1
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McKenzie TJ, Brunet T, Kissell LN, Strobbia P, Ayres N. Polydimethylsiloxane Polymerized Emulsions for Acoustic Materials Prepared Using Reactive Triblock Copolymer Surfactants. ACS Appl Mater Interfaces 2023; 15:58917-58930. [PMID: 38063480 DOI: 10.1021/acsami.3c14859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Porous polymers have interesting acoustic properties including wave dampening and acoustic impedance matching and may be used in numerous acoustic applications, e.g., waveguiding or acoustic cloaking. These materials can be prepared by the inclusion of gas-filled voids, or pores, within an elastic polymer network; therefore, porous polymers that have controlled porosity values and a wide range of possible mechanical properties are needed, as these are key factors that impact the sound-dampening properties. Here, the synthesis of acoustic materials with varying porosities and mechanical properties that could be controlled independent of the pore morphology using emulsion-templated polymerizations is described. Polydimethylsiloxane-based ABA triblock copolymer surfactants were prepared using reversible addition-fragmentation chain transfer polymerizations to control the emulsion template and act as an additional cross-linker in the polymerization. Acoustic materials prepared with reactive surfactants possessed a storage modulus of ∼300 kPa at a total porosity of 71% compared to materials prepared using analogous nonreactive surfactants that possessed storage modulus values of ∼150 kPa at similar porosities. These materials display very low longitudinal sound speeds of ∼35 m/s at ultrasonic frequencies, making them excellent candidates in the preparation of acoustic devices such as metasurfaces or lenses.
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Affiliation(s)
- Tucker J McKenzie
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Thomas Brunet
- Institut de Mécanique et d'Ingénierie, University of Bordeaux─CNRS─Bordeaux INP, Talence 33405, France
| | - Lyndsay N Kissell
- Department of Chemistry, University of Cincinnati, 201 Crosley Tower, 301 Clifton Ct, Cincinnati, Ohio 45221, United States
| | - Pietro Strobbia
- Department of Chemistry, University of Cincinnati, 201 Crosley Tower, 301 Clifton Ct, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
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2
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McKenzie T, Ayres N. Synthesis and Applications of Elastomeric Polymerized High Internal Phase Emulsions (PolyHIPEs). ACS Omega 2023; 8:20178-20195. [PMID: 37323392 PMCID: PMC10268022 DOI: 10.1021/acsomega.3c01265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/15/2023] [Indexed: 06/17/2023]
Abstract
Polymer foams (PFs) are among the most industrially produced polymeric materials, and they are found in applications including aerospace, packaging, textiles, and biomaterials. PFs are predominantly prepared using gas-blowing techniques, but PFs can also be prepared from templating techniques such as polymerized high internal phase emulsions (polyHIPEs). PolyHIPEs have many experimental design variables which control the physical, mechanical, and chemical properties of the resulting PFs. Both rigid and elastic polyHIPEs can be prepared, but while elastomeric polyHIPEs are less commonly reported than hard polyHIPEs, elastomeric polyHIPEs are instrumental in the realization of new materials in applications including flexible separation membranes, energy storage in soft robotics, and 3D-printed soft tissue engineering scaffolds. Furthermore, there are few limitations to the types of polymers and polymerization methods that have been used to prepare elastic polyHIPEs due to the wide range of polymerization conditions that are compatible with the polyHIPE method. In this review, an overview of the chemistry used to prepare elastic polyHIPEs from early reports to modern polymerization methods is provided, focusing on the applications that flexible polyHIPEs are used in. The review consists of four sections organized around polymer classes used in the preparation of polyHIPEs: (meth)acrylics and (meth)acrylamides, silicones, polyesters and polyurethanes, and naturally occurring polymers. Within each section, the common properties, current challenges, and an outlook is suggested on where elastomeric polyHIPEs can be expected to continue to make broad, positive impacts on materials and technology for the future.
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Affiliation(s)
| | - Neil Ayres
- N.A.:
email, ; tel, +01 513 556 9280; fax, +01 513 556 9239
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3
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McKenzie TJ, Cawood C, Davis C, Ayres N. Synthesis of patterned polyHIPE-hydrogel composite materials using thiol-ene chemistry. J Colloid Interface Sci 2023; 645:502-512. [PMID: 37159992 DOI: 10.1016/j.jcis.2023.04.132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/11/2023]
Abstract
Elastomeric materials combining multiple properties within a single composite are highly desired in applications including biomaterials interfaces, actuators, and soft robotics. High spatial resolution is required to impart different properties across the composite for the intended application, but many techniques used to prepare these composites rely on multistep and complex methods. There is a need for the development of simple and efficient platforms to design layered composite materials. Here, we report the synthesis of horizontally- and vertically-patterned composites consisting of PDMS-based polymerized high internal phase emulsion (polyHIPE) porous elastomers and PDMS/PEG hydrogels. Composites with defined interfaces that were mechanically robust were prepared, and rheological analysis of the polyHIPE and hydrogel layers showed storage moduli values of ∼ 35 kPa and 45 kPa respectively. The compressive Young's Modulus and maximum strain of the polyHIPEs were dependent on the thiol to ene ratio in the formulation and obtained values ranging from 6 to 25 kPa and 50-65% respectively. The mechanical properties, total porosity of the polyHIPE, and swelling ratio of the hydrogel were unaffected by the patterning technique compared to non-patterned controls. PolyHIPE-hydrogel composite materials having up to 7-different horizontally pattered layers could be prepared that could expand and contract up hydration and drying.
