Enzyme translocators in nanogap with 3' -esters

A system for nucleic acid sequencing comprising:

• at least one device including:
• at least one electrochemical sensor comprising a first electrode, a second electrode, and a dielectric layer defining a sensing zone between the first electrode and the second electrode;
• and a polymerase enzyme attached to the surface of the dielectric layer, wherein the polymerase enzyme targets a polynucleotide strand to the sensing zone;
• and
• a controller configured to:
• direct a first current through the first electrode and a second current through the second electrode to induce electron flow between the first and second electrodes to produce a measurable electrical signal when an electroactive label is present in the sensing zone;
• provide to the at least one device a sample including a polynucleotide strand and at least one modified nucleotide, the modified nucleotide having an electroactive label covalently bound to 3′-OH of a sugar ring of the nucleotide via an ester group;
• and
• detect the first current flowing from the first electrode and the second current flowing from the second electrode.

A method for forming a system for nucleic acid sequencing, the method comprising:

• providing a first electrode and a second electrode;
• positioning a dielectric layer between the first and second electrodes to define a sensing zone;
• attaching a polymerase enzyme to the surface of the dielectric layer, wherein the polymerase enzyme incorporates a modified nucleotide having an electroactive label covalently bound to 3′-OH of a sugar ring of the nucleotide via an ester group into a polynucleotide strand;
• and
• configuring the electrodes to detect a change in current when an electroactive label is present within the sensing zone.