Systems and methods for sensing analytes in GMR-based detection of biomarkers
Methods of, inter alia, detecting the presence of one or more analytes in one or more query samples include providing one or more sensor that each include biomolecules disposed on a functionalized surface of one or more giant magnetoresistance (GMR) sensors. Modes of operation remove or add magnetic beads from the vicinity of sensor surfaces by interactions with the biomolecules. The methods feature, inter alia, detecting the presence of one or more analytes in one or more query samples by measuring magnetoresistance change of the one or more GMR sensors based on determining magnetoresistance before and after passing magnetic particles over the one or more sensors.
1 . A method of amplifying a detection signal for detecting the presence of an analyte in a query sample, the method comprising:
(a) providing a sensor comprising double stranded DNA molecules disposed on a functionalized surface of a giant magnetoresistance (GMR) sensor, the double stranded DNA molecules comprising a first nucleic acid and a second nucleic acid bound to the first nucleic acid and being bound to a first member of a binding pair,
(b) passing the query sample over the sensor,
(c) passing a plurality of magnetic particles over the sensor after passing the query sample over the sensor, and
(d) detecting the presence of the analyte in the query sample by measuring magnetoresistance change of the GMR sensor based on determining magnetoresistance before and after passing the plurality of magnetic particles over the sensor, wherein determining magnetoresistance change of the GMR sensor comprises using at least one reference resistor to perform phase-sensitive solution of magnetoresistance change of the GMR sensor, thereby amplifying the detection signal.
2 . The method of amplifying a detection signal for detecting the presence of an analyte in a query sample according to claim 1 , wherein:
(a) the second nucleic acid comprises: a removable portion covalently bound to the second nucleic acid, removal of the removable portion being actualized by the presence of the analyte in the query sample; and the first member of the binding pair is coupled with the removable portion of the second nucleic acid, the first member of the binding pair being capable of binding a second member of the binding pair that comprises a magnetic nanoparticle; and
(b) passing the query sample over the sensor allows removal of the removable portion with the first member of the binding pair from the second nucleic acid if the analyte is present.
3 . The method of amplifying a detection signal for detecting the presence of an analyte in a query sample according to claim 1 , wherein:
(a) the second nucleic acid comprises: a protein binding portion that binds a protein at a protein binding site, the protein further comprising a portion separate from the protein binding site configured to bind the first member of the binding pair; and
(b) wherein the protein binding site of the protein binds the analyte if present in the query sample, thereby preventing binding of the protein to the protein binding portion of the second nucleic acid.
4 . The method of amplifying a detection signal for detecting the presence of an analyte in a query sample according to claim 3 , wherein:
the first member of the binding pair includes biotin; and
a second member of the binding pair includes streptavidin.
5 . The method of amplifying a detection signal for detecting the presence of an analyte in a query sample according to claim 3 , wherein:
the first member of the binding pair includes glutathione S-transferase; and
a second member of the binding pair includes glutathione.
6 . The method of amplifying a detection signal for detecting the presence of an analyte in a query sample according to claim 5 comprising:
before contacting the sensor with the plurality of magnetic particles, contacting the sensor with a secondary reagent that includes the second member of the binding pair and a first additional member of an additional binding pair;
wherein a second additional member of the additional binding pair includes a magnetic particle.
7 . The method according to claim 1 , wherein the first member of the binding pair comprises biotin and a second member of the binding pair comprises streptavidin.
8 . The method according to claim 1 , wherein the magnetoresistance change of the GMR sensor comprises an amplified magnetoresistance change.
9 . The method according to claim 1 , wherein the analyte comprises one or more heavy metals.
10 . The method according to claim 9 , wherein the one or more heavy metals include at least one of mercury, cadmium, lead, or arsenic.
