Method and system for multiplexed detection of one or more alleles in a sample

A method for detecting the presence of a cytochrome P450 allele of interest in a sample, the method comprising the steps of:

• a) providing an immobilized capture probe on a support, the immobilized capture probe comprising a first nucleotide capture sequence, the first nucleotide capture sequence designed to hybridize specifically with a first portion of a cytochrome P450 allele of interest;
• b) exposing the immobilized capture probe to a sample and removing any non-specific binding, whereby, if the sample contains the cytochrome P450 allele of interest, the first portion of the cytochrome P450 allele of interest specifically hybridizes to the first nucleotide sequence whereas, if the sample does not contain the cytochrome P450 allele of interest, nothing specifically hybridizes to the first nucleotide sequence;
• c) exposing the immobilized capture probe, and any cytochrome P450 allele of interest bound thereto, to a first initiator and removing any non-specific binding, wherein a first portion of the first initiator is designed to hybridize specifically to the cytochrome P450 allele of interest;
• d) exposing the immobilized capture probe, and any first initiator bound thereto, to first and second hairpin molecules and removing any non-specific binding, wherein the first and second hairpin molecules are designed to undergo a hybridization chain reaction when actuated by the first initiator, and wherein at least one of the first and second hairpin molecules is coupled to a tag;
• and
• e) determining the presence of the tag.

A system for use in electrochemically detecting an allele of interest in a sample, the system comprising:

• (a) a cartridge assembly, the cartridge assembly comprising
• (i) a cartridge, the cartridge comprising one or more wells and further comprising a corresponding electrochemical sensing element associated with each of the one or more wells, and
• (ii) a cover, the cover being removably mounted on the cartridge, the cover being shaped to include one or more fluid conduits in fluid communication with the one or more wells;
• and
• (b) a reader for electrochemically detecting the presence of an analyte of interest in each of the one or more wells, the analyte of interest being indicative of the presence of the allele of interest, the reader comprising
• (i) a potentiostat;
• (ii) one or more electrical connectors for electrically connecting the one or more electrochemical sensing elements to the potentiostat;
• (iii) a control unit operably coupled to the potentiostat for operating the potentiostat and for analyzing signals generated by the potentiostat;
• (iv) an output device operably coupled to the control unit for outputting results of analysis performed by the control unit;
• (v) a pump, the pump being operably coupled to the control unit;
• (vi) one or more fluid connectors operably coupled to the one or more fluid conduits in the cover and to the pump;
• (vii) a fluid waste receptacle operably coupled to the pump for receiving fluid removed from the one or more wells by the pump;
• and
• (viii) a power supply.