Publications by authors named "Stephen A Ferguson"

Droplet microfluidics is an enabling platform for high-throughput screens, single-cell studies, low-volume chemical diagnostics, and microscale material syntheses. Analytical methods for real-time and in situ detection of chemicals in the droplets will benefit these applications, but they remain limited. Reported herein is a novel heterogeneous chemical sensing strategy based on functionalization of the oil phase with rationally combined sensing reagents.

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A universal method for the detection, quantification, and characterization of polyquaterniums (PQs) in a simple background electrolyte solution and in more complex recreational swimming pool water samples is presented. This method involves the application of polycation-sensitive ion-selective optodes (ISOs) prepared by inkjet printing dinonylnaphthalenesulfonic acid (HDNNS) and chromoionophore I directly onto Whatman qualitative filter paper. No plasticizer or added polymer matrix is required for the fabrication of the sensing layer which is coated on the cellulose fibers of the filter paper.

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The detection of four different polyquaterniums (PQs) using a fully reversible potentiometric polyion sensor in three different detection modes is described. The polyion sensing "pulstrodes" serve as the detector for direct dose-response experiments, beaker titrations, and in a flow-injection analysis (FIA) system. Direct polycation response toward PQ-2, PQ-6, PQ-10, and poly(2-methacryloxyethyltrimethylammonium) chloride (PMETAC) yields characteristic information about each PQ species (e.

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Two facile, robust, and universal methods by which various polymeric quaternary ammonium salts (polyquaterniums (PQs)) can be quantified and characterized using simple potentiometric polymeric membrane polyion-sensitive electrodes as detectors are described. The two methods are (a) direct detection with polycation sensitive membrane electrodes based on the sodium salt of dinonylnaphthalenesulfonate (NaDNNS), and (b) indirect detection using polyanion sensors based on tridodecylmethylammonium chloride (TDMAC) and dextran sulfate (DS) as a titrant to complex the various polyquaternary species (four different PQs: PQ-2, PQ-6, PQ-10, and poly(2-methacryloxyethyltrimethylammonium) chloride (PMETAC)). Direct detection yields information regarding the charge density of the polycationic species.

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Polymeric quaternary ammonium salts (polyquaterniums) have found increasing use in industrial and cosmetic applications in recent years. More specifically, polyquaternium-10 (PQ-10) is routinely used in cosmetic applications as a conditioner in personal care product formulations. Herein, we demonstrate the use of potentiometric polyion-sensitive polymeric membrane-based electrodes to quantify PQ-10 levels.

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Article Synopsis
  • Western blotting is a protein analysis technique that is slow, requires manual effort, and generally analyzes only one protein per assay, consuming significant sample amounts (10-20 μg).
  • New methods using microfluidics and capillary electrophoresis have been developed to enhance automation, throughput, and sensitivity, enabling the detection of multiple proteins simultaneously.
  • The improved method allows different antibodies to probe multiple protein tracks from a single sample injection, achieving high resolution and detection of 11 proteins from a mere 400 ng of total protein, eliminating the need for time-consuming stripping and reprobing.
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