Publications by authors named "Indroneil Roy"

2 Publications

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High-Conductivity and High-Capacitance Electrospun Fibers for Supercapacitor Applications.

ACS Appl Mater Interfaces 2020 Apr 20;12(17):19369-19376. Epub 2020 Apr 20.

Howard P. Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States.

Electrospinning is a simple method for producing nanoscale or microscale fibers from a wide variety of materials. Intrinsically conductive polymers (ICPs), such as polyaniline (PANI), show higher conductivities with the use of secondary dopants like -cresol. However, due to the low volatility of most secondary dopants, it has not been possible to electrospin secondary doped ICP fibers. In this work, the concept of secondary doping has been applied for the first time to electrospun fibers. Using a novel design for rotating drum electrospinning, fibers were efficiently and reliably produced from a mixture of low- and high-volatility solvents. The conductivity of electrospun PANI-poly(ethylene oxide) (PEO) fibers prepared was 1.73 S/cm, two orders of magnitude higher than the average value reported in the literature. These conductive fibers were tested as electrodes for supercapacitors and were shown to have a specific capacitance as high as 3121 F/g at 0.1 A/g, the highest value reported, thus far, for PANI-PEO electrospun fibers.
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http://dx.doi.org/10.1021/acsami.9b21696DOI Listing
April 2020

Beyond electrostatics: Antimicrobial peptide selectivity and the influence of cholesterol-mediated fluidity and lipid chain length on protegrin-1 activity.

Biochim Biophys Acta Biomembr 2019 10 8;1861(10):182977. Epub 2019 May 8.

Department of Chemistry, Institute for Biophysical Dynamics and James Frank Institute, The University of Chicago, Chicago, IL 60637, United States. Electronic address:

Antimicrobial peptides (AMPs) are a promising class of innate host defense molecules for next-generation antibiotics, as they uniquely target and permeabilize membranes of pathogens. This selectivity has been explained by the electrostatic attraction between these predominantly cationic peptides and the bacterial membrane, which is heavily populated with anionic lipids. However, AMP-resistant bacteria have non-electrostatic countermeasures that modulate membrane rigidity and thickness. We explore how variations in physical properties affect the membrane affinity and disruption process of protegrin-1 (PG-1) in phosphatidylcholine (PC) membranes with altered lipid packing densities and thicknesses. From isothermal titration calorimetry and atomic force microscopy, our results showed that PG-1 could no longer insert into membranes of increasing cholesterol amounts nor into monounsaturated PC membranes of increasing thicknesses with similar fluidities. Prevention of PG-1's incorporation consequently made the membranes more resistant to peptide-induced structural transformations like pore formation. Our study provides evidence that AMP affinity and activity are strongly correlated with the fluidity and thickness of the membrane. A basic understanding of how physical mechanisms can regulate cell selectivity and resistance towards AMPs will aid in the development of new antimicrobial agents.
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http://dx.doi.org/10.1016/j.bbamem.2019.04.011DOI Listing
October 2019