Sensitive Detection of Blood Biomarker Pentraxin 3 – Development and Comparison of Amperometric and Capacitive Biosensors in Flow-Injection Systems

Sammanfattning: Within clinical diagnostics there is always a need for innovative methods that are rapid, sensitive, and more accurate. In this study two bioanalytical systems have been evaluated for pentraxin 3 (PTX3) detection. PTX3 is a blood biomarker involved in the native immune system that can indicate sepsis, a disease that currently lacks a fast and sensitive analytical method for early detection. Currently, a whole panel of tests supported by physical symptoms is used, and diagnosis can only be confirmed several days after the blood sample is taken. PTX3 can also indicate other diseases such as covid 19 and some types of cancer. The analytical platforms in this work all utilizes immobilized anti-PTX3 antibodies immobilized on an electropolymerized gold working electrode in combination with flow-injection analysis (FIA) to control the injections into a flow-cell with a three-electrode system. The first method used capacitance measurements and the results indicate that there is binding for PTX3 concentrations as low as 10-20 M in buffer. The second system utilizes amperometric measurements and results points towards binding at concentrations of 10-12 M of PTX3. Additionally, a capacitive model system with Protein G (PG) as an immobilized biorecognition element produced a clear signal when injecting 10-13 M antibodies as a target.