Sperm DNA Purification via Cellulose Binding and Epithelial Lysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for isolating sperm-associated DNA from complex samples are labor-intensive, technically demanding, and incompatible with automation, leading to a significant backlog of untested sexual assault kits.
Innovation Solution
A method involving the use of a digestion agent to lyse epithelial cells while preserving sperm cells, followed by the addition of a reducing agent to break disulfide bonds, and subsequent binding of sperm cells to a cellulose resin for purification and elution of sperm-associated DNA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If differential extraction is used to separate sperm-associated DNA, then separation can be achieved, but the process becomes labor-intensive and technically demanding
Solution Approach 1:
The patent introduces an intermediary substance (detergent) that selectively interacts with epithelial cells to cause their lysis while leaving sperm cells intact. This intermediary enables the separation process to occur automatically based on chemical properties rather than requiring manual technical manipulation, thus resolving the contradiction between separation purity and operational simplicity
Solution Approach 2:
The patent exploits parameter changes in cell membrane stability - epithelial cells have membranes that are sensitive to detergent-induced lysis, while sperm cell membranes are resistant. By changing the chemical environment (adding detergent), the system automatically separates the two cell types based on their differential response to the parameter change, achieving both high separation purity and ease of operation
2Measurement precision
If differential extraction is used to separate sperm-associated DNA, then separation can be achieved, but compatibility with automation is lost
Solution Approach 1:
The detergent acts as an intermediary that enables automatic separation by exploiting inherent differences in cell membrane composition. The process requires no manual intervention or technical skill, making it fully compatible with automated liquid handling systems and robotic platforms, thus resolving the contradiction between separation purity and automation compatibility
Solution Approach 2:
The separation process is designed to be self-service, where the chemical reagents automatically perform the separation function based on intrinsic cell properties. The sperm cells and epithelial cells separate themselves through their differential response to the detergent, eliminating the need for operator skill and enabling complete automation
3Measurement precision
If manual processing is used for sexual assault kits, then separation can be performed, but significant backlog accumulates
Solution Approach 1:
The patent uses parameter changes (detergent concentration, incubation time, temperature) that create rapid and complete separation in a standardized protocol. This standardization enables high-throughput processing where many samples can be processed simultaneously with consistent results, resolving the contradiction between separation accuracy and processing throughput
Solution Approach 2:
The automated, self-service nature of the chemical separation process eliminates bottlenecks associated with manual technical manipulation. Multiple samples can be processed in parallel without requiring proportional increases in skilled personnel, thus dramatically increasing productivity while maintaining separation accuracy
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 method enables efficient, cost-effective, and automated separation and purification of sperm-associated DNA, reducing contamination from epithelial cells and improving the yield and purity of DNA for forensic analysis.
Implementation Method 1
contacting a sample comprising sperm cells with a digestion agent (or concentration of digestion agent) capable of efficiently lysing epithelial cells, but not sperm cells
Implementation Method 2
adding a reducing agent to sperm cells, wherein the reducing agent breaks disulfide bonds present on the sperm cells
Implementation Method 3
contacting the sperm cells with a cellulose resin
Data Source
AI summary
Provided herein are methods, reagents, and kits for the isolation of sperm cells from other cell types and the purification of sperm-associated DNA from a complex sample. In particular, methods, reagents, and kits are provided for the separation of intact sperm cells from epithelial cells via binding of sperm cells to a cellulose material, and the extraction of sperm-associated DNA therefrom.