Mira Josowicz | Georgia Institute of Technology (original) (raw)
Papers by Mira Josowicz
ECS Meeting Abstracts
not Available.
Perspectives in Bioanalysis, 2005
... Temitope Aiyejorun a , Liz Thompson a , Janusz Kowalik a , Mira Josowicz a and Jiří Janata a.... more ... Temitope Aiyejorun a , Liz Thompson a , Janusz Kowalik a , Mira Josowicz a and Jiří Janata a. ... probe) and its distribution, packing density and orientation affect not only the recognition of the target but also influence the sensing performance of the probe (Ye and Ju, 2003). ...
Journal of The Electrochemical Society, 2005
Bilayer consisting of polypyrrole, PPy, as the inner and poly (2, 5-dithienyl-(-3-phosphorylpropy... more Bilayer consisting of polypyrrole, PPy, as the inner and poly (2, 5-dithienyl-(-3-phosphorylpropyl) pyrrole, as the outer layers was electropolymerized in layer-by-layer steps. Due to the presence of phosphonic acid functionality tethered to the backbone of ...
Journal of Chemical Education, 2006
A label-free electrochemical detection method for DNA hybridization has been developed and tested... more A label-free electrochemical detection method for DNA hybridization has been developed and tested in an advanced analytical chemistry course. A set of experiments was designed to explore several concepts relevant to electropolymerization of intrinsically conducting ...
Electrochimica Acta, 2006
The in situ synthesis of micrometer and nanometer gold particles in polyaniline ͑PANI/Au composit... more The in situ synthesis of micrometer and nanometer gold particles in polyaniline ͑PANI/Au composite͒ using chemical or electrochemical methods, has been compared. The direct chemical synthesis of PANI/Au is initiated via the spontaneous oxidation of aniline by AuCl 4 Ϫ. Gold colloid formation and subsequent reaction with PANI is monitored by in situ UV/vis spectroscopy. The emergent polymer nucleates on the gold as the PANI chain length increases, encapsulates the metal, and precipitates as its solubility limit is exceeded. Scanning electron microscopy images of these samples show relatively constant 1 m diam gold particles. Electrochemical PANI/Au synthesis is initiated by AuCl 4 Ϫ reduction into an a priori electrochemically deposited PANI film. This method also produces a nearly uniform dispersion of Au particles but with significantly smaller 150-300 nm particles. The results indicate that electrochemical methods are more suitable for controlling particle dimensions. A minimal decrease in conductance is observed for the chemically formed PANI/Au when compared to PANI samples without the gold. A significant decrease in conductance is observed for the electrochemically formed composite. The large decrease in conductance is related to the decrease in proton doping and a greater number of oxidized units in the polymer upon electrochemical uptake and reduction of AuCl 4 Ϫ .
Chemistry of Materials, 1995
... Comparison of Chemically and Electrochemically Prepared Polyaniline Films. 1. Electrical Prop... more ... Comparison of Chemically and Electrochemically Prepared Polyaniline Films. 1. Electrical Properties Douglas Chinn, Joel DuBow, and Martin Liess Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112 Mira Josowicz and JiEi Janata ...
Chemical Communications, 2013
The effect of pH on the spectral and redox properties of model GFP synthetic chromophores (Cros) ... more The effect of pH on the spectral and redox properties of model GFP synthetic chromophores (Cros) in a universal buffer system was investigated. The Cro hydroxy-derivatives demonstrated a Nernst-type electrochemical dependence of the anodic potential within the pH 2-8 range. Analogous studies on various fluorescent proteins were unsuccessful.
Analytical Chemistry, 2006
A label-free electrochemical detection method for DNA hybridization based on electrostatic modula... more A label-free electrochemical detection method for DNA hybridization based on electrostatic modulation of the ion-exchange kinetics of a polypyrrole film deposited at microelectrodes is reported. Synthetic single-stranded 27-mer oligonucleotides (probe) have been immobilized at 2,5-bis(2-thienyl)-N-(3-phosphorylpropyl)pyrrole film formed by electropolymerization on the previously formed polypyrrole layer. The 27- or 18-mer target oligonucleotides were monitored via the electrochemically driven anion exchange of the inner polypyrrole film. The performance of the miniaturized DNA biosensor system was studied in respect to selectivity, sensitivity, reproducibility, and regeneration of the sensor. Control experiments were performed with a noncomplementary target of 27-mer DNA and 12 base-pair mismatched 18-mer sequences, respectively, and did not show any unspecific binding. Under optimized experimental conditions, the label-free electrochemical biosensor enabled the detection limits of 0.16 and 3.5 fmol for the 18- and 27-mer DNA strand, respectively. Furthermore, we demonstrate reusability of the electrochemical DNA biosensor after successful recovery of up to 100% of the original signal by regenerating the DNA "label-free" electrode with 50 mM HCl at room temperature.
