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David C. Martin - One of the best experts on this subject based on the ideXlab platform.
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Conducting Polymer nanotubes improve electrical properties mechanical adhesion neural attachment and neurite outgrowth of neural electrodes
Small, 2010Co-Authors: Mohammad Reza Abidian, Joseph M Corey, Daryl R Kipke, David C. MartinAbstract:An in vitro comparison of Conducting-Polymer nanotubes of poly(3,4ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, charge-capacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same depositioncharge density, PPyfilms and nanotubesgrow relatively faster vertically, while PEDOT films and nanotubes grow more laterally. For the same deposition charge density (1.44C cm � 2 ), PPy nanotubes and PEDOT nanotubes have lower impedance (19.5 � 2.1kV for PPy nanotubes and 2.5 � 1.4kV for PEDOT nanotubes at 1kHz) and higher CCD (184 � 5.3mC cm � 2 for PPy nanotubesand 392 � 6.2mC cm � 2 for PEDOT nanotubes) compared to their film counterparts. However, PEDOT nanotubes decrease the impedance of neural-electrode sites by about two orders of magnitude (bare iridium 468.8 � 13.3kV at 1kHz) and increase capacity of charge density by about three orders of magnitude (bare iridium 0.1 � 0.5mC cm � 2 ). During cyclic voltammetry measurements, both PPy and PEDOT nanotubes remain adherent on the surface of the silicon dioxidewhilePPyandPEDOTfilmsdelaminate.In experimentsofprimary neurons with Conducting-Polymer nanotubes, cultured dorsal root ganglion explants remain more intact and exhibit longer neurites (1400 � 95 mm for PPy nanotubes and 2100 � 150 mm for PEDOT nanotubes) than their film counterparts. These findings suggest that Conducting-Polymer nanotubes may improve the long-term function of neural microelectrodes.
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Conducting Polymer nanotubes improve electrical properties mechanical adhesion neural attachment and neurite outgrowth of neural electrodes
Small, 2010Co-Authors: Mohammad Reza Abidian, Joseph M Corey, Daryl R Kipke, David C. MartinAbstract:An in vitro comparison of Conducting-Polymer nanotubes of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, charge-capacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same deposition charge density, PPy films and nanotubes grow relatively faster vertically, while PEDOT films and nanotubes grow more laterally. For the same deposition charge density (1.44 C cm(-2)), PPy nanotubes and PEDOT nanotubes have lower impedance (19.5 +/- 2.1 kOmega for PPy nanotubes and 2.5 +/- 1.4 kOmega for PEDOT nanotubes at 1 kHz) and higher CCD (184 +/- 5.3 mC cm(-2) for PPy nanotubes and 392 +/- 6.2 mC cm(-2) for PEDOT nanotubes) compared to their film counterparts. However, PEDOT nanotubes decrease the impedance of neural-electrode sites by about two orders of magnitude (bare iridium 468.8 +/- 13.3 kOmega at 1 kHz) and increase capacity of charge density by about three orders of magnitude (bare iridium 0.1 +/- 0.5 mC cm(-2)). During cyclic voltammetry measurements, both PPy and PEDOT nanotubes remain adherent on the surface of the silicon dioxide while PPy and PEDOT films delaminate. In experiments of primary neurons with Conducting-Polymer nanotubes, cultured dorsal root ganglion explants remain more intact and exhibit longer neurites (1400 +/- 95 microm for PPy nanotubes and 2100 +/- 150 microm for PEDOT nanotubes) than their film counterparts. These findings suggest that Conducting-Polymer nanotubes may improve the long-term function of neural microelectrodes.
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experimental and theoretical characterization of implantable neural microelectrodes modified with Conducting Polymer nanotubes
Biomaterials, 2008Co-Authors: Mohammad Reza Abidian, David C. MartinAbstract:Neural prostheses transduce bioelectric signals to electronic signals at the interface between neural tissue and neural microelectrodes. A low impedance electrode-tissue interface is important for the quality of signal during recording as well as quantity of applied charge density during stimulation. However, neural microelectrode sites exhibit high impedance because of their small geometric surface area. Here we analyze nanostructured-Conducting Polymers that can be used to significantly decrease the impedance of microelectrode typically by about two orders of magnitude and increase the charge transfer capacity of microelectrodes by three orders of magnitude. In this study poly(pyrrole) (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes were electrochemically Polymerized on the surface of neural microelectrode sites (1250 microm(2)). An equivalent circuit model comprising a coating capacitance in parallel with a pore resistance and interface impedance in series was developed and fitted to experimental results to characterize the physical and electrical properties of the interface. To confirm that the fitting parameters correlate with physical quantities of interface, theoretical equations were used to calculate the parameter values thereby validating the proposed model. Finally, an apparent diffusion coefficient was calculated for PPy film (29.2+/-1.1 x 10(-6) cm(2)/s), PPy nanotubes (PPy NTs) (72.4+/-3.3 x 10(-6) cm(2)/s), PEDOT film (7.4+/-2.1 x 10(-6) cm(2)/s), and PEDOT nanotubes (PEDOT NTs) (13.0+/-1.8 x 10(-6) cm(2)/s). The apparent diffusion coefficient of Conducting Polymer nanotubes was larger than the corresponding Conducting Polymer films.
