1
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Valimukhametova AR, Lee BH, Topkiran UC, Gries K, Gonzalez-Rodriguez R, Coffer JL, Akkaraju G, Naumov A. Cancer Therapeutic siRNA Delivery and Imaging by Nitrogen- and Neodymium-Doped Graphene Quantum Dots. ACS Biomater Sci Eng 2023; 9:3425-3434. [PMID: 37255435 DOI: 10.1021/acsbiomaterials.3c00369] [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: 06/01/2023]
Abstract
While small interfering RNA (siRNA) technology has become a powerful tool that can enable cancer-specific gene therapy, its translation to the clinic is still hampered by the inability of the genes alone to cell transfection, poor siRNA stability in blood, and the lack of delivery tracking capabilities. Recently, graphene quantum dots (GQDs) have emerged as a novel platform allowing targeted drug delivery and fluorescence image tracking in visible and near-infrared regions. These capabilities can aid in overcoming primary obstacles to siRNA therapeutics. Here, for the first time, we utilize biocompatible nitrogen- and neodymium-doped graphene quantum dots (NGQDs and Nd-NGQDs, respectively) for the delivery of Kirsten rat sarcoma virus (KRAS) and epidermal growth factor receptor (EGFR) siRNA effective against a variety of cancer types. GQDs loaded with siRNA noncovalently facilitate successful siRNA transfection into HeLa cells, confirmed by confocal fluorescence microscopy at biocompatible GQD concentrations of 375 μg/mL. While the GQD platform provides visible fluorescence tracking, Nd doping enables deeper-tissue near-infrared fluorescence imaging suitable for both in vitro and in vivo applications. The therapeutic efficacy of the GQD/siRNA complex is verified by successful protein knockdown in HeLa cells at nanomolar siEGFR and siKRAS concentrations. A range of GQD/siRNA loading ratios and payloads are tested to ultimately provide substantial inhibition of protein expression down to 31-45%, comparable with conventional Lipofectamine-mediated delivery. This demonstrates the promising potential of GQDs for the nontoxic delivery of siRNA and genes in general, complemented by multiwavelength image tracking.
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Affiliation(s)
- Alina R Valimukhametova
- Department of Physics and Astronomy, Texas Christian University, Fort Worth 76129, Texas, United States
| | - Bong Han Lee
- Department of Physics and Astronomy, Texas Christian University, Fort Worth 76129, Texas, United States
| | - Ugur C Topkiran
- Department of Physics and Astronomy, Texas Christian University, Fort Worth 76129, Texas, United States
| | - Klara Gries
- Department of Chemistry and Biochemistry, Heidelberg University, Heidelberg 69117, Germany
| | | | - Jeffery L Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth 76129, Texas, United States
| | - Giridhar Akkaraju
- Department of Biology, Texas Christian University, Fort Worth 76129, Texas, United States
| | - Anton Naumov
- Department of Physics and Astronomy, Texas Christian University, Fort Worth 76129, Texas, United States
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2
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Dossou AS, Mantsch ME, Kapic A, Burnett WL, Sabnis N, Coffer JL, Berg RE, Fudala R, Lacko AG. Mannose-Coated Reconstituted Lipoprotein Nanoparticles for the Targeting of Tumor-Associated Macrophages: Optimization, Characterization, and In Vitro Evaluation of Effectiveness. Pharmaceutics 2023; 15:1685. [PMID: 37376134 DOI: 10.3390/pharmaceutics15061685] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/29/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Reconstituted high-density lipoprotein nanoparticles (rHDL NPs) have been utilized as delivery vehicles to a variety of targets, including cancer cells. However, the modification of rHDL NPs for the targeting of the pro-tumoral tumor-associated macrophages (TAMs) remains largely unexplored. The presence of mannose on nanoparticles can facilitate the targeting of TAMs which highly express the mannose receptor at their surface. Here, we optimized and characterized mannose-coated rHDL NPs loaded with 5,6-dimethylxanthenone-4-acetic acid (DMXAA), an immunomodulatory drug. Lipids, recombinant apolipoprotein A-I, DMXAA, and different amounts of DSPE-PEG-mannose (DPM) were combined to assemble rHDL-DPM-DMXAA NPs. The introduction of DPM in the nanoparticle assembly altered the particle size, zeta potential, elution pattern, and DMXAA entrapment efficiency of the rHDL NPs. Collectively, the changes in physicochemical characteristics of rHDL NPs upon the addition of the mannose moiety DPM indicated that the rHDL-DPM-DMXAA NPs were successfully assembled. The rHDL-DPM-DMXAA NPs induced an immunostimulatory phenotype in macrophages pre-exposed to cancer cell-conditioned media. Furthermore, rHDL-DPM NPs delivered their payload more readily to macrophages than cancer cells. Considering the effects of the rHDL-DPM-DMXAA NPs on macrophages, the rHDL-DPM NPs have the potential to serve as a drug delivery platform for the selective targeting of TAMs.
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Affiliation(s)
- Akpedje S Dossou
- Department of Microbiology, Immunology and Genetics, UNT Health Science Center (UNTHSC), Fort Worth, TX 76107, USA
| | - Morgan E Mantsch
- College of Natural Sciences, University of Texas at Austin, Austin, TX 78705, USA
| | - Ammar Kapic
- Department of Microbiology, Immunology and Genetics, UNT Health Science Center (UNTHSC), Fort Worth, TX 76107, USA
| | - William L Burnett
- College of Science and Engineering, Texas Christian University (TCU), Fort Worth, TX 76129, USA
| | - Nirupama Sabnis
- Department of Microbiology, Immunology and Genetics, UNT Health Science Center (UNTHSC), Fort Worth, TX 76107, USA
| | - Jeffery L Coffer
- College of Science and Engineering, Texas Christian University (TCU), Fort Worth, TX 76129, USA
| | - Rance E Berg
- Department of Microbiology, Immunology and Genetics, UNT Health Science Center (UNTHSC), Fort Worth, TX 76107, USA
| | - Rafal Fudala
- Department of Microbiology, Immunology and Genetics, UNT Health Science Center (UNTHSC), Fort Worth, TX 76107, USA
| | - Andras G Lacko
- Department of Microbiology, Immunology and Genetics, UNT Health Science Center (UNTHSC), Fort Worth, TX 76107, USA
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Gonzalez-Rodriguez R, Hathaway E, Lin Y, Coffer JL, Cui J. Encapsulated MAPbBr 3 in nickel oxide nanotubes and their electroluminescence. Nanoscale 2022; 14:6417-6424. [PMID: 35416223 DOI: 10.1039/d2nr00019a] [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] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Metal halide perovskites have emerged as the next generation of light emitting semiconducting materials due to their excellent properties such as tunable bandgaps, high photoluminescence quantum yield, and high color purity. Nickel oxide is a hole transport material that has been used in planar light emitting diodes (LEDs). In this paper, we develop a novel method for the large scale fabrication of metal halide perovskite nanowire arrays encapsulated inside nickel oxide nanotubes. We study the structural and spectral properties of these infiltrated perovskites nanowires and, to the best of our knowledge, for the first time report on a working LED device consisting of perovskites encapsulated inside nickel oxide nanotubes. Finally, we study the photoluminescence and electroluminescence of an LED with MAPbBr3 inside nickel oxide nanotubes and obtain an outstanding current efficiency of 5.99 Cd A-1 and external quantum efficiency of 3.9% for the LED device.
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Affiliation(s)
| | - Evan Hathaway
- Department of Physics, University of North Texas, Denton, Texas, 76203, USA.
| | - Yuankun Lin
- Department of Physics, University of North Texas, Denton, Texas, 76203, USA.
| | - Jeffery L Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas, 76129, USA
| | - Jingbiao Cui
- Department of Physics, University of North Texas, Denton, Texas, 76203, USA.
