Multiplexer Point of Care device
Publication Date: 2014-Aug-25
The IP.com Prior Art Database
Disclosed is a method to store functionalized microbeads in a small sample of dissolvable gel within a microfluidic Point of Care (PoC) device. This method enables the deposition and containment of the beads at the desired location inside the microfluidic device in order to reduce damage and prevent contamination during fabrication and shipping.
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Multiplexer Point of Care device
Immunoassays using very specific antibodies in combination with a label are a common application of Point of Care (PoC) devices for medical treatment. Positive diagnostics occur when biological reaction binding of Antibody - antigen - antibody+marker group occurs. Fluorescent dyes are often used as markers to perform the diagnosis , but alternative detection methods exist (e.g., Colorimetric, Magnetic, Impedance changes). Point of Care devices are also often built to execute a single immunoassay analysis and are not able to execute more than one disease /protein/marker detection at the same time.
PoC devices often integrate the reagents involved in the immunoassay within the device by functionalizing with said reagents certain surface areas within the path of the biological sample. This functionalization often involves immobilizing reagents to the surface of the device (for instance, to the transparent cover) during the manufacturing process, posing stringent demands to the surface chemistry for the antibodies to bond easily and remain immobilized. Microchannels need to be very shallow to allow interaction of reagents with the biological sample. Reaction time is still limited by fluid speed as it flows along the functionalized area, which is a strong function of the geometry, often leading to inefficient use of all reagents . Deposition of antibodies on the device cover surface also requires micrometer precision. This also poses stringent demands on the manufacturing process, limiting the maximum temperature that can be used during bonding, reducing device lifetime to biological reagents' lifetime, increasing demands for sealing and vacuum conditions of final commercial device , and increasing the difficulty and cost for multiplexing of various reagents within same device .
To improve flexibility of the device while performing the immunoassay within the microfluidic device, current methods use microbeads or microspheres with the surfaces functionalized with reagents (instead of functionalizing the device surface), which can then flow with the fluid along the microchannels.
Despite the benefits the microbeads provide during manufacturing processes , depositing and containing the beads at the desired location inside the microfluidic device during fabrication and shipping is a challenge. A mechanism for trapping the beads at a desired location within the microchannels is necessary to prevent free movement of the beads within the microchannels while the device is not being used (e.g., during shipping). Without a good method to contain the beads until operation by the user, multiplexing of various tests on one single chip is also difficult due to the risk of cross-contamination. In addition, without a protection mechanism, antibodies on the bead surface within the microchannel can still be degraded during the fabrication and sealing process and exposure to high temperatures.
The novel contribution is a...