Multifluidic device and processing system for colorimetric multiplexed detection of a substance
A μPAD may include a paper-based substrate and a non-polar material printed on a surface of the substrate such that a portion the surface is exposed. The exposed portion may include a receiving area, a plurality of test areas, and a plurality of channels disposed between the receiving area and the test areas. The μPAD may further include colorimetric sensors respectively positioned in the test areas. The channel regions may be configured to receive an analyte solution from the receiving area and direct the analyte solution to the colorimetric sensors. A system may perform image processing on captured images of the μPAD to provide multiplexed analysis of analyte solutions applied to the μPAD.
1 . A microfluidic paper-based analytical device (μPAD) comprising:
a paper-based substrate
a non-polar material printed on a surface of the substrate such that a portion the surface is exposed, the exposed portion comprising a receiving area, a plurality of test areas, and a plurality of channels disposed between the receiving area and the test areas; and
a plurality of colorimetric sensors respectively positioned in the test areas, the colorimetric sensors having respective aptamers requiring different saturation times before they are ready for analysis, wherein the channels are configured to receive an analyte solution from the receiving area and direct the analyte solution to the colorimetric sensors,
wherein the receiving area is centrally positioned on the substrate and all of the test areas on the substrate are equidistant from the central receiving area to provide a consistent location for analysis of the test areas,
wherein the widths of each of the channels are not the same and are sized to control a flow velocity of the analyte solution to each test area, such that the analyte solution arrives at each of the respective aptamers at times coordinated with the required saturation time of that aptamer, thereby ensuring that all test areas, despite having the aptamers requiring the different saturation times, reach readiness for analysis simultaneously.
2 . The μPAD of claim 1 , wherein the non-polar material comprises UV curable ink.
3 . The μPAD of claim 1 , wherein the aptamers are configured to change color when in contact with a target substance included in the analyte solution.
4 . The μPAD of claim 3 , wherein the aptamers comprise gold nano-particles.
5 . The μPAD of claim 3 , wherein the aptamers are configured to change color in response to a heavy metal.
6 . The μPAD of claim 5 , wherein the heavy metal comprises Arsenic Mercury, or a combination thereof.
7 . The μPAD of claim 1 , wherein a pixel intensity of the non-polar material is different than a pixel intensity of the substrate.
8 . The μPAD of claim 1 , wherein the colorimetric sensors comprise a first and second colorimetric sensor, wherein the first colorimetric sensor comprises a first aptamer and the second colorimetric sensor comprises a second aptamer, wherein the first aptamer is configured to detect a different substance than the second aptamer.
9 . A method of making a microfluidic paper-based analytical device (μPAD), the method comprising:
printing a non-polar material on a paper substrate in a pattern that leaves a portion of the paper substrate exposed, the exposed portion comprising a receiving area centrally positioned on the substrate, a plurality of test areas, and a plurality of equidistant channels having different widths, the channels extending from the receiving area to the test areas, respectively; and
depositing a plurality of colorimetric sensors on the substrate in the test areas, respectively the colorimetric sensors having aptamers requiring different saturation times before they are ready for analysis,
wherein the differing widths of the channels control flow velocity of an analyte solution so as to coordinate delivery of the analyte solution to the aptamers at times coordinated with the required saturation times of the aptamers, thereby compensating for the different saturation times and providing substantially simultaneous readiness for the analysis of the colorimetric sensors.
10 . The method of claim 9 , wherein the non-polar material comprises UV curable ink, wax, or a combination thereof.
11 . The method of claim 9 , wherein the printing comprising screen printing or inkjet printing.
12 . The method of claim 9 , wherein the aptamers are configured to change color when in contact with a target substance included in the analyte solution.
13 . The method of claim 12 , wherein the aptamers comprise gold nano-particles.
14 . The method of claim 12 , wherein the aptamers are configured to change color in response to a heavy metal.
15 . The method of claim 9 , wherein depositing the colorimetric sensors further comprises:
depositing a first colorimetric sensor in a first test area and a second colorimetric sensor in a second area, wherein the first colorimetric sensor comprises a first aptamer and the second colorimetric sensor comprises a second aptamer, wherein the first aptamer is configured to detect a different substance than the second aptamer.