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4
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D'Achille AE, Wallace RM, Coffer JL. Morphology-dependent fluorescence of europium-doped cerium oxide nanomaterials. Nanoscale Adv 2021; 3:3563-3572. [PMID: 36133706 PMCID: PMC9417455 DOI: 10.1039/d1na00096a] [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] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/27/2021] [Indexed: 05/03/2023]
Abstract
Europium-doped CeO2 nanomaterials have been investigated for a variety of sensing and biological applications, as doping enhances the catalytic activity of CeO2 and contributes visible fluorescence to the nanomaterial. However, scant evidence is available that directly compares Eu3+ fluorescence from multiple morphologies establishing useful correlation(s) between physical and optical trends in such structures. To address this shortcoming, Eu3+-doped CeO2 nanorods, nanowires, nanocubes, and annealed nanorods were synthesized and characterized, representing a range of crystalline defect sizes, defect concentrations, and surface moieties. Morphologies rich with oxygen defects and hydroxyl groups (assessed via X-ray photoelectron spectroscopy) quenched the Eu3+ fluorescence, while samples with larger crystalline domains and lower Ce3+ concentrations have relatively stronger emission intensities. Of the four morphologies, nanocubes exhibit the strongest emission, as each structure is monocrystalline with few oxygen defects and associated quenching sites. Furthermore, the Eu3+ hypersensitive transition is more responsive to the dopant concentration in the nanocubes, as defects induced by the dopant are not removed by thermal annealing.
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Affiliation(s)
- Anne E D'Achille
- Department of Chemistry and Biochemistry, Texas Christian University Ft. Worth TX. 76129 USA
| | - Robert M Wallace
- Department of Materials Science and Engineering, University of Texas at Dallas Dallas TX 75080 USA
| | - Jeffery L Coffer
- Department of Chemistry and Biochemistry, Texas Christian University Ft. Worth TX. 76129 USA
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Coffer JL, Canham LT. Nanoporous Silicon as a Green, High-Tech Educational Tool. Nanomaterials (Basel) 2021; 11:nano11020553. [PMID: 33672198 PMCID: PMC7926729 DOI: 10.3390/nano11020553] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/25/2022]
Abstract
Pedagogical tools are needed that link multidisciplinary nanoscience and technology (NST) to multiple state-of-the-art applications, including those requiring new fabrication routes relying on green synthesis. These can both educate and motivate the next generation of entrepreneurial NST scientists to create innovative products whilst protecting the environment and resources. Nanoporous silicon shows promise as such a tool as it can be fabricated from plants and waste materials, but also embodies many key educational concepts and key industrial uses identified for NST. Specific mechanical, thermal, and optical properties become highly tunable through nanoporosity. We also describe exceptional properties for nanostructured silicon like medical biodegradability and efficient light emission that open up new functionality for this semiconductor. Examples of prior lecture courses and potential laboratory projects are provided, based on the author’s experiences in academic chemistry and physics departments in the USA and UK, together with industrial R&D in the medical, food, and consumer-care sectors. Nanoporous silicon-based lessons that engage students in the basics of entrepreneurship can also readily be identified, including idea generation, intellectual property, and clinical translation of nanomaterial products.
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Affiliation(s)
- Jeffery L. Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA
- Correspondence: (J.L.C.); (L.T.C.)
| | - Leigh T. Canham
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Correspondence: (J.L.C.); (L.T.C.)
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6
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D'Achille AE, Gonzalez-Rodriguez R, Campbell E, Lee BH, Coffer JL, Naumov AV. Rare-Earth-Doped Cerium Oxide Nanocubes for Biomedical Near-Infrared and Magnetic Resonance Imaging. ACS Biomater Sci Eng 2020; 6:6971-6980. [PMID: 33320629 DOI: 10.1021/acsbiomaterials.0c01193] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Near-infrared (NIR) fluorescence provides a new avenue for biomedical fluorescence imaging that allows for the tracking of fluorophore through several centimeters of biological tissue. However, such fluorophores are rare and, due to accumulation-derived toxicity, are often restricted from clinical applications. Deep tissue imaging not only provided by near-infrared fluorophores but also conventionally carried out by magnetic resonance imaging (MRI) or computed tomography (CT) is also hampered by the toxicity of the contrast agents. This work offers a biocompatible imaging solution: cerium oxide (CeO2) nanocubes doped with ytterbium or neodymium, and co-doped with gadolinium, showing simultaneous potential for near-infrared (NIR) fluorescence and magnetic resonance imaging (MRI) applications. A synthetic process described in this work allows for the stable incorporation of ytterbium or neodymium, both possessing emissive transitions in the NIR. As a biocompatible nanomaterial, the CeO2 nanocubes act as an ideal host material for doping, minimizing lanthanide fluorescence self-quenching as well as any potential toxicity associated with the dopants. The uptake of nanocubes by HeLa cells maximized at 12 h was monitored by hyperspectral imaging of the ytterbium or neodymium NIR emission, indicating the capacity of the lanthanide-doped nanocubes for in vitro and a potential for in vivo fluorescence imaging. The co-doped nanocubes demonstrate no significant loss of NIR emission intensity upon co-doping with 2 atomic % gadolinium and exhibit magnetic susceptibilities in the range of known negative contrast agents. However, a small increase to 6 atomic % gadolinium significantly affects the magnetic susceptibility ratio (r2/r1), shifting closer to the positive contrast range and suggesting the potential use of the CeO2 nanocube matrix doped with selected rare-earth ions as a tunable MRI contrast agent with NIR imaging capabilities.
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Affiliation(s)
- Anne E D'Achille
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas 76129, United States
| | - Roberto Gonzalez-Rodriguez
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas 76129, United States
| | - Elizabeth Campbell
- Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, Texas 76129, United States
| | - Bong Han Lee
- Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, Texas 76129, United States
| | - Jeffery L Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas 76129, United States
| | - Anton V Naumov
- Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, Texas 76129, United States
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7
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Gonzalez-Rodriguez R, Costa VCP, Delport G, Frohna K, Hoye RLZ, Stranks SD, Coffer JL. Structural and spectroscopic studies of a nanostructured silicon-perovskite interface. Nanoscale 2020; 12:4498-4505. [PMID: 32031192 DOI: 10.1039/c9nr09622a] [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] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
While extensively investigated in thin film form for energy materials applications, this work investigates the formation of APbBr3 structures (A = CH3NH3+ (MA), Cs+) in silicon and oxidized silicon nanotubes (SiNTs) with varying inner diameter. We carefully control the extent of oxidation of the nanotube host and correlate the relative Si/Si oxide content in a given nanotube host with the photoluminescence quantum efficiency (PLQE) of the perovskite. Complementing these measurements is an evaluation of average PL lifetimes of a given APbBr3 nanostructure, as evaluated by time-resolved confocal photoluminescence measurements. Increasing Si (decreasing oxide) content in the nanotube host results in a sensitive reduction of MAPbBr3 PLQE, with a concomitant decrease in average lifetime (τave). We interpret these observations in terms of decreased defect passivation by a lower concentration of oxide species surrounding the perovskite. In addition, we show that the use of selected nanotube templates leads to more stable perovskite PL in air over time (weeks). Taken in concert, such fundamental observations have implications for interfacial carrier interactions in tandem Si/perovskite photovoltaics.
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Affiliation(s)
- Roberto Gonzalez-Rodriguez
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas 76129, USA.
| | - Viviana C P Costa
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas 76129, USA.
| | - Géraud Delport
- Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, UK
| | - Kyle Frohna
- Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, UK
| | - Robert L Z Hoye
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB 3 0FS, UK
| | - Samuel D Stranks
- Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, UK and Department of Chemical Engineering & Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, United Kingdom
| | - Jeffery L Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, TCU Box 298860, Fort Worth, Texas 76129, USA.
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8
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Le NT, Akkaraju GR, Coffer JL. Formation of Platinum Nanocrystals on Silicon Nanotubes and Corresponding Anti-Cancer Activity in Vitro. ACS Appl Bio Mater 2020; 3:208-216. [DOI: 10.1021/acsabm.9b00719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Nguyen T. Le
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Giridhar R. Akkaraju
- Department of Biology, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Jeffery L. Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, United States
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9
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Veloz-Castillo MF, Paredes-Arroyo A, Vallejo-Espinosa G, Delgado-Jiménez JF, Coffer JL, González-Rodríguez R, Mendoza ME, Campos-Delgado J, Méndez-Rojas MA. Carbon nanotubes and carbon fibers in a flash: an easy and convenient preparation of carbon nanostructures using a conventional microwave. CAN J CHEM 2020. [DOI: 10.1139/cjc-2019-0244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The growing interest in nanomaterials in different application fields calls for the implementation of simple, economically appealing, and efficient preparative methods. Among the wide variety of nanomaterials, carbon nanostructures have a special place due to their potential technological applications. Here, we present a fast, cheap, and easy-to-implement microwave-assisted method for the preparation of carbon nanotubes (CNTs) and carbon fibers (CFs) at room pressure conditions. The synthesis involves heating a mixture of graphite and ferrocene contained in a simple glass tube using a conventional microwave oven. A mixture of multi-walled carbon nanotubes (MWCNTs) and Fe3O4 magnetic nanoparticles were obtained quickly (less than 30 s) and in good yields. The products were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and Raman spectroscopy.