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Polymerization of the Conducting Polymer poly 3 4 ethylenedioxythiophene pedot around living neural cells
Biomaterials, 2007Co-Authors: Sarah M Richardsonburns, Jeffrey L Hendricks, Brian Foster, Laura K Povlich, Donghwan Kim, David C. MartinAbstract:In this paper, we describe interactions between neural cells and the Conducting Polymer poly(3,4-ethylenedioxythiophene) (PEDOT) toward development of electrically conductive biomaterials intended for direct, functional contact with electrically active tissues such as the nervous system, heart, and skeletal muscle. We introduce a process for Polymerizing PEDOT around living cells and describe a neural cell-templated Conducting Polymer coating for microelectrodes and a hybrid Conducting Polymer-live neural cell electrode. We found that neural cells could be exposed to working concentrations (0.01 m) of the EDOT monomer for as long as 72 h while maintaining 80% cell viability. PEDOT could be electrochemically deposited around neurons cultured on electrodes using 0.5-1 microA/mm(2) galvanostatic current. PEDOT Polymerized on the electrode and surrounded the cells, covering cell processes. The Polymerization was impeded in regions where cells were well adhered to the substrate. The cells could be removed from the PEDOT matrix to generate a neural cell-templated biomimetic conductive substrate with cell-shaped features that were cell attracting. Live cells embedded within the conductive Polymer matrix remained viable for at least 120 h following Polymerization. Dying cells primarily underwent apoptotic cell death. PEDOT, PEDOT+live neurons, and neuron-templated PEDOT coatings on electrodes significantly enhanced the electrical properties as compared to the bare electrode as indicated by decreased electrical impedance of 1-1.5 orders of magnitude at 0.01-1 kHz and significantly increased charge transfer capacity. PEDOT coatings showed a decrease of the phase angle of the impedance from roughly 80 degrees for the bare electrode to 5-35 degrees at frequencies >0.1 kHz. Equivalent circuit modeling indicated that PEDOT-coated electrodes were best described by R(C(RT)) circuit. We found that an RC parallel circuit must be added to the model for PEDOT+live neuron and neuron-templated PEDOT coatings.
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Conducting Polymer nanotubes for controlled drug release
Advanced Materials, 2006Co-Authors: Mohammad Reza Abidian, David C. MartinAbstract:The ability to create materials with well-controlled structures on the nanometer length scale is of intense interest for a variety of applications,[1,2] including controlled drug delivery[3] and biomedical devices.[4] Preparing nanoscale objects using self-assembly and templated growth techniques has been described in some recent reviews.[2,5] For example, porous membranes can be used to synthesize desired materials within the pores.[4,6] Conducting Polymers are of considerable interest for a variety of biomedical applications.[7] Their response to electrochemical oxidation or reduction can produce a change in conductivity, color,[8,9] and volume.[10] A change in the electronic charge is accompanied by an equivalent change in the ionic charge, which requires mass transport between the Polymer and electrolyte.[11] When counterions enter a Polymer it expands and when they exit it contracts. The extent of expansion or contraction depends on the number and size of ions exchanged.[12] Electrochemical actuators using Conducting Polymers based on this principle have been developed by several investigators.[13–15] They can be doped with bioactive drugs, and can be used in actuators such as microfluidic pumps.[16,17] The precisely controlled local release of anti-inflammatory drugs at desired points in time is important for treating the inflammatory response of neural prosthetic devices in the central and peripheral nervous systems.[18] Here we report on a method to prepare Conducting-Polymer nanotubes that can be used for precisely controlled drug release. The fabrication process involves electrospinning of a biodegradable Polymer, into which a drug has been incorporated, followed by electrochemical deposition of a Conducting-Polymer around the drug-loaded, electrospun biodegradable Polymers. The Conducting-Polymer nanotubes significantly decrease the impedance and increase the charge capacity of the recording electrode sites on microfabricated neural prosthetic devices. The drugs can be released from the nanotubes in a desired fashion by electrical stimulation of the nanotubes; this process presumably proceeds by a local dilation of the tube that then promotes mass transport.
