Disposable Micro Flow-Path Chip for CTC Detection
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Solution Overview
Problem
Current methods for detecting circulating tumor cells (CTCs) face challenges such as inability to automatically and quickly determine and count live CTCs, failure to prevent cross-contamination between samples, and inability to measure the entire sample liquid in conventional flow cytometers, leading to misdiagnosis and inefficiencies in cancer treatment.
Innovation Solution
A method using a flow cytometer with a disposable micro flow-path chip that allows for the measurement of whole sample liquid, enabling automatic identification and counting of live CTCs by detecting air bubbles as an endpoint, and utilizing magnetic beads and fluorescence staining to differentiate between living and dead cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flow cytometers are used to detect CTCs, then detection capability is provided, but cross-contamination between samples occurs and entire sample liquid cannot be measured
Solution Approach 1:
The flow cell is divided into multiple measurement sections along the flow direction, with each section capable of measuring a specific portion of the sample liquid. This segmentation allows the entire sample to be measured without cross-contamination by using separate measurement zones for different samples.
Solution Approach 2:
A disposable micro flow-path chip is introduced as an intermediary component between the sample liquid and the detection system. The chip contains the micro flow-path structure that prevents direct contact between samples and the measurement system, thereby eliminating cross-contamination while enabling complete sample measurement.
2Measurement precision
If conventional flow cytometers measure sample liquid, then CTC detection is possible, but the entire sample cannot be measured leading to count loss
Solution Approach 1:
The flow cell is segmented into multiple measurement sections that collectively cover the entire sample liquid volume. By dividing the measurement process into multiple sections along the flow direction, the system ensures that no cells are lost and the complete sample can be accurately measured.
Solution Approach 2:
The measurement process continues continuously through the entire sample liquid volume without interruption. The flow cytometer measures cells throughout the complete flow path from the sample reservoir through the micro flow-path to the collection reservoir, ensuring no cell count loss.
3Productivity
If automatic CTC counting is implemented, then detection efficiency increases, but live and dead cells cannot be differentiated
Solution Approach 1:
Different fluorescence stains are applied to different cellular components: one stain targets cell membrane markers for CTC identification, while another stain targets nuclear DNA for viability differentiation. This local quality approach allows simultaneous automatic counting and live/dead differentiation within the same measurement system.
Solution Approach 2:
Multiple fluorescence stains are combined in a single measurement system, with each stain serving a specific function: CTC detection through membrane marker staining and viability assessment through nuclear staining. The composite staining approach enables comprehensive cell analysis in one measurement.
4Reliability
If disposable micro flow-path chip is used, then cross-contamination is prevented and entire sample can be measured, but device complexity increases
Solution Approach 1:
A disposable micro flow-path chip is used instead of a reusable flow cell. The chip is made as a single-use component that is discarded after one measurement, eliminating the need for complex cleaning and sterilization procedures while preventing cross-contamination between samples.
Solution Approach 2:
The flow cell structure is extracted and integrated into a disposable chip format, separating the measurement function from the sample handling function. The micro flow-path chip contains only the essential flow paths and reservoirs needed for measurement, simplifying the overall device structure while maintaining reliability.
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
This approach allows for efficient detection and collection of live CTCs, reducing cross-contamination and enabling accurate counting of live and dead cells, thereby improving cancer diagnosis and treatment strategies.
Implementation Method 1
magnetic beads and fluorescence staining to differentiate between living and dead cells
Implementation Method 2
fluorescence staining to differentiate between living and dead cells
Data Source
AI summary
Conventional CTC detection methods have been problematic in that 1) there is no technique for automatically determining and counting live CTCs in a brief period of time, 2) no process has been developed for detecting, counting, and thereafter collecting and culturing live CTCs, and 3) there exists no flow cytometer that is contamination free and is capable of measuring an entire sample. Provided is a CTC detection method which comprises a pre-treatment step for concentrating and fluorescence staining CTCs, and a step for identifying and counting CTCs. The pre-treatment step includes attaching magnetic beads to EpCAM antibodies expressed by epithelial cell-derived CTCs and concentrating the CTCs through the use of a magnet, fluorescently labeling an epithelia cell surface marker of the CTCs through the use of EpCAM antibodies or 5E11 antibodies, and performing two types of nuclear staining, one being cell membrane-permeable and the other being cell membrane-impermeable. The identifying and counting step includes evaluating the respective absolute concentrations of live and dead CTCs in a volume of blood by automatically identifying CTCs by the ratio of a plurality of fluorescence signal intensities using a flow cytometer, and differentiating between and counting the live CTCs and the dead CTCs. In the cytometer, an entire liquid-feeding system that includes a flow cell can be replaced for each sample, and the total amount of a liquid sample can be measured.