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Affiliation(s)
- María Fernanda Veloz-Castillo
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Ex Hacienda Sta. Catarina Mártir, San Andrés Cholula, Puebla 72820, México
| | - Antonio Paredes-Arroyo
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Ex Hacienda Sta. Catarina Mártir, San Andrés Cholula, Puebla 72820, México
| | - Gerardo Vallejo-Espinosa
- CARBOMEX, Investigación y Producción de Nanomateriales, Independencia 632, 16 de Septiembre Sur, Puebla 72474, México
| | - José Francisco Delgado-Jiménez
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Ex Hacienda Sta. Catarina Mártir, San Andrés Cholula, Puebla 72820, México
| | - Jeffery L. Coffer
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA
| | | | - Maria E. Mendoza
- Instituto de Física “Luis Rivera Terrazas”, Benemérita Universidad Autónoma de Puebla, Av. – San Claudio y 18 Sur, Ciudad Universitaria, Puebla 72570, México
| | - Jessica Campos-Delgado
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Ex Hacienda Sta. Catarina Mártir, San Andrés Cholula, Puebla 72820, México
| | - Miguel A. Méndez-Rojas
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Ex Hacienda Sta. Catarina Mártir, San Andrés Cholula, Puebla 72820, México
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10
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Hasan MT, Gonzalez-Rodriguez R, Ryan C, Coffer JL, Naumov AV. Variation of Optical Properties of Nitrogen-doped Graphene Quantum Dots with Short/Mid/Long-wave Ultraviolet for the Development of the UV Photodetector. ACS Appl Mater Interfaces 2019; 11:39035-39045. [PMID: 31553149 DOI: 10.1021/acsami.9b10365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nitrogen-doped graphene quantum dots (NGQDs) synthesized from a single glucosamine precursor are utilized to develop a novel UV photodetector. Optical properties of NGQDs can be altered with short- (254 nm), mid- (302 nm), and long-wave (365 nm) ultraviolet (UV) exposure leading to the reduction of absorption from deep to mid UV (200-320 nm) and enhancement above 320 nm. Significant quenching of blue and near-IR fluorescence accompanied by the dramatic increase of green/yellow emission of UV-treated NGQDs can be used as a potential UV-sensing mechanism. These emission changes are attributed to the reduction of functional groups detected by Fourier transformed infrared spectroscopy and free-radical-driven polymerization of the NGQDs increasing their average size from 4.70 to 11.20 nm at 60 min treatment. Due to strong UV absorption and sensitivity to UV irradiation, NGQDs developed in this work are utilized to fabricate UV photodetectors. Tested under long-/mid-/short-wave UV, these devices show high photoresponsivity (up to 0.59 A/W) and excellent photodetectivity (up to 1.03 × 1011 Jones) with highly characteristic wavelength-dependent reproducible response. This study suggests that the optical/structural properties of NGQDs can be controllably altered via different wavelength UV treatment leading us to fabricate NGQD-based novel UV photodetectors providing high responsivity and detectivity.
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Affiliation(s)
- Md Tanvir Hasan
- Department of Physics and Astronomy , Texas Christian University , TCU Box 298840, Fort Worth , Texas 76129 , United States
| | - Roberto Gonzalez-Rodriguez
- Department of Chemistry and Biochemistry , Texas Christian University , TCU Box 298860, Fort Worth , Texas 76129 , United States
| | - Conor Ryan
- Department of Physics and Astronomy , Texas Christian University , TCU Box 298840, Fort Worth , Texas 76129 , United States
| | - Jeffery L Coffer
- Department of Chemistry and Biochemistry , Texas Christian University , TCU Box 298860, Fort Worth , Texas 76129 , United States
| | - Anton V Naumov
- Department of Physics and Astronomy , Texas Christian University , TCU Box 298840, Fort Worth , Texas 76129 , United States
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11
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Burnett ME, Bodiford N, Goulet ME, Coffer JL, Green KN. Environmental effects of chitosan as an immobilization medium for electrochemically active small molecules. J COORD CHEM 2019. [DOI: 10.1080/00958972.2019.1655550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Marianne E. Burnett
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, TX, USA
| | - Nelli Bodiford
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, TX, USA
| | - Meghen E. Goulet
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, TX, USA
| | - Jeffery L. Coffer
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, TX, USA
| | - Kayla N. Green
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, TX, USA
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12
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Kalluri J, West J, Akkaraju GR, Canham LT, Coffer JL. Plant-Derived Tandem Drug/Mesoporous Silicon Microcarrier Structures for Anti-Inflammatory Therapy. ACS Omega 2019; 4:8359-8364. [PMID: 31459924 PMCID: PMC6648573 DOI: 10.1021/acsomega.9b00127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/15/2019] [Indexed: 06/10/2023]
Abstract
The properties of nanostructured plant-derived porous silicon (pSi) microparticles as potential candidates to increase the bioavailability of plant extracts possessing anti-inflammatory activity are described in this work. pSi drug carriers were fabricated using an eco-friendly route from the silicon accumulator plant bamboo (tabasheer) powder by magnesiothermic reduction of plant-derived silica and loaded with ethanolic extracts of Equisetum arvense, another silicon accumulator plant rich in polyphenolic compounds. The anti-inflammatory properties of the active therapeutics present in this extract were measured by sensitive luciferase reporter assays; this active extract was subsequently loaded and released from the pSi matrix, with a clear inhibition of the activity of the inflammatory signaling protein NF-κB over a period of hours in a sustained manner. Our results showed that after loading the extracts of E. arvense into pSi microparticles derived from tabasheer, enhanced anti-inflammatory activity was observed owing to enhanced solubility of the extract.
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Affiliation(s)
- Jhansi
R. Kalluri
- Department
of Chemistry and Biochemistry and Department of Biology, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Julianna West
- Department
of Chemistry and Biochemistry and Department of Biology, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Giridhar R. Akkaraju
- Department
of Chemistry and Biochemistry and Department of Biology, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Leigh T. Canham
- Nanoscale
Physics, Chemistry, and Engineering Research Laboratory, University of Birmingham, Birmingham B15 2TT, U.K.
| | - Jeffery L. Coffer
- Nanoscale
Physics, Chemistry, and Engineering Research Laboratory, University of Birmingham, Birmingham B15 2TT, U.K.
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13
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Gonzalez-Rodriguez R, Granitzer P, Rumpf K, Coffer JL. New MRI contrast agents based on silicon nanotubes loaded with superparamagnetic iron oxide nanoparticles. R Soc Open Sci 2018; 5:180697. [PMID: 30225066 PMCID: PMC6124042 DOI: 10.1098/rsos.180697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/20/2018] [Indexed: 05/03/2023]
Abstract
This article describes the preparation and fundamental properties of a new possible material as a magnetic resonance imaging contrast agent based on the incorporation of preformed iron oxide (Fe3O4) nanocrystals into hollow silicon nanotubes (Si NTs). Specifically, superparamagnetic Fe3O4 nanoparticles of two different average sizes (5 nm and 8 nm) were loaded into Si NTs of two different shell thicknesses (40 nm and 70 nm). To achieve proper aqueous solubility, the NTs were functionalized with an outer polyethylene glycol-diacid (600) moiety via an aminopropyl linkage. Relaxometry parameters r1 and r2 were measured, with the corresponding r2/r1 ratios in phosphate buffered saline confirming the expected negative contrast agent behaviour for these materials. For a given nanocrystal size, the observed r2 values are found to be inversely proportional to NT wall thickness, thereby demonstrating the role of nanostructured silicon template on associated relaxometry properties.