Jyongsik Jang - One of the best experts on this subject based on the ideXlab platform.
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aptamer functionalized multidimensional Conducting Polymer nanoparticles for an ultrasensitive and selective field effect transistor endocrine disruptor sensors
Advanced Functional Materials, 2014Co-Authors: Jun Seop Lee, Sung Gun Kim, Jaemoon Jun, Dong Hoon Shin, Jyongsik JangAbstract:An endocrine disruptor (ED) is a type of xenobiotic compound that can cause serious diseases related to the estrous cycle, as well as various types of cancer. At low ED concentrations, estrogen receptors may respond as they would under physiological conditions. In this work, aptamer-functionalized multidimensional Conducting-Polymer (3-carboxylate polypyrrole) nanoparticles (A_M_CPPyNPs) are fabricated for use in an FET sensor to detect bisphenol A (BPA). The multidimensional system, M_CPPyNPs, is first produced by means of dual-nozzle electrospray of pristine CPPyNPs and vapor deposition Polymerization of additional Conducting Polymer. The M_CPPyNPs are then immobilized on an amine-functionalized (–NH2) interdigitated-array electrode substrate, through the formation of covalent bonds with amide groups (–CONH). The amine-functionalized BPA-binding aptamer is then introduced in the same way as that for M_CPPyNP immobilization. The resulting A_M_CPPyNP-based FET sensors exhibit ultrasensitivity and selectivity towards BPA at unprecedentedly low concentrations (1 fm) and among molecules with similar structures. Additionally, due to the covalent bonding involved in the immobilization processes, a longer lifetime is expected for the FET sensor.
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Conducting Polymer nanomaterials for biomedical applications cellular interfacing and biosensing
Polymer Reviews, 2013Co-Authors: Oh Seok Kwon, Jyongsik JangAbstract:Recently, Conducting Polymer (CP) nanomaterials have shown outstanding chemical and physical properties compared with ceramic and metal nanomaterials. Thus, significant efforts have been made to fabricate CPs that enable various biomedical applications, such as high-performance biosensing and cellular interfacing. Although sensing or measuring devices based on CP nanomaterials have shown excellent electrical and physical properties, their limitations, such as the minimum detectable level (MDL), cytotoxicity assessments, and reliable synthesis methods, remain challenges to realizing high-performance biomedical geometries. In this article, we provide the general information on CP nanomaterials and their biomedical applications focusing especially on cellular interfacing and biosensing. Moreover, we discuss perspectives for state-of-the-art biomedical geometries using various CP nanomaterials.
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multidimensional Conducting Polymer nanotubes for ultrasensitive chemical nerve agent sensing
Nano Letters, 2012Co-Authors: Oh Seok Kwon, Jun Seop Lee, Seon Joo Park, Eunyu Park, Taejoon Kim, Hyunwoo Park, Sun Ah You, Hyeonseok Yoon, Jyongsik JangAbstract:Tailoring the morphology of materials in the nanometer regime is vital to realizing enhanced device performance. Here, we demonstrate flexible nerve agent sensors, based on hydroxylated poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes (HPNTs) with surface substructures such as nanonodules (NNs) and nanorods (NRs). The surface substructures can be grown on a nanofiber surface by controlling critical synthetic conditions during vapor deposition Polymerization (VDP) on the Polymer nanotemplate, leading to the formation of multidimensional Conducting Polymer nanostructures. Hydroxyl groups are found to interact with the nerve agents. Representatively, the sensing response of dimethyl methylphosphonate (DMMP) as a simulant for sarin is highly sensitive and reversible from the aligned nanotubes. The minimum detection limit is as low as 10 ppt. Additionally, the sensor had excellent mechanical bendability and durability.
