Chemical and Biomolecular Engineering - Research Publications

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    Antifogging Surface Facilitated by Nanoscale Coatings with Controllable Hydrophobicity and Cross-Linking Density
    Nam, E ; Wong, EHH ; Tan, S ; Fu, Q ; Blencowe, A ; Qiao, GG (WILEY-V C H VERLAG GMBH, 2017-01-01)
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    Fullerene peapod nanoparticles as an organic semiconductor-electrode interface layer
    Ren, JM ; Subbiah, J ; Zhang, B ; Ishitake, K ; Satoh, K ; Kamigaito, M ; Qiao, GG ; Wong, EHH ; Wong, WWH (ROYAL SOC CHEMISTRY, 2016-01-01)
    A syndiotactic poly(methyl methacrylate) bottlebrush polymer has been shown to complex with C60 fullerene and assemble into nanoparticles that can be dispersed in polar organic solvents. This composite material was used as an electrode interlayer in organic solar cell (OSC) devices leading to enhanced device performance.
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    Fabrication of Chiral Stationary Phases via Continuous Assembly of Polymers for Resolution of Enantiomers by Liquid Chromatography
    Guntari, SN ; Nam, E ; Pranata, NN ; Chia, K ; Wong, EHH ; Blencowe, A ; Goh, TK ; Caruso, F ; Qiao, GG (WILEY-V C H VERLAG GMBH, 2014-11-01)
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    Continuous assembly of polymers via solid phase reactions
    Nam, E ; Kim, J ; Guntari, SN ; Seyler, H ; Fu, Q ; Wong, EHH ; Blencowe, A ; Jones, DJ ; Caruso, F ; Qiao, GG (ROYAL SOC CHEMISTRY, 2014-09-01)

    The formation of cross-linked polymer films, with tunable thickness, proceeds directionally from the substrate surface by controlled polymerization in the solid state.

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    Low-Fouling, Biospecific Films Prepared by the Continuous Assembly of Polymers
    Guntari, SN ; Wong, EHH ; Goh, TK ; Chandrawati, R ; Blencowe, A ; Caruso, F ; Qiao, GG (AMER CHEMICAL SOC, 2013-08-01)
    We report that the continuous assembly of polymers (CAP) approach, mediated by ring-opening metathesis polymerization (ROMP), is a facile and versatile technology to prepare engineered nanocoatings for various biomedical applications. Low-fouling coatings on particles were obtained by the formation of multicompositional, layered films via simple and efficient tandem CAP(ROMP) processes that are analogous to chain extension reactions. In addition, the CAP(ROMP) approach allows for the efficient postfunctionalization of the CAP films with bioactive moieties via cross-metathesis reactions between the surface-immobilized catalysts and symmetrical alkene derivatives. The combined features of the CAP(ROMP) approach (i.e., versatile polymer selection and facile functionalization) allow for the fabrication and surface modification of various types of polymer films, including those with intrinsic protein-repellent properties and selective protein recognition capabilities. This study highlights the various types of advanced coatings and materials that the CAP approach can be used to generate, which may be useful for biomedical applications.
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    Assembly of Free-Standing Polypeptide Films via the Synergistic Combination of Hyperbranched Macroinitiators, the Grafting-From Approach, and Cross-Chain Termination
    Wibowo, SH ; Wong, EHH ; Sulistio, A ; Guntari, SN ; Blencowe, A ; Caruso, F ; Qiao, GG (WILEY-V C H VERLAG GMBH, 2013-09-06)
    Cross-linked polypeptide-based films are fabricated via a novel and robust method employing surface-initiated ring opening polymerization of α-amino acid N-carboxyanhydrides (NCA-ROP). The judicious combination of amine-based hyperbranched macroinitiators and benzyl ester-protected NCA derivatives promotes network formation by cross-chain terminations, which allows the formation of stable cross-linked peptide-based capsules in a one-pot system.
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    Tuning the Properties of Polymer Capsules for Cellular Interactions
    Sun, H ; Cui, J ; Ju, Y ; Chen, X ; Wong, EHH ; Tran, J ; Qiao, GG ; Caruso, F (AMER CHEMICAL SOC, 2017-07-01)
    Particle-cell interactions are governed by, among other factors, the composition and surface properties of the particles. Herein, we report the preparation of various polymer capsules with different compositions and properties via atom transfer radical polymerization mediated continuous assembly of polymers (CAPATRP), where the cellular interactions of these capsules, particularly fouling and specific targeting, are examined by flow cytometry and deconvolution microscopy. Acrylated eight-arm poly(ethylene glycol) (8-PEG) and poly(N-(2-hydroxypropyl)-methacrylamide) (PHPMA) as well as methacrylated hyaluronic acid (HA), poly(glutamic acid) (PGA), and poly(methacrylic acid) (PMA) are used as macro-cross-linkers to obtain a range of polymer capsules with different compositions (PEG, PHPMA, HA, PGA, and PMA). Capsules composed of low-fouling polymers, PEG and PHPMA, show negligible association with macrophage Raw 264.7, monocyte THP-1, and HeLa cells. HA capsules, although moderately low-fouling (<22%) to HeLa, BT474, Raw 264.7, and THP-1 cells, exhibit high targeting specificity to CD44-over-expressing MDA-MB-231 cells. In contrast, PGA and PMA capsules show high cellular association toward phagocytic Raw 264.7 and THP-1 cells. These findings demonstrate the capability of the CAPATRP technique in preparing polymer capsules with specific cellular interactions.
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    Photocontrolled Cargo Release from Dual Cross-Linked Polymer Particles
    Tan, 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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    Fabrication of ultra-thin polyrotaxane-based films via solid-state continuous assembly of polymers
    Tan, S ; Nam, E ; Cui, J ; Xu, C ; Fu, Q ; Ren, JM ; Wong, EHH ; Ladewig, K ; Caruso, F ; Blencowe, A ; Qiao, GG (ROYAL SOC CHEMISTRY, 2015-01-01)
    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.
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    (Super)hydrophobic and Multilayered Amphiphilic Films Prepared by Continuous Assembly of Polymers
    Guntari, SN ; Khin, ACH ; Wong, EHH ; Goh, TK ; Blencowe, A ; Caruso, F ; Qiao, GG (WILEY-V C H VERLAG GMBH, 2013-11-06)