Sinawang P.D., Fajs L., Marks R.S.
Ben-Gurion University of the Negev, IL
Keywords: biomarkers, dengue, diagnostics, electrochemistry, lateral-flow, pathogens, quantitative point-of-care, stroke
The development of a rapid, affordable, and sensitive diagnostic kit for point-of-care is important in most healthcare settings; however, only a few exhibit the needed quantitative capability. Our technology, ELLI, is a patented diagnostic device that aims to provide on-site quantitation by utilizing proprietary electroactive immunonanoparticles that bind to the target biomarker and subsequently move along toward the biofunctionalized screen-printed gold electrodes (SPGE) to generate an amperometric signal. The SPGE functions simultaneously as a signal transducer and a solid-state support for a sandwich immunoassay. The successful immunocomplex formation is then recorded electrochemically using a potentiostat, whereby the signal was contributed by the presence of ferrocene or a more hydrophilic redox label, radical TEMPO, immobilized on the formulated nanoparticles. A bifunctional ligand, thiolated polyethylene glycol (PEG-thiol), was used to stabilize 20 nm gold colloidal nanoparticles (AuNPs). The ligand was incorporated to not only prevent the salt-mediated AuNPs aggregations but also provide an anchor for antibody and redox species conjugation. To-date, we have miniaturized a 3D-printed prototype device able to sensitively detect and quantify dengue NS1 protein with only 0.6 µL human clinical serum samples (diluted in a volume ratio of 1:100 (PBS diluent)) in less than 30 min with a simple cyclic voltammetry analysis. The NS1 protein has been recognized as an important immunogen in dengue triage because this protein is secreted in the bloodstream and can be detected on day 1 after the onset of fever while a threshold level is indicative of a putative severe case. Other applications are being developed, including stroke prognosis using NT-proBNP biomarker, that is significantly associated with cardioembolic stroke and secondary stroke reoccurrence, with sensitivity >90% and specificity >80%. Initial results of this research in mock porcine plasma have shown that the label-free impedimetric electrochemical biosensor was capable of differentiating such concentrations in a low concentration range, especially among 0, 0.1, 0.5, 1, and 3 ng mL-1 within 25 min. This range is valuable not only for classifying cardioembolic stroke (0.5 ng mL-1) but also predicting the risk of secondary stroke reoccurrence (0.255 ng mL-1). We are now adapting these results to the ELLI platform. The applications above need quantitation as a measure of severity and a classification means. In dengue, for example, a simple, 1-2 step, point-of-care-format is recommended for disease surveillance in communities as a first line of defense, especially when there is no specific treatment for dengue/severe dengue. WHO suggests that early detection and access to proper medical care lowers fatality rates below 1%. Meanwhile, in stroke prognosis, a quantitative point-of-care device that reduces the delays in IV-tPA administration and predicts risks as well as secondary reoccurrence will be highly favored. ELLI promises to deliver sensitive measurements of the target biomarker and acts as a diagnostic intervention for faster therapeutics administration that eventually will contribute to a better disease emergency preparedness. ELLI is the answer to whichever applications that would require quantitation of biomarkers or pathogens at the point-of-care such as for HAZMAT teams, the military, or home use.
Journal: TechConnect Briefs
Volume: 3, Biotech, Biomaterials and Biomedical: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 110 - 113
Industry sector: Medical & Biotech
Topic: Diagnostics & Bioimaging
ISBN: 978-0-9988782-0-1