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Affiliation(s)
| | - Petra Granitzer
- Institute of Physics, Karl-Franzens-University Graz, Universitaetsplatz 5, 8010 Graz, Austria
| | - Klemens Rumpf
- Institute of Physics, Karl-Franzens-University Graz, Universitaetsplatz 5, 8010 Graz, Austria
| | - Jeffery L. Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129USA
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14
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Le NT, Kalluri JR, Loni A, Canham LT, Coffer JL. Biogenic Nanostructured Porous Silicon as a Carrier for Stabilization and Delivery of Natural Therapeutic Species. Mol Pharm 2017; 14:4509-4514. [PMID: 29111753 DOI: 10.1021/acs.molpharmaceut.7b00638] [Citation(s) in RCA: 7] [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] [Indexed: 01/10/2023]
Abstract
Nanostructured mesoporous silicon (pSi) derived from the silicon-accumulator plant Tabasheer (Bambuseae) is demonstrated to serve as a potential carrier matrix for carrying and stabilizing naturally active, but otherwise metastable, therapeutic agents. Particularly, in this study, garlic oil containing phytochemicals (namely, allicin) that are capable of inhibiting Staphylococcus aureus (S. aureus) bacterial growth were incorporated into Tabasheer-derived porous silicon. Thermogravimetric analysis (TGA) indicated that relatively high amounts of the extract (53.1 ± 2.2 wt %) loaded into pSi are possible by simple infiltration. Furthermore, by assessing the antibacterial activity of the samples using a combination technique of agar disk diffusion and turbidity assays against S. aureus, we report that biogenic porous silicon can be utilized to stabilize and enhance the therapeutic effects of garlic oil for up to 4 weeks when the samples were stored under refrigerated conditions (4 °C) and 1 week at room temperature (25 °C). Critically, under ultraviolet (UV) light (365 nm) irradiation for 24 h intervals, plant-derived pSi is shown to have superior performance in protecting garlic extracts over porous silica (pSiO2) derived from the same plant feedstock or extract-only controls. The mechanism for this effect has also been investigated.
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Affiliation(s)
- Nguyen T Le
- Department of Chemistry and Biochemistry, Texas Christian University , Fort Worth, Texas 76129, United States
| | - Jhansi R Kalluri
- Department of Chemistry and Biochemistry, Texas Christian University , Fort Worth, Texas 76129, United States
| | - Armando Loni
- pSiMedica Ltd. , Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ, U.K
| | - Leigh T Canham
- pSiMedica Ltd. , Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ, U.K.,Nanoscale Physics, Chemistry, and Engineering Research Laboratory, University of Birmingham , Birmingham B15 2TT, U.K
| | - Jeffery L Coffer
- Department of Chemistry and Biochemistry, Texas Christian University , Fort Worth, Texas 76129, United States
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15
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Pal K, Al-Suraih F, Gonzalez-Rodriguez R, Dutta SK, Wang E, Kwak HS, Caulfield TR, Coffer JL, Bhattacharya S. Multifaceted peptide assisted one-pot synthesis of gold nanoparticles for plectin-1 targeted gemcitabine delivery in pancreatic cancer. Nanoscale 2017; 9:15622-15634. [PMID: 28991294 PMCID: PMC5859336 DOI: 10.1039/c7nr03172f] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An astute modification of the plectin-1-targeting peptide KTLLPTP by introducing a C-terminal cysteine preceded by a tyrosine residue imparted a reducing property to the peptide. This novel property is then exploited to fabricate gold nanoparticles (GNP) via an in situ reduction of gold(iii) chloride in a one-pot, green synthesis. The modified peptide KTLLPTPYC also acts as a template to generate highly monodispersed, spherical GNPs with a narrow size distribution and improved stability. Plectin-1 is known to be aberrantly expressed in the surface of pancreatic ductal adenocarcinoma (PDAC) cells while showing cytoplasmic expression in normal cells. The synthesized GNPs are thus in situ surface modified with the peptides via the cysteine residue leaving the N-terminal KTLLPTP sequence free for targeting plectin-1. The visual molecular dynamics based simulations support the experimental observations like particle size, gemcitabine conjugation and architecture of the peptide-grafted nanoassembly. Additionally, GNPs conjugated to gemcitabine demonstrate significantly higher cytotoxicity in vitro in two established PDAC cell lines (AsPC-1 and PANC-1) and an admirable in vivo antitumor efficacy in a PANC-1 orthotopic xenograft model through selective uptake in PDAC tumor tissues. Altogether, this strategy represents a unique method for the fabrication of a GNP based targeted drug delivery platform using a multifaceted peptide that acts as reducing agent, template for GNP synthesis and targeting agent to display remarkable selectivity towards PDAC.
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Affiliation(s)
- Krishnendu Pal
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, Florida 32224, USA.
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16
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Enciso AE, Doni G, Nifosì R, Palazzesi F, Gonzalez R, Ellsworth AA, Coffer JL, Walker AV, Pavan GM, Mohamed AA, Simanek EE. Correction: Facile synthesis of stable, water soluble, dendron-coated gold nanoparticles. Nanoscale 2017; 9:10966. [PMID: 28731113 DOI: 10.1039/c7nr90151h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Correction for 'Facile synthesis of stable, water soluble, dendron-coated gold nanoparticles' by Alan E. Enciso, et al., Nanoscale, 2017, 9, 3128-3132.
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Affiliation(s)
- Alan E Enciso
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76109, USA
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17
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Enciso AE, Doni G, Nifosì R, Palazzesi F, Gonzalez R, Ellsworth AA, Coffer JL, Walker AV, Pavan GM, Mohamed AA, Simanek EE. Facile synthesis of stable, water soluble, dendron-coated gold nanoparticles. Nanoscale 2017; 9:3128-3132. [PMID: 28211928 DOI: 10.1039/c6nr09679d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Upon reduction with sodium borohydride, diazonium tetrachloroaurate salts of triazine dendrons yield dendron-coated gold nanoparticles connected by a gold-carbon bond. These robust nanoparticles are stable in water and toluene solutions for longer than one year and present surface groups that can be reacted to change surface chemistry and manipulate solubility. Molecular modeling was used to provide insight on the hydration of the nanoparticles and their observed solubilties.
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Affiliation(s)
- Alan E Enciso
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76109, USA
| | - Giovanni Doni
- Department of Physics, King's College, London Strand, London WC2R 2NS, UK
| | - Riccardo Nifosì
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Ferruccio Palazzesi
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, CH-8093 Zurich, Switzerland and Facoltá di Informatica, Istituto di Scienze Computazionali, Universitá della Svizzera Italiana, CH-6900 Lugano, Switzerland
| | - Roberto Gonzalez
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76109, USA
| | | | - Jeffery L Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76109, USA
| | - Amy V Walker
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080, USA and Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Giovanni M Pavan
- Department of Innovative Technologies, University of Applied Sciences and Arts of Southern Switzerland, Galleria 2, Via Cantonale 2c, CH-6928 Manno, Switzerland
| | - Ahmed A Mohamed
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76109, USA and Department of Chemistry, University of Sharjah, Sharjah, United Arab Emirates
| | - Eric E Simanek
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76109, USA
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18
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Wareing N, Szymanski K, Akkaraju GR, Loni A, Canham LT, Gonzalez-Rodriguez R, Coffer JL. In Vitro Gene Delivery with Large Porous Silicon Nanoparticles Fabricated Using Cost-Effective, Metal-Assisted Chemical Etching. Small 2017; 13:1602739. [PMID: 28084695 DOI: 10.1002/smll.201602739] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/23/2016] [Indexed: 05/28/2023]
Abstract
The cytocompatibility, cell membrane affinity, and plasmid DNA delivery from surface oxidized, metal-assisted stain-etched mesoporous silicon nanoscale particles (pSiNPs) to human embryonic kidney (HEK293) cells is demonstrated, suggesting the possibility of using such material for targeted transfection and drug delivery.
