Co-reporter:Xi Qian, Alex Levenstein, Jennifer E. Gagner, Jonathan S. Dordick, and Richard W. Siegel
Langmuir February 11, 2014 Volume 30(Issue 5) pp:1295-1303
Publication Date(Web):February 11, 2014
DOI:10.1021/la4048006
Understanding nanomaterial-biomolecule interactions is critical to develop broad applications in sensors, devices, and therapeutics. During the past decade, in-depth studies have been performed on the effect of nanoscale surface topography on adsorbed protein structure and function. However, a fundamental understanding of nanobio interactions at concave surfaces is limited; the greatest challenge is to create a nanostructure that allows such interactions to occur and to be characterized. We have synthesized hollow nanocages (AuNG) through careful control of morphology and surface chemistry. Lysozyme was used as a model to probe interactions between a protein and these nanostructures. Solid Au nanoparticles with a similar morphology and surface chemistry were also used as a reference. Through a series of quantitative analyses of protein adsorption profiles and enzymatic activity assays of both nanobioconjugates, we discovered that a significant amount of protein could be delivered into the core of AuNG, while maintaining a substantial fraction of native activity.
Co-reporter:Sung-Gil Hong;Jae Hyun Kim;Ryang Eun Kim
Biotechnology and Bioprocess Engineering 2016 Volume 21( Issue 4) pp:573-579
Publication Date(Web):2016 August
DOI:10.1007/s12257-016-0373-4
Glucose oxidase (GOx) was immobilized onto graphene oxide (GRO) via three different preparation methods: enzyme adsorption (EA), enzyme adsorption and crosslinking (EAC), and enzyme adsorption, precipitation and crosslinking (EAPC). EAPC formulations, prepared via enzyme precipitation with 60% ammonium sulfate, showed 1,980 and 1,630 times higher activity per weight of GRO than those of EA and EAC formulations, respectively. After 59 days at room temperature, EAPC maintained 88% of initial activity, while EA and EAC retained 42 and 45% of their initial activities, respectively. These results indicate that the steps of precipitation and crosslinking in the EAPC formulation are critical to achieve high enzyme loading and stability of EAPC. EA, EAC and EAPC were used to prepare enzyme electrodes for use as glucose biosensors. Optimized EAPC electrode showed 93- and 25-fold higher sensitivity than EA and EAC, respectively. To further increase the sensitivity of EAPC electrode, multi-walled carbon nanotubes (MWCNTs) were mixed with EAPC for the preparation of enzyme electrode. Surprisingly, the EAPC electrode with additional 99.5 wt% MWCNTs showed 7,800-fold higher sensitivity than the EAPC electrode without MWCNT addition. Immobilization and stabilization of enzymes on GRO via the EAPC approach can be used for the development of highly sensitive biosensors as well as to achieve high enzyme loading and stability.
Co-reporter:Xi Qian, Utthara Rameshbabu, Jonathan S. Dordick, Richard W. Siegel
Biomaterials 2016 Volume 75() pp:305-312
Publication Date(Web):January 2016
DOI:10.1016/j.biomaterials.2015.10.025
Nanoscale curvature plays a critical role in nanostructure-biomolecule interactions, yet the understanding of such effects in concave nanostructures is still very limited. Because concave nanostructures usually possess convex surface curvatures as well, it is challenging to selectively study the proteins on concave surfaces alone. In this work, we have developed a novel and facile method to address this issue by desorbing proteins on the external surfaces of hollow gold nanocages (AuNG), allowing the selective characterization of retained proteins immobilized on their internal concave surfaces. The selective desorption of proteins was achieved via varying the solution ionic strength, and was demonstrated by both calculation and experimental comparison with non-hollow nanoparticles. This method has created a new platform for the discrete observation of proteins adsorbed inside AuNG hollow cores, and this work suggests an expanded biomedical application space for hollow nanomaterials.
Co-reporter:J. Dordick
Chemie Ingenieur Technik 2014 Volume 86( Issue 9) pp:
Publication Date(Web):
DOI:10.1002/cite.201450712
No abstract is available for this article.
Co-reporter:Xi Qian, Alex Levenstein, Jennifer E. Gagner, Jonathan S. Dordick, and Richard W. Siegel
Langmuir 2014 Volume 30(Issue 5) pp:1295-1303
Publication Date(Web):2017-2-22
DOI:10.1021/la4048006
Understanding nanomaterial-biomolecule interactions is critical to develop broad applications in sensors, devices, and therapeutics. During the past decade, in-depth studies have been performed on the effect of nanoscale surface topography on adsorbed protein structure and function. However, a fundamental understanding of nanobio interactions at concave surfaces is limited; the greatest challenge is to create a nanostructure that allows such interactions to occur and to be characterized. We have synthesized hollow nanocages (AuNG) through careful control of morphology and surface chemistry. Lysozyme was used as a model to probe interactions between a protein and these nanostructures. Solid Au nanoparticles with a similar morphology and surface chemistry were also used as a reference. Through a series of quantitative analyses of protein adsorption profiles and enzymatic activity assays of both nanobioconjugates, we discovered that a significant amount of protein could be delivered into the core of AuNG, while maintaining a substantial fraction of native activity.
Co-reporter:Navdeep Grover;Cerasela Zoica Dinu;Ravi S. Kane
Applied Microbiology and Biotechnology 2013 Volume 97( Issue 8) pp:3293-3300
Publication Date(Web):2013 April
DOI:10.1007/s00253-013-4797-x
Development of noncorrosive, cost-effective, environmentally benign, and broad-spectrum antimicrobial formulations is necessary for clinical, industrial, and domestic purposes. Many current decontaminating formulations are effective, but they require the use of strong oxidizing agents or organic solvents that have deleterious effects on human health and the surrounding environment. The emergence of antibiotic-resistant pathogens has motivated researchers to develop enzyme-based self-decontaminating formulations as alternatives to such chemical decontamination approaches. Hydrolytic and oxidative enzymes can be used to deactivate pathogens, including bacteria, spores, viruses, and fungi. Laccases, haloperoxidases, and perhydrolases catalyze the generation of biocidal oxidants, such as iodine, bromine, hypohalous acid (e.g., HOCl or HOBr), and peracetic acid. These oxidants have broad-spectrum antimicrobial activity. Due to the multi-pathway action of these oxidants, it has proven extremely difficult for microbes to gain resistance. Thus far, few examples have been reported on enzyme-based antimicrobial formulations. For these reasons, various enzyme-containing antimicrobial formulations are highlighted in this review.
Co-reporter:Siddhartha Shrivastava, Scott A. McCallum, Joseph H. Nuffer, Xi Qian, Richard W. Siegel, and Jonathan S. Dordick
Langmuir 2013 Volume 29(Issue 34) pp:10841-10849
Publication Date(Web):August 1, 2013
DOI:10.1021/la401985d
We identify specific acylphosphatase (AcP) residues that interact with silica nanoparticles (SNPs) using a combined NMR spectroscopy and proteomics-mass spectrometry approach. AcP associated with 4- and 15-nm diameter SNPs through a common and specific interaction surface formed by amino acids from the two α-helices of the protein. Greater retention of native protein structure was obtained on 4-nm SNPs than on 15-nm particles, presumably due to greater surface curvature-induced protein stabilization with the smaller SNPs. These results demonstrate that proteins may undergo specific and size-dependent orientation on nanoparticle surfaces. Our approach can be broadly applied to various protein–material systems to help understand in much greater detail the protein–nanomaterial interface; it would also encourage better modeling, and thus prediction and design, of the behavior of functional proteins adsorbed onto different surfaces.
