System and method for magnetically concentrating and detecting biomarkers

1. A method for concentrating a non-magnetic particle in a liquid, comprising:

(a) applying a magnetic field to a mixture comprising a co-aggregate in a liquid to provide a collected co-aggregate in the liquid, wherein the co-aggregate comprises:

(i) a magnetic particle having a stimuli-responsive polymer attached thereto; and

(ii) a non-magnetic particle having a stimuli-responsive polymer attached thereto;

wherein the non-magnetic particle further comprises a first binding partner of a binding pair, wherein the liquid comprises a second binding partner of the binding pair, and wherein the co-aggregate comprises a non-magnetic particle having the first and second binding partners attached thereto;

(b) removing at least a portion of the liquid from the collected co-aggregate in the liquid;

(c) re-dissolving the co-aggregate to provide a mixture comprising the magnetic particle having the stimuli-responsive polymer attached thereto and the non-magnetic particle having the stimuli-responsive polymer and first and second binding partners attached thereto; and

(d) contacting the mixture comprising the magnetic particle having the stimuli-responsive polymer attached thereto and the non-magnetic particle having the stimuli-responsive polymer and first and second binding partners attached thereto with a solid phase effective to immobilize the non-magnetic particle having the stimuli-responsive polymer and first and second binding partners attached thereto.

2. The method of claim 1 , wherein the co-aggregate further comprises free stimuli-responsive polymer.

3. A method for capturing a diagnostic target in a liquid medium, comprising:

(a) contacting a liquid medium to be tested for the presence of a diagnostic target with a plurality of stimuli-responsive particles, wherein the plurality of stimuli-responsive particles comprises

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto, and

(ii) a plurality of non-magnetic particles, each having a stimuli-responsive polymer and a capture moiety attached thereto, wherein the capture moiety has an affinity to the diagnostic target,

wherein the plurality of stimuli-responsive particles is contacted with the liquid medium for a pre-determined period of time sufficient to effect binding of the diagnostic target, if present, to a portion of the plurality of the non-magnetic particles; and

wherein the liquid medium to be tested comprises a first and a second diagnostic target and the plurality of non-magnetic particles comprises

(i) a plurality of first non-magnetic particles, each having a stimuli-responsive polymer and a first capture moiety attached thereto, wherein the first capture moiety has an affinity to the first diagnostic target, and

(ii) a plurality of second non-magnetic particles, each having a stimuli-responsive polymer and a second capture moiety attached thereto, wherein the second capture moiety has an affinity to the second diagnostic target;

(b) applying an external stimulus to provide a co-aggregate in the liquid medium, wherein the co-aggregate comprises

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto, and

(ii) a plurality of non-magnetic particles, each having a stimuli-responsive polymer thereto, wherein at least a portion of the plurality of non-magnetic particles have the diagnostic target attached thereto when the diagnostic target is present in the liquid medium, and

wherein the co-aggregate is formed by the association of the stimuli-responsive polymer attached to the magnetic particle to the stimuli-responsive polymer attached to the non-magnetic particle;

(c) subjecting the co-aggregate to a magnetic field to magnetophorese the co-aggregate to a site within the liquid medium to provide a magnetophoresced co-aggregate in the liquid medium;

(d) removing at least portion of the liquid medium from the liquid medium comprising the magnetophoresced co-aggregate to provide the co-aggregate and optionally residual liquid medium;

(e) removing the stimulus and the magnetic field to provide a mixture comprising

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto,

(ii) a plurality of non-magnetic particles, each having a stimuli-responsive polymer thereto, wherein at least a portion of the plurality of non-magnetic particles have the diagnostic target attached thereto when the diagnostic target is present in the liquid medium, and

(iii) optionally residual liquid medium; and

(f) contacting the mixture with a solid phase to immobilize at least a portion of the first plurality of non-magnetic particles having the first diagnostic target attached thereto and to immobilize at least a portion of the second plurality of non-magnetic particles having the second diagnostic target attached thereto.

4. The method of claim 3 further comprising contacting the mixture with a solid phase to immobilize at least a portion of the plurality of non-magnetic particles having the diagnostic target attached thereto.

