Selenocystine Cell Uptake Evaluation via Fluorescence
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Solution Overview
Problem
Current methods for evaluating cystine uptake ability in cells are affected by fluorescent labels, require expensive and complex radioisotope use, or are indirect and lack accuracy, particularly in measuring glutamic acid release.
Innovation Solution
A method involving contacting cells with selenocystine, washing, and determining selenocystine in the cytoplasm using a reducing agent and fluorescent dye that reacts with selenocysteine to change fluorescence intensity, allowing for accurate and cost-effective cystine uptake evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fluorescence-labeled cystine derivative is used to evaluate cystine uptake ability, then the uptake can be visually detected, but the fluorescent label affects the uptake process and reduces measurement accuracy
Solution Approach 1:
The patent uses selenocystine as an intermediary substance that mimics cystine uptake without being affected by the same interference issues. Selenocystine serves as a mediator to evaluate cystine transporter activity indirectly, avoiding the harmful interaction between fluorescent labels and the uptake process while still enabling detection through fluorescence measurement of the selenocystine derivative inside cells
Solution Approach 2:
The patent creates a copy of the cystine uptake evaluation system by using selenocystine instead of cystine. This copy allows the same evaluation purpose to be achieved without the harmful effects of fluorescent labels on the original system, maintaining measurement accuracy while enabling visual detection
2Measurement precision
If a radioisotope-labeled cystine is used to evaluate cystine uptake ability, then the uptake measurement is accurate, but the operation becomes complicated and requires regulated radioisotope handling
Solution Approach 1:
The patent replaces expensive and regulated radioisotopes with a stable fluorescent dye-labeled selenocystine derivative that can be easily handled without special regulations. This disposable-like approach uses readily available fluorescent dyes instead of costly radioisotopes, simplifying operations while maintaining measurement capability
Solution Approach 2:
The patent substitutes the radioisotope-based measurement system with a fluorescence-based measurement system. This replacement eliminates the need for complex radioisotope handling procedures, special equipment, and regulated operations, while providing equivalent or superior detection sensitivity through fluorescence measurement
3Measurement precision
If a stable isotope-labeled cystine is used to evaluate cystine uptake ability, then the uptake can be accurately measured, but expensive mass spectrometer equipment is required and the analysis becomes very difficult
Solution Approach 1:
The patent replaces the complex mass spectrometer-based detection system with a simple fluorescence measurement system. This substitution uses readily available fluorescence plate readers or spectrophotometers instead of expensive mass spectrometers, dramatically reducing equipment complexity and cost while maintaining accurate measurement of uptake through fluorescence intensity correlation
Solution Approach 2:
The patent changes the detection parameter from mass-to-charge ratio (requiring mass spectrometry) to fluorescence intensity (detectable by simple equipment). By measuring fluorescence intensity of the selenocystine derivative inside cells and correlating it with uptake amount, the patent achieves accurate measurement without complex equipment
4Ease of manufacture
If glutamic acid release is measured to evaluate cystine uptake ability, then the method is indirect and lacks accuracy in measuring actual cystine uptake
Solution Approach 1:
The patent extracts the selenocystine derivative from the extracellular medium and measures it directly inside cells after uptake. This direct measurement of the transported substance within cells eliminates the indirect inference required by glutamic acid release measurement, providing accurate reflection of actual uptake without relying on countertransport stoichiometry assumptions
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 high-accuracy, low-cost evaluation of cystine uptake ability in cells, unaffected by cysteine or glutathione, and provides a kit for determining selenocysteine, enhancing the precision of cystine transporter activity assessment.
Implementation Method 1
determining selenocystine contained in the cytoplasm... selenocystine, which is a reduced product of selenocystine
Implementation Method 2
contacting the selenocysteine with a fluorescent dye that specifically reacts with the selenocysteine to change in one or both of a fluorescence wavelength and a fluorescence intensity
Data Source
AI summary
Disclosed are a method for evaluating the cystine uptake ability of cells having the steps of contacting cells with selenocystine to allow the cells to take up selenocystine, washing away selenocystine not taken up by the cells, and crushing the cells and determining selenocystine contained in the cytoplasm and a method for determining selenocysteine having a step of contacting selenocysteine with a fluorescent dye that specifically reacts with selenocysteine to change in one or both of fluorescence wavelength and fluorescence intensity, or reacting selenocysteine with a fluorescent dye under a condition that the fluorescent dye specifically reacts with selenocysteine to change in one or both of fluorescence wavelength and fluorescence intensity, followed by measuring the fluorescence intensity for determining selenocystine. A kit for evaluating the cystine uptake ability of cells, containing a reducing agent that reduces selenocystine to selenocysteine, a fluorescent dye represented by the following general formula (I), and a buffer solution at a pH of 5.5 to 6.5 is disclosed.