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Conducting Polymer nanomaterials for high performance sensor applications issues and challenges
Advanced Functional Materials, 2009Co-Authors: Hyeonseok Yoon, Jyongsik JangAbstract:Owing to their promising applications in electronic and optoelectronic devices, Conducting Polymers have been continuously studied during the past few decades. Nevertheless, only limited progress had been made in Conducting-Polymer-based sensors until nanostructured Conducting Polymers were demonstrated for high-performance signal transducers. Significant advances in the synthesis of Conducting-Polymer nanomaterials have been recently reported, with enhanced sensitivity relative to their bulk counterparts. Today, Conducting-Polymer nanomaterials rival metal and inorganic semiconductor nanomaterials in sensing capability. However, there are still several technological challenges to be solved for practical sensor applications of Conducting-Polymer nanomaterials. Here, the key issues on Conducting-Polymer nanomaterials in the development of state-of-the-art sensors are discussed. Furthermore, a perspective on next-generation sensor technology from a materials point of view is also given.
Alan J. Heeger - One of the best experts on this subject based on the ideXlab platform.
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reprint of ultrafast photoinduced electron transfer in Conducting Polymer buckminsterfullerene composites
Chemical Physics Letters, 2013Co-Authors: B Kraabel, D Moses, Changhee Lee, D Mcbranch, N S Sariciftci, Alan J. HeegerAbstract:Abstract We report time-resolved photoinduced absorption and time-resolved photoconductivity in Conducting Polymer-C 60 composites. Photoinduced electron transfer occurs at times τ 60 shows similar spectral features at early times ( 60 . Ultrafast photoinduced electron transfer improves the quantum efficiency for photogeneration of charge carriers; in the ps domain the photoconductivity of the Conducting Polymer host is enhanced by more than an order of magnitude upon mixing in a few percent C 60 .
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ultrafast photoinduced electron transfer in Conducting Polymer buckminsterfullerene composites
Chemical Physics Letters, 1993Co-Authors: B Kraabel, D Moses, Changhee Lee, D Mcbranch, N S Sariciftci, Alan J. HeegerAbstract:We report time-resolved photoinduced absorption and time-resolved photoconductivity in Conducting Polymer-C60 composites. Photoinduced electron transfer occurs at times < 1 ps. Two subgap features are observed in the photoinduced absorption of pure poly(3-octylthiophene) (P3OT); these form earlier than 1 ps and decay with τ<5 ps. P3OT mixed with C60 shows similar spectral features at early times (<1 ps); however, a new spectrum evolves after ≈1 ps as a result of electron transfer from P3OT to C60. Ultrafast photoinduced electron transfer improves the quantum efficiency for photogeneration of charge carriers; in the ps domain the photoconductivity of the Conducting Polymer host is enhanced by more than an order of magnitude upon mixing in a few percent C60.
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Photoinduced electron transfer from a Conducting Polymer to buckminsterfullerene.
Science (New York N.Y.), 1992Co-Authors: Laura Smilowitz, Alan J. Heeger, Fred WudlAbstract:Evidence for photoinduced electron transfer from the excited state of a Conducting Polymer onto buckminsterfullerene, C(60), is reported. After photo-excitation of the conjugated Polymer with light of energy greater than the pi-pi* gap, an electron transfer to the C(60) molecule is initiated. Photoinduced optical absorption studies demonstrate a different excitation spectrum for the composite as compared to the separate components, consistent with photo-excited charge transfer. A photoinduced electron spin resonance signal exhibits signatures of both the Conducting Polymer cation and the C(60) anion. Because the photoluminescence in the Conducting Polymer is quenched by interaction with C(60), the data imply that charge transfer from the excited state occurs on a picosecond time scale. The charge-separated state in composite films is metastable at low temperatures.
Mohammad Reza Abidian - One of the best experts on this subject based on the ideXlab platform.
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Conducting Polymer nanotubes improve electrical properties mechanical adhesion neural attachment and neurite outgrowth of neural electrodes
Small, 2010Co-Authors: Mohammad Reza Abidian, Joseph M Corey, Daryl R Kipke, David C. MartinAbstract:An in vitro comparison of Conducting-Polymer nanotubes of poly(3,4ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, charge-capacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same depositioncharge density, PPyfilms and nanotubesgrow relatively faster vertically, while PEDOT films and nanotubes grow more laterally. For the same deposition charge density (1.44C cm � 2 ), PPy nanotubes and PEDOT nanotubes have lower impedance (19.5 � 2.1kV for PPy nanotubes and 2.5 � 1.4kV for PEDOT nanotubes at 1kHz) and higher CCD (184 � 5.3mC cm � 2 for PPy nanotubesand 392 � 6.2mC cm � 2 for PEDOT nanotubes) compared to their film counterparts. However, PEDOT nanotubes decrease the impedance of neural-electrode sites by about two orders of magnitude (bare iridium 468.8 � 13.3kV at 1kHz) and increase capacity of charge density by about three orders of magnitude (bare iridium 0.1 � 0.5mC cm � 2 ). During cyclic voltammetry measurements, both PPy and PEDOT nanotubes remain adherent on the surface of the silicon dioxidewhilePPyandPEDOTfilmsdelaminate.In experimentsofprimary neurons with Conducting-Polymer nanotubes, cultured dorsal root ganglion explants remain more intact and exhibit longer neurites (1400 � 95 mm for PPy nanotubes and 2100 � 150 mm for PEDOT nanotubes) than their film counterparts. These findings suggest that Conducting-Polymer nanotubes may improve the long-term function of neural microelectrodes.
