Browsing by Author "McDevitt, John"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Integrated instrumentation for the analysis of biofluids at the point-of-care
    (2018-08-28) McDevitt, John; Haque, Ahmed; McRae, Michael; Simmons, Glen; Rice University; United States Patent and Trademark Office
    This disclosure describes the design and function of a bead-based lab-on-a-chip portable analyzer for analyzing biomarker assay cards used in point-of-care testing.
  • Thumbnail Image
    Item
    Isothermal Nucleic Acid Assays Based on Nucleic Acid Sequence Based Amplification (NASBA) and Recombinase Polymerase Amplification (RPA) for HIV-1 Diagnosis and Management in Low Resource Settings
    (2015-04-01) Rohrman, Brittany Ann; Richards-Kortum, Rebecca Rae; Biswal, Sibani L; McDevitt, John
    Over two-thirds of the estimated 35 million people worldwide infected with HIV live in the developing world. Nucleic acid tests (NATs) are necessary for early infant diagnosis and for monitoring patients receiving therapy. However, NATs cost $50-100 USD per test and require expensive thermal cycling equipment that may be unavailable in the developing world. This thesis presents two low-cost NATs for HIV-1 diagnosis and management that are based on isothermal amplification, which eliminates the need for expensive thermal cycling equipment. In one assay, HIV-1 viral RNA is detected using nucleic acid sequence based amplification (NASBA) and a custom lateral flow test. This assay costs about \$16 USD and only requires a heat block. When coupled with NASBA, the lateral flow test detected concentrations of synthetic RNA spanning the entire clinical range. When the assay was evaluated using pediatric plasma samples, the sensitivity (61%) and limit-of-detection (10,000 HIV-1 copies/mL plasma) were lower because of the genetic diversity of the samples, and the specificity was lower (88%) due to amplicon contamination. In the other assay, HIV-1 proviral DNA is amplified using recombinase polymerase amplification (RPA). This assay, which costs about \$5 per test, was integrated into a paper and plastic microfluidic device. The device was capable of amplifying 10 copies of plasmid HIV-1 DNA to detectable levels in 15 minutes. The assay was then adapted for real-time quantification. On average, the assay predicted sample concentrations within one order of magnitude of the correct concentration. In addition, a method for incubating RPA reactions without external equipment was developed. Using human body heat for incubation, all RPA reactions with 10 copies of plasmid HIV-1 DNA and 95% of reactions with 100 copies of plasmid HIV-1 DNA tested positive. Finally, concentrations of background DNA found in whole blood were shown to prevent the amplification of target DNA by RPA. To address this problem, three sequence-specific capture methods were developed to enrich target DNA concentration relative to background DNA concentration. These methods may be enable detection of high proviral loads in 0.1 mL infant blood samples but require improvement to detect lower proviral loads.
  • Thumbnail Image
    Item
    Multisample bionanochip platform
    (2016-02-02) McDevitt, John; Christodoulides, Nicolaos; Floriano, Pierre N.; Abram, Tim; Rice University; United States Patent and Trademark Office
    A bionanochip cartridge for analysis of multiple samples or analytes is provided herein, and the cartridge is dimensioned to take advantage of existing robotic microtiter plate handling equipment. Fluidics are specially designed to provide a small footprint and to prevent cross contamination.
  • Thumbnail Image
    Item
    Porous Bead-Based Diagnostic Platforms: Bridging the Gaps in Healthcare
    (MPDI, 2012) Chou, Jie; Wong, Jorge; Christodoulides, Nicolaos; Floriano, Pierre N.; Sanchez, Ximena; McDevitt, John
    Advances in lab-on-a-chip systems have strong potential for multiplexed detection of a wide range of analytes with reduced sample and reagent volume; lower costs and shorter analysis times. The completion of high-fidelity multiplexed and multiclass assays remains a challenge for the medical microdevice field; as it struggles to achieve and expand upon at the point-of-care the quality of results that are achieved now routinely in remote laboratory settings. This review article serves to explore for the first time the key intersection of multiplexed bead-based detection systems with integrated microfluidic structures alongside porous capture elements together with biomarker validation studies. These strategically important elements are evaluated here in the context of platform generation as suitable for near-patient testing. Essential issues related to the scalability of these modular sensor ensembles are explored as are attempts to move such multiplexed and multiclass platforms into large-scale clinical trials. Recent efforts in these bead sensors have shown advantages over planar microarrays in terms of their capacity to generate multiplexed test results with shorter analysis times. Through high surface-to-volume ratios and encoding capabilities; porous bead-based ensembles; when combined with microfluidic elements; allow for high-throughput testing for enzymatic assays; general chemistries; protein; antibody and oligonucleotide applications.
  • Thumbnail Image
    Item
    Programmable bio-nanochip-based cytologic testing of oral potentially malignant disorders in Fanconi anemia
    (Wiley, 2015) Floriano, Pierre; Abram, Tim; Taylor, Leander; Le, Cathy; Talavera, Humberto; Nguyen, Michael; Raja, Rameez; Gillenwater, Ann; McDevitt, John; Vigneswaran, Nadarajah
    Fanconi anemia (FA) is caused by mutations of DNA repair genes. The risk of oral squamous cell carcinoma (OSCC) among FA patients is 800-folds higher than in the general population. Early detection of OSCC, preferably at it precursor stage, is critical in FA patients to improve their survival. In an ongoing clinical trial, we are evaluating the effectiveness of the programmable bio-nanochip (p-BNC)-based oral cytology test in diagnosing oral potentially malignant disorders (OPMD) in non-FA patients. We used this test to compare cytomorphometric and molecular biomarkers in OSCC cell lines derived from FA and non-FA patients to brush biopsy samples of a FA patient with OPMD and normal mucosa of healthy volunteers. Our data showed that expression patterns of molecular biomarkers were not notably different between sporadic and FA-OSCC cell lines. The p-BNC assay revealed significant differences in cytometric parameters and biomarker MCM2 expression between cytobrush samples of the FA patient and cytobrush samples of normal oral mucosa obtained from healthy volunteers. Microscopic examination of the FA patient's OPMD confirmed the presence of dysplasia. Our pilot data suggests that the p-BNC brush biopsy test recognized dysplastic oral epithelial cells in a brush biopsy sample of a FA patient.