Enhancing the Detection of Urinary Tract Infections Using Two-Phase Aqueous Micellar Systems

Urinary tract infections (UTIs) are a leading cause of health expenditures, in part due to the expensive and lengthy diagnostic method that involves culturing bacteria. A new technique has been developed allowing for faster UTI diagnosis through an electrochemical chip to measure unique ribosomal RNA (rRNA) found in bacteria associated with UTIs. Although this technique has had success, concentrating the bacterial rRNA through the use of two-phase aqueous micellar systems in the urine sample prior to utilizing the chip may provide increased sensitivity. This approach is appealing because these systems are relatively inexpensive, easily scalable, and simple to use. In this study, we examined the partitioning behavior of bacterial RNA fragments, purified from Enteroccocus faecalis, in a two-phase micellar system comprised of the nonionic surfactant Triton X-114 and phosphate-buffered saline. Experimentally measured results were compared to theoretical values to determine the governing factors involved in RNA partitioning. We demonstrated that RNA fragments partition primarily due to steric, excluded-volume interactions that exist between the RNA and micelles. However, the presence of entrained micelle-poor, RNA-rich domains in the macroscopic micelle-rich, RNA-poor phase limits the extent of RNA partitioning in this system. Additionally, by manipulating the volume ratio, or the volume of the top, micelle-poor phase divided by that of the bottom, micelle-rich phase, we demonstrated that RNA fragments can be concentrated up to four-fold in a predictive manner. Concentrating the bacterial RNA with these two-phase micellar systems prior to detection with the UTI chip may facilitate the earlier detection of UTIs. Enhancing the Detection of Urinary Tract Infections Using Two-Phase Aqueous Micellar Systems