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Exploring structural modifications and biomarkers to optimize and expand the E-DNA scaffold sensor for applications in point of care serology

  • Author(s): Greenwood, Ava Shruti Kartik
  • Advisor(s): Plaxco, Kevin W.
  • et al.
Abstract

Serology provides comprehensive information about infection, disease progression, and immune history. Current technologies utilized for serological diagnosis exist in one of the following modalities: 1) rapid, qualitative and easy to use in complex clinical samples, but limited to a single diagnostic biomolecule, 2) cutting edge and quantitative but computationally expensive and unable to perform well in complex clinical samples, or 3) quantitative, robust and easily multiplexed using complex samples while being time and equipment intensive. To bridge the gap between rapid and qualitative and time/equipment intensive and quantitative, our group has developed electrochemical DNA (E-DNA) scaffold sensors to quantitively detect diagnostic antibodies in a rapid, single step, wash free, electrochemical system. The overreaching goal is to develop an inexpensive, multiplexed E-DNA scaffold sensor to detect multiple diagnostic antibodies at the point of care in less than 15 minutes – which will improve patient outcomes and reduce the number of patients lost to follow-up.

The work presented here focuses on improving the analytical and clinical performance of the E-DNA scaffold sensors, in addition to expanding the platform to diagnose multiple sexually transmitted infections. Compared to the scaffold sensor structure in previously published literature, various modifications of the scaffold sensor flexibility and utilization of a bivalent epitope probe did not improve the overall current, signal gain, or limit of detection of the E-DNA scaffold sensor. Attempts at expanding the E-DNA scaffold sensor to detect anti-gp41 diagnostic antibody in clinical samples resulted in a successful sensor that approaches the sensitivity and selectivity necessary clinical utilization, however incorporation of two linear epitopes of herpes simplex virus type 2 and hepatitis C were unsuccessful with the linear epitopes employed. Difficulties in expanding the diagnostic biomarkers utilized in this platform stem from issues incorporating linear immunodominant epitopes, which demonstrate positive and negative predictive value when challenged with human sera using gold standard techniques yet demonstrate no significant signal change when incorporated into the E-DNA scaffold.

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