Analytical Chemistry, 2008
The Journal of Physical …, 1999
... Angelopoulos, M.; Asturias, GE; Ermer, SP; Ray, A.; Scherr, EM; MacDiarmid, AG; Akhtar, M.; K... more ... Angelopoulos, M.; Asturias, GE; Ermer, SP; Ray, A.; Scherr, EM; MacDiarmid, AG; Akhtar, M.; Kiss, Z.; Epstein, AJ Mol. Cryst. Liq. Cryst. 1988, 160, 151. [CrossRef]. (11) (a) Huang, W.-S.; Humphrey, BD; MacDiarmid, AG J. Chem. Soc., Faraday Trans. 1, 1986, 82, 2385. ...
Journal of the American …, 2003
A new approach to the realization of the electrochemical DNA hybridization probe is described. It... more A new approach to the realization of the electrochemical DNA hybridization probe is described. It is based on the exchange of chloride ion between the polypyrrole layer and the buffer. The shape of the cyclic voltammogram is modulated by the negative charge density at this interface, resulting from the immobilized target DNA. The negative charge density increases when the complementary DNA hybridizes with the probe DNA. The hybridization event can be clearly seen in the cyclic voltammogram before and after the addition of the probe DNA. The immobilization is accomplished via the Mg2+ bridging complex between phosphonic acid groups of the poly[2,5-dithienyl-(N-3-phosphorylpropyl)pyrrole] grafted at the polypyrrole surface and the phosphate groups of the target DNA.
IEEE Sensors Journal
Rapid advancements in information processing and embedded systems require high selective and fast... more Rapid advancements in information processing and embedded systems require high selective and fast sensors. Conventional gas sensors are not suitable for the detection of isomers of organic compounds due to cross-sensitivity and the response time being limited by slow chemical kinetics. Amperometric gas sensors using conducting polymers modified with metal catalysts are a suitable and robust system due to many tunable properties. In this paper, conducting polymer polyaniline was electrochemically decorated with clusters containing precisely defined number of gold atoms to function as an electro-catalyst. The modified polymer composite showed fast reaction rate for the electro-oxidation of alcohols in both liquid and gas phases. The number of gold atoms affected the catalytic activity. Cyclic voltammograms were measured and results showed discriminable patterns between n-propanol and iso-propanol even at different gas concentrations. Thus, it was demonstrated that gas sensor arrays can be realized by decorating different number of gold atoms on polyaniline electrodes, to yield defined and different selectivity.
Reference Electrode for use in Ionic Liquids. [ECS Meeting Abstracts 701, 72 (2007)]. Amir H. Sah... more Reference Electrode for use in Ionic Liquids. [ECS Meeting Abstracts 701, 72 (2007)]. Amir H. Saheb, Jiri Janata, Mira Josowicz.
Chemistry of …, 1999
... 2) Kang, ET; Ting, YP; Neoh, KG; Tan, KL Polymer1993, 34, 4994. ... Composites of Intrinsical... more ... 2) Kang, ET; Ting, YP; Neoh, KG; Tan, KL Polymer1993, 34, 4994. ... Composites of Intrinsically Conducting Polymers as Sensing Nanomaterials. David W. Hatchett and Mira Josowicz. Chemical Reviews 2008 108 (2), 746-769. ...
ECS Meeting Abstracts
The emphasis of this presentation will be on the label-free detection method that is based on the... more The emphasis of this presentation will be on the label-free detection method that is based on the electrochemical properties of conducting polymer bi-layers which are deposited by a sequential electrochemical polymerization of differently tethered pyrrole monomers. The attachment ...
Langmuir : the ACS journal of surfaces and colloids, Jan 23, 2016
A sorption process of RuCl3 in phosphate buffer by polyaniline (PANI) powder chemically synthesiz... more A sorption process of RuCl3 in phosphate buffer by polyaniline (PANI) powder chemically synthesized from phosphoric acid was spectrophotometrically monitored as a function of time. It was determined that the sorption process follows the Langmuir and Freundlich isotherms, and their constants were evaluated. It was determined that chemisorption was the rate-controlling step. By conducting detailed studies, we assigned the chemisorption to Lewis acid based interactions of the sorbent electron pair localized at the benzenoid amine (-NH2) and quinoid imine (═NH) groups, with the sorbate, RuCl3, as the electron acceptor. The stability of the interaction over a period of ∼1 week showed that the presence of the Ru(III) in the PANI matrix reverses its state from emeraldine base to emeraldine salt, resulting in a change of conductivity. The partial electron donor based charge transfer is a slow process as compared to the sorption process involving Brønsted acid doping.
