Novel Proximity Assay Platform for the Quantitative Detection of Hepatitis B Virus Surface Antigen

SummaryThis proposal aims to develop a novel proximity technology to quantify the hepatitis B virusHBVsurface antigenHBsAgin blood for point of care testingHBsAg is an important serological marker that is highly predictive of HBV infection statusand response to anti viral treatmentChronic infection with HBV is a serious global health problem and among the leading causes of preventable deathThere aremillion people in the world living with chronic HBV infectionwith the greatest burden of disease in Asia and AfricaAboutpeople die each year worldwide from HBV related liver diseaseImproved diagnosis of HBV infectionmonitoringand treatment of HBV infected patients is urgently needed to reduce the morbidity and mortality associated with HBV infectionRisk of liver cancer isx higher for those who are chronically infectedWHO estimates that most of the infected have not been screened and are not aware of their infection because they often have no symptomsand andltof the infected that needs treatment are receiving treatmentLeft undiagnosed and untreatedchronic HBV infection carries achance of dying from liver cancer and liver cirrhosisAmong the major challenges in scaling up preventionsurveillancescreeningcareand treatment on a global scale are affordable and easy to use diagnostic and monitoring testsand affordable effective treatmentparticularly for the resource limited countries that have high prevalence and burden of HBVThe quantitative POC diagnostic assay we propose will have an important impact in this global effortSpecificallywe will develop a novel technology based on Fluorescence Resonance Energy TransferFRETusing our newly discovered quantum dotQDwith two emissions as FRET donorin which one emission peak without FRET serves as abuilt instandard and the other serves as FRET emission to interact with acceptor dye to quantify the biomarkerThe assay with a feature of thebuilt instandard could eliminate thematrix effectfor accurate quantification of the biomarkerThis Phase I project will demonstrate its feasibility using HBsAg as a model biomarkerWe will firstly prepare the QD and acceptor dye conjugates with relevant antibodiesusing methods that we have establishedWe will then establish the quantitative FRETQFRETassay and study the matrix effectsThe sensitivityspecificitydynamic rangeand reproducibility of the HBsAg QFRET assay will then be tested using antigenspiked serum sample from a healthynon HBV infected donorLastlyin this Phase I studywe will evaluate the performance of the HBsAg QFRET assay by measuring the levels of HBsAg in the serum samples of HBV patients and healthy volunteersOur QFRET HBsAg data will be compared with that of independent HBsAg assayssuch as ELISAand commercial gold standard assay for HBsAgOur Phase II project will extend of this QFRET assay platform to quantify other biomarkers of HBV and hepatitis C virusHCVinfectionsthus providing a comprehensive solution for the diagnosis and monitoring of these chronically infected patientsOur new assay has the advantages of simple sample preparationand a compact and inexpensive analyzer which is suitable for use in resource limited settings Project NarrativeThis project aims to develop a quantum dot based immunoassay to quantify Hepatitis disease related blood biomarkers in Point of Care setingsThe successful development of this assay can provide rapid and accessible diagnosis of the diseaseand therefore allow timely treatment intervention and monitoring of patient response to treatmentThis will potentially have a significant impact on reducing the global burden of this disease