Ratiometric Fluorescent pH Sensor for Extracellular Monitoring
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Solution Overview
Problem
Current pH sensors face challenges in accurately monitoring extracellular pH due to sensitivity to excitation intensity and distribution, limiting their effectiveness in high-throughput analysis of multiple samples, particularly in biomedical and industrial applications where precise extracellular pH monitoring is crucial for understanding cellular responses and microbial fermentation.
Innovation Solution
A water-soluble fluorescent pH sensor with ratiometric detection capabilities, specifically designed to be extracellularly localized, utilizing a copolymer comprising N-(2-hydroxypropyl)methacrylamide or 2-hydroxyethyl methacrylate, and monomers with positive or negative charges, allowing for high-accuracy pH measurement using a commercial microplate reader.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorescence intensity is used for pH detection, then sensitivity is improved, but measurement accuracy deteriorates due to sensitivity to excitation intensity and sensor distribution
Solution Approach 1:
The patent employs ratiometric detection using two emission peaks at different wavelengths (475 nm and 505 nm) that exhibit different responses to pH changes. By calculating the ratio of intensities at these two wavelengths, the sensor achieves accurate pH measurement that is independent of excitation intensity fluctuations and sensor distribution variations, thereby resolving the contradiction between sensitivity and measurement accuracy
Solution Approach 2:
The patent changes the detection parameter from single emission intensity to the ratio of emission intensities at two different wavelengths. This parameter transformation eliminates the influence of excitation intensity and sensor distribution on the measurement, while maintaining the high sensitivity of fluorescence detection for pH changes
2Measurement precision
If standard pH titration curve is used for calibration, then measurement accuracy is improved, but time consumption and complexity increase
Solution Approach 1:
The patent uses a commercial microplate reader to perform high-throughput pH measurements, copying the successful approach of multi-well parallel processing. This allows simultaneous measurement of multiple samples with different pH values, dramatically reducing calibration time while maintaining measurement accuracy through ratiometric detection
3Productivity
If fluorescence sensors are used for high-throughput measurement, then productivity is improved, but measurement accuracy deteriorates due to sensitivity to excitation conditions
Solution Approach 1:
The patent employs ratiometric detection using two emission peaks at different wavelengths (475 nm and 505 nm) that exhibit different responses to pH changes. By calculating the ratio of intensities at these two wavelengths, the sensor achieves accurate pH measurement that is independent of excitation intensity fluctuations and sensor distribution variations, thereby resolving the contradiction between sensitivity and measurement accuracy
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 sensor provides high-accuracy, extracellular pH monitoring with minimal cell toxicity, enabling high-throughput measurements and precise detection of pH changes in various biological samples, including bacteria and mammalian cells, without interference from excitation intensity or sensor distribution.
Implementation Method 1
fluorescence pH sensors... possess two emission peaks which have different responses to the same pH. The only factor affecting the ratio of emission intensity is pH
Data Source
AI summary
Fluorescent pH sensors are provided. The fluorescent pH sensor comprises a copolymer for sensing pH and a polymerized form of N-(2-hydroxypropyl)methacrylamide (HPMA) or 2-hydroxyethyl methacrylate (HEMA). The probe for sensing pH has formula (I):wherein R1 and R2 are as defined herein. The fluorescent pH sensors may be used in determining the pH of a sample and detecting extracellular pH in a sample. Methods for preparing the fluorescent pH sensors and the probe for sensing pH are also provided.