Abstract: Techniques for replacing nanopores within a nanopore based sequencing chip are provided. A first electrolyte solution is added to the external reservoir of the sequencing chip, introducing an osmotic imbalance between the reservoir and the well chamber located on the opposite side of a lipid bilayer membrane. The osmotic imbalance causes the membrane to change shape, and a nanopore within the membrane to be ejected. A second electrolyte solution is then added to the external reservoir to provide replacement nanopores and to restore the membrane shape. The replacement nanopores can be inserted into the membrane, effectively replacing the initial pore without causing the destruction of the membrane.

Abstract: Systems and methods for inserting a single pore into a membrane are described herein. A stepped or ramped voltage waveform can be applied across the membranes of the cells of an array, where the voltage waveform starts at first voltage and increases in magnitude over a period of time to a second voltage. The first voltage is selected to be low enough to reduce the risk of damaging the membrane, while the rate of voltage increase is selected to provide sufficient time for the pores to insert into the membranes. Once a pore is inserted into the membrane, the voltage across the membrane rapidly drops, thereby reducing the risk of damaging the membrane even if the applied voltage between the electrodes is further increased.

Abstract: Systems and methods for inserting a single pore into a membrane are described herein. A stepped or ramped voltage waveform can be applied across the membranes of the cells of an array, where the voltage waveform starts at first voltage and increases in magnitude over a period of time to a second voltage. The first voltage is selected to be low enough to reduce the risk of damaging the membrane, while the rate of voltage increase is selected to provide sufficient time for the pores to insert into the membranes. Once a pore is inserted into the membrane, the voltage across the membrane rapidly drops, thereby reducing the risk of damaging the membrane even if the applied voltage between the electrodes is further increased.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.

Abstract: Systems and methods for inserting a single pore into a membrane under faradaic conditions are described herein. A stepped or ramped voltage waveform can be applied across the membranes of the cells of an array, where the voltage waveform starts at first voltage and increases in magnitude over a period of time to a second voltage. The voltage waveform has a polarity that maintains a first species of a redox couple in its current oxidation state. The first voltage is selected to be low enough to reduce the risk of damaging the membrane, while the rate of voltage increase is selected to provide sufficient time for the pores to insert into the membranes. Once a pore is inserted into the membrane, the voltage across the membrane rapidly drops, thereby reducing the risk of damaging the membrane even if the applied voltage between the electrodes is further increased.

Abstract: Systems and methods for inserting a single pore into a membrane are described herein. A stepped or ramped voltage waveform can be applied across the membranes of the cells of an array, where the voltage waveform starts at first voltage and increases in magnitude over a period of time to a second voltage. The first voltage is selected to be low enough to reduce the risk of damaging the membrane, while the rate of voltage increase is selected to provide sufficient time for the pores to insert into the membranes. Once a pore is inserted into the membrane, the voltage across the membrane rapidly drops, thereby reducing the risk of damaging the membrane even if the applied voltage between the electrodes is further increased.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.

Abstract: Techniques for replacing nanopores within a nanopore based sequencing chip are provided. A first electrolyte solution is added to the external reservoir of the sequencing chip, introducing an osmotic imbalance between the reservoir and the well chamber located on the opposite side of a lipid bilayer membrane. The osmotic imbalance causes the membrane to change shape, and a nanopore within the membrane to be ejected. A second electrolyte solution is then added to the external reservoir to provide replacement nanopores and to restore the membrane shape. The replacement nanopores can be inserted into the membrane, effectively replacing the initial pore without causing the destruction of the membrane.

Abstract: A method is provided for preparing nanopore sequencing complexes in membranes for sequencing of polymers, e.g., polynucleotides and polypeptides. The nanopore sequencing complex is formed by the sequential linking of an enzyme to a nanopore that is inserted in a membrane, and of a polymer to the enzyme. Alternatively, the nanopore sequencing complex is formed by linking a preformed enzyme-polymer complex to a nanopore that is inserted in a membrane. The enzyme polymer complex is interchangeable.

Abstract: The present disclosure provides variant OmpG polypeptides, compositions comprising the OmpG variant polypeptides, and methods for using the variant OmpG polypeptides as nanopores for determining the sequence of single stranded nucleic acids. The variant OmpG nanopores reduce the ionic current noise versus the parental OmpG polypeptide from which they are derived and thereby enable sequencing of polynucleotides with single nucleotide resolution. The reduced ionic current noise also provides for the use of these OmpG nanopore variants in other single molecule sensing applications, e.g., protein sequencing.