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Affiliation(s)
- Tucker J McKenzie
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States
| | - Christian Cawood
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States
| | - Chelsea Davis
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221, United States.
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4
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Smith A, Ayres N. Open-cell PDMS polyHIPEs prepared using polymethylvinylsiloxane to prevent pore collapse. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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5
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Ruhunage CK, Dhawan V, McKenzie TJ, Hoque A, Rahm CE, Nawarathne CP, Ayres N, Cui XT, Alvarez NT. Hydrophilic Micro- and Macroelectrodes with Antibiofouling Properties for Biomedical Applications. ACS Biomater Sci Eng 2022; 8:2920-2931. [PMID: 35710337 PMCID: PMC10080669 DOI: 10.1021/acsbiomaterials.2c00173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Implantable neural electrodes are generally used to record the electrical activity of neurons and to stimulate neurons in the nervous system. Biofouling triggered by inflammatory responses can dramatically affect the performance of neural electrodes, resulting in decreased signal sensitivity and consistency over time. Thus, long-term clinical applications require electrically conducting electrode materials with reduced dimensions, high flexibility, and antibiofouling properties that can reduce the degree of inflammatory reactions and increase the lifetime of neural electrodes. Carbon nanotubes (CNTs) are well known to form flexible assemblies such as CNT fibers. Herein, we report the covalent functionalization of predefined CNT fiber and film surfaces with hydrophilic, antibiofouling phosphorylcholine (PC) molecules. The electrochemical and spectroscopic characteristics, impedance properties, hydrophilicity, and in vitro antifouling nature of the functionalized CNT surfaces were evaluated. The hydrophilicity of the functionalized CNT films was demonstrated by a decrease in the static contact angle from 134.4° ± 3.9° before to 15.7° ± 1.5° after one and fully wetting after three functionalization cycles, respectively. In addition, the extent of protein absorption on the functionalized CNT films was significantly lower than that on the nonfunctionalized CNT film. Surprisingly, the faradic charge-transfer properties and impedance of the CNT assemblies were preserved after functionalization with PC molecules. These functionalized CNT assemblies are promising for the development of low-impedance neural electrodes with higher hydrophilicity and protein-fouling resistance to inhibit inflammatory responses.
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Affiliation(s)
- Chethani K Ruhunage
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Tucker J McKenzie
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Abdul Hoque
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Connor E Rahm
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Chaminda P Nawarathne
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Noe T Alvarez
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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6
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Dalton E, Morris Z, Ayres N. Synthesis and characterization of sulfated-lactose polyurethane hydrogels. Polym Chem 2022. [DOI: 10.1039/d2py00227b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polyurethanes (PUs) are widely used due to their durability, flexibility, and biocompatibility. PU hydrogels have been used in biomedical applications tissue engineering, synthetic extracellular matrices, and drug delivery. In this...
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7
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McKenzie TJ, Smail S, Rost K, Rishi K, Beaucage G, Ayres N. Multi-layered polymerized high internal phase emulsions with controllable porosity and strong interfaces. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.124116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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8
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Chimala P, Perera MM, Wade A, McKenzie T, Allor J, Ayres N. Hyperbranched polymer hydrogels with large stimuli-responsive changes in storage moduli and peroxide-induced healing. Polym Chem 2021. [DOI: 10.1039/d1py00560j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogels prepared using hyperbranched polymers with dynamic disulfide bonds show larger changes in moduli upon exposure to chemical stimuli for both softening and stiffening responses compared to linear polymers.
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Affiliation(s)
| | - M. Mario Perera
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Aissatou Wade
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Tucker McKenzie
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Joshua Allor
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Neil Ayres
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
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9
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Perera MM, Chimala P, Elhusain-Elnegres A, Heaton P, Ayres N. Reversibly Softening and Stiffening Organogels Using a Wavelength-Controlled Disulfide-Diselenide Exchange. ACS Macro Lett 2020; 9:1552-1557. [PMID: 35617082 DOI: 10.1021/acsmacrolett.0c00718] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Wavelength-dependent light-responsive seleno-sulfide dynamic covalent bonds were used to prepare organogels with reversible changes in stiffness. The disulfide cross-link organogels prepared from norbornene-terminated poly(ethylene glycol) (PEG-diNB) and poly(2-hydroxypropyl methacrylate-stat-mercaptoethyl acrylate) (PEG-diNB-poly(HPMA-stat-MEMA)) polymers underwent exchange reactions with 5,5'-diselenide-bis(2-aminobenzoic acid) upon irradiation with UV light. Following irradiation with visible light, the seleno-sulfide bonds were cleaved, reforming disulfide cross-links and the 5,5'-diselenide-bis(2-aminobenzoic acid). Reduction in G' with disulfide-diselenide exchange was consistent with that observed following a thiol-disulfide exchange reaction. Recovery of G' upon disulfide bond formation was 85-95% of the initial value in the as-prepared gel over five cycles of bond cleaving and reformation. This initial study shows the potential of the wavelength-controlled disulfide-diselenide chemistry to develop light-responsive reversible organogels. These organogels have the potential to be used in functional materials such as polymeric actuators or biomimetic soft robotics.
