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Microchamber arrays with an integrated long luminescence lifetime pH sensor
Elisabeth Poehler1, Simon A Pfeiffer1, Marc Herm2
1Institut für Analytische Chemie, Universität Leipzig, Johannisallee 29, 04103, Leipzig, Germany.
Analytical and Bioanalytical Chemistry
|November 23, 2015
Summary
Researchers developed a novel pH sensor for cell culture dishes, enabling real-time monitoring of pH changes within microchambers. This advancement allows for detailed analysis of cellular environments and growth dynamics.
Area of Science:
- Biomedical Engineering
- Materials Science
- Analytical Chemistry
Background:
- Accurate monitoring of pH is crucial for understanding cellular processes and optimizing cell culture conditions.
- Existing pH sensing methods may lack the spatial resolution or real-time capabilities required for complex microenvironment studies.
Purpose of the Study:
- To develop and characterize a novel, covalently coupled pH probe integrated into a microfluidic cell culture platform.
- To demonstrate the capability of the integrated sensor for long-term, spatially resolved pH monitoring of microbial cultures.
Main Methods:
- Covalent coupling of 6-carboxynaphthofluorescein (CNF) to ruthenium-tris-(1,10-phenanthroline)(2+) to create a luminescent pH probe.
- Immobilization of the pH probe onto amino-modified poly-(2-hydroxyethyl)methacrylate (pHEMA) to form a sensor matrix.
- Integration of the sensor matrix into microcavity arrays within cell culture dishes via spin coating.
- Development of a microscopic setup for long-term imaging and analysis of pH dynamics.
Main Results:
- The developed pH probe exhibited a microsecond luminescence lifetime and pH-dependent Förster Resonance Energy Transfer (FRET).
- The sensor matrix demonstrated a working pH range of approximately 6.5 to 9.0 with a pKa of 7.79 ± 0.14.
- The integrated sensor system allowed for fast, bidirectional response times and enabled real-time, spatially resolved pH monitoring of Escherichia coli cultures over extended periods.
- Differences in cell growth and associated pH changes were successfully resolved and quantified across individual microchambers.
Conclusions:
- The study successfully developed a robust, integrated pH sensing system for microfluidic cell culture applications.
- The sensor platform provides a powerful tool for investigating microenvironmental pH dynamics and its impact on cellular behavior.
- This technology has the potential to advance cell-based assays and microbial studies by enabling detailed, real-time monitoring.