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Affiliation(s)
- Nancy Wareing
- Department of Biology, Texas Christian University, Fort Worth, TX, 76129, USA
| | - Kyle Szymanski
- Department of Biology, Texas Christian University, Fort Worth, TX, 76129, USA
| | - Giridhar R Akkaraju
- Department of Biology, Texas Christian University, Fort Worth, TX, 76129, USA
| | - Armando Loni
- pSiMedica Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire, WR14 3 SZ, UK
| | - Leigh T Canham
- pSiMedica Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire, WR14 3 SZ, UK
| | | | - Jeffery L Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, TX, 76129, USA
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19
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Kalluri JR, Gonzalez-Rodriguez R, Hartman PS, Loni A, Canham LT, Coffer JL. Single Plant Derived Nanotechnology for Synergistic Antibacterial Therapies. PLoS One 2016; 11:e0163270. [PMID: 27684478 PMCID: PMC5042556 DOI: 10.1371/journal.pone.0163270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/05/2016] [Indexed: 12/03/2022] Open
Abstract
Multiple new approaches to tackle multidrug resistant infections are urgently needed and under evaluation. One nanotechnology-based approach to delivering new relevant therapeutics involves silicon accumulator plants serving as a viable silicon source in green routes for the fabrication of the nanoscale drug delivery carrier porous silicon (pSi). If the selected plant leaf components contain medicinally-active species as well, then a single substance can provide not only the nanoscale high surface area drug delivery carrier, but the drug itself. With this idea in mind, porous silicon was fabricated from joints of the silicon accumulator plant Bambuseae (Tabasheer) and loaded with an antibacterial extract originating from leaves of the same type of plant (Bambuseae arundinacea). Preparation of porous silicon from Tabasheer includes extraction of biogenic silica from the ground plant by calcination, followed by reduction with magnesium in the presence of sodium chloride, thereby acting as a thermal moderator that helps to retain the mesoporous structure of the feedstock. The purified product was characterized by a combination of scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), and low temperature nitrogen gas adsorption measurements. Antimicrobial activity and minimum inhibitory concentration of a leaf extract of Bambuseae arundinacea was tested against the bacteria Escherichia Coli (E. Coli) and Staphylococcus aureus (S. Aureus), along with the fungus Candida albicans (C. Albicans). A S. aureus active ethanolic leaf extract was loaded into the above Tabasheer-derived porous silicon. Initial studies indicate sustained in vitro antibacterial activity of the extract-loaded plant derived pSi (25 wt %, TGA), as measured by disk diffusion inhibitory zone assays. Subsequent chromatographic separation of this extract revealed that the active antimicrobial species present include stigmasterol and 2,6-dimethoxy-p-benzoquinone.
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Affiliation(s)
- Jhansi R. Kalluri
- Department of Chemistry, Texas Christian University, Fort Worth, TX, 76129, United States of America
| | | | - Phil S. Hartman
- Department of Biology, Texas Christian University, Fort Worth, TX 76129, United States of America
| | - Armando Loni
- pSiMedica Ltd., Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire, WR14 3 SZ, United Kingdom
| | - Leigh T. Canham
- pSiMedica Ltd., Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire, WR14 3 SZ, United Kingdom
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Edgbaston B152TT, United Kingdom
| | - Jeffery L. Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, TX, 76129, United States of America
- * E-mail:
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20
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Gonzalez-Rodriguez R, Arad-Vosk N, Rozenfeld N, Sa'ar A, Coffer JL. Control of CH3 NH3 PbI3 Perovskite Nanostructure Formation through the Use of Silicon Nanotube Templates. Small 2016; 12:4477-4480. [PMID: 27416485 DOI: 10.1002/smll.201601291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/23/2016] [Indexed: 06/06/2023]
Abstract
A new route to formation of methylammonium lead iodide perovskite nanostructures is reported whose dimensions are controlled by the use of porous silicon nanotube templates. Optical absorption and photoluminescence properties for perovskite nanostructures of 70 and 200 nm in width are evaluated, along with comparisons with larger 1D microwires of the same composition.
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Affiliation(s)
| | - Neta Arad-Vosk
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Naama Rozenfeld
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Amir Sa'ar
- Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Jeffery L Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, TX, 76129, USA
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21
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Ramírez-Crescencio F, Enciso AE, Hasan M, da Costa VCP, Annunziata O, Redón R, Coffer JL, Simanek EE. Thermoregulated Coacervation, Metal-Encapsulation and Nanoparticle Synthesis in Novel Triazine Dendrimers. Molecules 2016; 21:molecules21050599. [PMID: 27187331 PMCID: PMC6273988 DOI: 10.3390/molecules21050599] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/19/2016] [Accepted: 04/28/2016] [Indexed: 12/18/2022] Open
Abstract
The synthesis and solubility behaviors of four generation five (G5) triazine dendrimers are studied. While the underivatized cationic dendrimer is soluble in water, the acetylated and propanoylated derivatives undergo coacervation in water upon increasing temperature. Occurring around room temperature, this behavior is related to a liquid-liquid phase transition with a lower critical solution temperature (LCST) and is explained by differences in composition, notably, the hydrophobic nature of the terminal groups. Interestingly, the water solubility of the acetylated dendrimer is affected by the addition of selected metal ions. Titrating solutions of acetylated dendrimer at temperatures below the LCST with gold or palladium ions promoted precipitation, but platinum, iridium, and copper did not. Gold nanoparticles having diameters of 2.5 ± 0.8 nm can be obtained from solutions of the acetylated dendrimer at concentrations of gold less than that required to induce precipitation by treating the solution with sodium borohydride.
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Affiliation(s)
- Fermín Ramírez-Crescencio
- Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Cd. Universitaria, A.P. 70-186, C.P., Cd. Mx. 04510, Mexico.
| | - Alan E Enciso
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA.
| | - Mirza Hasan
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA.
| | - Viviana C P da Costa
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA.
| | - Onofrio Annunziata
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA.
| | - Rocío Redón
- Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Cd. Universitaria, A.P. 70-186, C.P., Cd. Mx. 04510, Mexico.
| | - Jeffery L Coffer
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA.
| | - Eric E Simanek
- Department of Chemistry & Biochemistry, Texas Christian University, Fort Worth, TX 76129, USA.
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22
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Granitzer P, Rumpf K, Gonzalez-Rodriguez R, Coffer JL, Reissner M. The effect of nanocrystalline silicon host on magnetic properties of encapsulated iron oxide nanoparticles. Nanoscale 2015; 7:20220-6. [PMID: 26575478 DOI: 10.1039/c5nr05232g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The purpose of this work is a detailed comparison of the fundamental magnetic properties of nanocomposite systems consisting of Fe3O4 nanoparticle-loaded porous silicon as well as silicon nanotubes. Such composite structures are of potential merit in the area of magnetically guided drug delivery. For magnetic systems to be utilized in biomedical applications, there are certain magnetic properties that must be fulfilled. Therefore magnetic properties of embedded Fe3O4-nanoparticles in these nanostructured silicon host matrices, porous silicon and silicon nanotubes, are investigated. Temperature-dependent magnetic investigations have been carried out for four types of iron oxide particle sizes (4, 5, 8 and 10 nm). The silicon host, in interplay with the iron oxide nanoparticle size, plays a sensitive role. It is shown that Fe3O4 loaded porous silicon and SiNTs differ significantly in their magnetic behavior, especially the transition between superparamagnetic behavior and blocked state, due to host morphology-dependent magnetic interactions. Importantly, it is found that all investigated samples meet the magnetic precondition of possible biomedical applications of exhibiting a negligible magnetic remanence at room temperature.
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Affiliation(s)
- P Granitzer
- Institute of Physics, Karl-Franzens-University Graz, 8010 Graz, Austria.
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23
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Tesfaye AT, Gonzalez R, Coffer JL, Djenizian T. Porous Silicon Nanotube Arrays as Anode Material for Li-Ion Batteries. ACS Appl Mater Interfaces 2015; 7:20495-20498. [PMID: 26352212 DOI: 10.1021/acsami.5b05705] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the electrochemical performance of Si nanotube vertical arrays possessing thin porous sidewalls for Li-ion batteries. Porous Si nanotubes were fabricated on stainless steel substrates using a sacrificial ZnO nanowire template method. These porous Si nanotubes are stable at multiple C-rates. A second discharge capacity of 3095 mAh g(-1) with a Coulombic efficiency of 63% is attained at a rate of C/20 and a stable gravimetric capacity of 1670 mAh g(-1) obtained after 30 cycles. The high capacity values are attributed to the large surface area offered by the porosity of the 3D nanostructures, thereby promoting lithium-ion storage according to a pseudocapacitive mechanism.
