Cell Settling Monitoring With Indicator Beads in Multi-Well Plates
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Solution Overview
Problem
High-throughput automated sample handling systems face inaccuracies in cell counting due to cell settling and evaporation in multi-well sample plates over extended periods, leading to inconsistent and unreliable data.
Innovation Solution
Incorporating indicator beads with varying specific gravities into samples or sentinel wells to detect and correct for settling and evaporation by comparing observed bead counts to expected ratios, allowing for real-time adjustments and remedial actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If samples are kept in multi-well plates for extended periods for high-throughput analysis, then productivity is improved, but cell settling and evaporation occur causing measurement precision to deteriorate
Solution Approach 1:
Indicator beads are introduced as intermediary particles with known properties and specific gravities that differ from cells. These beads serve as reference markers to detect and quantify settling and evaporation effects, allowing the system to distinguish between actual cell count changes and artifacts caused by sample degradation over time.
Solution Approach 2:
The system continuously monitors the distribution and concentration of indicator beads in the sample over time. By comparing observed bead positions and concentrations against expected values, the system generates feedback signals that indicate the degree of settling and evaporation, enabling real-time corrections to be applied to cell count measurements.
2Productivity
If sequential analysis of multiple multi-well plates is performed, then productivity is improved, but samples sit in stasis for extended periods causing reliability to deteriorate
Solution Approach 1:
Indicator beads are added to samples before they are placed in the analysis queue. This preliminary action establishes a reference state that allows subsequent detection of any changes in sample conditions during the extended waiting period inherent in high-throughput sequential processing.
Solution Approach 2:
The indicator bead monitoring system provides continuous feedback on sample condition throughout the extended processing time. This feedback mechanism allows the system to identify and compensate for reliability-deteriorating effects such as settling and evaporation that occur during the necessary waiting periods between sample preparation and analysis.
3Measurement precision
If indicator beads with varying specific gravities are added to detect settling, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system exploits changes in physical parameters (specific gravity, position, concentration) of indicator beads to detect settling and evaporation. By measuring how these parameters change over time relative to expected values, the system achieves precise detection of sample degradation without requiring complex analytical instruments.
Solution Approach 2:
The indicator beads are designed to be homogeneous in size and shape within each population, with populations differentiated only by specific gravity. This homogeneity simplifies the detection methodology, as uniform bead properties make it easier to distinguish between beads affected by settling versus those affected by evaporation.
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
Enhances the accuracy of cell counts by detecting and correcting for settling and evaporation, ensuring consistent and reliable data across multiple samples.
Implementation Method 1
detecting a consistency of the biological sample... determining, based on the first count, the consistency of the biological sample
Implementation Method 2
generating, by a flow cytometer receiving the extracted volume of the biological sample, a first count of a population of indicator beads
Data Source
Figure 1A~3B
Figure 4
Figure 5
AI summary
Samples in the wells of a multi-well sample plate can be sampled by automated systems, allowing for efficient, high-throughput assessment of hundreds or thousands of samples in a relatively short period of time. However, the time taken to sample every well of a plate is non- zero, and the contents of the samples can settle, exhibit evaporation, or undergo other biological or chemical changes across the sampling time period. Cells and other particles suspended in multi-sample containers can be periodically shaken or otherwise resuspended to ameliorate these effects, but the timing and effectiveness of such intervention is often undetermined. Embodiments herein provide for improved sample resuspension and sample consistency verification by detecting the amounts of different indicator beads, having different specific gravities, in volumes extracted from the samples. The observed ratio of the bead populations is then used to verify the accuracy of cell counts measured from the sample plate and/or to determine when to resuspend the sample plate.