Confocal Microscope Scanning for Low Concentration Particle Detection
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Solution Overview
Problem
Current optical analysis techniques, such as FCS and FIDA, struggle with accurately analyzing particles at concentrations below 1 nM due to rare particle entry into the micro region, leading to incomplete or inaccurate fluorescence intensity measurements, and require complex procedures and larger sample amounts.
Innovation Solution
An optical analysis method using a confocal or multiphoton microscope with a moving light detection region to individually detect light-emitting particles in a sample solution, generating time series light intensity data and computing characteristic values to identify the presence of each particle, allowing for concentration and number density determination without statistical fluctuation analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical analysis techniques (FCS, FIDA) are used to detect particles in solution, then measurement sensitivity can achieve single photon level, but accurate analysis becomes difficult when particle concentration is below 1 nM due to rare particle entry into the micro region
Solution Approach 1:
The patent applies dynamics by moving the light detection region through the sample solution at a controlled speed. Instead of keeping the detection region stationary and waiting for particles to diffuse into it, the system actively moves the detection region to scan through the solution, increasing the probability of encountering and detecting rare particles at concentrations below 1 nM.
Solution Approach 2:
The patent introduces temporal dimension to the detection process by performing sequential measurements at multiple positions along a movement trajectory. The light detection region moves through different spatial positions (z-direction) and time points, creating a four-dimensional detection space (x, y, z, t) that increases the likelihood of detecting rare particles.
2Measurement precision
If statistical fluctuation analysis is used to determine particle concentration, then concentration information can be extracted from fluorescence intensity variations, but the analysis process becomes complex and requires large sample amounts
Solution Approach 1:
The patent extracts concentration information directly from the movement trajectory data and light intensity measurements without requiring complex statistical fluctuation analysis. By measuring fluorescence intensity at multiple positions along a known movement path, the system can calculate particle concentration through direct computation rather than statistical inference, simplifying the analysis procedure.
Solution Approach 2:
The patent performs preliminary actions by pre-defining the movement trajectory and detection positions before measurement. The system establishes a known spatial-temporal framework in advance, allowing concentration calculation to be performed through straightforward data processing rather than complex statistical analysis during measurement.
3Stability of the object's composition
If a stationary light detection region is used, then the optical system can maintain stable detection conditions, but particle detection efficiency decreases when particle concentration is very low
Solution Approach 1:
The patent resolves this contradiction by making the light detection region dynamic rather than stationary. The detection region moves through the sample solution at a controlled speed, maintaining stable detection conditions at each position while increasing overall detection efficiency by scanning through multiple positions, thereby encountering more particles in a given time period.
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 precise detection and quantification of particle concentrations as low as 10 fM, reducing sample volume requirements and simplifying the analysis process compared to conventional methods, while maintaining sensitivity and accuracy.
Implementation Method 1
detection of light from an atom, a molecule or an aggregate (Hereafter, these are called a 'particle'.) dispersed or dissolved in a solution... by using an optical system, such as the optical system of a confocal microscope or a multiphoton microscope, which can detect light from a micro region in a solution
Data Source
Figure 1(A)~1(D)
Figure 2(A)~2(D)
Figure 3(A)~4(B)
AI summary
There is provided an optical analysis technique enabling the detection of the condition or characteristic of a particle to be observed contained at a low concentration or number density in a sample solution. The inventive optical analysis technique uses an optical system capable of detecting light from a micro region in a solution, such as an optical system of a confocal microscope or a multiphoton microscope, to detect the light from the light-emitting particle to be observed while moving the position of the micro region in the sample solution (while scanning the inside of the sample solution with the micro region); generates time series light intensity data, computes a characteristic value of the light intensity indicating the presence or absence of the light from a single light-emitting particle in every time section of a predetermined width in the light intensity data; and detects the light-emitting particle crossing the inside of the micro region individually using the characteristic value, thereby enabling the counting of the light-emitting particle(s) or the acquisition of the information on the concentration or number density of the light-emitting particle.