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Affiliation(s)
- Alexander T Tesfaye
- Aix-Marseille University , CNRS, MADIREL Laboratory, UMR 7246, 13397 Marseille, France
- FR CNRS 3104, ALISTORE-ERI , Nantes, France
| | - Roberto Gonzalez
- Department of Chemistry, Texas Christian University , Fort Worth, Texas 76129, United States
| | - Jeffery L Coffer
- Department of Chemistry, Texas Christian University , Fort Worth, Texas 76129, United States
| | - Thierry Djenizian
- Aix-Marseille University , CNRS, MADIREL Laboratory, UMR 7246, 13397 Marseille, France
- FR CNRS 3104, ALISTORE-ERI , Nantes, France
- FR CNRS 3459, Réseau sur le Stockage Electrochimique de l'Energie (RS2E) , Paris, France
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Wang M, Hartman PS, Loni A, Canham LT, Bodiford N, Coffer JL. Influence of Surface Chemistry on the Release of an Antibacterial Drug from Nanostructured Porous Silicon. Langmuir 2015; 31:6179-85. [PMID: 25970551 DOI: 10.1021/acs.langmuir.5b01372] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Nanostructured mesoporous silicon possesses important properties advantageous to drug loading and delivery. For controlled release of the antibacterial drug triclosan, and its associated activity versus Staphylococcus aureus, previous studies investigated the influence of porosity of the silicon matrix. In this work, we focus on the complementary issue of the influence of surface chemistry on such properties, with particular regard to drug loading and release kinetics that can be ideally adjusted by surface modification. Comparison between drug release from as-anodized, hydride-terminated hydrophobic porous silicon and the oxidized hydrophilic counterpart is complicated due to the rapid bioresorption of the former; hence, a hydrophobic interface with long-term biostability is desired, such as can be provided by a relatively long chain octyl moiety. To minimize possible thermal degradation of the surfaces or drug activity during loading of molten drug species, a solution loading method has been investigated. Such studies demonstrate that the ability of porous silicon to act as an effective carrier for sustained delivery of antibacterial agents can be sensitively altered by surface functionalization.
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Affiliation(s)
| | | | - Armando Loni
- §pSiMedica Ltd., Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ, U.K
| | - Leigh T Canham
- §pSiMedica Ltd., Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ, U.K
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Huang X, Gonzalez-Rodriguez R, Rich R, Gryczynski Z, Coffer JL. Fabrication and size dependent properties of porous silicon nanotube arrays. Chem Commun (Camb) 2013; 49:5760-2. [DOI: 10.1039/c3cc41913d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Abstract
ABSTRACTWe report here the use of nucleotides as stabilizers in the formation of quantum-confined (‘Q-size’) CdS, with the size and composition of the nucleotide exerting a significant effect on the resultant CdS structure. In general, CdS formed from equimolar Cd+2 and S2− (6 × 10−4 M) in the presence of a number of nucleotides yields clusters possessing similar absorption spectra but which differ significantly with respect to emissive behavior and overall physical stability. CdS/polynucleotide colloids (DNA, poly [A], poly[C]) exhibit strong trap luminescence and are stable on a timescale of months, but analogous CdS prepared from the mononucleotides ATP and AMP are virtually nonemissive and flocculate within hours, even upon stabilization at lower temperatures (5 to −60°C). In addition to their preparation and spectroscopic properties, the results of TEM, AFM, and computer modeling studies on these CdS/nucleotide colloids are discussed.
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Zhang L, Coffer JL, Gnade BE, Xu D, Pinizzotto RF. The Influence of Local Ambient Atmosphere on the Electroluminescent Stability of Porous Silicon Diodes. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-358-671] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTIn this work, the influence of surrounding ambient atmosphere on the stability of electroluminescent (EL) porous Si (PS) diodes fabricated from anodic oxidation of epitaxially grown p-type layers on n-type Si substrates is investigated. These structures are characterized using photoluminescence (PL), electroluminescence (EL), and infrared (IR) spectrosopies, as well as scanning electron microscopy (SEM). Such structures yield orange emission with maxima near 620 nm upon the application of moderate applied voltages (3-7 V). In strong oxidizing environments, EL intensity degrades completely within 30 minutes; in contrast, the integrated intensity remains essentially unchanged in the same timeframe in the presence of a vigorous flow of inert gases such as nitrogen and argon. Infrared spectroscopic studies strongly suggest that electroluminescence degradation is related to porous silicon surface oxidation.
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Coffer JL, Lilley SC, Martin RA, Files-Sesler LA. The Effect of Lewis Base Chemisorption on the Luminscence of Porous Silicon. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-283-305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTWe report here studies on the effects of Lewis base addition on the observed luminescence of porous silicon generated non-anodically from a stain etch of <100> p-type wafers and whose surface morphology has been characterized by atomic force microscopy (AFM). Addition of dilute heptane solutions of alkyl amines such as n-butyl amine (C4H7NH2) results in dramatic quenching of the steady-state photoluminescence (PL) near 625 nm. The observed fractional changes in integrated PL intensity as a function of amine concentration have been fit to a simple equilibrium model demonstrating Langmuir-type behavior from which adduct formation constants have been calculated. These steady-state PL measurements are complemented by Fourier Transform Infrared (FT IR) spectroscopic measurements monitoring the effect of amine adsorption on the silicon hydride stretching modes [v(Si-Hx)] near 2100 cm-1. Based on these results, a physical model for the amine interactions with the porous silicon surface is presented.
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Coffer JL, Li X, John JS, Pinizzotto RF, Chen Y, Newey J, Canham LT. Fabrication and Characterization of Calcium Phosphate / Porous Silicon / Silicon Structures Doped with Platinum Antitumor Compounds. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-599-61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractA process has been developed which permits the encapsulation of an established class of platinum anticancer drugs such as cis-Platin (cis-diammine-dichloroplatinum (II)) within synthetic biocompatible calcium phosphate films that are electrochemically-grown on porous Si/Si substrates. These platinum complex-doped hydroxyapatite / porous Si / Si materials have been characterized by scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (XEDS), and secondary ion mass spectrometry (SIMS). Upon immersion of these structures into aqueous media, the desired platinum species can be released into the surrounding environment. This study also focuses on the influence of initial platinum concentration for a given complex in the deposition process on the rate and resultant amount of platinum complex that can be delivered to the surroundings in vitro. Both inductively-coupled plasma (ICP) spectroscopy and uv-visible absorption spectrometry have been employed to monitor the release of the encapsulated drug from the calcium phosphate layers.
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Fan D, Akkaraju GR, Couch EF, Canham LT, Coffer JL. The role of nanostructured mesoporous silicon in discriminating in vitro calcification for electrospun composite tissue engineering scaffolds. Nanoscale 2011; 3:354-361. [PMID: 21107480 DOI: 10.1039/c0nr00550a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The impact of mesoporous silicon (PSi) particles-embedded either on the surface, or totally encapsulated within electrospun poly (ε-caprolactone) (PCL) fibers-on its properties as a tissue engineering scaffold is assessed. Our findings suggest that the resorbable porous silicon component can sensitively accelerate the necessary calcification process in such composites. Calcium phosphate deposition on the scaffolds was measured via in vitro calcification assays both at acellular and cellular levels. Extensive attachment of fibroblasts, human adult mesenchymal stem cells, and mouse stromal cells to the scaffold were observed. Complementary cell differentiation assays and ultrastructural measurements were also carried out; the levels of alkaline phosphatase expression, a specific biomarker for mesenchymal stem cell differentiation, show that the scaffolds have the ability to mediate such processes, and that the location of the Si plays a key role in levels of expression.