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Affiliation(s)
- M. Mario Perera
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Prathyusha Chimala
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Abdul Elhusain-Elnegres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Paul Heaton
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
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10
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McKenzie TJ, Heaton PS, Rishi K, Kumar R, Brunet T, Beaucage G, Mondain-Monval O, Ayres N. Storage Moduli and Porosity of Soft PDMS PolyMIPEs Can Be Controlled Independently Using Thiol–Ene Click Chemistry. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00217] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tucker J. McKenzie
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Paul S. Heaton
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Kabir Rishi
- Department of Chemical and Materials Engineering, The University of Cincinnati, Cincinnati, Ohio 45242-0012, United States
| | - Raj Kumar
- University of Bordeaux—CNRS, Centre de Recherche Paul Pascal, Pessac 33600, France
| | - Thomas Brunet
- Institut de Mécanique et d’Ingénierie, University of Bordeaux—CNRS—Bordeaux INP, Talence 33402, France
| | - Gregory Beaucage
- Department of Chemical and Materials Engineering, The University of Cincinnati, Cincinnati, Ohio 45242-0012, United States
| | | | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
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11
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Gallagher ZJ, Fleetwood S, Kirley TL, Shaw MA, Mullins ES, Ayres N, Foster EJ. Heparin Mimic Material Derived from Cellulose Nanocrystals. Biomacromolecules 2020; 21:1103-1111. [DOI: 10.1021/acs.biomac.9b01460] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zahra J. Gallagher
- Macromolecules Innovation Institute, Department of Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Sara Fleetwood
- Macromolecules Innovation Institute, Department of Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Terence L. Kirley
- Department of Pharmacology and Systems Physiology, College of Medicine, The University of Cincinnati, Cincinnati, Ohio 45267, United States
| | - Maureen A. Shaw
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children’s Research Foundation, Cincinnati, Ohio 45229, United States
| | - Eric S. Mullins
- Division of Hematology, Cancer and Blood Diseases Institute, Cincinnati Children’s Research Foundation, Cincinnati, Ohio 45229, United States
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - E. Johan Foster
- Macromolecules Innovation Institute, Department of Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
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12
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Abstract
A review of hydrogels containing dynamic bonds that are shown to provide benefits for applications including self-healing and stimuli-induced stiffness changes.
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Affiliation(s)
- M. Mario Perera
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Neil Ayres
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
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13
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Affiliation(s)
- Emily Dalton
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
| | - Qinyuan Chai
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
| | - Molly W. Shaw
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center Cincinnati Ohio 45229
| | - Tucker J. McKenzie
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
| | - Eric S. Mullins
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center Cincinnati Ohio 45229
| | - Neil Ayres
- The Department of Chemistry The University of Cincinnati Cincinnati Ohio 45221
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14
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Abstract
Matrix dynamics can influence fibroblast activation.
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Affiliation(s)
- M. Mario Perera
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Demetria M. Fischesser
- Cincinnati Children's Hospital Medical Center
- Division of Molecular Cardiovascular Biology
- Cincinnati
- USA
| | - Jeffery D. Molkentin
- Cincinnati Children's Hospital Medical Center
- Division of Molecular Cardiovascular Biology
- Cincinnati
- USA
| | - Neil Ayres
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
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15
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Chidanguro T, Blank DR, Garrett A, Reese CM, Schekman JM, Yu X, Patton DL, Ayres N, Simon YC. Fabrication of single-chain nanoparticles through the dimerization of pendant anthracene groups via photochemical upconversion. Dalton Trans 2018; 47:8663-8669. [DOI: 10.1039/c8dt01392f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Visible light is used to drive the intramolecular dimerization of anthracenes on a methacrylic polymer to form single-chain nanoparticles.
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Affiliation(s)
- Tamuka Chidanguro
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
| | - Danielle R. Blank
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
- Department of Chemistry
| | - Alexandra Garrett
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
| | - Cassandra M. Reese
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
| | - Jacob M. Schekman
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
| | - Xinjun Yu
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Derek L. Patton
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
| | - Neil Ayres
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Yoan C. Simon
- School of Polymer Science and Engineering
- The University of Southern Mississippi
- Hattiesburg 39406
- USA
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16
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Wijesiri N, Ozkaya-Ahmadov T, Wang P, Zhang J, Tang H, Yu X, Ayres N, Zhang P. Photodynamic Inactivation of Multidrug-Resistant Staphylococcus aureus Using Hybrid Photosensitizers Based on Amphiphilic Block Copolymer-Functionalized Gold Nanoparticles. ACS Omega 2017; 2:5364-5369. [PMID: 30023747 PMCID: PMC6044965 DOI: 10.1021/acsomega.7b00738] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/22/2017] [Indexed: 05/23/2023]
Abstract
Multidrug-resistant Staphylococcus aureus (MRSA) has become one of the major causes of various infections, leading to morbidity in both healthy and immune-compromised populations worldwide. Herein, we report a novel type of hybrid photosensitizer based on amphiphilic block copolymer-functionalized gold nanoparticles. The design of the nanoparticles provides a facile means to incorporate hydrophobic photosensitizing molecules for use in aqueous media. The hybrid photosensitizers display greatly enhanced singlet oxygen generation and outstanding photodynamic inactivation (PDI) efficacy against MRSA under light illumination. These hybrid photosensitizers greatly improve the effectiveness of PDI against MRSA while not involving antibiotics.
