Methods and compositions for isolating an analyte

Abstract

Disclosed are methods for isolating an analyte from a sample. In some aspects, the methods are for selectively isolating a microbial cell analyte, such as a nucleic acid, from a sample containing or suspected of containing mammalian cells. The selective isolation method includes selective lysis of the mammalian cells and filtration of the resulting lysate through a filter that retains intact microbial cells, followed by on-filter lysis of the retained microbial cells to release the microbial cell analyte. The released analyte is then eluted from the filter. In other aspects, the methods utilize on-filter lysis of a sample containing intact cells (e.g., microbial cells) to release the analytes, followed by elution of the released analytes from the filter by passing an immiscible liquid through the filter. The isolated analytes may be analyzed using a suitable assay depending on the type of analyte molecule. Also disclosed are fluidic systems and lysis solutions that may be used for isolating an analyte according to the disclosed methods.