A bacteria separation chip with hemocyte lysis based on joule heating

Abstract

Sepsis is an infection of the blood by bacteria that causes systemic inflammatory response syndrome. In patients with sepsis, mortality increases by 8% per hour, so they should be diagnosed early and given appropriate antibiotics. For proper treatment, it is essential to selectively culture and separate bacteria from the blood at low concentrations (1~1000 CFU/mL). The total time required for diagnosis and prescription is currently 3-5 days, and the reduction in time is directly related to patient survival. In this study, it was confirmed that hemocytes exhibit lower heat resistance than bacteria due to differences in membrane properties. Thus, selective lysis of hemocytes upon heating is possible. Therefore, we suggest the device for the lysis of hemocytes by Joule heating, followed by rapid separation of bacteria. For sample preparation, blood was diluted 20 times with PBS, and Escherichia coli was spiked (50-500CFU/ml). Next, the sample was injected into the chip, and a direct current was applied to the electrode system to confirm the operability of the proposed chip. At a flow rate of 15 ml/h, the hemocytes lysis efficiency was 86%, and the bacteria recovery efficiency was 82% on average. This advance is expected to reduce the time needed to diagnose sepsis significantly.