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Conducting Polymer nanotubes improve electrical properties mechanical adhesion neural attachment and neurite outgrowth of neural electrodes
Small, 2010Co-Authors: Mohammad Reza Abidian, Joseph M Corey, Daryl R Kipke, David C. MartinAbstract:An in vitro comparison of Conducting-Polymer nanotubes of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(pyrrole) (PPy) and to their film counterparts is reported. Impedance, charge-capacity density (CCD), tendency towards delamination, and neurite outgrowth are compared. For the same deposition charge density, PPy films and nanotubes grow relatively faster vertically, while PEDOT films and nanotubes grow more laterally. For the same deposition charge density (1.44 C cm(-2)), PPy nanotubes and PEDOT nanotubes have lower impedance (19.5 +/- 2.1 kOmega for PPy nanotubes and 2.5 +/- 1.4 kOmega for PEDOT nanotubes at 1 kHz) and higher CCD (184 +/- 5.3 mC cm(-2) for PPy nanotubes and 392 +/- 6.2 mC cm(-2) for PEDOT nanotubes) compared to their film counterparts. However, PEDOT nanotubes decrease the impedance of neural-electrode sites by about two orders of magnitude (bare iridium 468.8 +/- 13.3 kOmega at 1 kHz) and increase capacity of charge density by about three orders of magnitude (bare iridium 0.1 +/- 0.5 mC cm(-2)). During cyclic voltammetry measurements, both PPy and PEDOT nanotubes remain adherent on the surface of the silicon dioxide while PPy and PEDOT films delaminate. In experiments of primary neurons with Conducting-Polymer nanotubes, cultured dorsal root ganglion explants remain more intact and exhibit longer neurites (1400 +/- 95 microm for PPy nanotubes and 2100 +/- 150 microm for PEDOT nanotubes) than their film counterparts. These findings suggest that Conducting-Polymer nanotubes may improve the long-term function of neural microelectrodes.
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experimental and theoretical characterization of implantable neural microelectrodes modified with Conducting Polymer nanotubes
Biomaterials, 2008Co-Authors: Mohammad Reza Abidian, David C. MartinAbstract:Neural prostheses transduce bioelectric signals to electronic signals at the interface between neural tissue and neural microelectrodes. A low impedance electrode-tissue interface is important for the quality of signal during recording as well as quantity of applied charge density during stimulation. However, neural microelectrode sites exhibit high impedance because of their small geometric surface area. Here we analyze nanostructured-Conducting Polymers that can be used to significantly decrease the impedance of microelectrode typically by about two orders of magnitude and increase the charge transfer capacity of microelectrodes by three orders of magnitude. In this study poly(pyrrole) (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes were electrochemically Polymerized on the surface of neural microelectrode sites (1250 microm(2)). An equivalent circuit model comprising a coating capacitance in parallel with a pore resistance and interface impedance in series was developed and fitted to experimental results to characterize the physical and electrical properties of the interface. To confirm that the fitting parameters correlate with physical quantities of interface, theoretical equations were used to calculate the parameter values thereby validating the proposed model. Finally, an apparent diffusion coefficient was calculated for PPy film (29.2+/-1.1 x 10(-6) cm(2)/s), PPy nanotubes (PPy NTs) (72.4+/-3.3 x 10(-6) cm(2)/s), PEDOT film (7.4+/-2.1 x 10(-6) cm(2)/s), and PEDOT nanotubes (PEDOT NTs) (13.0+/-1.8 x 10(-6) cm(2)/s). The apparent diffusion coefficient of Conducting Polymer nanotubes was larger than the corresponding Conducting Polymer films.
