Nucleic acid probe, chemical sensor, and detection method

A nucleic acid probe, comprising:

• a first nucleic acid including a binding site, the binding site being configured to trap a target substance;
• and
• a second nucleic acid configured to pair with a portion of the first nucleic acid,
• the first nucleic acid including
• a first base sequence,
• a second base sequence bound to the first base sequence,
• a third base sequence bound to the second base sequence,
• a fourth base sequence that is complimentary to the third base sequence,
• a fifth base sequence that is complimentary to the second base sequence,
• a sixth base sequence bound to the fifth base sequence, and
• a seventh base sequence that is complimentary to the sixth base sequence,
• the binding site being positioned at least between the fourth base sequence and the seventh base sequence,
• the second nucleic acid including an eighth base sequence,
• the eighth base sequence being complimentary with at least a portion of the first base sequence and at least a portion of the second base sequence,
• a number of bases of the eighth base sequence being more than a number of bases of the second base sequence.