to UV light, the noncovalent cross-links were disrupted resulting in increased permeability and burst release of the cargo (50 mol % within 1 s) as visualized by time-lapse fluorescence microscopy. As sunlight contains UV light at low intensities, the particles can potentially be incorporated into systems used in agriculture, environmental control, and food packaging, whereby sunlight could control the release of nutrients and antimicrobial agents.
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ItemFabrication of ultra-thin polyrotaxane-based films via solid-state continuous assembly of polymersTan, S ; Nam, E ; Cui, J ; Xu, C ; Fu, Q ; Ren, JM ; Wong, EHH ; Ladewig, K ; Caruso, F ; Blencowe, A ; Qiao, GG (ROYAL SOC CHEMISTRY, 2015)Surface-confined ultra-thin polyrotaxane (PRX)-based films with tunable composition, surface topology and swelling characteristics were prepared by solid-state continuous assembly of polymers (ssCAP). The PRX-based films supported cell attachment, and their degradation in biological media could be tuned. This study provides a versatile nano-coating technology with potential applications in biomedicine, including tissue engineering and medical devices.