ECS Meeting Abstracts
not Available.
Perspectives in Bioanalysis, 2005
... Temitope Aiyejorun a , Liz Thompson a , Janusz Kowalik a , Mira Josowicz a and Jiří Janata a.... more ... Temitope Aiyejorun a , Liz Thompson a , Janusz Kowalik a , Mira Josowicz a and Jiří Janata a. ... probe) and its distribution, packing density and orientation affect not only the recognition of the target but also influence the sensing performance of the probe (Ye and Ju, 2003). ...
Journal of The Electrochemical Society, 2005
Bilayer consisting of polypyrrole, PPy, as the inner and poly (2, 5-dithienyl-(-3-phosphorylpropy... more Bilayer consisting of polypyrrole, PPy, as the inner and poly (2, 5-dithienyl-(-3-phosphorylpropyl) pyrrole, as the outer layers was electropolymerized in layer-by-layer steps. Due to the presence of phosphonic acid functionality tethered to the backbone of ...
Journal of Chemical Education, 2006
A label-free electrochemical detection method for DNA hybridization has been developed and tested... more A label-free electrochemical detection method for DNA hybridization has been developed and tested in an advanced analytical chemistry course. A set of experiments was designed to explore several concepts relevant to electropolymerization of intrinsically conducting ...
Electrochimica Acta, 2006
The in situ synthesis of micrometer and nanometer gold particles in polyaniline ͑PANI/Au composit... more The in situ synthesis of micrometer and nanometer gold particles in polyaniline ͑PANI/Au composite͒ using chemical or electrochemical methods, has been compared. The direct chemical synthesis of PANI/Au is initiated via the spontaneous oxidation of aniline by AuCl 4 Ϫ. Gold colloid formation and subsequent reaction with PANI is monitored by in situ UV/vis spectroscopy. The emergent polymer nucleates on the gold as the PANI chain length increases, encapsulates the metal, and precipitates as its solubility limit is exceeded. Scanning electron microscopy images of these samples show relatively constant 1 m diam gold particles. Electrochemical PANI/Au synthesis is initiated by AuCl 4 Ϫ reduction into an a priori electrochemically deposited PANI film. This method also produces a nearly uniform dispersion of Au particles but with significantly smaller 150-300 nm particles. The results indicate that electrochemical methods are more suitable for controlling particle dimensions. A minimal decrease in conductance is observed for the chemically formed PANI/Au when compared to PANI samples without the gold. A significant decrease in conductance is observed for the electrochemically formed composite. The large decrease in conductance is related to the decrease in proton doping and a greater number of oxidized units in the polymer upon electrochemical uptake and reduction of AuCl 4 Ϫ .
Chemistry of Materials, 1995
... Comparison of Chemically and Electrochemically Prepared Polyaniline Films. 1. Electrical Prop... more ... Comparison of Chemically and Electrochemically Prepared Polyaniline Films. 1. Electrical Properties Douglas Chinn, Joel DuBow, and Martin Liess Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112 Mira Josowicz and JiEi Janata ...
Chemical Communications, 2013
The effect of pH on the spectral and redox properties of model GFP synthetic chromophores (Cros) ... more The effect of pH on the spectral and redox properties of model GFP synthetic chromophores (Cros) in a universal buffer system was investigated. The Cro hydroxy-derivatives demonstrated a Nernst-type electrochemical dependence of the anodic potential within the pH 2-8 range. Analogous studies on various fluorescent proteins were unsuccessful.
Analytical Chemistry, 2006
A label-free electrochemical detection method for DNA hybridization based on electrostatic modula... more A label-free electrochemical detection method for DNA hybridization based on electrostatic modulation of the ion-exchange kinetics of a polypyrrole film deposited at microelectrodes is reported. Synthetic single-stranded 27-mer oligonucleotides (probe) have been immobilized at 2,5-bis(2-thienyl)-N-(3-phosphorylpropyl)pyrrole film formed by electropolymerization on the previously formed polypyrrole layer. The 27- or 18-mer target oligonucleotides were monitored via the electrochemically driven anion exchange of the inner polypyrrole film. The performance of the miniaturized DNA biosensor system was studied in respect to selectivity, sensitivity, reproducibility, and regeneration of the sensor. Control experiments were performed with a noncomplementary target of 27-mer DNA and 12 base-pair mismatched 18-mer sequences, respectively, and did not show any unspecific binding. Under optimized experimental conditions, the label-free electrochemical biosensor enabled the detection limits of 0.16 and 3.5 fmol for the 18- and 27-mer DNA strand, respectively. Furthermore, we demonstrate reusability of the electrochemical DNA biosensor after successful recovery of up to 100% of the original signal by regenerating the DNA "label-free" electrode with 50 mM HCl at room temperature.
