Microfluidic Unbound Bilirubin Assay Using Electrowetting and Surfactants
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Solution Overview
Problem
Current technologies for screening newborns for high levels of unbound unconjugated bilirubin are not readily available in point-of-birth testing systems, and existing methods lack specificity and efficiency in detecting this critical condition that can lead to kernicterus.
Innovation Solution
A microfluidics platform using an electrowetting cartridge with a biochemical assay that includes glucose oxidase, peroxidase, and UnaG to oxidize and detect unbound bilirubin, employing surfactants like Tween 80 and Facade-TEM to maintain sample integrity and minimize fluorescence interference, allowing for precise measurement of unbound bilirubin levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oxidative decomposition methods are used to detect unbound bilirubin, then the detection can be performed, but the method lacks specificity for unconjugated bilirubin
Solution Approach 1:
The patent introduces albumin as an intermediary substance that selectively binds unconjugated bilirubin. By adding albumin to the sample, unbound unconjugated bilirubin is captured specifically, while other bilirubin forms remain unaffected. This intermediary approach enables specific detection of unbound unconjugated bilirubin through subsequent oxidative decomposition of the albumin-bilirubin complex.
2Measurement precision
If current screening technologies are used, then bilirubin levels can be measured, but they are not readily available in point-of-birth testing systems
Solution Approach 1:
The patent extracts and isolates the specific detection step for unbound unconjugated bilirubin from complex laboratory-based screening systems. By focusing on a single, specific biochemical reaction (oxidative decomposition of albumin-bound unbound unconjugated bilirubin) that can be performed with minimal equipment, the method enables deployment in point-of-birth settings without requiring full laboratory infrastructure.
Solution Approach 2:
The assay is designed to be self-contained, requiring only the addition of albumin and oxidation reagents to the blood sample. The biochemical reactions proceed automatically without requiring sophisticated instrumentation or complex operational procedures, enabling ease of use in point-of-birth testing by personnel with minimal training.
3Loss of time
If rapid screening is performed to enable timely intervention, then kernicterus risk can be reduced, but measurement accuracy may be compromised
Solution Approach 1:
The patent performs preliminary binding of unbound unconjugated bilirubin to albumin before the oxidative decomposition step. This preliminary action stabilizes the target analyte and ensures that only unbound unconjugated bilirubin is captured and subsequently measured. The pre-established albumin-bilirubin complex provides a stable basis for accurate and rapid measurement, eliminating the need for lengthy sample preparation or equilibration periods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and efficient point-of-birth screening for unbound bilirubin, reducing the risk of kernicterus by providing a reliable and specific method for detecting unbound bilirubin levels in newborns, thus facilitating timely intervention.
Implementation Method 1
an oxidative decomposition reaction can be used to oxidize unbound bilirubin and the rate of absorbance loss is then used to determine how much unbound bilirubin is in a sample
Implementation Method 2
a fluorescence-based method for detecting unconjugated bilirubin using a protein, UnaG, that is specific for unconjugated bilirubin
Implementation Method 3
The loading, combining, dispensing, and/or initiating may be performed using electrowetting-mediated droplet operations
Implementation Method 4
combining the blood sample with a buffer reagent having a surfactant to provide a diluted blood sample, wherein the surfactant may, for example, be selected to permit electrowetting to conduct droplet operations
Data Source
AI summary
A method for assaying analytes in a blood sample by loading a blood sample onto a microfluidic device; combining the blood sample with a buffer reagent comprising a surfactant to provide a diluted blood sample and conduct an assay. The surfactant is selected to permit the use of electrowetting to conduct droplet operations using the blood sample and to permit the use of a fluorescence-based droplet operation. The assay may be an unbound bilirubin assay.