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Affiliation(s)
- Niranga Wijesiri
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Tevhide Ozkaya-Ahmadov
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Peng Wang
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Jinnan Zhang
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Hong Tang
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Xinjun Yu
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Peng Zhang
- Department of Chemistry, University
of Cincinnati, Cincinnati, Ohio 45221, United States
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17
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Han D, Yu X, Chai Q, Ayres N, Steckl AJ. Stimuli-Responsive Self-Immolative Polymer Nanofiber Membranes Formed by Coaxial Electrospinning. ACS Appl Mater Interfaces 2017; 9:11858-11865. [PMID: 28263054 DOI: 10.1021/acsami.6b16501] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The first self-immolative polymer (SIP) nanofiber membrane is demonstrated in this report, in which the immolation can be triggered by external stimulus. Electrospun SIP/polyacrylonitrile (PAN) fibers provide depolymerization that is ∼25 times quicker and more responsive (i.e., immolation) than that of a cast film in the triggering condition. Depolymerization of SIP in the SIP/PAN blended fiber membrane results in the transition of the surface properties from hydrophobic (∼110°) to hygroscopic (∼0°). Triggered release of encapsulated functional molecules was demonstrated using coaxially electrospun fiber membrane made of a SIP/PAN blend sheath and polyvinylpyrrolidone/dye core. Coaxial fibers with the SIP/PAN sheath provide minimal release of the encapsulated material in nontriggering solution, while it releases the encapsulated material instantly when the triggering condition is met. Its versatility has been strengthened compared to that of non-SIP coaxial fibers that provide no triggering reaction by external stimulus.
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Affiliation(s)
- Daewoo Han
- Nanoelectronics Laboratory, Department of Electrical Engineering and Computing Systems, University of Cincinnati , Cincinnati, Ohio 45221, United States
| | - Xinjun Yu
- Department of Chemistry, University of Cincinnati , Cincinnati, Ohio 45221, United States
| | - Qinyuan Chai
- Department of Chemistry, University of Cincinnati , Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department of Chemistry, University of Cincinnati , Cincinnati, Ohio 45221, United States
| | - Andrew J Steckl
- Nanoelectronics Laboratory, Department of Electrical Engineering and Computing Systems, University of Cincinnati , Cincinnati, Ohio 45221, United States
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18
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Abstract
Gelatin based dynamic stiffening–softening hydrogels were prepared via thiol–norbornene click reactions.
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Affiliation(s)
- M. Mario Perera
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Neil Ayres
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
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19
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Abstract
Shape memory foams have been prepared using a heparin-inspired polyurea/urethane that displays excellent resistance to platelet adherence.
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Affiliation(s)
- Q. Chai
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - Y. Huang
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - T. L. Kirley
- Department of Pharmacology and Cell Biophysics
- College of Medicine
- The University of Cincinnati
- Cincinnati
- USA
| | - N. Ayres
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
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20
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De Coen R, Vanparijs N, Risseeuw MDP, Lybaert L, Louage B, De Koker S, Kumar V, Grooten J, Taylor L, Ayres N, Van Calenbergh S, Nuhn L, De Geest BG. pH-Degradable Mannosylated Nanogels for Dendritic Cell Targeting. Biomacromolecules 2016; 17:2479-88. [DOI: 10.1021/acs.biomac.6b00685] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | - Leeanne Taylor
- Department
of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Neil Ayres
- Department
of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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21
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Abd Ellah NH, Taylor L, Ayres N, Elmahdy MM, Fetih GN, Jones HN, Ibrahim EA, Pauletti GM. NF-κB decoy polyplexes decrease P-glycoprotein-mediated multidrug resistance in colorectal cancer cells. Cancer Gene Ther 2016; 23:149-55. [PMID: 27125866 DOI: 10.1038/cgt.2016.17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 02/14/2016] [Accepted: 02/26/2016] [Indexed: 11/09/2022]
Abstract
Multidrug resistance (MDR), a major cause for chemotherapy failure, has been linked to upregulation of ATP-dependent membrane efflux systems that limit intracellular accumulation of cytotoxic anticancer agents. P-glycoprotein (P-gp) encoded by the human ABCB1 gene was the first efflux transporter identified to contribute to MDR. ABCB1 gene expression is correlated with constitutive activation of the NF-κB signaling pathway in tumor cells. The objective of this research is to modulate P-gp activity in colon cancer cells using NF-κB decoy oligodeoxynucleotides (ODNs) that are effectively delivered into the nucleus of colorectal cancer cells by self-assembling nonviral nanoparticles comprising the novel poly[N-(2-hydroxypropyl)methacrylamide]-poly(N,N-dimethylaminoethylmethacrylate) diblock copolymer (pHPMA-b-pDMAEMA). Ethidium bromide intercalation and gel retardation assays demonstrated high DNA condensation capacity of pHPMA-b-pDMAEMA. Nanoparticles prepared with and without decoy ODNs did not significantly compromise cellular safety at N/P ratios ⩽4. Transfection efficiency of pHPMA-b-pDMAEMA polyplexes (N/P=4) in Caco-2 cells was comparable to TurboFect transfection standard, resulting in a 98% reduction in P-gp protein levels. As a pharmacodynamic consequence, intracellular accumulation of the P-gp substrate Rhodamine123 significantly increased by almost twofold. In conclusion, NF-κB ODN polyplexes fabricated with pHPMA-b-pDMAEMA polymer effectively reduced P-gp-mediated efflux activity in Caco-2 cells, suggesting successful interference with NF-κB-binding sites in the promoter region of the ABCB1 gene.