Co-reporter:Siddhartha Shrivastava, Joseph H. Nuffer, Richard W. Siegel, and Jonathan S. Dordick
Nano Letters 2012 Volume 12(Issue 3) pp:1583-1587
Publication Date(Web):February 2, 2012
DOI:10.1021/nl2044524
We describe a method for determining the orientation of cytochrome c, RNase A, and lysozyme on silica nanoparticles (SNPs) using chemical modification combined with proteolysis-mass spectrometry. The proteins interacted with SNPs through preferential adsorption sites, which are dependent on SNP diameter; 4 nm SNPs induce greater structural stabilization than 15 nm particles, presumably due to greater surface curvature of the former. These results suggest that nanoparticle size and protein structure influence protein orientation on SNPs.
Co-reporter:Seok Joon Kwon, Mauricio Mora-Pale, Moo-Yeal Lee, Jonathan S Dordick
Current Opinion in Chemical Biology 2012 Volume 16(1–2) pp:186-195
Publication Date(Web):April 2012
DOI:10.1016/j.cbpa.2012.02.001
The enormous pool of chemical diversity found in nature serves as an excellent inventory for accessing biologically active compounds. This chemical inventory, primarily found in microorganisms and plants, is generated by a broad range of enzymatic pathways under precise genetic and protein-level control. In vitro pathway reconstruction can be used to characterize individual pathway enzymes, identify pathway intermediates, and gain an increased understanding of how pathways can be manipulated to generate natural product analogs. Moreover, through in vitro approaches, it is possible to achieve a diversification that is not restricted by toxicity, limited availability of intracellular precursors, or preconceived (by nature) regulatory controls. Additionally, combinatorial biosynthesis and high-throughput techniques can be used to generate both known natural products and analogs that would not likely be generated naturally. This current opinion review will focus on recent advances made in performing in vitro pathway-driven natural product diversification and opportunities for exploiting this approach for elucidating and entering this new chemical biology space.Highlights► Natural product pathways can be performed in vitro to generate new complex chemical and biological diversity. ► Core scaffold generating enzymes followed by tailoring enzymes can be exploited to yield novel bioactive compounds. ► High-throughput methodologies will play an increasingly important role in yielding unique chemical and biological diversity.
Co-reporter:Luciana Meli, Eric T. Jordan, Douglas S. Clark, Robert J. Linhardt, Jonathan S. Dordick
Biomaterials 2012 33(35) pp: 9087-9096
Publication Date(Web):
DOI:10.1016/j.biomaterials.2012.08.065
Co-reporter:Jennifer E. Gagner, Xi Qian, Maria M. Lopez, Jonathan S. Dordick, Richard W. Siegel
Biomaterials 2012 33(33) pp: 8503-8516
Publication Date(Web):
DOI:10.1016/j.biomaterials.2012.07.009
Co-reporter:Dhiral A. Shah, Seok-Joon Kwon, Shyam S. Bale, Akhilesh Banerjee, Jonathan S. Dordick, Ravi S. Kane
Biomaterials 2011 32(12) pp: 3210-3219
Publication Date(Web):
DOI:10.1016/j.biomaterials.2010.11.077
Co-reporter:Jennifer E. Gagner, Marimar D. Lopez, Jonathan S. Dordick, Richard W. Siegel
Biomaterials 2011 32(29) pp: 7241-7252
Publication Date(Web):
DOI:10.1016/j.biomaterials.2011.05.091
Co-reporter:Jianjun Miao, Ravindra C. Pangule, Elena E. Paskaleva, Elizabeth E. Hwang, Ravi S. Kane, Robert J. Linhardt, Jonathan S. Dordick
Biomaterials 2011 32(36) pp: 9557-9567
Publication Date(Web):
DOI:10.1016/j.biomaterials.2011.08.080
Co-reporter:Diana I Paredes;Kyle Watters;Derek J Pitman
BMC Structural Biology 2011 Volume 11( Issue 1) pp:
Publication Date(Web):2011 December
DOI:10.1186/1472-6807-11-42
Psychrophiles, cold-adapted organisms, have adapted to live at low temperatures by using a variety of mechanisms. Their enzymes are active at cold temperatures by being structurally more flexible than mesophilic enzymes. Even though, there are some indications of the possible structural mechanisms by which psychrophilic enzymes are catalytic active at cold temperatures, there is not a generalized structural property common to all psychrophilic enzymes.We examine twenty homologous enzyme pairs from psychrophiles and mesophiles to investigate flexibility as a key characteristic for cold adaptation. B-factors in protein X-ray structures are one way to measure flexibility. Comparing psychrophilic to mesophilic protein B-factors reveals that psychrophilic enzymes are more flexible in 5-turn and strand secondary structures. Enzyme cavities, identified using CASTp at various probe sizes, indicate that psychrophilic enzymes have larger average cavity sizes at probe radii of 1.4-1.5 Å, sufficient for water molecules. Furthermore, amino acid side chains lining these cavities show an increased frequency of acidic groups in psychrophilic enzymes.These findings suggest that embedded water molecules may play a significant role in cavity flexibility, and therefore, overall protein flexibility. Thus, our results point to the important role enzyme flexibility plays in adaptation to cold environments.
Co-reporter:Cerasela Zoica Dinu;Guangyu Zhu;Shyam Sundhar Bale;Gaurav An;Philippa J. Reeder;Karl Sanford;Gregg Whited;Ravi S. Kane
Advanced Functional Materials 2010 Volume 20( Issue 3) pp:392-398
Publication Date(Web):
DOI:10.1002/adfm.200901388
Abstract
Perhydrolase S54V (AcT) effectively catalyzes the perhydrolysis of propylene glycol diacetate (PGD) to generate peracetic acid (PAA). PAA is a potent oxidant used for sanitization and disinfection, with broad effectiveness against bacteria, yeasts, fungi, and spores. In this study, active and stable composites are developed by incorporating AcT–carbon nanotube conjugates into polymer and latex-based paint. At a conjugate loading of 0.16% (w/v), the composite generated 11 mM PAA in 20 min, capable of killing more than 99% spores initially charged at 106 colony-forming units per milliliter.
