Mid-Infrared QCL Cell Sorting via Microfluidic Single-Cell Analysis
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Solution Overview
Problem
Current methods for cell sorting, such as fluorescence-activated cell sorting (FACS), face challenges including low accuracy, safety concerns, and damage to cells due to high-energy UV light and chemical markers, while mid-IR spectroscopy is limited by strong water absorption and scattering issues.
Innovation Solution
The use of mid-infrared quantum cascade lasers (QCLs) for label-free cell sorting, which focuses high-energy onto a single cell for accurate, high-speed measurements, and incorporates microfluidic channels with optimized materials and designs to minimize scattering and orientation effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorescence-activated cell sorting (FACS) is used for cell sorting, then cell separation can be achieved, but cell damage occurs due to high-energy UV light and chemical markers
Solution Approach 1:
The patent changes the fundamental parameter of light wavelength from UV/visible range to mid-infrared range (3-15 microns). This parameter change results in lower photon energy that does not damage cells, while still providing sufficient signal for sorting through absorption spectroscopy of water and other cellular components.
Solution Approach 2:
The patent extracts and eliminates the harmful components from the FACS process: removing fluorescent markers that cause chemical damage and UV light that causes photon damage. The system achieves cell sorting through label-free mid-infrared absorption spectroscopy alone.
2Object-affected harmful factors
If mid-infrared spectroscopy is used for cell sorting, then photon damage is reduced, but strong water absorption and scattering issues limit effectiveness
Solution Approach 1:
The patent applies partial action by focusing the mid-infrared beam onto a small volume containing a single cell or a small number of cells. This concentrated energy delivery provides sufficient absorption signal from the target cell without requiring the entire cell population to be processed, thereby overcoming the limitations of water absorption and scattering.
Solution Approach 2:
The patent replaces the traditional flow cytometry approach with a microfluidic system that provides precise spatial control and single-cell positioning. This substitution enables accurate measurement of absorption signals despite the challenges of water absorption and scattering by ensuring optimal optical path length and cell-beam alignment.
3Measurement precision
If high-intensity UV laser beams are used for cell sorting, then sorting accuracy can be achieved, but chromosomal damage occurs in cells
Solution Approach 1:
The patent fundamentally changes the energy parameter of the illumination source from high-energy UV photons to lower-energy mid-infrared photons. This parameter change maintains the ability to detect cellular differences through absorption spectroscopy while eliminating the harmful chromosomal damage caused by UV radiation.
Solution Approach 2:
The patent introduces mid-infrared absorption spectroscopy as an intermediary measurement method between the illumination source and the detection system. This intermediary approach allows accurate cellular characterization without the direct harmful effects of UV light, using absorption characteristics as the basis for sorting decisions.
4Measurement precision
If fluorescent markers and intense UV light are used for cell classification, then cell identification is achieved, but quantitative measurements become difficult due to scattering and absorption
Solution Approach 1:
The patent extracts and removes the fluorescent marker component from the system, achieving cell classification through label-free mid-infrared absorption spectroscopy. This eliminates the scattering and absorption issues that plague fluorescent-based quantitative measurements, as the method directly measures absorption without relying on emitted fluorescence.
Solution Approach 2:
The patent substitutes the fluorescent emission-based measurement system with a direct absorption spectroscopy system using mid-infrared light. This substitution provides superior quantitative measurement capability by measuring the absorption spectrum directly, avoiding the energy losses and measurement difficulties associated with fluorescent markers and UV illumination.
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 accurate, high-throughput cell sorting with reduced photon damage and improved signal-to-noise ratio, allowing for precise classification and separation of cells without labels or dyes, including differentiation of sperm cells by DNA content.
Implementation Method 1
delivering mid-infrared light to a cell to induce resonant absorption by DNA or other analytes
Implementation Method 2
This light is absorbed as a result of molecular bond vibrations within the cellular structure
Data Source
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AI summary
In embodiments of the present invention, a system and method of cytometry may include presenting a single sperm cell to at least one laser source configured to deliver light to the sperm cell in order to induce bond vibrations in the sperm cell DNA, and detecting the signature of the bond vibrations. The bond vibration signature is used to calculate a DNA content carried by the sperm cell which is used to identify the sperm cell as carrying an X-chromosome or Y-chromosome. Another system and method may include flowing cells past at least one QCL source one-by-one using a fluid handling system, delivering QCL light to a single cell to induce resonant mid-IR absorption by one or more analytes of the cell, and detecting, using a mid-infrared detection facility, the transmitted mid-infrared wavelength light, wherein the transmitted mid-infrared wavelength light is used to identify a cell characteristic.