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Conducting Polymer nanotubes for controlled drug release
Advanced Materials, 2006Co-Authors: Mohammad Reza Abidian, David C. MartinAbstract:The ability to create materials with well-controlled structures on the nanometer length scale is of intense interest for a variety of applications,[1,2] including controlled drug delivery[3] and biomedical devices.[4] Preparing nanoscale objects using self-assembly and templated growth techniques has been described in some recent reviews.[2,5] For example, porous membranes can be used to synthesize desired materials within the pores.[4,6] Conducting Polymers are of considerable interest for a variety of biomedical applications.[7] Their response to electrochemical oxidation or reduction can produce a change in conductivity, color,[8,9] and volume.[10] A change in the electronic charge is accompanied by an equivalent change in the ionic charge, which requires mass transport between the Polymer and electrolyte.[11] When counterions enter a Polymer it expands and when they exit it contracts. The extent of expansion or contraction depends on the number and size of ions exchanged.[12] Electrochemical actuators using Conducting Polymers based on this principle have been developed by several investigators.[13–15] They can be doped with bioactive drugs, and can be used in actuators such as microfluidic pumps.[16,17] The precisely controlled local release of anti-inflammatory drugs at desired points in time is important for treating the inflammatory response of neural prosthetic devices in the central and peripheral nervous systems.[18] Here we report on a method to prepare Conducting-Polymer nanotubes that can be used for precisely controlled drug release. The fabrication process involves electrospinning of a biodegradable Polymer, into which a drug has been incorporated, followed by electrochemical deposition of a Conducting-Polymer around the drug-loaded, electrospun biodegradable Polymers. The Conducting-Polymer nanotubes significantly decrease the impedance and increase the charge capacity of the recording electrode sites on microfabricated neural prosthetic devices. The drugs can be released from the nanotubes in a desired fashion by electrical stimulation of the nanotubes; this process presumably proceeds by a local dilation of the tube that then promotes mass transport.
D Moses - One of the best experts on this subject based on the ideXlab platform.
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reprint of ultrafast photoinduced electron transfer in Conducting Polymer buckminsterfullerene composites
Chemical Physics Letters, 2013Co-Authors: B Kraabel, D Moses, Changhee Lee, D Mcbranch, N S Sariciftci, Alan J. HeegerAbstract:Abstract We report time-resolved photoinduced absorption and time-resolved photoconductivity in Conducting Polymer-C 60 composites. Photoinduced electron transfer occurs at times τ 60 shows similar spectral features at early times ( 60 . Ultrafast photoinduced electron transfer improves the quantum efficiency for photogeneration of charge carriers; in the ps domain the photoconductivity of the Conducting Polymer host is enhanced by more than an order of magnitude upon mixing in a few percent C 60 .
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ultrafast photoinduced electron transfer in Conducting Polymer buckminsterfullerene composites
Chemical Physics Letters, 1993Co-Authors: B Kraabel, D Moses, Changhee Lee, D Mcbranch, N S Sariciftci, Alan J. HeegerAbstract:We report time-resolved photoinduced absorption and time-resolved photoconductivity in Conducting Polymer-C60 composites. Photoinduced electron transfer occurs at times < 1 ps. Two subgap features are observed in the photoinduced absorption of pure poly(3-octylthiophene) (P3OT); these form earlier than 1 ps and decay with τ<5 ps. P3OT mixed with C60 shows similar spectral features at early times (<1 ps); however, a new spectrum evolves after ≈1 ps as a result of electron transfer from P3OT to C60. Ultrafast photoinduced electron transfer improves the quantum efficiency for photogeneration of charge carriers; in the ps domain the photoconductivity of the Conducting Polymer host is enhanced by more than an order of magnitude upon mixing in a few percent C60.
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high quantum efficiency luminescence from a Conducting Polymer in solution a novel Polymer laser dye
Applied Physics Letters, 1992Co-Authors: D MosesAbstract:A novel dye laser based on the soluble Conducting Polymer poly[2‐methoxy, 5‐(2’ ethyl‐hexyloxy)‐p‐phenylenevinylene], MEH‐PPV, has been demonstrated. Laser action has been tested in a transverse cavity configuration where the Conducting Polymer laser was pumped by light pulses generated from the second harmonic radiation of a Q‐switched Nd:YAG laser. The performance of MEH‐PPV in solution as a laser dye was compared to that of rhodamine 6G in solution under identical conditions. The results indicate that the quantum yield of MEH‐PPV laser is comparable to that of rhodamine 6G.