Nanomembrane Biosensor for Single-Cell Thermal Diffusivity

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Solution Overview

Problem

Current methods for measuring thermal diffusivity lack the spatial resolution needed to measure individual biological cells effectively, particularly due to their irregular shapes, and are ineffective in targeting cancerous cells without affecting adjacent healthy cells.

Innovation Solution

A method utilizing gallium nitride nanomembranes, which spectrally shift their photoluminescence emission in response to laser-induced heating, allowing for precise measurement of thermal diffusivity by detecting the spectral shift in photoluminescent radiation, and a kit comprising nanomembranes and metallic disks for accurate thermal conductivity determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional thermal diffusivity measurement methods are used, then measurement capability is provided, but spatial resolution is insufficient to measure individual biological cells effectively

Engineering Contradiction:
Improvespatial resolutionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs ultrathin nanomembranes (few nanometers to micrometers thick) as flexible thermal probes that can conform to and contact individual biological cells. These thin film structures enable high spatial resolution thermal measurements at the single-cell level while maintaining mechanical flexibility for biological compatibility.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent replaces conventional mechanical thermal measurement systems with an optically-based photoluminescence technique. The nanomembrane's photoluminescence spectral shifts are used to detect temperature changes, substituting direct thermal sensing with optical detection for higher precision and non-contact measurement capability.

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

2Adaptability or versatility

If conventional measurement methods are used, then general measurement capability is provided, but ability to target cancerous cells specifically without affecting adjacent healthy cells is lost

Engineering Contradiction:
Improvecell targeting capabilityVSAvoidsingle-cell measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement process into individual cell-level operations using microscale nanomembranes that can be positioned on specific cells. This segmentation enables independent measurement and manipulation of each cell, allowing selective targeting of cancerous cells while leaving healthy cells unaffected.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using nanomembranes with spatially localized photoluminescence properties that can be selectively excited and measured. The metallic disk structures on the nanomembranes create localized thermal zones that affect only the targeted cell region, enabling precise spatial control for cancer cell identification and treatment.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If nanomembrane photoluminescence spectral shift detection is used, then high-resolution thermal diffusivity measurement is achieved, but requirement for precise spectral detection increases system complexity

Engineering Contradiction:
Improvethermal diffusivity measurement precisionVSAvoidspectral shift detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent utilizes photoluminescence spectral shifts (color changes in the optical spectrum) of the nanomembrane material as a direct indicator of temperature changes. By monitoring the shift in emission wavelength, the system achieves high-precision thermal diffusivity measurements through optical detection rather than direct thermal sensing.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The nanomembrane acts as an intermediary between the laser excitation source and the temperature measurement. The nanomembrane absorbs laser energy, undergoes photoluminescence with temperature-dependent spectral shifts, and thereby mediates the conversion of optical energy into measurable thermal information through its photoluminescent response.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables high-resolution, single-cell thermal diffusivity measurement with a 2.2% error rate, facilitating efficient targeting of cancerous cells and improving thermal distribution modeling, while being applicable to both biological and non-biological samples.

Implementation Method 1

directing a laser beam to fall onto the nanomembrane over the biological sample, operating a radiation sensor to detect photoluminescent radiation emitted by the nanomembrane in response to the laser beam

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

determining a spectral shift in the detected photoluminescent radiation emitted by the nanomembrane

Methodology Applied
Scientific EffectSpectral shift:

Implementation Method 3

directing a laser beam to fall onto the nanomembrane over the biological sample

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 4

measuring the thermal diffusivity of single-cells with only a 2.2 percent error rate

Methodology Applied
Scientific EffectThermal diffusion: Diffusion

Implementation Method 5

disposing a nanomembrane over the biological sample and over the metallic disc so that the nanomembrane, the metallic disk and the biological sample are in thermal equilibrium with one another

Methodology Applied
Scientific EffectThermal equilibrium:

Data Source

PatentEP3405789B1A high-resolution, nanomembrane-based, thermal diffusivity biosensor for living cells
Publication Date: 2020.03.04 KING ABDULLAH UNIV OF SCI & TECH
  • EP3405789B1 patent drawingFigure 1~2e
  • EP3405789B1 patent drawingFigure 3a~4e
  • EP3405789B1 patent drawingFigure 5~6

AI summary

A method for measuring thermal diffusivity/conductivity of a microscale sample includes placing a metallic disk atop the sample, and disposing a nanomembrane over the sample and over the metallic disk so that the nanomembrane, so that the metallic disk, the nanomembrane and the sample are in thermal equilibrium with one another. A laser beam is directed to fall onto the nanomembrane over the sample, while a radiation sensor is operated to detect photoluminescent radiation emitted by the nanomembrane in response to the laser beam. A spectral shift in the detected photoluminescent radiation emitted by the nanomembrane is determined, and thermal diffusivity/conductivity is calculated from the determined spectral shift of the photoluminescence.