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Enzyme Entrapment In Polyaniline Films Observed Via Florescence Anisotropy And Antiquenching, Louis R. Nemzer, Marissa Mccaffrey, Arthur J. Epstein
Enzyme Entrapment In Polyaniline Films Observed Via Florescence Anisotropy And Antiquenching, Louis R. Nemzer, Marissa Mccaffrey, Arthur J. Epstein
Louis R Nemzer
The facile entrapment of oxidoreductase enzymes within polyaniline polymer films by inducing hydrophobic collapse using phosphate buffered saline (PBS) has been shown to be a cost-effective method for fabricating organic biosensors. Here, we use fluorescence anisotropy measurements to verify enzyme immobilization and subsequent electron donation to the polymer matrix, both prerequisites for an effective biosensor. Specifically, we measure a three order of magnitude decrease in the ratio of the fluorescence to rotational lifetimes. In addition, the observed fluorescence antiquenching supports the previously proposed model that the polymer chain assumes a severely coiled conformation when exposed to PBS. These results help …
Ethanol Shock And Lysozyme Aggregation, Louis R. Nemzer, Bret N. Flander, Jeremy D. Schmit, Amitabha Chakrabarti, Christopher M. Sorensen
Ethanol Shock And Lysozyme Aggregation, Louis R. Nemzer, Bret N. Flander, Jeremy D. Schmit, Amitabha Chakrabarti, Christopher M. Sorensen
Louis R Nemzer
Irreversible protein–protein aggregation is associated with several human maladies, including Alzheimer's disease, and poses a challenge to pharmaceutical formulation and preservation efforts. The existence of multiple agglomeration pathways that lead to different final morphologies complicates the ability to determine the aggregation fate of proteins under various reaction conditions. Using lysozyme (3 mg/mL) as a model protein for dynamic light scattering and circular dichroism studies, we observed dense, non-fibrous aggregation triggered under acidic (pH 4) conditions by a destabilizing “ethanol shock” of 16% (v/v) ethanol. However, ethanol concentrations 15% and below did not lead to aggregation. The aggregation fate of these …
Us Patent #8,326,389 - A System For In Vivo Biosensing Based On The Optical Response, Arthur Epstein, Louis R. Nemzer
Us Patent #8,326,389 - A System For In Vivo Biosensing Based On The Optical Response, Arthur Epstein, Louis R. Nemzer
Louis R Nemzer
A system for continuous in vivo biosensing of specific analyte molecule concentrations based on the dynamic optical properties of electronic polymers is disclosed. The biosensor system includes at least one implant member subcutaneously exposed to the interstitial fluid of the subject, and a reader member at least temporarily positioned over the implant member to probe it with light of specific wavelengths through the skin. The system has many potential applications, including the real-time monitoring of blood glucose levels in diabetics as a method to supplement or replace conventional capillary blood testing.
Exciton Broadening In Polyaniline Chains During Ion Induced Hydrophobic Collapse And Aggregation, Louis R. Nemzer, Arthur Epstein
Exciton Broadening In Polyaniline Chains During Ion Induced Hydrophobic Collapse And Aggregation, Louis R. Nemzer, Arthur Epstein
Louis R Nemzer
The ion-induced reprecipitation of the emeraldine base form of polyaniline from an aqueous-organic binary solution is a facile method for obtaining polymer nanoparticles and microscale clusters. The hydrophobic collapse and aggregation that accompanies the addition of various cosolutes induces changes in the peak wavelength and linewidth of the main exciton absorption. In particular, we find that the addition of ionic cosoutes leads to a redshifting and broadening of this spectroscopic feature, with divalent coions exhibiting an additional hypsochromic reversal at high concentrations. The denaturant urea, in contrast, causes a blueshift and line-narrowing at all concentrations. Using a quantitative Lorentz fit, …
Enzyme Entrapment In Reprecipitated Polyaniline Nano- And Microparticles, Louis R. Nemzer, Austin Schwartz, Arthur Epstein
Enzyme Entrapment In Reprecipitated Polyaniline Nano- And Microparticles, Louis R. Nemzer, Austin Schwartz, Arthur Epstein
Louis R Nemzer
We introduce a novel method for fabricating nano- and microscale polyaniline particles containing an entrapped oxidoreductase enzyme for use in biosensing applications. This facile process utilizes the reprecipitation of the emeraldine base form of polyaniline from an aqueous-organic suspension, with hydrophobic collapse and subsequent cross-linking of the polymer induced by adjusting the ionic strength beyond a critical threshold. We present UV-vis spectroscopy data, including a quantitative treatment of the spectral line width, along with dynamic light scatting results, to explain the conformation changes in the polyaniline chains that accompany this transition. The resultant aggregated supermolecular polyaniline formations immobilize enzymes via …
A Polyaniline-Based Optical Biosensing Platform Using An Entrapped Oxidoreductase Enzyme, Louis R. Nemzer, Arthur Epstein
A Polyaniline-Based Optical Biosensing Platform Using An Entrapped Oxidoreductase Enzyme, Louis R. Nemzer, Arthur Epstein
Louis R Nemzer
A novel optical biosensing platform utilizing the unique solubility and chemochromic properties of polyaniline is presented. A facile, ion-induced reprecipitation method leads to the entrapment of a chosen oxidoreductase enzyme, which, in the presence of its associated substrate, catalyzes a reversible redox change in the host polymer. This change is monitored via the UV–vis absorption and subsequently analyzed to fit a Michaelis–Menten model. Here, in vitro prototype devices demonstrate selective sensing of glucose, choline, and uric acid, and the potential to be adapted for use as part of real-time in vivo monitoring systems is discussed