Real-Time Bacterial Capture and Sorting Using Dielectrophoresis

摘要

Fluid-Screen, Inc. presents a bacterial capture and sorting method that bypasses the need for time-consuming culture-based methods of bacterial sample preparation. When combined with current rapid bacterial identification methods, the Fluid-Screen sample sorter has potential to reduce the time it takes to detect bacterial contamination from days to minutes. The technology has applications in biodefense; the municipal, recreational, and environmental water industries; clinical diagnostics; and sterile manufacturing quality control among other industries. Fluid-Screen technology is based on dielectrophoresis (DEP) and is independent of bacterial growth. DEP has been known to influence particle motion and capture since the 1960's1, however, technology based on DEP has historically had low efficiency, limiting its use for practical applications2'3. Fluid-Screen has developed a novel electrode that induces high electric field gradients to make use of DEP for bacterial capture4. The design of this sample-sorting electrode allows for rapid and efficient isolation of diverse bacteria from a variety of aqueous solutions5. Furthermore, by precisely controlling electronic conditions, the Fluid-Screen device can differentially process distinct types of bacteria for selective manipulation. The Fluid-Screen sample sorter captures both Gram-positive and Gram-negative bacteria, along with those lacking a cell wall. Notably, it works with bacteria of a range of sizes6. Not only fluorescent laboratory-defined strains of bacteria, but also environmental bacteria, and bacteria endogenous to a sample respond to the electric field. Furthermore, bacteria behave differently from larger particles such as mammalian cells, opening the possibility of using the technology for sterilization or filtration applications to selectively remove bacteria from a contaminated source. Bacteria are either attracted to or repelled from the Fluid-Screen sample sorter based on the applied frequency and voltage of the electric field, allowing for controlled capture and release. By selectively isolating and immobilizing bacteria from fluid, the sample sorter concentrates bacteria from a low-titer sample for low-volume release and transport into any number of bacterial detection or identification systems. This allows for real- time detection of bacterial contamination without time-consuming amplification methods. Although current Fluid-Screen designs are optimized to capture bacteria, the electrode feature design may be customized to capture and manipulate other particles such as viruses, proteins, and chemicals for efficient sample preparation prior to detection.