Nanoparticle Characterization via Modulated Photothermal Imaging
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Solution Overview
Problem
Current methods for characterizing nanoparticles, such as lock-in thermography, face limitations including the need for invasive and time-consuming measurements, reliance on single-point data collection, and challenges in complex environments, as well as the introduction of artifacts from fluorescent labeling and complex sample preparation.
Innovation Solution
A method and device utilizing modulated homogenous light with multiple wavelengths to stimulate nanoparticles, detecting heat radiation with an infrared camera, and applying lock-in thermography for demodulation to determine physical properties without the need for fluorescent dyes or extensive sample preparation, using LED light sources for 2D stimulation and characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard calorimetric methods (fiberoptic cables or thermocouples) are used to measure heat produced by particles, then the measurement setup is easy to install, but the data analysis is challenging and the measurements are very time consuming and invasive
Solution Approach 1:
The patent replaces mechanical contact-based calorimetric methods (thermocouples and fiberoptic cables requiring physical insertion into the sample) with a non-contact optical measurement system. The system uses a light source to illuminate the sample and a camera to detect thermal radiation, eliminating the need for physical sensor insertion and thereby reducing measurement time and invasiveness while maintaining ease of setup.
2Ease of manufacture
If standard calorimetric methods are used to measure heat produced by particles, then the measurement setup is easy to install, but the measurements provide only single one-dimensional points data, limiting reproducibility and accuracy
Solution Approach 1:
The patent transitions from one-dimensional point measurements (single thermocouple or fiberoptic cable position) to two-dimensional spatial mapping by using a camera to detect thermal radiation across the entire sample area. This dimensional expansion provides multiple measurement points simultaneously, improving reproducibility and accuracy by capturing spatial distribution of heat produced by particles.
3Adaptability or versatility
If fluorescent labeling and complex sample preparation are used for particle characterization, then detection methods are available, but artifacts are introduced and particle characterization in complex environments is extremely difficult
Solution Approach 1:
The patent extracts and eliminates the need for fluorescent labeling and complex sample preparation by using a direct optical-thermal detection method. The system measures heat produced by particles through their intrinsic photothermal properties when illuminated, without requiring any external labels or modifications to the particles. This extraction of unnecessary preparation steps prevents artifact introduction and enables characterization in complex environments.
4Measurement precision
If lock-in thermography is used to detect heat produced by particles, then quantitative and qualitative information is obtained, but choosing the right experimental setup and measurement conditions is of great importance
Solution Approach 1:
The patent creates a universal experimental setup where a standard light source and camera system can characterize different types of particles (metallic, carbon-based, organic) with varying photothermal properties. The system accommodates different particle types and experimental conditions through software-based lock-in thermography analysis rather than requiring hardware modifications, reducing setup complexity while maintaining measurement precision.
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 non-invasive, faster characterization of nanoparticles with improved accuracy and precision, avoiding artifacts and complex data analysis, and is suitable for complex matrices without the need for costly instrumentation or sophisticated data treatment.
Implementation Method 1
metal containing nano- and microparticles (e.g. pure metals, metal alloys, metal oxides etc.), but also carbon based materials (e.g. carbon nanotubes, graphene, fullerenes), can produce heat upon electromagnetic wave absorption or scattering
Implementation Method 2
metal containing nano- and microparticles (e.g. pure metals, metal alloys, metal oxides etc.), but also carbon based materials (e.g. carbon nanotubes, graphene, fullerenes), can produce heat upon electromagnetic wave absorption or scattering
Implementation Method 3
heat radiated by the at least one particle of the particle sample as a result of the stimulation is detected by means of a detector
Data Source
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AI summary
A method for characterizing particles producing heat when exposed to light is proposed. The method comprises the steps of stimulating a particle sample (2e) alternatingly with homogenous light waves (8a, 10a, 12a, 14a) with at least a first wavelength and a second wavelength, detecting by means of a detector (18a) heat (16a) radiated by the particle sample as a result of the stimulation, thereby yielding time-dependent images of a modulated heat distribution pattern, converting the time-dependent image of the modulated heat distribution pattern into the frequency domain and demodulating the image of the modulated heat distribution pattern, and determining a physical property of the particle sample based on the at least one demodulated image of heat distribution.