Selective Filtration and On-Filter Lysis for Analyte Isolation
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Solution Overview
Problem
Current molecular diagnostics methods struggle to achieve high sensitivity for analyte detection, particularly in low-volume samples, due to low analyte concentrations, leading to inefficiencies in time, cost, and instrumentation requirements, as seen in applications like direct blood sepsis pathogen detection and liquid biopsies.
Innovation Solution
A method involving selective filtering and lysis of samples using specific lysis solutions and filters with controlled pore sizes to enrich analytes, followed by lysis and elution, enhancing sensitivity through larger sample volumes and efficient analyte isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sample extraction methods are used, then the detection sensitivity is limited by low analyte concentrations in small sample volumes, but increasing sample volume is not feasible with current methods
Solution Approach 1:
The method segments the sample processing into distinct stages: initial filtration to concentrate analytes from large volume, selective lysis to release target molecules, and final elution to obtain concentrated analyte in small volume. This segmentation enables processing of large sample volumes (e.g., 1-10 mL blood) while achieving high detection sensitivity through progressive concentration at each stage.
Solution Approach 2:
The invention transitions from processing samples in a single liquid phase to using multiple phases and dimensions: filtration through porous membranes (adding spatial dimension), selective lysis in solution phase, and elution to concentrate analytes. This dimensional approach enables handling large sample volumes while achieving high analyte concentration for sensitive detection.
2Measurement precision
If pathogen enrichment by blood culturing is used, then pathogen presence can be detected, but the process is time consuming (24-72 hours) and has low detection sensitivity
Solution Approach 1:
The method performs preliminary filtration and concentration of pathogens from blood samples before detection, eliminating the need for time-consuming culture steps. By pre-concentrating analytes from large sample volumes through filtration and selective lysis, the assay achieves high detection sensitivity within hours rather than days, significantly reducing assay time while maintaining or improving sensitivity.
3Measurement precision
If magnetic particles coupled with pathogen-specific antibodies are used for enrichment, then pathogen detection sensitivity improves, but storage stability, lot-to-lot variation, and cost issues arise
Solution Approach 1:
The invention extracts and removes antibodies from the enrichment process, replacing them with antibody-free filtration and selective lysis steps. This eliminates storage stability and lot-to-lot variation issues associated with antibody-based methods while maintaining high detection sensitivity through physical filtration and selective cell lysis approaches.
4Measurement precision
If centrifugation in a closed system is used for enrichment, then pathogen detection can be achieved, but bulky instruments and specific fluidics are required
Solution Approach 1:
The invention replaces complex mechanical centrifugation systems with simple filtration-based enrichment using porous membranes and selective lysis. This substitution eliminates the need for bulky centrifuges and complex closed-system fluidics, enabling portable and simplified device designs while achieving equivalent or superior pathogen detection sensitivity through filtration and elution processes.
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
Improves assay sensitivity and efficiency by processing larger sample volumes, enabling effective detection of low-concentration analytes using nucleic acid amplification and detection modalities, while reducing assay time and instrumentation complexity.
Implementation Method 1
filtering the first lysate through a filter having a pore size that retains the intact microbial cells
Implementation Method 2
contacting the filter containing the retained microbial cells with a second lysis solution that is effective to lyse the microbial cells and release therefrom an analyte
Data Source
AI summary
Disclosed are methods for isolating an analyte from a sample. In some aspects, the methods are for selectively isolating a microbial cell analyte, such as a nucleic acid, from a sample containing or suspected of containing mammalian cells. The selective isolation method includes selective lysis of the mammalian cells and filtration of the resulting lysate through a filter that retains intact microbial cells, followed by on-filter lysis of the retained microbial cells to release the microbial cell analyte. The released analyte is then eluted from the filter. In other aspects, the methods utilize on-filter lysis of a sample containing intact cells (e.g., microbial cells) to release the analytes, followed by elution of the released analytes from the filter by passing an immiscible liquid through the filter. The isolated analytes may be analyzed using a suitable assay depending on the type of analyte molecule. Also disclosed are fluidic systems and lysis solutions that may be used for isolating an analyte according to the disclosed methods.