Bio-fet-based peptide sequencing method and device

A biosensor field effect transistor (bio-FET) comprising:

• a source;
• a drain;
• a channel region arranged between the source and the drain, the channel region having a channel region surface;
• an electrolyte gate covering at least the channel region surface;
• a peptide attached to the channel region surface via a base end of the peptide;
• a molecular probe that is attached to an amino acid at a free end of the peptide;
• and
• a charge tag that is linked to the molecular probe,
• wherein a distance between the charge tag and the channel region surface is less than 3 nm.

A biosensor device for sequencing peptides, the biosensor device comprising:

• a bio-FET comprising a source, a drain, a channel region having a channel region surface, and an electrolyte gate covering at least the channel region surface;
• a measurement unit configured to measure a parameter of the bio-FET, wherein the parameter depends on a threshold voltage of the bio-FET;
• a flow controller configured to provide liquid flows to the electrolyte gate;
• and
• a processor,
• wherein the processor is configured to:
• control the flow controller to provide a liquid flow that includes a peptide into the electrolyte gate such that a base end of the peptide attaches to the channel region surface;
• control the measurement unit to obtain a first measurement of the parameter of the bio-FET;
• control the flow controller to provide a liquid flow that includes one or more first molecular probes into the electrolyte gate, wherein each first molecular probe is linked to a respective charge tag;
• control the measurement unit to obtain a second measurement of the parameter of the bio-FET;
• determine whether a shift of the parameter occurred between the first measurement and the second measurement, wherein a shift of the parameter between the first measurement and the second measurement indicates that one of the first molecular probes attached to an amino acid at a free end of the peptide;
• and
• responsive to determining that the shift of the parameter between the first measurement and the second measurement occurred, determine a type of the amino acid at the free end of the peptide based on a type of the first molecular probes.