Browsing by Author "Paul, Sai"

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    Developing Low-Cost Paper-Based Assays to Reduce Overtreatment at the Point of Care
    (2022-09-30) Paul, Sai; Richards-Kortum, Rebecca
    Access to diagnostics is critical for successful treatment. Limitations of trained technicians, financial resources, and infrastructure often prevent the use of conventional diagnostics in low-resource areas. Without appropriate diagnostics, clinicians may choose to overtreat, which can harm patients’ health, waste precious resources, and contribute to public health issues, such as antimicrobial resistance. In this thesis, I describe the development of three low-cost paper-based assays for cervical cancer screening and neonatal sepsis. Current cervical cancer screening methods prioritize sensitivity over specificity, leading to overtreatment that can cause unnecessary pregnancy complications and physical harm in women who naturally resolve HPV infections. To address these limitations, I developed a HPV oncoprotein test to specifically detect progression to cervical cancer. As for neonatal sepsis, infants are often empirically treated in low-resource settings where infrastructure requirements, cost, and result turnaround time limit the use of blood culture. I developed two tests for neonatal sepsis to A) safely discontinue antibiotics in neonates being treated and B) to identify neonates at high risk of sepsis. These tests utilize the natural wicking properties of paper membranes to sequentially drive reagents for immunoassay binding reactions. By automating reagent delivery, these tests minimize hands-on time and result turnaround time to minimize training requirements and allow for timely decision-making. These tests will enable better diagnosis of cervical cancer and neonatal sepsis to reduce overtreatment at the point of care.
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    Sample-to-answer, extraction-free, real-time RT-LAMP test for SARS-CoV-2 in nasopharyngeal, nasal, and saliva samples: Implications and use for surveillance testing
    (Public Library of Science, 2022) Kundrod, Kathryn A.; Natoli, Mary E.; Chang, Megan M.; Smith, Chelsey A.; Paul, Sai; Ogoe, Dereq; Goh, Christopher; Santhanaraj, Akshaya; Price, Anthony; Eldin, Karen W.; Patel, Keyur P.; Baker, Ellen; Schmeler, Kathleen M.; Richards-Kortum, Rebecca; Bioengineering
    The global COVID-19 pandemic has highlighted the need for rapid, accurate and accessible nucleic acid tests to enable timely identification of infected individuals. We optimized a sample-to-answer nucleic acid test for SARS-CoV-2 that provides results in <1 hour using inexpensive and readily available reagents. The test workflow includes a simple lysis and viral inactivation protocol followed by direct isothermal amplification of viral RNA using RT-LAMP. The assay was validated using two different instruments, a portable isothermal fluorimeter and a standard thermocycler. Results of the RT-LAMP assay were compared to traditional RT-qPCR for nasopharyngeal swabs, nasal swabs, and saliva collected from a cohort of patients hospitalized due to COVID-19. For all three sample types, positive agreement with RT-LAMP performed using the isothermal fluorimeter was 100% for samples with Ct <30 and 69–91% for samples with Ct <40. Following validation, the test was successfully scaled to test the saliva of up to 400 asymptomatic individuals per day as part of the campus surveillance program at Rice University. Successful development, validation, and scaling of this sample-to-answer, extraction-free real-time RT-LAMP test for SARS-CoV-2 adds a highly adaptable tool to efforts to control the COVID-19 pandemic, and can inform test development strategies for future infectious disease threats.