Luminescent Indicator Dye for Near-Neutral pH Sensing
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Solution Overview
Problem
Existing luminescent indicator dyes based on PET dyes with high pK values are not suitable for determining near-neutral pH values in aqueous samples, particularly in physiological pH ranges, and 4-difluorobora-3a,4a-diaza(s)-indacene dyes are unstable in water-containing environments.
Innovation Solution
A luminescent dye with a general formula incorporating a luminophoric moiety, such as an amino-naphthalimide or xanthenone group, with specific substituents and a pK value near neutral pH, immobilized in a hydrophilic matrix, allowing for significant luminance changes in the pH range of 6.8 to 8.0, particularly suitable for blood, plasma, or serum analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PET dyes with high pK values are used, then the dyes show strong luminescence difference between protonated and deprotonated states, but they are not suitable for determining near-neutral pH values
Solution Approach 1:
The patent modifies the chemical structure of the PET dye by introducing electron-withdrawing groups (such as fluorine atoms at positions 2 and 6 of the pyridine ring) to adjust the pK value from high (unsuitable for neutral pH) to near-neutral (6.8-7.4). This parameter change enables the dye to function accurately in physiological pH ranges while maintaining its luminescence quenching mechanism.
2Illumination intensity
If 4-difluorobora-3a,4a-diaza(s)-indacene dyes are used, then the dyes exhibit luminescence properties, but they are unstable in water-containing environments
Solution Approach 1:
The patent creates a composite structure by combining the luminophoric moiety (4-difluorobora-3a,4a-diaza(s)-indacene) with a stable pyridine-based PET donor unit. This composite molecular structure leverages the luminescence properties of the indacene core while the pyridine donor provides chemical stability in aqueous environments, resolving the contradiction between luminescence intensity and aqueous stability.
3Adaptability or versatility
If the pK of the PET donor group is adjusted to near neutral, then the dye becomes suitable for blood pH determination, but the luminescence intensity difference between protonated and deprotonated species decreases
Solution Approach 1:
The patent introduces fluorine atoms at specific positions (2 and 6) of the pyridine ring to create localized electron-withdrawing effects. This local modification optimizes the electron distribution in the donor unit, maintaining strong luminescence quenching capability in the deprotonated state while achieving the desired near-neutral pK value for physiological pH determination.
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 dye exhibits a dramatic change in luminance in the pH range of 6.8 to 8.0, enabling accurate determination of near-neutral pH values in aqueous media, including blood and serum, while maintaining stability in aqueous environments.
Implementation Method 1
luminescence intensity of the electronically excited acceptor part
Implementation Method 2
The 'PET effect' (PET=photoinduced electron transfer) denotes the photone induced transfer of electrons from a donor to luminophoric moiety
Data Source
AI summary
The present invention relates to a chemical compound that has applications as a luminescent indicator dye, and to an optical sensor, typically employed for determination of near-neutral pH values of aqueous samples. The optical sensor has particular application in the pH determination of body liquids such as, for example, blood, plasma and serum.