Co-reporter:Thomas V. Doherty, Mauricio Mora-Pale, Sage E. Foley, Robert J. Linhardt and Jonathan S. Dordick
Green Chemistry 2010 vol. 12(Issue 11) pp:1967-1975
Publication Date(Web):11 Oct 2010
DOI:10.1039/C0GC00206B
Effective pretreatment of lignocellulosic biomass is vital to its bioconversion to a usable liquid fuel. A growing body of work has focused on using room temperature ionic liquids (RTILs) to pretreat lignocellulose for subsequent fermentation. However, little is known about the physicochemical parameters of RTILs that promote effective pretreatment. In this work we examine the relationship between the Kamlet–Taft α, β, and π* solvent polarity parameters of different RTILs ([Emim][OAc], [Bmim][OAc], and [Bmim][MeSO4]) and effective pretreatment of lignocellulosic biomass. We find the β parameter is an excellent predictor of pretreatment efficacy. Acetate containing RTILs (β > 1.0) remove >32% of lignin from maple wood flour and significantly reduce cellulose crystallinity, resulting in >65% glucose yields after 12 h cellulase hydrolysis. Pretreatment in [Bmim][MeSO4] (β = 0.60) results in the removal of only 19% of the wood flour's lignin with no decrease in crystallinity, and no improvement in sugar yield over untreated wood flour. The addition of water and the dilution of the acetate anion with the methyl sulfate anion decrease the β value and subsequently have a negative impact on lignin extraction, cellulose crystallinity, and sugar yields.
Co-reporter:Luciana Meli, Jianjun Miao, Jonathan S. Dordick and Robert J. Linhardt
Green Chemistry 2010 vol. 12(Issue 11) pp:1883-1892
Publication Date(Web):12 Oct 2010
DOI:10.1039/C0GC00283F
Polymer electrospinning has emerged as a powerful technique for the fabrication of nanofibrous materials with high specific surface areas, controllable compositions, and high porosities for a wide range of applications. The electrospinning of biopolymers for fiber formation is of particular interest not only because the resources are renewable, but also because of the desirable characteristics of these biomacromolecules, including biocompatibility, biodegradability, and exquisite specificity. Electrospinning has routinely relied on organic solvents for the dissolution of polymeric materials, which are evaporated in the course of nanofiber formation. Most biopolymers, however, are insoluble in organic solvents so they cannot be electrospun using conventional approaches. Room temperature ionic liquids (RTILs) offer a solution to overcome these difficulties due to their exceptional solvent properties, allowing the electrospinning of recalcitrant biopolymers like cellulose. Moreover, non-volatile RTILs can provide a ‘greener’ processing alternative by preventing the release of harmful volatile compounds to the environment. This review provides an overview of the advantages and challenges of polymer electrospinning from highly conductive, non-volatile RTIL solutions, emphasizing the utility of RTILs in the dissolution of biopolymers, and the fabrication of advanced functional biopolymer composite fibers.
Co-reporter:Philippa J. Reeder, Yao-Ming Huang, Jonathan S. Dordick, and Christopher Bystroff
Biochemistry 2010 Volume 49(Issue 51) pp:
Publication Date(Web):November 23, 2010
DOI:10.1021/bi100975z
The sequential order of secondary structural elements in proteins affects the folding and activity to an unknown extent. To test the dependence on sequential connectivity, we reconnected secondary structural elements by their solvent-exposed ends, permuting their sequential order, called “rewiring”. This new protein design strategy changes the topology of the backbone without changing the core side chain packing arrangement. While circular and noncircular permutations have been observed in protein structures that are not related by sequence homology, to date no one has attempted to rationally design and construct a protein with a sequence that is noncircularly permuted while conserving three-dimensional structure. Herein, we show that green fluorescent protein can be rewired, still functionally fold, and exhibit wild-type fluorescence excitation and emission spectra.
Co-reporter:Seok Joon Kwon Dr.;Moon Il Kim Dr.;Bosung Ku Dr.;Lydie Coulombel Dr.;Jin-Hwan Kim Dr.;Joseph H. Shawky;Robert J. Linhardt
ChemBioChem 2010 Volume 11( Issue 4) pp:573-580
Publication Date(Web):
DOI:10.1002/cbic.200900674
Abstract
Receptor tyrosine kinases are critical targets for the regulation of cell survival. Cancer patients with abnormal receptor tyrosine kinases (RTK) tend to have more aggressive disease with poor clinical outcomes. As a result, human epidermal growth factor receptor kinases, such as EGFR (HER1), HER2, and HER3, represent important therapeutic targets. Several plant polyphenols including the type III polyketide synthase products (genistein, curcumin, resveratrol, and epigallocatechin-3-galate) possess chemopreventive activity, primarily as a result of RTK inhibition. However, only a small fraction of the polyphenolic structural universe has been evaluated. Along these lines, we have developed an in vitro route to the synthesis and subsequent screening of unnatural polyketide analogues with N-acetylcysteamine (SNAc) starter substrates and malonyl-coenzyme A (CoA) and methylmalonyl-CoA as extender substrates. The resulting polyketide analogues possessed a similar structural polyketide backbone (aromatic-2-pyrone) with variable side chains. Screening chalcone synthase (CHS) reaction products against BT-474 cells resulted in identification of several trifluoromethylcinnamoyl-based polyketides that showed strong suppression of the HER2-associated PI3K/AKT signaling pathway, yet did not inhibit the growth of nontransformed MCF-10A breast cells (IC50>100 μM). Specifically, 4-trifluoromethylcinnamoyl pyrone (compound 2 e) was highly potent (IC50<200 nM) among the test compounds toward proliferation of several breast cancer cell lines. This breadth of activity likely stems from the ability of compound 2 e to inhibit the phosphorylation of HER1, HER2, and HER3. Therefore, these polyketide analogues might prove to be useful drug candidates for potential breast cancer therapy.
