Homogeneous and Universal Transduction of Various Nucleic acids to Off-Shelf Device Based on Programmable Toehold Switch Sensing

Translating non-glucose species to personal glucose meters (PGMs) via invertase transduction is a highly-valuable strategy to enrich portable diagnostics. However, its stability and practicability is still challenged by complex operations such as conjugation, labelling, and bead separation. Here we construct the first Sensing Plasmid containing both RNA toehold switch and invertase reporter gene. The expression of invertase can be activated merely when the specific targeting oligonucleotide opens the toehold switch and releases AUG start codon. In this way, the whole detection is simplified into a completely label-free, separation-free and homogeneous condition, being more reproducible, user-friendly, and reagent-saving. When coupling this method with isothermal amplification, as few as 20 molecular copies of Zika template genes can be significantly recognized using a PGM. Through importing a four-way junction-based transduction, one well-designed Sensing Plasmid is further allowed to detect any other non-relevant sequence, for example, as few as 6 CFU of Enterobacter sakazaki bacteria.