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Affiliation(s)
- N H Abd Ellah
- James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH, USA.,Faculty of Pharmacy, Assiut University, Assiut, Arab Republic of Egypt
| | - L Taylor
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | - N Ayres
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | - M M Elmahdy
- Faculty of Pharmacy, Assiut University, Assiut, Arab Republic of Egypt
| | - G N Fetih
- Faculty of Pharmacy, Assiut University, Assiut, Arab Republic of Egypt
| | - H N Jones
- Division of General and Thoracic Surgery and Reproductive Sciences, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - E A Ibrahim
- Faculty of Pharmacy, Assiut University, Assiut, Arab Republic of Egypt
| | - G M Pauletti
- James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH, USA
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Affiliation(s)
- Yongshun Huang
- Department of Chemistrythe University of CincinnatiP.O. Box 210172Cincinnati Ohio45221
| | - Qinyuan Chai
- Department of Chemistrythe University of CincinnatiP.O. Box 210172Cincinnati Ohio45221
| | - Mary R. Warmin
- Department of Chemistrythe University of CincinnatiP.O. Box 210172Cincinnati Ohio45221
| | - Neil Ayres
- Department of Chemistrythe University of CincinnatiP.O. Box 210172Cincinnati Ohio45221
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23
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Ding R, Yu X, Wang P, Zhang J, Zhou Y, Cao X, Tang H, Ayres N, Zhang P. Hybrid photosensitizer based on amphiphilic block copolymer stabilized silver nanoparticles for highly efficient photodynamic inactivation of bacteria. RSC Adv 2016. [DOI: 10.1039/c6ra01660j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We report the development of a type of novel hybrid photosensitizers for photodynamic inactivation of broad-spectrum bacteria.
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Affiliation(s)
- Rui Ding
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Xinjun Yu
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Peng Wang
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Jinnan Zhang
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Yan Zhou
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Xian Cao
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Hong Tang
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Neil Ayres
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
| | - Peng Zhang
- Department of Chemistry
- University of Cincinnati
- Cincinnati
- USA
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24
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Huang Y, Shaw MA, Warmin MR, Mullins ES, Ayres N. Blood compatibility of heparin-inspired, lactose containing, polyureas depends on the chemistry of the polymer backbone. Polym Chem 2016. [DOI: 10.1039/c6py00616g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sulfated glycopolymers were synthesized from diisocyanates and lactose containing diamines. Blood compatibility assays indicated highly sulfated glycopolymers with methylene bis(4-cyclohexyl isocyanate) backbones result in prolonged clotting times.
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Affiliation(s)
- Y. Huang
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - M. A. Shaw
- Cancer and Blood Diseases Institute
- Cincinnati Children's Hospital Medical Center
- Cincinnati
- USA
| | - M. R. Warmin
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
| | - E. S. Mullins
- Cancer and Blood Diseases Institute
- Cincinnati Children's Hospital Medical Center
- Cincinnati
- USA
| | - N. Ayres
- Department of Chemistry
- The University of Cincinnati
- Cincinnati
- USA
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25
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Abd Ellah N, Taylor L, Troja W, Owens K, Ayres N, Pauletti G, Jones H. Development of Non-Viral, Trophoblast-Specific Gene Delivery for Placental Therapy. PLoS One 2015; 10:e0140879. [PMID: 26473479 PMCID: PMC4608830 DOI: 10.1371/journal.pone.0140879] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/01/2015] [Indexed: 12/14/2022] Open
Abstract
Low birth weight is associated with both short term problems and the fetal programming of adult onset diseases, including an increased risk of obesity, diabetes and cardiovascular disease. Placental insufficiency leading to intrauterine growth restriction (IUGR) contributes to the prevalence of diseases with developmental origins. Currently there are no therapies for IUGR or placental insufficiency. To address this and move towards development of an in utero therapy, we employ a nanostructure delivery system complexed with the IGF-1 gene to treat the placenta. IGF-1 is a growth factor critical to achieving appropriate placental and fetal growth. Delivery of genes to a model of human trophoblast and mouse placenta was achieved using a diblock copolymer (pHPMA-b-pDMAEMA) complexed to hIGF-1 plasmid DNA under the control of trophoblast-specific promoters (Cyp19a or PLAC1). Transfection efficiency of pEGFP-C1-containing nanocarriers in BeWo cells and non-trophoblast cells was visually assessed via fluorescence microscopy. In vivo transfection and functionality was assessed by direct placental-injection into a mouse model of IUGR. Complexes formed using pHPMA-b-pDMAEMA and CYP19a-923 or PLAC1-modified plasmids induce trophoblast-selective transgene expression in vitro, and placental injection of PLAC1-hIGF-1 produces measurable RNA expression and alleviates IUGR in our mouse model, consequently representing innovative building blocks towards human placental gene therapies.