Co-reporter:Seok Joon Kwon Dr.;Moon Il Kim Dr.;Bosung Ku Dr.;Lydie Coulombel Dr.;Jin-Hwan Kim Dr.;Joseph H. Shawky;Robert J. Linhardt
ChemBioChem 2010 Volume 11( Issue 4) pp:
Publication Date(Web):
DOI:10.1002/cbic.201090011
Co-reporter:Shyam Sundhar Bale, Seok Joon Kwon, Dhiral A. Shah, Akhilesh Banerjee, Jonathan S. Dordick and Ravi S. Kane
ACS Nano 2010 Volume 4(Issue 3) pp:1493
Publication Date(Web):March 4, 2010
DOI:10.1021/nn901586e
Despite recent advances in nanomaterial-based delivery systems, their applicability as carriers of cargo, especially proteins for targeting cellular components and manipulating cell function, is not well-understood. Herein, we demonstrate the ability of hydrophobic silica nanoparticles to deliver proteins, including enzymes and antibodies, to a diverse set of mammalian cells, including human cancer cells and rat stem cells, while preserving the activity of the biomolecule post-delivery. Specifically, we have explored the delivery and cytosolic activity of hydrophobically functionalized silica nanoparticle−protein conjugates in a human breast cancer cell line (MCF-7) and rat neural stem cells (NSCs) and elucidated the mechanism of cytosolic transport. Importantly, the proteins were delivered to the cytosol without extended entrapment in the endosomes, which facilitated the retention of biological activity of the delivered proteins. As a result, delivery of ribonuclease A (RNase A) and the antibody to phospho-Akt (pAkt) resulted in the initiation of cell death. Delivery of control protein conjugates (e.g., those containing green fluorescent protein or goat antirabbit IgG) resulted in minimal cell death, indicating that the carrier-mediated toxicity was low. The results presented here provide insight into the design of nanomaterials as protein carriers that enable control of cell function.Keywords: mechanism of cellular uptake; nanoparticle−protein conjugates; protein delivery; signaling pathways; stem cell delivery
Co-reporter:Ravindra C. Pangule, Sarah J. Brooks, Cerasela Zoica Dinu, Shyam Sundhar Bale, Sharon L. Salmon, Guangyu Zhu, Dennis W. Metzger, Ravi S. Kane and Jonathan S. Dordick
ACS Nano 2010 Volume 4(Issue 7) pp:3993
Publication Date(Web):July 6, 2010
DOI:10.1021/nn100932t
Infection with antibiotic-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) is one of the primary causes of hospitalizations and deaths. To address this issue, we have designed antimicrobial coatings incorporating carbon nanotube−enzyme conjugates that are highly effective against antibiotic-resistant pathogens. Specifically, we incorporated conjugates of carbon nanotubes with lysostaphin, a cell wall degrading enzyme, into films to impart bactericidal properties against Staphylococcus aureus and Staphylococcus epidermidis. We fabricated and characterized nanocomposites containing different conjugate formulations and enzyme loadings. These enzyme-based composites were highly efficient in killing MRSA (>99% within 2 h) without release of the enzyme into solution. Additionally, these films were reusable and stable under dry storage conditions for a month. Such enzyme-based film formulations may be used to prevent growth of pathogenic and antibiotic-resistant microorganisms on various common surfaces in hospital settings. Polymer and paint films containing such antimicrobial conjugates, in particular, could be advantageous to prevent risk of staphylococcal-specific infection and biofouling.Keywords: antimicrobial film; carbon nanotube; lysostaphin; methicillin-resistant Staphylococcus aureus (MRSA); nanocomposite
Co-reporter:Moon Il Kim, Seok Joon Kwon and Jonathan S. Dordick
Organic Letters 2009 Volume 11(Issue 17) pp:3806-3809
Publication Date(Web):August 4, 2009
DOI:10.1021/ol901243e
Polyketide analogues are produced via in vitro reconstruction of a precursor-directed polyketide biosynthetic pathway. Malonyl-CoA synthetase (MCS) was used in conjunction with chalcone synthase (CHS), thereby allowing efficient use of synthetic starter molecules and malonate as extender. Coenzyme-A was recycled up to 50 times. The use of a simple immobilization procedure resulted in up to a 30-fold higher yield of pyrone CHS products than that obtained with the free enzyme solutions.
Co-reporter:Mauricio Mora-Pale, Michel Weïwer, Jingjing Yu, Robert J. Linhardt, Jonathan S. Dordick
Bioorganic & Medicinal Chemistry 2009 Volume 17(Issue 14) pp:5146-5152
Publication Date(Web):15 July 2009
DOI:10.1016/j.bmc.2009.05.061
Enzymatic oxidation of apocynin, which may mimic in vivo metabolism, affords a large number of oligomers (apocynin oxidation products, AOP) that inhibit vascular NADPH oxidase. In vitro studies of NADPH oxidase activity were performed to identify active inhibitors, resulting in a trimer hydroxylated quinone (IIIHyQ) that inhibited NADPH oxidase with an IC50 = 31 nM. Apocynin itself possessed minimal inhibitory activity. NADPH oxidase is believed to be inhibited through prevention of the interaction between two NADPH oxidase subunits, p47phox and p22phox. To that end, while apocynin was unable to block the interaction of his-tagged p47phox with a surface immobilized biotinylated p22phox peptide, the IIIHyQ product strongly interfered with this interaction (apparent IC50 = 1.6 μM). These results provide evidence that peroxidase-generated AOP, which consist of oligomeric phenols and quinones, inhibit critical interactions that are involved in the assembly and activation of human vascular NADPH oxidase.
Co-reporter:SarahJ. Brooks;Lydie Coulombel;Disha Ahuja;DouglasS. Clark;JonathanS. Dordick
Advanced Synthesis & Catalysis 2008 Volume 350( Issue 10) pp:1517-1525
Publication Date(Web):
DOI:10.1002/adsc.200800188
Abstract
Oxidative biocatalytic reactions were performed on solid-supported substrates, thus expanding the repertoire of biotransformations that can be carried out on the solid phase. Various phenylacetic and benzoic acid analogues were attached to controlled pore glass beads via an enzyme-cleavable linker. Reactions catalyzed by peroxidases (soybean and chloro), tyrosinase, and alcohol oxidase/dehydrogenase gave a range of products, including oligophenols, halogenated aromatics, catechols, and aryl aldehydes. The resulting products were recovered following cleavage from the beads using α-chymotrypsin to selectively hydrolyze a chemically non-labile amide linkage. Controlled pore glass (CPG) modified with a polyethylene glycol (PEG) linker afforded substantially higher product yields than non-PEGylated CPG or non-swellable polymeric resins. This work represents the first attempt to combine solid-phase oxidative biotransformations with subsequent protease-catalyzed cleavage, and serves to further expand the use of biocatalysis in synthetic and medicinal chemistry.
Co-reporter:Tiago G. Fernandes, Seok-Joon Kwon, Moo-Yeal Lee, Douglas S. Clark, Joaquim M. S. Cabral and Jonathan S. Dordick
Analytical Chemistry 2008 Volume 80(Issue 17) pp:6633
Publication Date(Web):July 26, 2008
DOI:10.1021/ac800848j
We have developed an immunofluorescence-based assay for high-throughput analysis of target proteins on a three-dimensional cellular microarray platform. This process integrates the use of three-dimensional cellular microarrays, which should better mimic the cellular microenvironment, with sensitive immunofluorescence detection and provides quantitative information on cell function. To demonstrate this assay platform, we examined the accumulation of the α subunit of the hypoxia-inducible factor (HIF-1α) after chemical stimulation of human pancreatic tumor cells encapsulated in 3D alginate spots in volumes as low as 60 nL. We also tested the effect of the known dysregulator of HIF-1α, 2-methoxyestradiol (2ME2), on the levels of HIF-1α using a dual microarray stamping technique. This chip-based in situ Western immunoassay protocol was able to provide quantitative information on cell function, namely, the cellular response to hypoxia mimicking conditions and the reduction of HIF-1α levels after cell treatment with 2ME2. This system is the first to enable high-content screening of cellular protein levels on a 3D human cell microarray platform.
Co-reporter:Tae-Joon Park, Moo-Yeal Lee, Jonathan S. Dordick, Robert J. Linhardt
Analytical Biochemistry 2008 Volume 383(Issue 1) pp:116-121
Publication Date(Web):1 December 2008
DOI:10.1016/j.ab.2008.07.037
A heparin glycan chip (HepGlyChip) with a 4800-fold enhanced signal-to-noise ratio as compared with the control without heparin was developed for high-throughput analysis of heparin–protein interactions for new drug development and for screening biological samples in diagnostic applications. As a proof of concept, a heparin glycan microarray was prepared on a poly(styrene-co-maleic anhydride) (PS–MA)-coated glass slide. Heparin was covalently immobilized on poly-l-lysine (PLL) layer with multiple binding sites by sulfo-ethylene glycol bis(succinimidylsuccinate) (sulfo-EGS), increasing the signal-to-noise ratio, minimizing nonspecific binding of target proteins, and resulting in a three-dimensional (3D) structure on the HepGlyChip. This on-chip signal amplification platform was successfully demonstrated by probing the heparin microarray with the highly specific heparin-binding protein antithrombin III (AT III).
