Systems and methods for detection and quantification of analytes
Devices, systems, and methods for detecting molecules of interest within a collected sample are described herein. In certain embodiments, self-contained sample analysis systems are disclosed, which include a reusable reader component, a disposable cartridge component, and a disposable sample collection component. In some embodiments, the reader component communicates with a remote computing device for the digital transmission of test protocols and test results. In various disclosed embodiments, the systems, components, and methods are configured to identify the presence, absence, and/or quantity of particular nucleic acids, proteins, or other analytes of interest, for example, in order to test for the presence of one or more pathogens or contaminants in a sample.
1. A method for identifying a presence and/or quantity of a target analyte within a sample in a cartridge, the method comprising:
initiating a mixing protocol to form a mixture within a reservoir of the cartridge, wherein the mixture comprises a plurality of magnetic particles each bound directly or indirectly to a respective one of a plurality of agents comprising oxidizing enzymes and/or the target analyte present in the sample;
facilitating movement of the mixture from the reservoir into an analysis channel of the cartridge, wherein the magnetic particles and the agents and/or the target analyte bound thereto localize on a portion of the analysis channel within a magnetic field, forming a localized sample;
facilitating movement of a plurality of substrates into the analysis channel, wherein the oxidizing enzymes of the agents within the localized sample oxidize the substrates;
receiving a signal from an electrochemical sensor, wherein at least a portion of the signal results from the oxidation of the substrates; and
analyzing the signal to identify the presence and/or quantity of the target analyte in the sample.
2. The method of claim 1 , wherein the method is performed by an analyte reader coupled to the cartridge.
3. The method of claim 2 , further comprising detecting identification information associated with the cartridge coupled to the analyte reader; and identifying a protocol appropriate for the cartridge based at least in part on the identification information.
4. The method of claim 2 , wherein the sample is introduced into the reservoir by insertion of a sample collection device into the reservoir of the cartridge, and wherein the method further comprises detecting insertion of the sample collection device into the reservoir.
5. The method of claim 4 , wherein the mixing protocol is initiated upon detecting the insertion of the sample collection device.
6. The method of claim 1 , wherein initiating the mixing protocol comprises stimulating a piezoelectric component in or near the reservoir.
7. The method of claim 1 , wherein the agents comprise at least one of detector agents and competitive binding agents, wherein said competitive binding agents each comprise a target analyte and a signaling agent.
8. The method of claim 7 , wherein:
if the detector agents are provided, the mixture more specifically comprises: a plurality of sandwich complexes each formed of the target analyte bound both to an affinity molecule on a surface of one of the magnetic particles and to one of the detector agents, and/or
if the competitive binding agents are provided, the mixture more specifically comprises: a plurality of molecule complexes each formed of one of the competitive binding agents bound to a affinity molecule on a surface of one of the magnetic particles.
9. The method of claim 1 , wherein facilitating movement of the mixture from the reservoir comprises stimulating a heating element thermally coupled to a valve in an outlet of the reservoir such that the valve undergoes a phase change and the mixture flows from the reservoir into the analysis channel.
10. The method of claim 1 , wherein facilitating movement of the plurality of substrates comprises stimulating a heating element thermally coupled to a valve in an outlet of a substrate-holding reservoir within the cartridge such that the valve undergoes a phase change and the substrates flows from the substrate-holding reservoir into the analysis channel.
11. The method of claim 1 , further comprising stimulating a heating element thermally coupled to a valve in an outlet of a wash-holding reservoir within the cartridge such that the valve undergoes a phase change and a wash solution flows from the wash-holding reservoir into the analysis channel, wherein the wash solution removes, from the localized sample, agents unbound to magnetic particles.
12. The method of claim 7 , wherein:
if the detector agents are present, a quantity of electrons released from the electrochemical sensor is proportional to a quantity of target analyte present within the localized sample, and/or
if the competitive binding agents are present, a quantity of electrons released from the electrochemical sensor is inversely proportional to a quantity of target analyte present within the localized sample.
13. The method of claim 1 , wherein analyzing the signal received from the electrochemical sensor comprises detecting a first signal at a recording electrode of the electrochemical sensor; detecting a second signal comprising noise at a reference electrode of the electrochemical sensor; and calculating a resultant signal by applying an algorithm to remove the second signal from the first signal.
14. The method of claim 1 , further comprising transmitting signals to a mobile computing device, wherein the signals identify the presence and/or quantity of the target analyte in the sample.
15. The method of claim 1 , wherein the magnetic particles comprise at least one or both of: a plurality of larger magnetic particles each having a first affinity molecule on its surface configured to bind to a first target analyte, or a plurality of smaller magnetic particles each having a second affinity molecule on its surface configured to bind to a second target analyte.
16. The method of claim 15 , wherein localizing on the portion of the analysis channel comprises localizing over a plurality of magnetic fields within the portion of the analysis channel, thereby forming a plurality of localized samples, wherein the magnetic particles localize over the magnetic fields based on size and strength such that the larger magnetic particles localize over a smaller upstream magnetic field and a first electrochemical sensor, and the smaller magnetic particles localize over a larger downstream magnetic field and a second electrochemical sensor.
17. The method of claim 16 , wherein analyzing the signal comprises processing and analyzing a signal from the first electrochemical sensor to identify a presence and/or quantity of the first target analyte; and processing and analyzing a signal from the second electrochemical sensor to identify a presence and/or quantity of the second target analyte.
18. The method of claim 11 , wherein an absorbent material at a downstream-most end of the analysis channel absorbs waste liquids.
19. The method of claim 1 , wherein the magnetic field is generated by at least one of a permanent magnet and an electromagnet.
20. The method of claim 19 , wherein the magnetic field comprises a plurality of magnetic fields generated by magnets of varying size or varying distance from the analysis channel.