Ectoine Stabilization of Dehydrogenase in Dry Diagnostic Test Elements
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Solution Overview
Problem
Diagnostic test elements face challenges in maintaining enzymatic activity of sensitive enzymes like dehydrogenases during storage and temperature fluctuations, leading to incorrect test results due to enzyme denaturation and oxidation processes, especially in solvent-free environments.
Innovation Solution
A dry composition comprising a dehydrogenase, redox cofactor, an agent eliciting optical changes in an indicator reagent, and a compatible solute like ectoine or its derivatives, which helps maintain enzymatic activity by reducing the effects of heat and oxidation, is developed. This composition is formulated to be essentially solvent-free, using suitable solvents and drying methods like heat treatment, and includes a carrier for diagnostic test elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enzymes are stored in solvent-free environment to improve stability and prevent microbial growth, then storage safety is improved, but enzyme denaturation and oxidation increase leading to loss of enzymatic activity
Solution Approach 1:
The patent introduces compatible solutes (ectoine, hydroxyectoine, glycine betaine) as intermediary substances that mediate between the solvent-free environment and the enzyme. These compounds form a protective matrix around the enzyme molecules, preventing direct exposure to harmful oxidative conditions while maintaining the solvent-free storage benefits. The compatible solutes act as molecular shields that preserve enzyme structure and function without requiring aqueous environments.
Solution Approach 2:
The patent changes the chemical composition parameters of the storage environment by incorporating specific compatible solutes at optimized concentrations. This parameter modification transforms the harsh solvent-free condition into a benign protective atmosphere that maintains enzymatic activity. The presence of these solutes alters the physical-chemical properties of the storage medium, creating a stable environment that prevents both denaturation and oxidation.
2Reliability
If heat treatment is applied during manufacture or storage to eliminate contaminants, then storage safety is improved, but enzyme denaturation increases reducing overall enzymatic activity
Solution Approach 1:
The patent applies compatible solutes before heat treatment during the manufacturing process. These solutes form a protective cushion around the enzyme molecules, preemptively shielding them from thermal denaturation. When heat treatment is subsequently applied to eliminate contaminants, the enzymes are protected by this pre-established protective layer, allowing sterilization to occur without significant loss of enzymatic activity.
3Device complexity
If batch-wise calibration is used for test elements to simplify manufacturing, then manufacturing complexity is reduced, but individual differences in treatment and storage lead to inaccurate test results
Solution Approach 1:
The patent modifies the storage environment parameters by incorporating compatible solutes, which stabilizes enzymes against variations in treatment and storage conditions. This parameter change reduces the sensitivity of enzymes to environmental fluctuations, thereby minimizing individual differences between batch elements. As a result, batch-wise calibration becomes more accurate because the enzymes exhibit more consistent behavior across different test elements.
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 ectoine or its derivatives in the dry composition significantly preserves enzymatic activity during storage and use, maintaining at least 60% of the original activity even at elevated temperatures, preventing denaturation and aggregation, and does not interfere with the optical detection system.
Implementation Method 1
at least one compatible solute being ectoine or a derivative thereof... which preserves the enzymatic activity of the dehydrogenase under storage conditions and/or temperature fluctuations
Implementation Method 2
essentially solvent-free environment which may promote even such oxidation processes
Data Source
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AI summary
The present invention is concerned with means and methods for maintaining and preserving enzymatic activity. In particular, the invention relates to a dry composition comprising a dehydrogenase, a redox cofactor, an agent capable of eliciting at least one optical change in an optical property of an indicator reagent in the presence of redox equivalents, an indicator reagent, and at least one compatible solute being ectoine or a derivative thereof. The invention further contemplates a diagnostic test element for the determination of an analyte from a body fluid sample and a method for the manufacture of such a test element. Further envisaged by the present invention is the use of at least one compatibie solute as mentioned above for reducing a decrease of the enzymatic activity of at least one enzyme in a composition under dry conditions. Furthermore, contemplated is a method for determining the presence or amount analyte in a body fluid sample based on the test element according to the invention.