Introduction: Studies conducted in our laboratory on proteomic profiling of breast cancer serum among women by shotgun LC-MS methodology have identified several biomarkers for early detection of breast cancer. However, not all of the identified biomarkers have been validated due to costs involved with validation tests. The development of a reliable, cost-effective highly sensitive portable system, the Electrochemiluminescence (ECL) biosensor in our laboratory will enable us to validate identified biomarkers that have valuable diagnostic applications. Electrochemical immunosensors have significantly improved the sensitivity of detecting low molecular weight biomarkers present in early stages of cancer. There is a great need for such easily accessible systems for early detection of cancer because of disease prevalence high rates of mortality from breast cancer.

Purpose: of this project is to develop the ECL biosensor using ubiquitous mobile technologies to detect biomarkers of breast cancer. ECL offers great advantages over fluorescence based measurement: ECL is a highly localized and time-triggered detection method. Instrumentation can be minimized as it requires only voltage to trigger the reaction. Cell phone-ubiquity and connectivity creates opportunities to simplify healthcare instrumentation, brings closer to end users, and enable instant data sharing.

Methods: A highly compact and affordable instrumentation was designed and constructed using the mobile technology replacing the traditional ECL detector, computer interface, and data analyzer in an all-in-one mode. Ru (bpy)32+ was embedded in silicon nanoparticles and sandwich immunoassay was conducted. Antibody is conjugated to the Silicon nanoparticles where Ru (bpy)32+ is embedded and the other antibody is attached to magnetic bead so that the bound complex can be attracted to the electrode surface separating the false positive signals. Coreactant tri-n-propylamine (TPrA) or 2-(dibutylamino)ethanol (DBAE) was tested for their ability to enhance the signal.

Results: TPrA provided stronger signals for carbon electrodes and optimal concentration was determined for low signal measurements. The sensing conditions were optimized by experimenting with variables of buffer conditions, trigger voltage, and electrode conditions. The target sensing molecule, vitamin-D binding protein (DBP) was detected at the hundreds of nano-molar level with the optimized conditions.

Conclusion: The sensor demonstrated that a new instrumentation with mobile technology in the point-of-care diagnostics could provide reliability and sensitivity of a high-end equipment. This project is funded by the NSF CBET division.

[Hyun Kwon and Padma Uppala will co-present this work.]

Citation Format: Hyun Kwon, Padma P. Tadi Uppala, Elmer Ccopa Rivera, Rodney Summerscales. Development of a cell phone-based electrochemiluminescence biosensor to detect breast cancer biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1636.