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Affiliation(s)
- Noura Abd Ellah
- James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH, 45267, United States of America
- Faculty of Pharmacy, Assiut University, 71515, Assiut, Arab Republic of Egypt
| | - Leeanne Taylor
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, 45221, United States of America
| | - Weston Troja
- Divisions of General and Thoracic Surgery and Reproductive Sciences, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, 45229, United States of America
| | - Kathryn Owens
- Divisions of General and Thoracic Surgery and Reproductive Sciences, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, 45229, United States of America
| | - Neil Ayres
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, 45221, United States of America
| | - Giovanni Pauletti
- James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH, 45267, United States of America
| | - Helen Jones
- Divisions of General and Thoracic Surgery and Reproductive Sciences, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, 45229, United States of America
- * E-mail:
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26
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Affiliation(s)
- Qinyuan Chai
- Department of Chemistry; The University of Cincinnati; Cincinnati Ohio 45221-0172
| | - Yongshun Huang
- Department of Chemistry; The University of Cincinnati; Cincinnati Ohio 45221-0172
| | - Neil Ayres
- Department of Chemistry; The University of Cincinnati; Cincinnati Ohio 45221-0172
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Yu X, Cao X, Chen X, Ayres N, Zhang P. Triplet-triplet annihilation upconversion from rationally designed polymeric emitters with tunable inter-chromophore distances. Chem Commun (Camb) 2014; 51:588-91. [PMID: 25414975 DOI: 10.1039/c4cc07589g] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report an investigation of triplet-triplet annihilation upconversion (TTA-UC) based on polymeric emitters with tunable inter-chromophore distances. Poly[(9-anthrylmethyl methacrylate)-co-(methyl methacrylate)] (poly(AnMMA-co-MMA)) with different percentages of AnMMA was synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization, and used as an emitter in association with platinum octaethylporphyrin as a sensitizer to form TTA-UC systems. It is observed that the TTA-UC intensity first increases with increasing AnMMA percentage in the polymers then decreases, and ultimately disappears, upon further increasing the AnMMA percentage. The results shed light on the key factors affecting TTA-UC in polymers, and have implications for the design of polymer-based TTA-UC systems.
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Affiliation(s)
- Xinjun Yu
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221.
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Abstract
![]()
Polyurea-based synthetic glycopolymers
containing sulfated glucose,
mannose, glucosamine, or lactose as pendant groups have been synthesized
by step-growth polymerization of hexamethylene diisocyanate and corresponding
secondary diamines. The obtained polymers were characterized by gel
permeation chromatography, nuclear magnetic resonance spectroscopy,
and Fourier transform infrared spectroscopy. The nonsulfated polymers
showed similar results to the commercially available biomaterial polyurethane
TECOFLEX in a platelet adhesion assay. The average degree of sulfation
after reaction with SO3 was calculated from elemental analysis
and found to be between three and four −OSO3 groups
per saccharide. The blood-compatibility of the synthetic polymers
was measured using activated partial thromboplastin time, prothrombin
time, thrombin time, anti-IIa, and anti-Xa assays. Activated partial
thromboplastin time, prothrombin time, and thrombin time results indicated
that the mannose and lactose based polymers had the highest anticoagulant
activities among all the sulfated polymers. The mechanism of action
of the polymers appears to be mediated via an anti-IIa pathway rather
than an anti-Xa pathway.
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Affiliation(s)
- Yongshun Huang
- Department of Chemistry and ‡Materials Science and Engineering Program, The University of Cincinnati , Cincinnati, Ohio 45221, United States
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Abd Ellah NH, Potter SJ, Taylor L, Ayres N, Elmahdy MM, Fetih GN, Ibrahim ESA, Pauletti GM. Safety and efficacy of amine-containing methacrylate polymers as nonviral gene delivery vectors. ACTA ACUST UNITED AC 2014. [DOI: 10.7243/2050-120x-3-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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30
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Chen X, Fei P, Cavicchi KA, Yang W, Ayres N. The poor solubility of ureidopyrimidone can be used to form gels of low molecular weight N-alkyl urea oligomers in organic solvents. Colloid Polym Sci 2013. [DOI: 10.1007/s00396-013-3087-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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31
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Huang Y, Taylor L, Chen X, Ayres N. Synthesis of a polyurea from a glucose- or mannose-containing N
-alkyl urea peptoid oligomer. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pola.26953] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yongshun Huang
- Department of Chemistry; The University of Cincinnati; P.O. Box 210172, Cincinnati Ohio 45221
| | - Leeanne Taylor
- Department of Chemistry; The University of Cincinnati; P.O. Box 210172, Cincinnati Ohio 45221
