Biomolecule measurement system and biomolecule measurement method
To introduce a biomolecule into a nanopore without the need to check the position of the nanopore in a thin film. In addition, displacement stability is ensured and stable acquisition of blocking signals is realized. An immobilization member 107 having a larger size than a thin film 113 with a nanopore 112 is used, and biomolecules are immobilized on the biomolecule immobilization member 107 at a density that allows at least one biomolecule 108 to enter an electric field region around the nanopore when the biomolecule immobilization member 107 has moved close to a nanopore device 101.
1. A biomolecule measurement method comprising:
a step of applying a voltage across a thin film with a nanopore disposed in an electrolytic solution via the nanopore, thereby generating an electric field around the nanopore, the thin film having a first exposed surface with the nanopore to be exposed to the electrolytic solution;
a step of driving a biomolecule-immobilized member in the electrolytic solution in a direction toward the thin film, the biomolecule-immobilized member having a biomolecule-immobilized region facing the first exposed surface of the thin film with the nanopore, the biomolecule-immobilized region having a surface area with a larger size than a surface area of the first exposed surface of the thin film, and having a lower surface with a plurality of biomolecules immobilized thereon;
providing a stopper disposed between the biomolecule-immobilized member and the first exposed surface of the thin film, the stopper covering an unexposed surface of the thin film surrounding the first exposed surface of the thin film to provide a space between the first exposed surface of the thin film and the biomolecule-immobilized region of the biomolecule-immobilized member, the stopper having an opening to allow the first exposed surface of the thin film to be exposed to the biomolecule-immobilized region of the biomolecule-immobilized member;
a step of stopping drive of the biomolecule-immobilized member when the biomolecule-immobilized member has moved to a predetermined distance from the thin film, by contacting the stopper;
a step of confirming that one of the biomolecules on the biomolecule-immobilized member has entered the nanopore from monitoring a change in an ion current that flows through the nanopore;
a step of measuring the ion current while driving the biomolecule-immobilized member in a direction away from the thin film; and
a step of acquiring information from the measured ion current to identify a molecule that forms the biomolecule.
2. The biomolecule measurement method according to claim 1 , further comprising:
a step of detecting that the biomolecule has come out of the nanopore from a change in the ion current value when driving the biomolecule-immobilized member in a direction away from the thin film;
a step of stopping drive of the biomolecule-immobilized member upon detecting that the biomolecule has come out of the nanopore; and
repeatedly performing a step of measuring the ion current while driving the biomolecule-immobilized member in a direction toward the thin film and a step of measuring the ion current while driving the biomolecule-immobilized member in a direction away from the thin film, thereby acquiring information to identify a molecule that forms the biomolecule from the ion current measured in each step.
3. The biomolecule measurement method according to claim 1 , wherein:
a plurality of thin films each having a nanopore is prepared, and
an ion current that flows through each of the plurality of nanopores is independently measured to identify a molecule that forms each of the plurality of biomolecules.