Browsing by Author "Barron, Monica"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Electrochemical Erasing Using a Polymer Lithography Editor for the Fabrication of Photoactive Devices
    (ACS, 2019) Becerra-Mora, Nathalie; Vargas-Lizarazo, Annie Y.; Orrison, Connor; Barron, Monica; Balaraman, Rajesh P.; Kohli, Punit; Chemistry and Chemical Biology, School of Science
    Electrochemical erasing of conductive coatings at microscale for the fabrication of functional devices on flexible and hard surfaces is demonstrated. The nanoporous pyramidal-shaped nano- and microscale polyacrylamide hydrogel PLE probes allowed delivery of electrochemical etchants to the surface, providing on-demand maskless patterning at microscale. Highly efficient erasing (silver and copper metals erasing efficiency ≈ 100%), areal erasing rate ≈ 80 μm2/s, and pressure dependent spatial erasing feature dimensions between 3 μm to many tens of microns on metal surfaces allowed for the fabrication of microelectrodes of various geometries. Overall, PLE-based microscale erasing allowed for rapid and accessible fabrication of organic electron–hole carrier pair-based microphotodetector, as well as the assembly of LED on flexible and rigid ITO substrates.
  • Thumbnail Image
    Item
    Multiplexed Signal Ion Emission Reactive Release Amplification (SIERRA) Assay for the Culture-Free Detection of Gram-Negative and Gram-Positive Bacteria and Antimicrobial Resistance Genes
    (American Chemical Society, 2021) Pugia, Michael; Bose, Tiyash; Tjioe, Marco; Frabutt, Dylan; Baird, Zane; Cao, Zehui; Vorsilak, Anna; McLuckey, Ian; Barron, M. Regina; Barron, Monica; Denys, Gerald; Carpenter, Jessica; Das, Amitava; Kaur, Karamjeet; Roy, Sashwati; Sen, Chandan K.; Deiss, Frédérique; Chemistry and Chemical Biology, School of Science
    The global prevalence of antibiotic-resistant bacteria has increased the risk of dangerous infections, requiring rapid diagnosis and treatment. The standard method for diagnosis of bacterial infections remains dependent on slow culture-based methods, carried out in central laboratories, not easily extensible to rapid identification of organisms, and thus not optimal for timely treatments at the point-of-care (POC). Here, we demonstrate rapid detection of bacteria by combining electrochemical immunoassays (EC-IA) for pathogen identification with confirmatory quantitative mass spectral immunoassays (MS-IA) based on signal ion emission reactive release amplification (SIERRA) nanoparticles with unique mass labels. This diagnostic method uses compatible reagents for all involved assays and standard fluidics for automatic sample preparation at POC. EC-IA, based on alkaline phosphatase-conjugated pathogen-specific antibodies, quantified down to 104 bacteria per sample when testing Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa lysates. EC-IA quantitation was also obtained for wound samples. The MS-IA using nanoparticles against S. aureus, E. coli, Klebsiella pneumoniae, and P. aeruginosa allowed selective quantitation of ∼105 bacteria per sample. This method preserves bacterial cells allowing extraction and amplification of 16S ribosomal RNA genes and antibiotic resistance genes, as was demonstrated through identification and quantitation of two strains of E. coli, resistant and nonresistant due to β-lactamase cefotaximase genes. Finally, the combined immunoassays were compared against culture using remnant deidentified patient urine samples. The sensitivities for these immunoassays were 83, 95, and 92% for the prediction of S. aureus, P. aeruginosa, and E. coli or K. pneumoniae positive culture, respectively, while specificities were 85, 92, and 97%. The diagnostic platform presented here with fluidics and combined immunoassays allows for pathogen isolation within 5 min and identification in as little as 15 min to 1 h, to help guide the decision for additional testing, optimally only on positive samples, such as multiplexed or resistance gene assays (6 h).