Design nanoprobe based on DNA tetrahedron supported hybridization chain reaction and its application to in situ analysis of bacteria

A new nanoprobe (DTAAT) has been well designed based on DNA tetrahedron supported hybridization chain reaction (HCR) and further applied for in situ analysis of bacteria. Antibody-aptamer conjugate (AA) has been coupled with DNA tetrahedron (DT) followed by the linkage of trigger strand (A). Bacteria can be preciously recognized by dual binding of both antibody and aptamer in DTAAT, to release trigger strand which is com-plementary with aptamer. By virtue of proximity effect, the released trigger strand can further efficiently induce the simultaneous occurrence of arrays of HCR at three vertices of DT, with rapid reaction rate of 359.29 min-1 in comparison with that of 212.60 min-1 for free HCR. DTAAT can be served for in situ imaging of bacteria by confocal laser scanning microscopy and single-cell characterization by flow cytometry. Moreover, using DTAAT as probe, the quantitative analysis of bacteria can be realized with high specificity and anti-interference capa-bility. In a word, the developed DTAAT nanoprobe has a great potential for accurate and sensitive in situ analysis of bacteria.

Automated summary

A new nanoprobe (DTAAT) was designed based on DNA tetrahedron supported hybridization chain reaction (HCR) for in situ analysis of bacteria. By coupling antibody-aptamer conjugate (AA) with DNA tetrahedron (DT) and linking it with trigger strand (A), DTAAT can precisely recognize bacteria through dual binding, releasing a trigger strand complementary to the aptamer. The released trigger strand induces efficient HCR at three vertices of DT using proximity effect, with a reaction rate of 359.29 min-1 compared to 212.60 min-1 for free HCR. DTAAT enables in situ imaging and single-cell characterization of bacteria, with high specificity and anti-interference capability for quantitative analysis.