Efficient single-cell oxygen consumption rate characterization based on frequency domain fluorescence lifetime...

Understanding cell metabolism is essential for studying energy homeostasis and cellular function. Traditional methods often analyze cells in bulk, which limits the ability to detect individual cell differences. Single-cell analysis has emerged as a promising alternative to explore cellular heterogeneity. Prior research has shown that oxygen consumption rate (OCR) is a key indicator of metabolic activity. However, no prior work had resolved how to efficiently measure OCR at the single-cell level. This gap motivated the development of new tools that combine microfluidics and fluorescence imaging. Existing techniques lack the resolution and throughput needed for high-precision single-cell studies. The need for a more efficient and accurate method has driven recent innovations in this field. Researchers have proposed integrating microfluidic platforms with advanced imaging techniques to address these limitations.

This study aimed to develop a new method for measuring single-cell oxygen consumption rates. The goal was to overcome the limitations of bulk cell analysis by enabling high-resolution single-cell characterization. The researchers sought to integrate microfluidics with fluorescence lifetime imaging to improve OCR measurement accuracy. The motivation was to better understand cellular metabolism and heterogeneity. The approach was designed to provide efficient and precise OCR data at the individual cell level. The study focused on breast cancer cells as a model system. The researchers proposed using a microfluidic device to isolate and trap single cells in microwells. This setup allowed for controlled oxygen tension measurements using a phosphorescent dye.

The study combined a microfluidic platform with widefield frequency domain fluorescence lifetime imaging microscopy (FD-FLIM). The microfluidic device was designed to trap individual cells in microwells filled with a buffer solution containing an oxygen-sensitive dye. FD-FLIM was used to measure fluorescence lifetime changes, which correlate with oxygen tension. The oxygen consumption rate was calculated based on these lifetime measurements. The system allowed for efficient and accurate single-cell OCR characterization. The setup enabled simultaneous imaging and data collection from multiple cells. The researchers tested the system using MCF-7 breast cancer cells. The method provided a high-throughput and high-resolution approach to single-cell OCR analysis.

The developed system successfully measured OCR at the single-cell level using FD-FLIM and microfluidics. The results showed significant variability in OCR among individual MCF-7 cells. The fluorescence lifetime measurements correlated well with oxygen tension changes in the microwells. The system demonstrated high accuracy and reproducibility in OCR calculations. The heterogeneity observed in OCR values suggests differences in metabolic activity between cells. The microfluidic platform enabled efficient cell isolation and stable imaging conditions. The FD-FLIM technique provided detailed lifetime data with minimal noise. The study confirmed the feasibility of the approach for single-cell OCR characterization.

The study demonstrated that the integration of microfluidics and FD-FLIM can efficiently characterize OCR at the single-cell level. The results suggest that this approach can reveal metabolic heterogeneity among cells. The developed method provides a reliable and high-resolution platform for OCR measurements. The system's performance was validated using breast cancer cells. The findings support the potential of this method for advancing cellular metabolism studies. The approach may enable more detailed investigations into cell function and behavior. The results align with the authors' hypothesis that combining microfluidics with FD-FLIM improves OCR analysis. The study proposes that this method could be applied to other cell types and disease models.