| | - Xiaoping Chen
- Department of Chemistry; The University of Cincinnati; P.O. Box 210172, Cincinnati Ohio 45221
| | - Neil Ayres
- Department of Chemistry; The University of Cincinnati; P.O. Box 210172, Cincinnati Ohio 45221
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Taylor L, Chen X, Ayres N. Synthesis of a glycosaminoglycan polymer mimetic using an N
-alkyl-N
,N
-linked urea oligomer containing glucose pendant groups. POLYM INT 2013. [DOI: 10.1002/pi.4567] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Leeanne Taylor
- University of Cincinnati; Department of Chemistry; 301 Clifton Court, PO Box 210172 Cincinnati OH 45221 USA
| | - Xiaoping Chen
- University of Cincinnati; Department of Chemistry; 301 Clifton Court, PO Box 210172 Cincinnati OH 45221 USA
| | - Neil Ayres
- University of Cincinnati; Department of Chemistry; 301 Clifton Court, PO Box 210172 Cincinnati OH 45221 USA
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Chen X, Ding K, Ayres N. Investigation into fiber formation in N-alkyl urea peptoid oligomers and the synthesis of a water-soluble PEG/N-alkyl urea peptoid oligomer conjugate. Polym Chem 2011. [DOI: 10.1039/c1py00284h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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37
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Affiliation(s)
- Xiaoping Chen
- Department of Chemistry, The University of Cincinnati, 301 Clifton Court, PO Box 210172, Cincinnati, Ohio 45221
| | - Neil Ayres
- Department of Chemistry, The University of Cincinnati, 301 Clifton Court, PO Box 210172, Cincinnati, Ohio 45221
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39
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Ayres N, Holt DJ, Jones CF, Corum LE, Grainger DW. Polymer Brushes Containing Sulfonated Sugar Repeat Units: Synthesis, Characterization and In Vitro Testing of Blood Coagulation Activation. ACTA ACUST UNITED AC 2008; 46:7713-7724. [PMID: 19859552 DOI: 10.1002/pola.23075] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A new polymer brush chemistry containing sulfonated carbohydrate repeat units has been synthesized from silicon substrates using ATRP methods and characterized both in bulk and using surface analysis. The polymer brush was designed to act as a mimic for the naturally occurring sulfonated glycosaminoglycan, heparin, commonly used for modifying blood-contacting surfaces both in vitro and in vivo. Surface analysis showed conversion of brush saccharide precursor chemistry to the desired sulfonated polymer product. The sulfonated polymer brush surface was further analyzed using three conventional in vitro tests for blood compatibility -- plasma recalcification times, complement activation, and thrombin generation. The sulfonated polymer brush films on silicon oxide wafers exhibited better assay performance in these blood component assays than the unsulfonated sugar functionalized polymer brush in all tests performed.
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Affiliation(s)
- N Ayres
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112-5820 USA
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40
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Ayres N, Cyrus CD, Brittain WJ. Stimuli-responsive surfaces using polyampholyte polymer brushes prepared via atom transfer radical polymerization. Langmuir 2007; 23:3744-9. [PMID: 17319701 DOI: 10.1021/la062417+] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The synthesis of AB diblock copolymer polyampholyte polymer brushes of the type Si/SiO2//poly(acrylic acid-b-vinyl pyridine) prepared using atom transfer radical polymerization is reported. Both 2- and 4-vinyl pyridine have been used. The diblock polyampholyte polymer brushes demonstrate stimuli-responsive behavior with respect to pH, showing both polyelectrolyte and polyampholyte effects. Furthermore, we have quaternized the 4-vinyl pyridine segments to form a mixed weak/strong, or annealed/quenched, polyelectrolyte system. The quaternized polymer brush exhibits different pH-responsive behavior, with decreasing film thickness being observed with increasing pH.
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Affiliation(s)
- Neil Ayres
- The University of Akron, Department of Polymer Science, Goodyear Polymer Center, Akron, Ohio 44325-3909, USA
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41
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Ayres N, Boyes SG, Brittain WJ. Stimuli-responsive polyelectrolyte polymer brushes prepared via atom-transfer radical polymerization. Langmuir 2007; 23:182-9. [PMID: 17190502 DOI: 10.1021/la061526l] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We present an account of our research into polyelectrolyte polymer brushes that are capable of acting as stimuli-responsive films. We first detail the synthesis of poly(acrylic acid) polymer brushes using ATRP in a "grafting from" strategy. Significantly, we employed a chemical-free deprotection step that should leave the anchoring ester groups intact. We have demonstrated how these polymer assemblies respond to stimuli such as pH and electrolyte concentration. We have used poly(acrylic acid) polymer brushes for the synthesis of metallic nanoparticles and review this work. We have used XPS, ATR-FTIR, and AFM spectroscopy to show the presence of silver and palladium nanoparticles within polymer brushes. Finally, we report the synthesis of AB diblock polyampholyte polymer brushes that represent an extension of polyelectrolyte polymer brushes.
