Electric-Field Droplet Ejection for Rare Cell Mass Tag Detection
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Solution Overview
Problem
Existing methods for detecting rare cells and molecules are inefficient, requiring lengthy purification steps, low sensitivity, and are limited by sample interference, making it difficult to accurately analyze and quantify these targets in complex biological samples.
Innovation Solution
An apparatus and method using an essentially non-absorbent membrane with pores and an electric field generator to release precise droplets of detection liquid for mass spectrometry analysis, allowing for the formation and delivery of mass spectrometry labels without dilution, enhancing the detection of rare cells and molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional affinity assays are used to detect rare molecules, then the detection can be achieved, but the method requires a number of molecular copies far above the numbers found for rare molecules
Solution Approach 1:
The patent applies preliminary action by performing multiple amplification steps before detection. The method involves purifying nucleic acids, performing PCR amplification to generate multiple copies, and then detecting the amplified products. This preliminary amplification ensures that rare molecules reach detectable levels before analysis.
Solution Approach 2:
The patent changes parameters by converting rare molecules into detectable forms through biochemical transformations. Nucleic acids are extracted and purified, then amplified by PCR to generate numerous copies from single or few original molecules, fundamentally changing the quantity parameter to enable detection.
2Measurement precision
If conventional nucleic acid assays are used to detect rare molecules, then detection can be achieved, but one or more lengthy purification steps and amplifications are required that can take several days for analysis time
Solution Approach 1:
The patent performs preliminary purification of nucleic acids from the sample before amplification and detection. This preliminary action removes interfering substances that would otherwise require lengthy purification steps during the assay, reducing overall analysis time while maintaining detection accuracy.
Solution Approach 2:
The patent skips intermediate purification steps by performing direct PCR amplification on purified nucleic acids. The method rushes through the detection process by using highly efficient amplification protocols that minimize the time required while still achieving accurate detection of rare molecules.
3Productivity
If mass spectroscopy is used for rare target detection, then analysis can be performed, but sensitivity is reduced due to background in clinical sample (picomolar reduced to nanomolar)
Solution Approach 1:
The patent extracts and purifies nucleic acids from complex clinical samples before amplification and detection. This extraction removes background interference from proteins, lipids, and other molecules that would otherwise reduce mass spectrometry sensitivity, allowing detection at picomolar concentrations rather than nanomolar.
Solution Approach 2:
The patent changes the concentration parameter by performing PCR amplification that increases the amount of target nucleic acid from picomolar to much higher concentrations. This parameter change overcomes the sensitivity reduction caused by mass spectrometry background interference, enabling detection of rare molecules.
4Measurement precision
If cell filtration techniques are used to separate rare cells, then separation by size can be achieved, but only a few rare cells are yielded
Solution Approach 1:
The patent uses PCR amplification to create copies of genetic material from rare cells. Instead of relying on physical separation that yields only a few cells, the method amplifies DNA/RNA from separated cells to generate numerous copies, effectively multiplying the quantity of analyte available for detection.
Solution Approach 2:
The patent changes the quantity parameter by amplifying nucleic acids from separated rare cells. Even though cell filtration yields only a few cells, the subsequent PCR amplification increases the amount of detectable material by orders of magnitude, compensating for the low cell recovery.
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 rapid and sensitive detection of rare cells and molecules by minimizing dilution and interference, improving analysis time and accuracy in complex biological samples.
Implementation Method 1
An electric field generator is provided. A voltage is provided to the sample to release a droplet through the at least one pore
Implementation Method 2
The droplet is analyzed for presence of the mass spectrometry label, for example by mass spectrometry analysis of an ionized mass spectrometry label
Data Source
AI summary
The invention generally relates to mass tag analysis for rare cells and cell free molecules. In certain embodiments, the invention provides an apparatus including an essentially non-absorbent membrane having at least one pore, a microwell operably associated with the essentially non-absorbent membrane, and an electric field generator. The apparatus may be configured such that an electric field produced by the electric field generator operably interacts with a sample in the microwell and expels a droplet of the sample through the at least one pore in the essentially non-absorbent membrane. In certain embodiments, apparatuses of the invention are used for detection, and optionally quantification, of a target analyte from a heterogeneous sample, such as a rare target analyte (e.g., rare cell) from a biological sample.