Co-reporter:Moo-Yeal Lee;R. Anand Kumar;Sumitra M. Sukumaran;Michael G. Hogg;Douglas S. Clark;
Proceedings of the National Academy of Sciences 2008 105(1) pp:59-63
Publication Date(Web):December 26, 2007
DOI:10.1073/pnas.0708756105
We have developed a miniaturized 3D cell-culture array (the Data Analysis Toxicology Assay Chip or DataChip) for high-throughput
toxicity screening of drug candidates and their cytochrome P450-generated metabolites. The DataChip consists of human cells
encapsulated in collagen or alginate gels (as small as 20 nl) arrayed on a functionalized glass slide for spatially addressable
screening against multiple compounds. A single DataChip containing 1,080 individual cell cultures, used in conjunction with
the complementary human P450-containing microarray (the Metabolizing Enzyme Toxicology Assay Chip or MetaChip), simultaneously
provided IC50 values for nine compounds and their metabolites from CYP1A2, CYP2D6, and CYP3A4 and a mixture of the three P450s designed
to emulate the human liver. Similar responses were obtained with the DataChip and conventional 96-well plate assays, demonstrating
that the near 2,000-fold miniaturization does not influence the cytotoxicity response. The DataChip may therefore enable toxicity
analyses of drug candidates and their metabolites at throughputs compatible with the availability of compounds at early-stage
drug discovery.
Co-reporter:S. S. Bale;P. Asuri;S. S. Karajanagi;J. S. Dordick;R. S. Kane
Advanced Materials 2007 Volume 19(Issue 20) pp:3167-3170
Publication Date(Web):17 OCT 2007
DOI:10.1002/adma.200701981
Studies of silver nanoparticle formation using MWNT-protein/polypeptide conjugates are reported. Our findings suggest that there is selectivity in the formation of silver nanoparticles depending on the nature of the protein. Protein-mediated mineralization is facile and can be carried out under mild conditions, thereby enabling retention of the biological activity of the protein.
Co-reporter:Seok Joon Kwon, Moo-Yeal Lee, Bosung Ku, David H. Sherman and Jonathan S. Dordick
ACS Chemical Biology 2007 Volume 2(Issue 6) pp:419
Publication Date(Web):May 25, 2007
DOI:10.1021/cb700033s
The generation of biological diversity by engineering the biosynthetic gene assembly of metabolic pathway enzymes has led to a wide range of “unnatural” variants of natural products. However, current biosynthetic techniques do not allow the rapid manipulation of pathway components and are often fundamentally limited by the compatibility of new pathways, their gene expression, and the resulting biosynthetic products and pathway intermediates with cell growth and function. To overcome these limitations, we have developed an entirely in vitro approach to synthesize analogues of natural products in high throughput. Using several type III polyketide synthases (PKS) together with oxidative post-PKS tailoring enzymes, we performed 192 individual and multienzymatic reactions on a single glass microarray. Subsequent array-based screening with a human tyrosine kinase led to the identification of three compounds that acted as modest inhibitors in the low-micromolar range. This approach, therefore, enables the rapid construction of analogues of natural products as potential pharmaceutical lead compounds.
Co-reporter:Bilge Eker;Prashanth Asuri
Applied Biochemistry and Biotechnology 2007 Volume 143( Issue 2) pp:153-163
Publication Date(Web):2007 November
DOI:10.1007/s12010-007-0035-2
Room-temperature ionic liquids (RTILs) are intriguing solvents, which are recognized as “green” alternatives to volatile organics. Although RTILs are nonvolatile and can dissolve a wide range of charged, polar, and nonpolar organic and inorganic molecules, there remain substantial challenges in their use, not the least of which is the solvents’ high viscosity that leads to potential mass transfer limitations. In the course of this work, we discovered that the simple adsorption of the bacterial protease, proteinase K, onto single-walled carbon nanotubes (SWNTs) results in intrinsically high catalytic turnover. The high surface area and the nanoscopic dimensions of SWNTs offered high enzyme loading and low mass transfer resistance. Furthermore, the enzyme–SWNT conjugates displayed enhanced thermal stability in RTILs over the native suspended enzyme counterpart and allowed facile reuse. These enzyme–SWNT conjugates may therefore provide a way to overcome key operational limitations of RTIL systems.
Co-reporter:George John ;Guangyu Zhu Dr.;Jun Li Dr.
Angewandte Chemie 2006 Volume 118(Issue 29) pp:
Publication Date(Web):10 JUL 2006
DOI:10.1002/ange.200690100
Co-reporter:George John ;Guangyu Zhu Dr.;Jun Li Dr.
Angewandte Chemie 2006 Volume 118(Issue 29) pp:
Publication Date(Web):8 JUN 2006
DOI:10.1002/ange.200600989
Über kurz oder lang: Die regioselektive enzymkatalysierte Acylierung des Disaccharids Trehalose lieferte eine Familie von niedermolekularen Gelatoren mit neuartigen Eigenschaften. Dank der Selektivität der Enzymkatalyse gelang es, die Gelierungseigenschaften einfach durch Variation der Acylkettenlänge zu steuern und damit das Gelieren in so unterschiedlich polaren Lösungsmitteln wie Acetonitril und Cyclohexan zu erreichen.
Co-reporter:George John ;Guangyu Zhu Dr.;Jun Li Dr.
Angewandte Chemie International Edition 2006 Volume 45(Issue 29) pp:
Publication Date(Web):10 JUL 2006
DOI:10.1002/anie.200690100
Co-reporter:George John ;Guangyu Zhu Dr.;Jun Li Dr.
Angewandte Chemie International Edition 2006 Volume 45(Issue 29) pp:
Publication Date(Web):8 JUN 2006
DOI:10.1002/anie.200600989
The long and short of it: A regioselective enzyme-catalyzed acylation of the disaccharide trehalose generated a family of low-molecular-weight gelators with unprecedented properties. The selectivity of enzymatic catalysis enables direct control over gelation properties by simply varying the acyl-chain length to give gelation in solvents ranging from the highly hydrophilic acetonitrile to the highly hydrophobic cyclohexane.
Co-reporter:Sylvain Antoniotti;Jonathan S. Dordick
Advanced Synthesis & Catalysis 2005 Volume 347(Issue 7-8) pp:
Publication Date(Web):1 JUN 2005
DOI:10.1002/adsc.200505036
Enzyme-catalyzed CC bond formation has been performed on solid-supported phenols, thereby expanding the repertoire of enzymatic catalysis on resin-bound substrates. In the presence of hydroquinone bound to various commercial resins, soybean peroxidase catalyzed the coupling of apocynin (acetovanillone) to give dimers, trimers, and oligomers with structures similar to what is obtained in solution-phase reactions. In addition to phenolic coupling, peroxidase catalyzed a Fries rearrangement presumably due to rearrangement of the acyl phenolic radicals generated on the solid phase through peroxidase catalysis. This represents the first enzymatic Fries rearrangement reported to date. Together with the solid-phase biocatalytic phenolic coupling, these results provide a route to the further expansion of enzymatic catalysis in combinatorial library synthesis.
