Materials and surface properties optimization to prevent biofouling of a novel bacterial concentrator

Traditionally, bacterial pathogens in the blood have been identified using culture-based methods that can take several days to obtain results. This can lead to physicians making treatment decisions based on an incomplete diagnosis, which can increase the patient's risk of death. One major limitation to the development of faster diagnostic methods is that bacteria are found in very low concentrations in the blood, thus to detect them one either needs to increase their numbers by culturing the bacteria or effectively isolate and concentrate them from the blood. We are developing a device that purifies as few as 10 bacteria from 10 milliliters of whole blood, and concentrates the bacteria into a 30 microliter volume through a combination of preferential cell lysis and centrifugation steps. To enable the efficient capture of so few bacteria in a sea of billions of blood cells, the material properties of the device were optimized. Critical parameters include material selecti on, manufacturing method, surface roughness, and surface chemistry. In this paper, we present the design of this novel concentrator, optimization of these parameters, and the achieved performance.