Blood Sampling Device with Vanadium Salt PLD Inhibitor
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Solution Overview
Problem
The formation of phosphatidylethanol (PEth) post-sampling due to active phospholipase D (PLD) enzyme activity in blood samples leads to erroneous measurements and false interpretations, particularly in dried blood spot sampling, where existing inhibitors like halopemide and FIPI are unsuitable for clinical use due to low potency and high costs.
Innovation Solution
Incorporating salts of vanadium or tungsten, such as sodium metavanadate (NaVO3) or sodium tungstate, as inhibitors of phospholipase D in blood sample collection devices, including test tubes and capillary means, to prevent PEth formation by coating the inner surfaces or using them in a microfluidic device, ensuring effective inhibition without significant cost or potency issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dried blood spot sampling is used for PEth measurement, then sampling convenience and economy are improved, but post-sampling PEth formation occurs due to active PLD enzyme, leading to measurement errors
Solution Approach 1:
The patent applies preliminary action by incorporating PLD inhibitors (halopemide or FIPI) into the blood collection device before blood sampling occurs. This ensures that the enzyme activity is inhibited from the start, preventing post-sampling PEth formation while maintaining the convenience of dried blood spot sampling. The inhibitor is pre-positioned in the collection device to immediately act on the PLD enzyme when blood is introduced.
2Reliability
If halopemide and FIPI are used as PLD inhibitors, then post-sampling PEth formation is prevented, but the costs increase and potency is reduced
Solution Approach 1:
The patent applies the principle of using inexpensive, disposable collection devices containing PLD inhibitors. Instead of using expensive, potent inhibitors that require careful handling and storage, the invention uses affordable inhibitor salts that can be incorporated into disposable blood collection tubes or cards. This makes the inhibitor-containing device economically viable for routine clinical use while maintaining reliable PEth measurement by preventing post-sampling PEth formation.
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
The use of vanadium or tungsten salts effectively blocks the formation of PEth, providing a reliable, economical, and convenient assay for phosphatidylethanol, reducing the risk of false measurements and enabling accurate alcohol consumption monitoring.
Implementation Method 1
at least one inhibitor of the enzyme phospholipase D selected from at least one of a salt of vanadium and a salt of tungsten
Data Source
AI summary
A device configured to collect a blood sample comprising a capillary means, wherein the capillary means is configured to collect and dry the blood sample and comprises an effective amount of a distributed inhibitor of phospholipase D. The device may be configured to receive, transport and collect a blood sample comprising a compartment in fluid connection with the capillary means, wherein the capillary means is configured to collect and dry the blood sample and comprises an effective amount of a distributed PLD inhibitor. The device may be a microfluidic device comprising an inlet portion, an outlet portion comprising a capillary means configured to collect and dry the blood sample, and optionally a metering function, wherein the microfluidic device comprises an effective amount of a distributed PLD inhibitor. The PLD inhibitor is distributed in a water soluble film, preferably a PVA film, or in an absorbent paper or polymer or in the capillary means. The PLD inhibitor may be selected from a salt of a transition metal belonging to column 5 or 6 of the periodic table, a salt of vanadium and a salt of tungsten, a salt comprising a vanadium oxyanion and a salt comprising a tungsten oxyanion, and/or at least one of NaVO3 (sodium metavanadate) and Na2WO4 (sodium tungstate). A method of preparing a sample for analysis of phosphatidylethanol (PEth) comprises providing a blood sample with a volume of less than 10 ml to the device; contacting the blood sample with at least one inhibitor of the enzyme phospholipase D selected from at least one of a salt of vanadium and a salt of tungsten; and admitting inhibition of phospholipase D so formation of PEth is blocked.