Co-reporter:Lino Ferreira, Maria H. Gil, Antonio M.S. Cabrita, Jonathan S. Dordick
Biomaterials 2005 Volume 26(Issue 23) pp:4707-4716
Publication Date(Web):August 2005
DOI:10.1016/j.biomaterials.2004.11.051
We have prepared unique macroporous and ordered dextran-based hydrogels using a single-step biocatalytic transesterification reaction between dextran and divinyladipate in neat dimethylsulfoxide. These hydrogels show a unimodal distribution of interconnected pores with average diameters from 0.4 to 2.0 μm depending on the degree of substitution. In addition, the hydrogels show a higher elastic modulus for a given swelling ratio than chemically synthesized dextran-based hydrogels. In vivo studies in rats show that the hydrogel networks are degradable over a range of time scales from 5 to over 40 days, and possess good biocompatibility, as reflected in only a mild inflammatory reaction and minor fibrous capsule formation during the time-frame of subcutaneous implantation. These combined properties may offer competitive advantages in biomedical applications ranging from tissue engineering to controlled drug delivery.
Co-reporter:Moo-Yeal Lee;Chan Beum Park;Douglas S. Clark
PNAS 2005 Volume 102 (Issue 4 ) pp:983-987
Publication Date(Web):2005-01-25
DOI:10.1073/pnas.0406755102
The clinical progression of new chemical entities to pharmaceuticals remains hindered by the relatively slow pace of technology
development in toxicology and clinical safety evaluation, particularly in vitro approaches, that can be used in the preclinical and early clinical phases of drug development. To alleviate this bottle-neck,
we have developed a metabolizing enzyme toxicology assay chip (MetaChip) that combines high-throughput P450 catalysis with
cell-based screening on a microscale platform. The MetaChip concept is demonstrated by using sol-gel encapsulated P450s to
activate the prodrug cyclophosphamide, which is the major constituent of the anticancer drug Cytoxan, as well as other compounds
that are activated by P450 metabolism. The MetaChip provides a high-throughput microscale alternative to currently used in vitro methods for human metabolism and toxicology screening based on liver slices, cultured human hepatocytes, purified microsomal
preparations, or isolated and purified P450s. This technology creates opportunities for rapid and inexpensive assessment of
ADME/Tox (absorption, distribution, metabolism, excretion/toxicology) at very early phases of drug development, thereby enabling
unsuitable candidates to be eliminated from consideration much earlier in the drug discovery process.
Co-reporter:Ana Rafael;Meriem Lamghari;Lino Ferreira;Mario A. Barbosa;Maria H. Gil;António M. S. Cabrita
Journal of Biomedical Materials Research Part A 2004 Volume 68A(Issue 3) pp:584-596
Publication Date(Web):12 JAN 2004
DOI:10.1002/jbm.a.20102
The biocompatibility of chemoenzymatically generated dextran-acrylate hydrogels has been evaluated in vitro, using human foreskin fibroblasts, and in vivo, by subcutaneous and intramuscular implantation in Wistar rats for up to 40 days. In vitro tests show that hydrogel extracts only minimally reduced (<10%) the mitochondrial metabolic activity of fibroblasts. Direct contact of the hydrogels with cells induced a cellular proliferation inhibition index (CPII) of 50–80%, compared with a control, whereas through indirect contact, the CPII values were <16%, suggesting that the high CPII values achieved in the direct assay test were likely due to mechanical stress or limitations in oxygen diffusion. Hence, the hydrogels were noncytotoxic. Moreover, cell–material interaction studies show that these hydrogels were nonadhesive. Finally, histologic evaluation of tissue response to subcutaneous and intramuscular implants showed acceptable levels of biocompatibility, as characterized by a normal cellular response and the absence of necrosis of the surrounding tissues of the implant. In the first 10 days, the foreign-body reaction in the intramuscular implantation was more severe than in subcutaneous implantation, becoming identical after 30 days. In both cases, dextran hydrogels did not show signs of degradation 6 weeks postimplantation and were surrounded by a thin fibrous capsule and some macrophages and giant cells. This response is typical with a number of nondegradable biocompatible materials. These results indicate that dextran hydrogels are biocompatible, and may have suitable applications as implantable long-term peptide/protein delivery systems or scaffolds for tissue engineering. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 584–596, 2004
Co-reporter:Jonathan S. Dordick, Douglas S. Clark
Current Opinion in Chemical Biology 2002 Volume 6(Issue 2) pp:123-124
Publication Date(Web):1 April 2002
DOI:10.1016/S1367-5931(02)00315-0
Co-reporter:Inmar Z. Munir;Shanghui Hu;Jonathan S. Dordick
Advanced Synthesis & Catalysis 2002 Volume 344(Issue 10) pp:
Publication Date(Web):29 NOV 2002
DOI:10.1002/1615-4169(200212)344:10<1097::AID-ADSC1097>3.0.CO;2-S
The selective oxidation and halogenation of nitroaromatics is a difficult task both chemically and enzymatically. We have discovered that vanadium chloro- and bromoperoxidases from Curvularia inaequalis and Corralina officinalis, respectively, are capable of catalyzing the hydroxylation, halogenation, and demethylation of 2,4,6-trinitrotoluene (TNT) under alkaline conditions. At pH 8, the conversions for hydroxylation and demethylation reached 38 and 45%, respectively, while direct halogenation was minimal. Vanadium chloroperoxidase generated trinitrobenzyl alcohol with initial rates of 0.27 μM/h-unit enzyme as compared with 0.11 μM/h-unit enzyme for the vanadium bromoperoxidase. The products of the enzymatic reaction were easily separated and purified and the unreacted substrate recovered. In the presence of PCl5, the trinitrobenzyl alcohol produced by vanadium chloroperoxidase was readily converted to trinitrobenzyl chloride (TNBCl). This chemoenzymatic synthesis may be useful in the environmentally benign synthesis of hexanitrostilbene, a key component of heat-resistant explosive materials.
Co-reporter:Lino Ferreira, Maria H. Gil, Jonathan S. Dordick
Biomaterials 2002 Volume 23(Issue 19) pp:3957-3967
Publication Date(Web):October 2002
DOI:10.1016/S0142-9612(02)00132-1
Dextran, a natural glucose-containing polysaccharide, has been acylated by Proleather FG-F and lipase AY, a protease and lipase from Bacillus sp. and Candida rugosa, respectively, in anhydrous dimethylsulfoxide in the presence of vinyl acrylate (VA). The efficiency of the reaction in the presence of Proleather FG-F and the isolated yields were ca. 71% and 45%, respectively. Dextran derivatized with VA (dexT70-VA) was characterized by gel permeation chromatography and its structure was established by NMR indicating two positional isomers at the 2 and 3 positions on the glucose moieties in equal amounts. Furthermore, the dextran glucopyranose residues were mono-substituted. The benefits of the biocatalytic synthesis of dextran acrylates was demonstrated using 4-dimethylaminopyridine as a chemical catalyst. Gels were prepared by free radical polymerization of aqueous solutions of dexT70-VA with different degrees of substitution and monomer concentrations. Intermolecular linkages and physical entanglements are predominantly formed by concentrated solutions, however, a part of the acrylate groups did not react. Gel pore sizes were calculated from swelling experiments and ranged from ca. 18 to 182 Å.
