Capture and detection of target nucleic acid in dipstick assays

A kit for testing for the presence of a target nucleic acid in a sample solution suspected of containing target nucleic acid which comprises:

• i) a dipstick comprising:
• a chromatographic strip having a contact end for contacting the sample solution;
• and
• a capture probe immobilised at a capture zone of the chromatographic strip remote from the contact end, the capture probe being capable of hybridising to a first sequence of the target nucleic acid;
• ii) a helper probe capable of hybridising to a second sequence of the target nucleic acid and thereby enhancing hybridisation of the capture probe to the target nucleic acid;
• and optionally
• iii) a detection probe capable of attaching to the target nucleic acid to allow direct or indirect detection of the target nucleic acid.

A kit for testing for the presence of a target nucleic acid in a sample solution suspected of containing target nucleic acid which comprises:

• i) a dipstick comprising:
• a chromatographic strip having a contact end for contacting the sample solution;
• and a capture probe immobilised at a capture zone of the chromatographic strip remote from the contact end, the capture probe being capable of hybridising to a first sequence of the target nucleic acid;
• ii) a detection probe capable of hybridising to a second sequence of the target nucleic acid to allow direct or indirect detection of the target nucleic acid;
• and
• iii) a helper probe capable of hybridising to a third sequence of the target nucleic acid and thereby enhancing hybridisation of the detection probe to the second sequence.

A kit for testing for the presence of a target nucleic acid in a sample solution suspected of containing target nucleic acid which comprises:

• i) a dipstick comprising:
• a chromatographic strip having a contact end for contacting the sample solution;
• and a capture moiety immobilised at a capture zone of the chromatographic strip remote from the contact end,
• ii) a capture probe capable of hybridising to a first sequence of the target nucleic acid and which can be bound by the capture moiety when the capture probe has hybridised to the first sequence;
• iii) a helper probe capable of hybridising to a second sequence of the target nucleic acid and thereby enhancing hybridisation of the capture probe to the first sequence;
• and optionally
• iii) a detection probe capable of attaching to the target nucleic acid to allow direct or indirect detection of the target nucleic acid.

A kit for testing for the presence of a target nucleic acid in a sample solution suspected of containing target nucleic acid which comprises:

• i) a dipstick comprising:
• a chromatographic strip having a contact end for contacting the sample solution;
• and a capture moiety immobilised at a capture zone of the chromatographic strip remote from the contact end;
• ii) a capture probe capable of hybridising to a first sequence of the target nucleic acid and which can be bound by the capture moiety when the capture probe has hybridised to the first sequence;
• iii) a detection probe capable of hybridising to a second sequence of the target nucleic acid to allow direct or indirect detection of the target nucleic acid;
• and
• iv) a helper probe capable of hybridising to a third sequence of the target nucleic acid and thereby enhancing hybridisation of the detection probe to the second sequence.

A chromatographic strip for testing for the presence of a target nucleic acid in a sample solution which comprises:

• a contact end for contacting the sample solution;
• a capture moiety immobilised at a capture zone of the chromatographic strip remote from the contact end, the capture moiety being capable of binding a capture probe hybridised to the target nucleic acid;
• a capture probe releasably immobilised to the chromatographic strip between the contact end and the capture zone, the capture probe being capable of hybridising to the target nucleic acid;
• and optionally
• a helper probe releasably immobilised to the chromatographic strip between the contact end and the capture zone, the helper probe being capable of hybridising to the target nucleic acid and thereby enhancing hybridisation of the capture probe to the target nucleic acid.

A chromatographic strip for testing for the presence of a target nucleic acid in a sample solution which comprises:

• a contact end for contacting the sample solution;
• a capture moiety immobilised at a capture zone of the chromatographic strip remote from the contact end, the capture moiety being capable of binding a capture probe hybridised to the target nucleic acid;
• a detection probe releasably immobilised to the chromatographic strip between the contact end and the capture zone, the detection probe being capable of hybridising to the target nucleic acid thereby allowing direct or indirect detection of target nucleic acid utilising the detection probe;
• and optionally:
• i) a capture probe releasably immobilised to the chromatographic strip between the contact end and the capture zone, the capture probe being capable of hybridising to the target nucleic acid and capable of being bound by the capture moiety;
• and/or
• ii) a helper probe capable of hybridising to the target nucleic acid and thereby enhancing hybridisation of the detection probe to the target nucleic acid.