11 . A method of detecting the presence of one or more analytes in one or more query samples in a multiplex detection scheme, the method comprising:
(a) providing at least two spatially disposed giant magnetoresistance (GMR) sensors, wherein at least two of the GMR sensors comprise a first GMR sensor with a first number of double-stranded DNA molecules disposed on a functionalized surface of the first GMR sensor and a second GMR sensor with a second number of double-stranded DNA molecules disposed on a functionalized surface of the second GMR sensor, wherein:
the first number of double-stranded DNA molecules includes a first nucleic acid and a second nucleic acid bound to the first nucleic acid and being bound to a first member of a first binding pair; and
the second number of double-stranded DNA molecules includes a first additional nucleic acid and a second additional nucleic acid bound to the first additional nucleic acid and being bound to a first additional member of a second binding pair different from the first binding pair;
(b) passing magnetic particles over the at least two GMR sensors after passing the one or more query samples over the at least two GMR sensors; and
(c) detecting the presence of at least one of the one or more analytes in the one or more query samples by measuring magnetoresistance change of at least one of the at least two GMR sensors based on determining magnetoresistance before and after passing magnetic particles over the at least two GMR sensors.
12 . The method of detecting the presence of one or more analytes in one or more query samples in a multiplex detection scheme according to claim 11 , wherein:
(a) individual second nucleic acids and second additional nucleic acids comprise: a removable portion covalently bound to the individual second nucleic acids or the second additional nucleic acids, removal being actualized by the presence of at least one of the one or more analytes in the one or more query samples; and the first member of the first binding pair and the first additional member of the second binding pair being capable of binding a magnetic nanoparticle; and
(b) passing the one or more query samples over the at least two GMR sensors allows removal of the removable portion with the first member of the first binding pair or the first additional member of the second binding pair from one or more second nucleic acids or one or more second additional nucleic acids if at least one of the one or more analytes is present.
13 . The method of detecting the presence of one or more analytes in one or more query samples in a multiplex detection scheme according to claim 11 , wherein:
(a) the second nucleic acid and the second additional nucleic acid comprises: a portion that binds protein at a protein binding site, the protein further comprising a portion separate from the protein binding site configured to bind the first member of the first binding pair or the first additional member of the second binding pair; and
(b) the one or more query samples are passed as a mixture with the protein over the at least two GMR sensors, wherein the protein binding site of the protein binds the one or more analytes if present in the one or more query samples, thereby preventing binding of the protein to the protein binding site of the second nucleic acid or the second additional nucleic acid.
14 . The method of detecting the presence of one or more analytes in one or more query samples in a multiplex detection scheme according to claim 13 , wherein:
the first member of the first binding pair includes a first metalloregulatory repressor protein;
a second member of the first binding pair includes a first substance that binds to the first metalloregulatory repressor protein;
the first additional member of the second binding pair includes a second metalloregulatory repressor protein; and
a second additional member of the second binding pair includes a second substance that binds to the second metalloregulatory repressor protein.
15 . The method according to claim 11 , wherein the at least two spatially disposed GMR sensors are disposed in a channel of a GMR sensor chip, wherein the GMR sensor chip comprises at least one channel.
16 . The method according to claim 11 , wherein the at least two spatially disposed GMR sensors are disposed in a channel of a GMR sensor chip, wherein the GMR sensor chip comprises a plurality of channels or the least two spatially disposed GMR sensors are each disposed different channels of a GMR sensor chip, wherein the GMR sensor chip comprises a plurality of channels.
17 . The method according to claim 14 , wherein the first metalloregulatory repressor protein includes glutathione S-transferase and the second metalloregulatory repressor protein include a poly-histidine.
18 . The method according to claim 11 , wherein at least one of the one or more analytes includes a heavy metal.
19 . The method according to claim 18 , wherein the heavy metal includes mercury, cadmium, lead, or arsenic.
20 . A method of amplifying a detection signal for detecting the presence of an analyte in a query sample, the method comprising:
providing a sensor comprising double stranded DNA molecules disposed on a functionalized surface of a giant magnetoresistance (GMR) sensor, the double stranded DNA molecules comprising a first nucleic acid and a second nucleic acid bound to the first nucleic acid and being configured to bind a detection protein, the detection protein also being capable of binding the analyte,
passing the detection protein over the sensor;
passing the query sample over the sensor,
passing a reporter protein over the sensor after passing the query sample over the sensor, the reporter protein capable of binding the detection protein and the reporter protein configured to bind to magnetic nanoparticles;
passing a plurality of magnetic particles comprising a first member of a binding pair over the sensor after passing the query sample over the sensor, then passing a plurality of magnetic particles comprising a second member of the binding pair over the sensor; and
detecting the presence of the analyte by measuring amplified magnetoresistance change of the GMR sensor based on determining magnetoresistance before and after passing magnetic particles over the sensor; thereby amplifying the detection signal.