Co-reporter:Scott J. Novick, Jonathan S. Dordick
Biomaterials 2002 Volume 23(Issue 2) pp:441-448
Publication Date(Web):January 2002
DOI:10.1016/S0142-9612(01)00123-5
The incorporation of enzymes and other proteins into hydrophobic polymeric coatings and films has been investigated in this study with the goal of generating biologically active materials for biocatalysis, antifouling surfaces, and biorecognition. The protein–polymer composites are created using standard solution coating techniques with poly(methyl methacrylate), polystyrene, and poly(vinyl acetate) as polymers and α-chymotrypsin and trypsin as biocatalysts. The specific enzyme is first extracted into a nonpolar organic solvent using hydrophobic ion-pairing. The ion-paired enzyme is dried and redissolved into a solvent also miscible with the polymer. This solution is then poured over a surface and the solvent is allowed to evaporate to form the enzyme-containing coating, which can then be delaminated to form a film. Leaching of enzyme from and activity of the biocatalytic coatings and films were evaluated. The biocatalytic coatings showed no loss of activity over ca. one week. For the biocatalytic films, the leaching rate was initially high followed by a slow rate of enzyme loss. Activity was measurable for at least one month, with only ca. one-third of the initial activity lost in that time, while, being continuously incubated in a buffer solution. Activity was also exhibited on macromolecular (protein) substrates. The biocatalytic coatings could be reused over 100 times with only a modest loss of activity. Finally, coatings and films containing a lectin (Concanavalin A) were capable of selectively binding to glycoproteins, thereby extending the application of such films for use in bioseparations and biorecognition.
Co-reporter:Navdeep Grover, Elena E. Paskaleva, Krunal K. Mehta, Jonathan S. Dordick, Ravi S. Kane
Enzyme and Microbial Technology (September 2014) Volume 63() pp:1-6
Publication Date(Web):1 September 2014
DOI:10.1016/j.enzmictec.2014.04.018
•We identified a new enzyme LysB from mycobacteriophage Bxz2.•Its esterase activity was significantly higher than that of a reported LysB (Ms6).•Presence of surfactant (Tween 80 or Triton X-100) increased the activity of LysB.•Phage-derived endolysins can inhibit the growth of mycobacterium.We report the ability of mycobacteriophage-derived endolysins to inhibit the growth of Mycobacterium smegmatis. We expressed and purified LysB from mycobacteriophage Bxz2 and compared its activity with that of a previously reported LysB from mycobacteriophage Ms6. The esterase activity of Bxz2 LysB with pNP esters was 10-fold higher than that of the previously reported LysB but its lipolytic activity was significantly lower. The presence of surfactant – Tween 80 or Triton X-100 – significantly increased the activity of LysB. Characterization of LysB-treated M. smegmatis cells and LysB-treated purified cell wall by mass spectroscopy confirmed the hydrolytic activity of the enzyme. Both enzymes were equally effective in inhibiting the growth of M. smegmatis, demonstrating their potential as bacteriostatic agents.
Co-reporter:Cerasela Zoica Dinu, Indrakant V. Borkar, Shyam Sundhar Bale, Alan S. Campbell, Ravi S. Kane, Jonathan S. Dordick
Journal of Molecular Catalysis B: Enzymatic (March 2012) Volume 75() pp:20-26
Publication Date(Web):1 March 2012
DOI:10.1016/j.molcatb.2011.11.003
We have developed a strategy to preserve the activity and operational stability of a large multi-subunit enzyme immobilized onto carbon nanotubes and incorporated into latex paint. Our strategy involved the intramolecular crosslinking of perhydrolase S54V (AcT, a homo-octamer) and the subsequent immobilization of the crosslinked AcT onto single-walled carbon nanotubes (SWNTs). We employed aldehyde dextran – a bulky polymeric aldehyde obtained by oxidation of dextran with sodium metaperiodate – as a crosslinking reagent. The activity of AcT crosslinked with aldehyde dextran and covalently attached to SWNTs (AcT-dex-SWNTs) was ∼40% of that of native AcT and more than two-fold higher than that of enzyme immobilized directly, i.e., without crosslinking. This relatively high retention of AcT activity was consistent with the nearly complete retention of the enzyme's secondary structure upon attachment to the nanoscale support. Further incorporation of the AcT-dex-SWNTs conjugates into a latex-based paint led to active composites that were used to decontaminate Bacillus spores.Graphical abstractAcT enzyme crosslinked with aldehyde dextran and entrapped within paint composites is stable and decontaminates Bacillus spores.Download full-size imageHighlights► Perhydrolase S54V (AcT, a homo-octamer) is crosslinked with aldehyde dextran intramolecular crosslinker. ► Crosslinked AcT attached to single walled carbon nanotubes retain ∼40% activity of that of native AcT. ► High retention of AcT activity is consistent with the nearly complete retention of the enzyme's secondary structure. ► Conjugates of AcT incorporated into a latex-based paint lead to active composites able to decontaminate Bacillus spores.
Co-reporter:Luciana Meli, Hélder S.C. Barbosa, Anne Marie Hickey, Leyla Gasimli, Gregory Nierode, Maria Margarida Diogo, Robert J. Linhardt, Joaquim M.S. Cabral, Jonathan S. Dordick
Stem Cell Research (July 2014) Volume 13(Issue 1) pp:36-47
Publication Date(Web):1 July 2014
DOI:10.1016/j.scr.2014.04.004
•We employed a new 3D platform for neural stem cell growth and differentiation.•We showed that this microplatform can discern differential small molecule toxicity.•We followed stem cell differentiation using an on-chip immunofluorescence assay.•We studied differential responses of stem cells vs. differentiated cells.We developed a three-dimensional (3D) cellular microarray platform for the high-throughput (HT) analysis of human neural stem cell (hNSC) growth and differentiation. The growth of an immortalized hNSC line, ReNcell VM, was evaluated on a miniaturized cell culture chip consisting of 60 nl spots of cells encapsulated in alginate, and compared to standard 2D well plate culture conditions. Using a live/dead cell viability assay, we demonstrated that the hNSCs are able to expand on-chip, albeit with lower proliferation rates and viabilities than in conventional 2D culture platforms. Using an in-cell, on-chip immunofluorescence assay, which provides quantitative information on cellular levels of proteins involved in neural fate, we demonstrated that ReNcell VM can preserve its multipotent state during on-chip expansion. Moreover, differentiation of the hNSCs into glial progeny was achieved both off- and on-chip six days after growth factor removal, accompanied by a decrease in the neural progenitor markers. The versatility of the platform was further demonstrated by complementing the cell culture chip with a chamber system that allowed us to screen for differential toxicity of small molecules to hNSCs. Using this approach, we showed differential toxicity when evaluating three neurotoxic compounds and one antiproliferative compound, and the null effect of a non-toxic compound at relevant concentrations. Thus, our 3D high-throughput microarray platform may help predict, in vitro, which compounds pose an increased threat to neural development and should therefore be prioritized for further screening and evaluation.