Analytical Chemistry, 2008
The Journal of Physical …, 1999
... Angelopoulos, M.; Asturias, GE; Ermer, SP; Ray, A.; Scherr, EM; MacDiarmid, AG; Akhtar, M.; K... more ... Angelopoulos, M.; Asturias, GE; Ermer, SP; Ray, A.; Scherr, EM; MacDiarmid, AG; Akhtar, M.; Kiss, Z.; Epstein, AJ Mol. Cryst. Liq. Cryst. 1988, 160, 151. [CrossRef]. (11) (a) Huang, W.-S.; Humphrey, BD; MacDiarmid, AG J. Chem. Soc., Faraday Trans. 1, 1986, 82, 2385. ...
Journal of the American …, 2003
A new approach to the realization of the electrochemical DNA hybridization probe is described. It... more A new approach to the realization of the electrochemical DNA hybridization probe is described. It is based on the exchange of chloride ion between the polypyrrole layer and the buffer. The shape of the cyclic voltammogram is modulated by the negative charge density at this interface, resulting from the immobilized target DNA. The negative charge density increases when the complementary DNA hybridizes with the probe DNA. The hybridization event can be clearly seen in the cyclic voltammogram before and after the addition of the probe DNA. The immobilization is accomplished via the Mg2+ bridging complex between phosphonic acid groups of the poly[2,5-dithienyl-(N-3-phosphorylpropyl)pyrrole] grafted at the polypyrrole surface and the phosphate groups of the target DNA.
IEEE Sensors Journal
Rapid advancements in information processing and embedded systems require high selective and fast... more Rapid advancements in information processing and embedded systems require high selective and fast sensors. Conventional gas sensors are not suitable for the detection of isomers of organic compounds due to cross-sensitivity and the response time being limited by slow chemical kinetics. Amperometric gas sensors using conducting polymers modified with metal catalysts are a suitable and robust system due to many tunable properties. In this paper, conducting polymer polyaniline was electrochemically decorated with clusters containing precisely defined number of gold atoms to function as an electro-catalyst. The modified polymer composite showed fast reaction rate for the electro-oxidation of alcohols in both liquid and gas phases. The number of gold atoms affected the catalytic activity. Cyclic voltammograms were measured and results showed discriminable patterns between n-propanol and iso-propanol even at different gas concentrations. Thus, it was demonstrated that gas sensor arrays can be realized by decorating different number of gold atoms on polyaniline electrodes, to yield defined and different selectivity.
Reference Electrode for use in Ionic Liquids. [ECS Meeting Abstracts 701, 72 (2007)]. Amir H. Sah... more Reference Electrode for use in Ionic Liquids. [ECS Meeting Abstracts 701, 72 (2007)]. Amir H. Saheb, Jiri Janata, Mira Josowicz.
Chemistry of …, 1999
... 2) Kang, ET; Ting, YP; Neoh, KG; Tan, KL Polymer1993, 34, 4994. ... Composites of Intrinsical... more ... 2) Kang, ET; Ting, YP; Neoh, KG; Tan, KL Polymer1993, 34, 4994. ... Composites of Intrinsically Conducting Polymers as Sensing Nanomaterials. David W. Hatchett and Mira Josowicz. Chemical Reviews 2008 108 (2), 746-769. ...
ECS Meeting Abstracts
The emphasis of this presentation will be on the label-free detection method that is based on the... more The emphasis of this presentation will be on the label-free detection method that is based on the electrochemical properties of conducting polymer bi-layers which are deposited by a sequential electrochemical polymerization of differently tethered pyrrole monomers. The attachment ...
Langmuir : the ACS journal of surfaces and colloids, Jan 23, 2016
A sorption process of RuCl3 in phosphate buffer by polyaniline (PANI) powder chemically synthesiz... more A sorption process of RuCl3 in phosphate buffer by polyaniline (PANI) powder chemically synthesized from phosphoric acid was spectrophotometrically monitored as a function of time. It was determined that the sorption process follows the Langmuir and Freundlich isotherms, and their constants were evaluated. It was determined that chemisorption was the rate-controlling step. By conducting detailed studies, we assigned the chemisorption to Lewis acid based interactions of the sorbent electron pair localized at the benzenoid amine (-NH2) and quinoid imine (═NH) groups, with the sorbate, RuCl3, as the electron acceptor. The stability of the interaction over a period of ∼1 week showed that the presence of the Ru(III) in the PANI matrix reverses its state from emeraldine base to emeraldine salt, resulting in a change of conductivity. The partial electron donor based charge transfer is a slow process as compared to the sorption process involving Brønsted acid doping.