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Affiliation(s)
- Neil Ayres
- Department of Polymer Science, Goodyear Polymer Center, 170 University Avenue, University of Akron, Akron, Ohio 44325, USA
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42
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Ezell RG, Gorman I, Lokitz B, Ayres N, McCormick CL. Stimuli-responsive ampholytic terpolymers ofN-acryloyl-valine, acrylamide, and (3-acrylamidopropyl)trimethylammonium chloride: Synthesis, characterization, and solution properties. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21408] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Affiliation(s)
- Neil D. Treat
- Department of Polymer Science, The University of Southern Mississippi, Southern Station Box 10076, Hattiesburg, Mississippi 39406-0076; Department of Polymer Science, Goodyear Polymer Center, 170 University Ave., University of Akron, Akron, Ohio 44325; and Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401
| | - Neil Ayres
- Department of Polymer Science, The University of Southern Mississippi, Southern Station Box 10076, Hattiesburg, Mississippi 39406-0076; Department of Polymer Science, Goodyear Polymer Center, 170 University Ave., University of Akron, Akron, Ohio 44325; and Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401
| | - Stephen G. Boyes
- Department of Polymer Science, The University of Southern Mississippi, Southern Station Box 10076, Hattiesburg, Mississippi 39406-0076; Department of Polymer Science, Goodyear Polymer Center, 170 University Ave., University of Akron, Akron, Ohio 44325; and Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401
| | - William J. Brittain
- Department of Polymer Science, The University of Southern Mississippi, Southern Station Box 10076, Hattiesburg, Mississippi 39406-0076; Department of Polymer Science, Goodyear Polymer Center, 170 University Ave., University of Akron, Akron, Ohio 44325; and Department of Chemistry and Geochemistry, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401
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44
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Vasilieva YA, Scales CW, Thomas DB, Ezell RG, Lowe AB, Ayres N, McCormick CL. Controlled/living polymerization of methacrylamide in aqueous media via the RAFT process. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pola.20786] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Convertine AJ, Ayres N, Scales CW, Lowe AB, McCormick CL. Facile, Controlled, Room-Temperature RAFT Polymerization of N-Isopropylacrylamide. Biomacromolecules 2004; 5:1177-80. [PMID: 15244427 DOI: 10.1021/bm049825h] [Citation(s) in RCA: 212] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Poly(N-isopropyl acrylamide) is a thermoresponsive polymer that has been widely investigated for drug delivery. Herein, we report conditions facilitating the controlled, room-temperature RAFT polymerization of N-isopropylacrylamide (NIPAM). The key to success is the appropriate choice of both a suitable RAFT chain transfer agent (CTA) and initiating species. We show that the use of 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid, a trithiocarbonate RAFT CTA, in conjunction with the room-temperature azo initiator 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), in DMF, at 25 degrees C, yields conditions leading to NIPAM homopolymerizations which bear all of the characteristics of a controlled/"living" polymerization. We also demonstrate facile size exclusion chromatographic analysis of PNIPAM samples in DMF at 60 degrees C, directly on aliquots withdrawn during the polymerizations, which avoids the problems previously reported in the literature.
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Affiliation(s)
- Anthony J Convertine
- Department of Polymer Science, University of Southern Mississippi, Hattiesburg, Mississippi 39406, USA
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46
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Ayres N, Haddleton DM, Shooter AJ, Pears DA. Synthesis of Hydrophilic Polar Supports Based on Poly(dimethylacrylamide) via Copper-Mediated Radical Polymerization from a Cross-Linked Polystyrene Surface: Potential Resins for Oligopeptide Solid-Phase Synthesis. Macromolecules 2002. [DOI: 10.1021/ma0116001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Ayres
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL UK, and Avecia, PO Box 42, Blackley, Manchester M9 8ZS, UK
| | - D. M. Haddleton
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL UK, and Avecia, PO Box 42, Blackley, Manchester M9 8ZS, UK
| | - A. J. Shooter
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL UK, and Avecia, PO Box 42, Blackley, Manchester M9 8ZS, UK
| | - D. A. Pears
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL UK, and Avecia, PO Box 42, Blackley, Manchester M9 8ZS, UK
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47
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Angot S, Ayres N, Bon SAF, Haddleton DM. Living Radical Polymerization Immobilized on Wang Resins: Synthesis and Harvest of Narrow Polydispersity Poly(methacrylate)s. Macromolecules 2001. [DOI: 10.1021/ma0011690] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stephanie Angot
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, U.K
| | - Neil Ayres
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, U.K
| | - Stefan A. F. Bon
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, U.K
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48
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Abstract
Milrinone, a new positive inotropic agent, was evaluated and compared to isoproterenol in an immature isolated isovolumic rabbit heart model. Three age groups were studied: newborns (0-6 days), juveniles (4-6 weeks old) and adults (5-7 months old). Heart rate did not change significantly with milrinone or isoproterenol in adults or juveniles, but increased in newborns from 144 +/- 1 to 162 +/- (SEM) 6 beats/min at peak milrinone effect. Milrinone had a greater effect on the contractility (maximum positive dP/dt) of the mature hearts, with newborns increasing to 134 +/- 6% of baseline, juveniles to 154 +/- 8% and adults to 216 +/- 15%. Results were similar for isoproterenol, although the positive inotropic effect occurred over a wider dosage range for this drug. No additive effects of the two drugs were noted. We conclude, that although milrinone is a positive inotropic drug in all age groups studied, the response of the newborn heart is quantitatively much weaker than that of the adult.
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Affiliation(s)
- M D Parrish
- Department of Pediatrics, University of Texas Health Science Center, Dallas
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49
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Rheuban KS, Ayres N, Still JG, Alford B. Pulmonary artery sling: a new diagnostic tool and clinical review. Pediatrics 1982; 69:472-5. [PMID: 7070894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The pulmonary artery sling is a vascular anomaly that produces severe respiratory disease in infancy. The differential diagnosis is lengthy, and the diagnostic work-up frequently includes such invasive maneuvers as bronchography, bronchoscopy, and cardiac catheterization. In this paper the use of a new noninvasive diagnostic tool, computer tomography, to aid in the diagnosis of this form of vascular ring, is discussed and a review of salient features of this cardiovascular malformation is presented.
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