Co-reporter:Bilge Eker, Dmitri Zagorevski, Guangyu Zhu, Robert J. Linhardt, Jonathan S. Dordick
Journal of Molecular Catalysis B: Enzymatic (July 2009) Volume 59(Issues 1–3) pp:177-184
Publication Date(Web):1 July 2009
DOI:10.1016/j.molcatb.2009.02.018
Soybean peroxidase (SBP) was used to catalyze the polymerization of phenols in room-temperature ionic liquids (RTILs). Phenolic polymers with number average molecular weights ranging from 1200 to 4100 Da were obtained depending on the composition of the reaction medium and the nature of the phenol. Specifically, SBP was highly active in methylimidazolium-containing RTILs, including 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(BF4)), and 1-butyl-3-methylpyridinium tetrafluoroborate (BMPy(BF4)) with the ionic liquid content as high as 90% (v/v); the balance being aqueous buffer. Gel permeation chromatography and MALDI-TOF analysis indicated that higher molecular weight polymers can be synthesized in the presence of higher RTIL concentrations, with selective control over polymer size achieved by varying the RTIL concentration. The resulting polyphenols exhibited high thermostability and possessed thermosetting properties.
Co-reporter:Ruchir V Mundra, Xia Wu, Jeremy Sauer, Jonathan S Dordick, Ravi S Kane
Current Opinion in Biotechnology (August 2014) Volume 28() pp:25-32
Publication Date(Web):1 August 2014
DOI:10.1016/j.copbio.2013.10.012
•CNTs may be used as delivery vehicles or heat sources for treating cancer.•CNTs may continue to find applications in life sciences and medical diagnosis.•CNTs are increasingly being used as scaffolds for tissue engineering.•CNT–enzyme conjugates are being used to develop antimicrobial surfaces.Researchers over the last few years have recognized carbon nanotubes (CNTs) as promising materials for a number of biological applications. CNTs are increasingly being explored as potent drug carriers for cancer treatment, for biosensing, and as scaffolds for stem cell culture. Moreover, the integration of CNTs with proteins has led to the development of functional nanocomposites with antimicrobial properties. This review aims at understanding the critical role of CNTs in biological applications with a particular emphasis on more recent studies.Download high-res image (232KB)Download full-size image
Co-reporter:Jonathan S Dordick, Kelvin H Lee
Current Opinion in Biotechnology (August 2014) Volume 28() pp:iv-v
Publication Date(Web):1 August 2014
DOI:10.1016/j.copbio.2014.06.015
Co-reporter:Gregory J. Nierode, Brian C. Perea, Sean K. McFarland, Jorge F. Pascoal, ... Jonathan S. Dordick
Stem Cell Reports (8 November 2016) Volume 7(Issue 5) pp:970-982
Publication Date(Web):8 November 2016
DOI:10.1016/j.stemcr.2016.10.001
•Demonstrated chip platform for HTS of protein expression and toxicity of 3D cultures•Dose-response viability and proliferation of a 24-compound library on human NPC lines•Assessed differential toxicity between progenitors and differentiating progeny•Identified five compounds more toxic to undifferentiated progenitorsA 3D cell culture chip was used for high-throughput screening of a human neural progenitor cell line. The differential toxicity of 24 compounds was determined on undifferentiated and differentiating NPCs. Five compounds led to significant differences in IC50 values between undifferentiated and differentiating cultures. This platform has potential use in phenotypic screening to elucidate molecular toxicology on human stem cells.Download high-res image (220KB)Download full-size image
Co-reporter:Navdeep Grover, Indrakant V. Borkar, Cerasela Zoica Dinu, Ravi S. Kane, Jonathan S. Dordick
Enzyme and Microbial Technology (10 May 2012) Volume 50(Issues 6–7) pp:271-279
Publication Date(Web):10 May 2012
DOI:10.1016/j.enzmictec.2012.01.006
Laccase and chloroperoxidase (CPO) were separately immobilized onto multi-walled carbon nanotubes (MWNTs) and subsequently mixed with a commercial eco-friendly paint to generate biocatalytic coatings. The laccase-nanotube based paints showed >99% bactericidal activity against Escherichia coli and Staphylococcus aureus (both challenged with 106 CFU/mL) within 30 min and >98% sporicidal activity against Bacillus cereus and Bacillus anthracis-ΔSterne (initially challenged with 104 CFU/mL) within 120 min. The CPO-nanotube based paints also showed >99% antimicrobial activity within 30 min against E. coli and S. aureus (both challenged with 106 CFU/mL). These enzyme-nanotube based formulations provide an eco-friendly route to generate biocidal compounds, which can prevent the growth of a broad spectrum of bacterial pathogens, including spores. These enzyme-containing paints may be envisioned to be applied as self-decontaminating coatings onto a wide range of surfaces, such as hospital infrastructure, medical devices and equipment, food processing and packaging, etc.; in all cases effective killing of a variety of infectious organisms is critical.Highlights► Laccase- and chloroperoxidase (CPO)-nanotube containing biocatalytic paint coatings were prepared and found to possess bactericidal and sporicidal activity. ► An ecofriendly route to generate HOCl and I2 for biocidal activity was demonstrated. ► Laccase antimicrobial activity could be activated within the paint upon addition of methyl syringate as a redox mediator. ► CPO formulations showed broad spectrum antibacterial activity but lacked sporicidal activity.
Co-reporter:Anne Marie Hickey, Ujjwal Bhaskar, Robert J. Linhardt, Jonathan S. Dordick
Journal of Biotechnology (10 June 2013) Volume 165(Issues 3–4) pp:175-177
Publication Date(Web):10 June 2013
DOI:10.1016/j.jbiotec.2013.03.018
•Deletion of eliminase results in a ca. 50% drop in heparosan production by the cell.•Eliminase exerts considerable control over production and shedding of heparosan by Escherichia coli K5.•The enzyme is not solely responsible for heparosan shedding since, in its absence, the cells still produce and export heparosan, yet it appears to be the major contributor in E. coli K5.Escherichia coli K5 produces heparosan and sheds it into the growth medium in a temperature dependent manner. The shedding is believed to be controlled, at least in part, by enzyme action on the cell-associated capsular polysaccharide, heparosan. One candidate enzyme in such shedding is eliminase. The eliminase gene (elmA) was deleted from the genome of E. coli K5 and its effect on secreted and cell-associated heparosan was investigated. Deletion of the eliminase gene resulted in a significant reduction in heparosan shedding into the medium and heparosan content in the capsule of the cells, indicating its pivotal role in heparosan synthesis and shedding by E. coli K5.
![5'-O-[hydroxy(sulfooxy)phosphoryl]adenosine 3'-(dihydrogen phosphate)](http://img.cochemist.com/ccimg/500/482-67-7.png)
![5'-O-[hydroxy(sulfooxy)phosphoryl]adenosine 3'-(dihydrogen phosphate)](http://img.cochemist.com/ccimg/500/482-67-7_b.png)
