Surfactant Reagent for Selective Small Dense LDL Measurement
Solution Overview
Problem
Conventional methods for measuring small, dense LDLs are inconvenient, time-consuming, and require expensive facilities, with insufficient specificity and accuracy, and often necessitate specimen pretreatment for separation.
Innovation Solution
A method using a specific surfactant concentration with cholesterol esterase and cholesterol oxidase to selectively eliminate other lipoproteins, allowing for direct measurement of small, dense LDLs without pretreatment, utilizing a two-step process to differentiate and quantify cholesterol in small, dense LDLs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (ultracentrifugation, electrophoresis, HPLC) are used to measure small dense LDLs, then measurement accuracy is improved, but device complexity and loss of time increase significantly
Solution Approach 1:
The patent replaces complex mechanical separation systems (ultracentrifugation, electrophoresis, HPLC) with a chemical reaction system using cholesterol esterase, cholesterol oxidase, and surfactants. The enzymatic reaction and optical detection substitute for mechanical separation, achieving accurate measurement of small dense LDL cholesterol without expensive facilities.
Solution Approach 2:
The patent introduces surfactants as intermediaries that selectively interact with different lipoprotein types. The surfactant concentration is controlled to preferentially bind to non-small dense LDLs, allowing enzymatic hydrolysis and detection of small dense LDL cholesterol while excluding other lipoproteins, thus achieving specificity without complex separation equipment.
2Measurement precision
If conventional methods (ultracentrifugation, electrophoresis, HPLC) are used to measure small dense LDLs, then measurement accuracy is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary selective binding of surfactants to non-small dense LDLs before the enzymatic reaction. This pre-separation step occurs automatically as part of the reaction mixture incubation, eliminating the need for separate, time-consuming separation procedures. The surfactant-prepared reaction mixture is then directly applied for enzymatic hydrolysis and detection.
Solution Approach 2:
The patent replaces time-consuming mechanical separation processes with a rapid enzymatic reaction system. The cholesterol esterase and cholesterol oxidase enzymes quickly hydrolyze and oxidize cholesterol in small dense LDLs, with results detected through optical measurement, completing the analysis in minutes rather than hours.
3Ease of operation
If turbidity-based absorbance measurement is used, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent substitutes turbidity-based optical measurement with an enzymatic reaction-based colorimetric method. Cholesterol esterase hydrolyzes cholesterol esters to free cholesterol, which is then oxidized by cholesterol oxidase to produce a colored product detectable at specific wavelengths. This chemical detection method provides higher specificity than turbidity measurement while maintaining operational simplicity.
Solution Approach 2:
The patent utilizes color changes produced by the enzymatic reaction for detection. The cholesterol oxidase reaction generates a colored product (typically through coupling with 4-aminoantipyrine and phenol to form a quinone imine dye) that can be measured spectrophotometrically. This colorimetric detection provides both ease of operation and high measurement precision through specific wavelength detection.
4Measurement precision
If separation procedures are used to isolate small dense LDLs, then measurement precision is improved, but device complexity and loss of time increase
Solution Approach 1:
The patent changes the concentration parameter of surfactants to achieve selective interaction with different lipoprotein types. By optimizing surfactant concentration, the system preferentially binds to non-small dense LDLs while leaving small dense LDLs available for enzymatic reaction. This parameter optimization provides separation-based specificity without requiring complex separation equipment or procedures.
Solution Approach 2:
The patent uses surfactants as intermediary agents that mediate the selective separation of lipoproteins based on their surface properties. The surfactants act as molecular mediators that preferentially associate with certain lipoprotein types, enabling biochemical differentiation and specific detection of small dense LDL cholesterol through subsequent enzymatic reactions.
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 rapid, convenient, and specific measurement of small, dense LDLs cholesterol without separation, improving accuracy and reducing the need for expensive equipment or pretreatment.
Implementation Method 1
a first step of eliminating lipoproteins other than small, dense LDLs in a sample in the presence of 0.9 U/mL to 3.0 U/mL cholesterol esterase
Implementation Method 2
cholesterol oxidase or cholesterol dehydrogenase, the rates of the enzymes' reaction with small, dense LDLs can be changed
Implementation Method 3
This change is accomplished through the use of a specific surfactant at a specific concentration, so that lipoproteins other than small, dense LDLs can be led to the outside of the reaction system
Data Source
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AI summary
A reagent for fractional measurement of small, dense LDLs without pretreatment of a specimen, which is adaptable to a rapid and convenient autoanalyzer, is provided. A method for quantitatively determining cholesterol in small, dense LDLs in a sample is further provided, comprising: a first step of eliminating lipoproteins other than small, dense LDLs in a sample in the presence of cholesterol esterase and 0.05 g/L to 1.0 g/L of a surfactant that acts on the lipoproteins other than small, dense LDLs; and a second step of quantitatively determining cholesterol in small, dense LDLs that remain after the first step.