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Affiliation(s)
- Dongmei Fan
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
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Huang X, Coffer JL. Non-lithographic formation of three dimensional periodic nanostructures by germanium nanowire etching. Chem Commun (Camb) 2011; 47:11665-7. [DOI: 10.1039/c1cc13882k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wu J, Wieligor M, Zerda TW, Coffer JL. The impact of erbium incorporation on the structure and photophysics of silicon-germanium nanowires. Nanoscale 2010; 2:2657-2667. [PMID: 20931125 DOI: 10.1039/c0nr00476f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this paper, we report multi-step processes for the fabrication of Er3+-doped SiGe nanowires (NWs) and characterization of their emissive properties. Three different alloyed architectures are obtained by altering the deposition sequences of Si and Er3+ on a Ge core NW, each involving a fixed concentration of these three elements. The deposition of Si onto the Ge NW core, followed by an Er3+-rich layer on the outermost surface, permits facile formation of a SiGe alloy given the lack of an erbium diffusion barrier; yet clustering of the erbium centers on the NW surface produces the weakest emitter. For nanowires prepared by co-depositing Si and Er3+ on top of the Ge core, the presence of impurity Er3+ ions greatly reduces the alloying rate of Si and Ge such that less Si can diffuse into the Ge core. For this structure, the reduction of Er-Er interactions by a polycrystalline Si shell results in the strongest emission at 1540 nm. If an Er3+ layer is inserted between the Ge and Si layers (a sandwich structure), it is found that Er3+ ions diffuse preferentially into the SiGe core instead of the silicon-rich shell, with a correspondingly weaker luminescence intensity. A combination of high resolution transmission electron microscopy, energy dispersive X-ray mapping, micro-Raman spectroscopy, and photoluminescence spectroscopy are employed to derive these conclusions.
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Affiliation(s)
- Ji Wu
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
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Wang M, Coffer JL, Dorraj K, Hartman PS, Loni A, Canham LT. Sustained Antibacterial Activity from Triclosan-Loaded Nanostructured Mesoporous Silicon. Mol Pharm 2010; 7:2232-9. [DOI: 10.1021/mp100227m] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Kashanian S, Harding F, Irani Y, Klebe S, Marshall K, Loni A, Canham L, Fan D, Williams KA, Voelcker NH, Coffer JL. Evaluation of mesoporous silicon/polycaprolactone composites as ophthalmic implants. Acta Biomater 2010; 6:3566-72. [PMID: 20350620 DOI: 10.1016/j.actbio.2010.03.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 03/18/2010] [Accepted: 03/22/2010] [Indexed: 10/19/2022]
Abstract
The suitability of porous silicon (pSi) encapsulated in microfibers of the biodegradable polymer polycaprolactone (PCL) for ophthalmic applications was evaluated, using both a cell attachment assay with epithelial cells and an in vivo assessment of biocompatibility in rats. Microfibers of PCL containing encapsulated pSi particles at two different concentrations (6 and 20 wt.%) were fabricated as non-woven fabrics. Given the dependence of Si particle dissolution kinetics on pSi surface chemistry, two different types of pSi particles (hydride-terminated and surface-oxidized) were evaluated for each of the two particle concentrations. Significant attachment of a human lens epithelial cell line (SRA 01/04) to all four types of scaffolds within a 24h period was observed. Implantation of Si fabric samples beneath the conjunctiva of rat eyes for 8 weeks demonstrated that the composite materials did not cause visible infection or inflammation, and did not erode the ocular surface. We suggest that these novel composite materials hold considerable promise as scaffolds in tissue engineering with controlled release applications.
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Jiang K, Fan D, Belabassi Y, Akkaraju G, Montchamp JL, Coffer JL. Medicinal surface modification of silicon nanowires: impact on calcification and stromal cell proliferation. ACS Appl Mater Interfaces 2009; 1:266-9. [PMID: 20305799 PMCID: PMC2841355 DOI: 10.1021/am800219r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Medicinal surface modification of silicon nanowires (SiNWs) with selected bisphosphonates, such as the known antiosteoporotic drug alendronate, is described. In terms of specific assays relevant to orthopedic applications, the impact of selected bisphosphonate attachment on acellular calcification in simulated plasma is reported. To further investigate biocompatibility, proliferation assays of these modified nanowires were carried out using an orthopedically relevant cell line: mesenchymal stem cells derived from mouse stroma. It is found that the identity of the bisphosphonate ligand strongly and sensitively impacts its resultant cytotoxicity.
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Affiliation(s)
- Ke Jiang
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
| | - Dongmei Fan
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
| | - Yamina Belabassi
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
| | - Giridhar Akkaraju
- Department of Biology, Texas Christian University, Fort Worth, TX 76129, USA
| | - Jean-Luc Montchamp
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
| | - Jeffery L. Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
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Seregin VV, Coffer JL. Mechanism of calcium disilicide-induced calcification of crystalline silicon surfaces in simulated body fluid under zero bias. J Biomed Mater Res A 2008; 87:15-24. [DOI: 10.1002/jbm.a.31691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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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Whitehead MA, Fan D, Mukherjee P, Akkaraju GR, Canham LT, Coffer JL. High-Porosity Poly(ε-Caprolactone)/Mesoporous Silicon Scaffolds: Calcium Phosphate Deposition and Biological Response to Bone Precursor Cells. ACTA ACUST UNITED AC 2008. [DOI: 10.1089/ten.2006.0370] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Whitehead MA, Fan D, Mukherjee P, Akkaraju GR, Canham LT, Coffer JL. High-Porosity Poly(ε-Caprolactone)/Mesoporous Silicon Scaffolds: Calcium Phosphate Deposition and Biological Response to Bone Precursor Cells. Tissue Eng Part A 2008; 14:195-206. [DOI: 10.1089/ten.a.2006.0370] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Dongmei Fan
- Department of Chemistry, Texas Christian University, Fort Worth, Texas
| | | | | | - Leigh T. Canham
- pSi Medica, Malvern Hills Science Park, Malvern, United Kingdom
| | - Jeffery L. Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, Texas
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Whitehead MA, Fan D, Akkaraju GR, Canham LT, Coffer JL. Accelerated calcification in electrically conductive polymer composites comprised of poly(ɛ-caprolactone), polyaniline, and bioactive mesoporous silicon. J Biomed Mater Res A 2007; 83:225-34. [PMID: 17647228 DOI: 10.1002/jbm.a.31547] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [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: 01/26/2023]
Abstract
In this study the fabrication and characterization of an electrically conductive composite material comprised of poly(epsilon-caprolactone) (PCL), polyaniline (PANi), and bioactive mesoporous silicon (BioSilicon) is discussed. The influence of PANi and silicon on calcium phosphate induction was assessed via ex vitro calcification analyses (by acellular simulated body fluid (SBF) exposure) both with and without electrical bias. Acceleration of calcium phosphate formation is one possible desirable feature of "smart" synthetic scaffolds for selected orthopedic-relevant applications. In addition, electrical stability assays were performed in growth medium (DMEM) to determine the stability of such structures to bias in an authentic electrolyte during a typical cell experiment. The cytocompatibility of the composites was evaluated in vitro using human kidney fibroblasts (HEK 293) cell proliferation assays, along with more orthopedically relevant mesenchymal stem cells from mouse stroma. Importantly, these composites demonstrate accelerated calcification in SBF when electrical bias is applied cathodically to the scaffold. Furthermore, these scaffolds exhibit noncytotoxic behavior in the presence of fibroblasts over an 8-day culture period, and attachment of stromal cells to the semiconducting scaffold was directly imaged via scanning electron microscopy. Overall, these results suggest that materials of this type of composition have potential merit as a biomaterial.
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Affiliation(s)
- Melanie A Whitehead
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129, USA
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Abstract
The incorporation of CaSi(2) grains within a polycaprolactone (PCL) framework results in bioactive and biodegradable scaffolds which may be used in bone tissue regeneration. Porous PCL scaffolds were prepared via a combination of salt-leaching and microemulsion methods. To provide markedly different structural environments for the inorganic phase, calcium disilicide powder was either added to a mixed-composition porogen during a given scaffold preparation, or alternatively added to pre-formed scaffolds. Selective fluorescent labeling, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis were employed to assess scaffold calcification in vitro. The process of CaSi(2)/PCL scaffold calcification under zero bias, during which calcium phosphate growth is significantly dependent on the structural degradation of CaSi(2) grains, has a similar mechanism as the calcium phosphate growth on bioactive glasses/ceramics. The biomineralization of these scaffolds is initiated solely by the silicide phase and can be accelerated by the degradation of the polymer matrix.
