Fluidic Force Discrimination Assays: A New Technology for Tetrodotoxin Detection

Tetrodotoxin (TTX) is a low molecular weight (~319 Da) neurotoxin found in a number of animal species, including pufferfish. Protection from toxin tainted food stuffs requires rapid, sensitive, and specific diagnostic tests. An emerging technique for the detection of both proteins and nucleic acids is Fluidic Force Discrimination (FFD) assays. This simple and rapid method typically uses a sandwich immunoassay format labeled with micrometer-diameter beads and has the novel capability of removing nonspecifically attached beads under controlled, fluidic conditions. This technique allows for near real-time, multiplexed analysis at levels of detection that exceed many of the conventional transduction methods (e.g., ELISAs). In addition, the large linear dynamic range afforded by FFD should decrease the need to perform multiple sample dilutions, a common challenge for food testing. By applying FFD assays to an inhibition immunoassay platform specific for TTX and transduction via low magnification microscopy, levels of detection of ~15 ng/mL and linear dynamic ranges of 4 to 5 orders of magnitude were achieved. The results from these studies on the first small molecule FFD assay, along with the impact to detection of seafood toxins, will be discussed in this manuscript

A New Methodology for Quantitative LSPR Biosensing and Imaging

A new quantitative analysis methodology for localized surface plasmon resonance (LSPR) biosensing which determines surface-receptor fractional occupancy, as well as an LSPR imaging technique for the spatiotemporal mapping of binding events, is presented. Electron beam nanolithography was used to fabricate 20 × 20 arrays of gold nanostructures atop glass coverslips. A single biotinylated array was used to measure the association kinetics of neutravidin to the surface by spectroscopically determining the fractional occupancy as a function of time. By regenerating the same array, a reliable comparison of the kinetics could be made between control samples and neutravidin concentrations ranging from 1 μM to 50 nM. CCD-based imagery of the array, taken simultaneously with the spectroscopic measurements, reveals the binding of neutravidin to the surface as manifested by enhanced scattering over the majority of the resonance peak. The temporal resolution of the LSPR imaging technique was 200 ms and the spatial resolution was 8 μm²

Rapid design and fielding of four diagnostic technologies in Sierra Leone, Thailand, Peru, and Australia: Successes and challenges faced introducing these biosensors

Febrile illnesses are among the most common reasons for visits to hospitals and clinics worldwide. Since fevers can arise from a wide range of diseases, identifying the causative pathogen is essential not only for effective personal treatment but also for early detection of outbreaks. The Defense Threat Reduction Agency (DTRA) tasked a coalition of commercial, academic, and government researchers with moving diagnostic technology concepts from ideation to field use as rapidly as possible using scientifically sound evaluations. DTRA\u27s 24 Month Challenge program examined \u3e30 technologies before fielding four technologies on four continents. \u3e10,000 in field test results were recorded. Here we discuss our tiered evaluation system to assess candidate technologies developed by commercial partners and the process of field testing those technologies at various front-line clinics in Sierra Leone, Thailand, Peru, and Australia. We discuss successes and challenges for introducing two multiplexed lateral flow immunoassay(LFI) tests that detect malaria, dengue fever, melioidosis, and the plague. Additionally we discuss the use of a LFI reader that assisted the interpretation of the assay, communicated results to a data cloud, and greatly facilitated reach-back support. Lastly, we discuss the concurrent field testing of a multiplexed PCR assay on the FilmArray platform, which had an assay pouch specially designed for the 24 Month Challenge. Either standard-of-care or gold-standard testing were run alongside our fielded technologies to benchmark their performance

Rapid design and fielding of four diagnostic technologies in Sierra Leone, Thailand, Peru, and Australia: Successes and challenges faced introducing these biosensors

© 2018 Febrile illnesses are among the most common reasons for visits to hospitals and clinics worldwide. Since fevers can arise from a wide range of diseases, identifying the causative pathogen is essential not only for effective personal treatment but also for early detection of outbreaks. The Defense Threat Reduction Agency (DTRA) tasked a coalition of commercial, academic, and government researchers with moving diagnostic technology concepts from ideation to field use as rapidly as possible using scientifically sound evaluations. DTRA\u27s 24 Month Challenge program examined \u3e30 technologies before fielding four technologies on four continents. \u3e10,000 in field test results were recorded. Here we discuss our tiered evaluation system to assess candidate technologies developed by commercial partners and the process of field testing those technologies at various front-line clinics in Sierra Leone, Thailand, Peru, and Australia. We discuss successes and challenges for introducing two multiplexed lateral flow immunoassay (LFI) tests that detect malaria, dengue fever, melioidosis, and the plague. Additionally we discuss the use of a LFI reader that assisted the interpretation of the assay, communicated results to a data cloud, and greatly facilitated reach-back support. Lastly, we discuss the concurrent field testing of a multiplexed PCR assay on the FilmArray platform, which had an assay pouch specially designed for the 24 Month Challenge. Either standard-of-care or gold-standard testing were run alongside our fielded technologies to benchmark their performance

High-Quality Uniform Dry Transfer of Graphene to Polymers

In this paper we demonstrate high-quality, uniform dry transfer of graphene grown by chemical vapor deposition on copper foil to polystyrene. The dry transfer exploits an azide linker molecule to establish a covalent bond to graphene and to generate greater graphene–polymer adhesion compared to that of the graphene–metal foil. Thus, this transfer approach provides a novel alternative route for graphene transfer, which allows for the metal foils to be reused