Live Cell Interferometry for Single-Cell Mass Measurement

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Solution Overview

Problem

Current methods are inadequate for rapidly and simultaneously measuring the masses of individual cells or cell populations, particularly in understanding how cells regulate their size and the relationship between cell mass and biochemical pathways.

Innovation Solution

The development of a live cell interferometry system that uses a Michelson-type interference microscope to measure the fractional phase shift between a test beam and a reference beam, allowing for the determination of cell mass through the equation m = α ∫ φ λ dA, where m is the cell mass, α is a constant, ϕ is the measured fractional phase shift, λ is the illumination wavelength, and integration is performed across the cell area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional optical microscopy is used to measure cell mass, then the measurement approach is simple, but the measurement precision and detection sensitivity are insufficient

Engineering Contradiction:
Improvecell mass measurement precisionVSAvoidinterferometry system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical/optical microscopy measurement systems with an interferometry-based measurement system. The interferometer uses light interference patterns to detect changes in optical path length caused by cell mass changes, achieving picogram-level measurement precision that conventional microscopy cannot provide.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an interferometric measurement system as an intermediary between the cell sample and the detection process. The system uses reference beams and test beams that interfere with each other, creating measurable interference patterns that encode cell mass information, thereby enabling precise indirect measurement of cell mass.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If single-cell mass measurements are performed using existing methods, then individual cell data can be obtained, but the measurement speed and throughput are too slow

Engineering Contradiction:
Improvemeasurement throughputVSAvoidsingle-cell mass measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement process into parallel independent measurements of individual cells within a population. The interferometry system captures interference patterns from multiple cells simultaneously, allowing each cell's mass to be measured independently and precisely while maintaining high throughput across the entire cell population.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from sequential single-cell measurement to parallel multi-cell measurement by utilizing the spatial dimension. The interferometer field of view encompasses multiple cells, and the system processes interference data from numerous cells simultaneously, effectively adding a spatial parallelism dimension to the measurement process.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of time

If cell mass measurements are performed over time to observe cellular dynamics, then temporal changes can be tracked, but the measurement duration and time consumption increase

Engineering Contradiction:
Improvemeasurement timeVSAvoidcell culture observation duration
Core Design Contradiction:
Loss of timeVSDuration of action of stationary object

Solution Approach 1:

The patent implements continuous, non-invasive measurement of cell mass over time. The interferometry system can repeatedly measure the same live cells without disrupting their growth or requiring sample removal, enabling continuous temporal monitoring of cellular dynamics including cell division, growth, and response to treatments.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent allows cells to maintain their natural growth and division processes undisturbed while the interferometry system passively monitors their mass changes. The measurement process does not require external intervention, sample preparation, or disruption of cell culture conditions, enabling cells to 'serve themselves' while being observed.

Inventive Principle:
Principle #25Self-service

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

Enables real-time, precise measurement of cell mass and its changes over time, allowing for the observation of cellular responses to therapeutic agents and environmental stimuli, with applications in assessing drug sensitivity and cellular dynamics.

Implementation Method 1

an adaptation of this technique, Live Cell Interferometry (LCI), can sensitively detect and track the nanomechanical properties of hundreds of cells simultaneously

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

measuring a fractional phase shift between a test beam of light and a reference beam of light

Methodology Applied
Scientific EffectPhase shift:

Data Source

PatentEP2739937B1Rapid, massively parallel single-cell drug response measurements via live cell interferometry
Publication Date: 2023.03.01 RGT UNIV OF CALIFORNIA
  • EP2739937B1 patent drawingFigure 1a~1c
  • EP2739937B1 patent drawingFigure 2a~2d
  • EP2739937B1 patent drawingFigure 3a~3d

AI summary

A central question in cancer therapy is how individual cells within a population of tumor cells respond to drugs designed to arrest their growth. However, the absolute growth of cells, their change in physical mass, whether cancerous or physiologic, is difficult to measure directly with traditional techniques. Embodiments of the invention provide live cell interferometry (LCI) for rapid, realtime quantification of cell mass in cells exposed to a changing environment. Overall, LCI provides a conceptual advance for assessing cell populations to identify, monitor, and measure single cell responses, such as to therapeutic drugs.