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Affiliation(s)
- Vladimir V Seregin
- Department of Chemistry, Texas Christian University, TCU Box 298860, Fort Worth, 76129, USA
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Coffer JL. Semiconductor Nanocrystals and Silicate Nano-particles. Structure and Bonding, 118 Edited by Xiaogang Peng (University of Arkansas, USA) and D. M. P. Mingos (Oxford University, UK). Series Edited by D. M. P. Mingos. Springer: Berlin, Heidelberg, New York. 2005. xii + 190 pp. $179.00. ISBN 3-540-27805-2. J Am Chem Soc 2006. [DOI: 10.1021/ja069705c] [Citation(s) in RCA: 0] [Impact Index Per Article: 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]
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Seregin VV, Coffer JL. Bias-assisted in vitro calcification of calcium disilicide growth layers on spark-processed silicon. Biomaterials 2006; 27:3726-37. [PMID: 16564571 DOI: 10.1016/j.biomaterials.2006.02.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 02/13/2006] [Indexed: 10/24/2022]
Abstract
A dry-etch spark ablation method was used to produce calcium disilicide (CaSi2/Si) layers on silicon (Si) surfaces for the electrochemical growth of apatitic phosphates (calcium phosphate, CaP). CaSi2/Si composite electrodes readily calcify in vitro under the application of a small electric potential, and with proper treatment, the electrodeposition of CaP is localized to the sparked areas. In addition to increasing the local concentration of calcium, interfacial layers of CaSi2 on Si exhibit exceptional site selectivity towards CaP formation under bias due to the difference in conductivity between Si and CaSi2. The proposed mechanism for bias-assisted biomineralization of CaSi2/Si layers on spark-processed Si accounts for the physicochemical properties of deposited CaP films. This work also describes routes to surface modification of calcified composite electrodes with medicinally relevant compounds such as alendronate and norfloxacin. To assess the suitability of this material as a drug-delivery platform, release of the latter compound was also monitored as a function of time.
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Affiliation(s)
- Vladimir V Seregin
- Department of Chemistry, Texas Christian University, TCU Box 298860, Fort Worth, TX 76129, USA
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Abstract
The controlled release of substances from a semiconducting calcium phosphate/porous Si structure is reported. This is demonstrated principally for the case of the reversible adsorption and release of dyes (such as an anionic salt of fluorescein) upon the switching of the direction of bias to the underlying porous Si/Si substrate. The effect of bias on the diffusion of the cationic dyes ethidium bromide and acridine orange has also been investigated. For these species, their delivery can be mediated in part by the use of a surface layer of the biodegradable polymer poly-caprolactone (PCL).
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Affiliation(s)
- Indu Batra
- Department of Chemistry, Texas Christian University, Ft. Worth, 76129, USA
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Mukherjee P, Whitehead MA, Senter RA, Fan D, Coffer JL, Canham LT. Biorelevant mesoporous silicon / polymer composites: directed assembly, disassembly, and controlled release. Biomed Microdevices 2006; 8:9-15. [PMID: 16491326 DOI: 10.1007/s10544-006-6377-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [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: 11/29/2022]
Abstract
We describe in this account a general, yet facile strategy for the directed assembly of bioactive composite materials comprised of an erodible organic polymer such as polycaprolactone and physiologically-resorbable inorganic mesoporous silicon. This method exploits a combination of capillary forces and selective interfacial coupling chemistry to produce isolable macroscale (mm sized) structures possessing a diverse range of geometries through simple mixing rather than intricate molding processes. Furthermore, we demonstrate the ability of such constructs to dissociate into their individual building blocks, with the concomitant release of embedded model compounds in a sustained manner.
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Coffer JL. Binary Rare Earth Oxides Edited by G. Adachi (Juri Institute for Environmental Science and Chemistry, Osaka), N. Imanaka (Osaka University), and Z. C. Kang (International Center for Quantum Structures and State Key Laboratory for Surface Sciences, Beijing). Kluwer Academic Publishers: Dordrecht, The Netherlands. 2004. xiv + 258 pp. $125.00. ISBN 1-4020-2568-8. J Am Chem Soc 2005. [DOI: 10.1021/ja041010t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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]
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Coffer JL, Pinizzotto RF, Rho YG. Nanostructured DNA templates. Methods Mol Biol 2005; 303:167-78. [PMID: 15923683 DOI: 10.1385/1-59259-901-x:167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 05/02/2023]
Abstract
We have developed methods for nanostructure fabrication relying on the size and shape of a polynucleotide to dictate the overall structure of an assemblage of individual semiconductor nanoparticles. Use of the circular plasmids pUCLeu4 and phi chi 174 when anchored to a suitably derivatized substrate yields arrays of semiconductor nanoparticles matching the shapes of the biopolymer stabilizer. The viability of the methodology was confirmed using high-resolution transmission electron microscopy and selected-area electron diffraction.
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Affiliation(s)
- Jeffery L Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, USA
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Senter RA, Pantea C, Wang Y, Liu H, Zerda TW, Coffer JL. Structural influence of erbium centers on silicon nanocrystal phase transitions. Phys Rev Lett 2004; 93:175502. [PMID: 15525088 DOI: 10.1103/physrevlett.93.175502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2003] [Revised: 06/28/2004] [Indexed: 05/24/2023]
Abstract
Two different types of erbium-doped silicon nanocrystals, along with undoped, oxide-capped Si dots, are employed to probe the impact of the impurity center location on phase transition pressure. Using a combination of high pressure optical absorption, micro-Raman, and x-ray diffraction measurements in a diamond anvil cell, it is demonstrated that the magnitude of this phase transition elevation is strongly dictated by the average spatial location of impurity centers introduced into the nanocrystal along with the interfacial quality of the surrounding oxide.
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Affiliation(s)
- Robert A Senter
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129, USA
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Samia ACS, Lou Y, Burda C, Senter RA, Coffer JL. Effect of the erbium dopant architecture on the femtosecond relaxation dynamics of silicon nanocrystals. J Chem Phys 2004; 120:8716-23. [PMID: 15267802 DOI: 10.1063/1.1695318] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Femtosecond pump-probe absorption spectroscopy is used to investigate the role of Er(3+) dopants in the early relaxation pathways of photoexcited Si nanocrystals. The fate of photoexcited electrons in three different Si nanostructures was studied and correlated with the effect of Er-doping and the nature of the dopant architecture. In Si nanocrystals without Er(3+) dopant, a trapping component was identified to be a major electron relaxation mechanism. Addition of Er(3+) ions into the core or surface shell of the nanocrystals was found to open up additional nonradiative relaxation pathways, which is attributed to Er-induced trap states in the Si host. Analysis of the photodynamics of the Si nanocrystal samples reveals an electron trapping mechanism involving trap-to-trap hopping in the doped nanocrystals, whereby the density of deep traps seem to increase with the presence of erbium. To gain additional insights on the relative depths of the trapping sites on the investigated nanostructures, benzoquinone was used as a surface adsorbed electron acceptor to facilitate photoinduced electron transfer across the nanocrystal surface and subsequently assist in back electron transfer. The established reduction potential (-0.45 V versus SCE) of the electron acceptor helped reveal that the erbium-doped nanocrystal samples have deeper trapping sites than the undoped Si. Furthermore, the measurements indicate that internally Er-doped Si have relatively deeper trapping sites than the erbium surface-enriched nanocrystals. The electron-shuttling experiment also reveals that the back electron transfer seems not to recover completely to the ground state in the doped Si nanocrystals, which is explained by a mechanism whereby the electrons are captured by deep trapping sites induced by erbium addition in the Si lattice.
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Affiliation(s)
- A C S Samia
- Center for Chemical Dynamics and Nanomaterials Research, Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Affiliation(s)
- Zhaoyu Wang
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129
| | - Jeffery L. Coffer
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129
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Coffer JL, Montchamp JL, Aimone JB, Weis RP. Routes to calcified porous silicon: implications for drug delivery and biosensing. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/pssa.200306520] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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