Functional nucleic acids for detecting bacteria

Bacterial infection represents one of the leading causes of disease and death, and as such, bacterial detection is an important step in managing infectious diseases. The current protocol requires growing cell cultures, which can take several days. Fast detection of low copies of bacterial cells has thus posed an analytical challenge. Among the new strategies developed to achieve this goal, functional nucleic acids (FNAs) have emerged to be a promising platform. FNAs include DNAzymes, aptamers, and aptazymes, all of which can recognize analytes other than complementary nucleic acids. FNAs are obtained using a combinatorial biology technique called systematic evolution of ligands by exponential enrichment (SELEX). FNAs have been isolated against not only purified proteins and surface markers from bacterial cells but also whole cells. A diverse range of signaling mechanisms including fluorescence, color, and electrochemistry-based detection has been reported. Although the majority of current sensors cannot achieve single-cell sensitivity, with improved combinatorial selection techniques and the incorporation of nanomaterials to realize multivalent binding and signal amplification, FNAs represent a feasible solution for bacterial detection