Which of the following is used to detect captured hybrids in hybrid capture assays?

The use of alkaline phosphatase-conjugated secondary antibodies in hybrid capture assays is an effective method for detecting captured hybrids. In these assays, a target nucleic acid sequence is hybridized to a complementary probe that is typically bound to a solid surface. Once the hybridization occurs, the alkaline phosphatase-conjugated secondary antibodies attach to this complex. The enzyme's activity enables the visualization of the hybrids through the catalysis of a substrate reaction that produces a detectable signal, often involving a colorimetric or chemiluminescent output. This method provides high specificity and sensitivity, allowing for clear identification of the target nucleic acids.

Other detection methods, such as fluorescent probes, while useful in various molecular assays, are not the primary means of detection in hybrid capture assays specifically, where enzyme-linked secondary antibodies provide a more robust signal. Gold nanoparticles are more commonly associated with imaging techniques and may not directly apply to hybrid capture formats. Polymerase enzymes are crucial in amplification processes but do not play a role in the detection phase of captured hybrids in these assays. Thus, the use of alkaline phosphatase-conjugated secondary antibodies aligns directly with the operational needs of hybrid capture assays.