5. The method of claim 3 , wherein the diagnostic target is an antigen and the capture moiety is an antibody.

6. The method of claim 3 , wherein the diagnostic target is a biomarker for a disease or disorder.

7. The method of claim 3 , wherein the non-magnetic particles having the first diagnostic target attached thereto are immobilized on the solid phase at a first position and the non-magnetic particles having the second diagnostic target attached thereto are immobilized on the solid phase at a second position, wherein the first and second positions are not the same.

8. A method for capturing a diagnostic target in a liquid medium, comprising:

(a) contacting a liquid medium to be tested for the presence of a diagnostic target with a first binding partner having an affinity to the diagnostic target and plurality of stimuli-responsive particles, wherein the plurality of stimuli-responsive particles comprises

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto, and

(ii) a plurality of non-magnetic particles, each having a stimuli-responsive polymer and a second binding partner attached thereto, wherein the second binding partner has an affinity to the first binding partner,

wherein the plurality of stimuli-responsive particles is contacted with the liquid medium for a pre-determined period of time sufficient to effect binding of the diagnostic target, if present, to a portion of the plurality of non-magnetic particles through the association of the first and second binding partners;

(b) applying an external stimulus to provide a co-aggregate in the liquid medium, wherein the co-aggregate comprises

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto, and

(ii) a plurality of non-magnetic particles, each having a stimuli-responsive polymer thereto, wherein at least a portion of the plurality of non-magnetic particles have the diagnostic target attached thereto when the diagnostic target is present in the liquid medium, and

wherein the co-aggregate is formed by the association of the stimuli-responsive polymer attached to the magnetic particle to the stimuli-responsive polymer attached to the non-magnetic particle;

(c) subjecting the co-aggregate to a magnetic field to magnetophorese the co-aggregate to a site within the liquid medium to provide a magnetophoresced co-aggregate in the liquid medium;

(d) removing at least portion of the liquid medium from the liquid medium comprising the magnetophoresced co-aggregate to provide the co-aggregate and optionally residual liquid medium;

(e) removing the stimulus and the magnetic field to provide a mixture comprising

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto,

(ii) a plurality of non-magnetic particles, each having a stimuli-responsive polymer thereto, wherein at least a portion of the plurality of non-magnetic particles have the diagnostic target attached thereto when the diagnostic target is present in the liquid medium, and

(iii) optionally residual liquid medium; and

(f) contacting the mixture with a solid phase to immobilize at least a portion of the plurality of non-magnetic particles have the diagnostic target attached thereto.

9. The method of claim 8 , wherein the liquid medium to be tested for a diagnostic target is to be tested for first and second diagnostic targets,

wherein contacting the liquid medium comprises contacting with a first binding partner having an affinity to the first diagnostic target, a third binding partner having an affinity to the second diagnostic target, and plurality of stimuli-responsive particles, wherein the plurality of stimuli-responsive particles comprises

(i) a plurality of magnetic particles, each having a stimuli-responsive polymer attached thereto,

(ii) a plurality of first non-magnetic particles, each having a stimuli-responsive polymer and a second binding partner attached thereto, wherein the second binding partner has an affinity to the first binding partner, and

(iii) a plurality of second non-magnetic particles, each having a stimuli-responsive polymer and a fourth binding partner attached thereto, wherein the fourth binding partner has an affinity to the third binding partner,

wherein the plurality of stimuli-responsive particles is contacted with the liquid medium for a pre-determined period of time sufficient to effect binding of the first and second diagnostic targets, if present, to a portion of the pluralities of the first and second non-magnetic particles through the association of the first and second, and third and fourth binding partners, respectively.

10. The method of claim 9 further comprising contacting the mixture with a solid phase to immobilize at least a portion of the plurality of first non-magnetic particles having the first diagnostic target attached thereto and to immobilize at least a portion of the plurality of second non-magnetic particles having the second diagnostic target attached thereto.

11. The method of claim 10 , wherein the non-magnetic particles having the first diagnostic target attached thereto are immobilized on the solid phase at a first position and the non-magnetic particles having the second diagnostic target attached thereto are immobilized on the solid phase at a second position, wherein the first and second positions are not the same.