Rapid Nucleic Acid Extraction for Bone, Tooth, and Semen STR Profiling
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Solution Overview
Problem
Current methods for nucleic acid extraction from forensic samples such as bone, tooth, and semen are cumbersome, time-consuming, and inefficient, requiring sophisticated equipment and skilled technicians, making them unsuitable for field-forward rapid DNA identification.
Innovation Solution
A simplified process involving vigorous mixing of bone or tooth samples in a minimal volume of demineralization buffer, such as 0.5 M EDTA, without complete dissolution, and a rapid sperm disruption method for semen samples, allowing extraction and purification in under an hour, suitable for automated systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional nucleic acid extraction methods are used from bone, tooth, and semen samples, then DNA purification is achieved, but the process is time-consuming (hours to days), requires sophisticated equipment, and needs skilled technicians
Solution Approach 1:
The extraction process is segmented into discrete, automated steps performed in separate chambers within a single cartridge: lysis, demineralization, binding, washing, and elution. Each chamber performs a specific function, allowing the complex process to be broken down into manageable, automated segments that eliminate the need for multiple pieces of sophisticated equipment.
Solution Approach 2:
The integrated extraction system performs multiple functions (lysis, demineralization, binding, washing, elution) within a single automated instrument using a unified cartridge design. This multi-functional approach replaces the need for multiple separate sophisticated devices, reducing equipment complexity while maintaining high productivity through automation.
2Productivity
If conventional nucleic acid extraction methods are used, then DNA is purified, but the process requires multiple steps including complete dissolution of bone/tooth samples and extensive processing
Solution Approach 1:
The bone and tooth samples are pre-ground into fine powder before being placed in the extraction cartridge. This preliminary action increases the surface area available for demineralization and nucleic acid release, allowing the extraction process to proceed much faster without requiring complete dissolution of the sample matrix, thereby reducing total processing time while maintaining productivity.
Solution Approach 2:
Instead of requiring complete dissolution of bone and tooth samples, the method uses partial demineralization with EDTA to release sufficient nucleic acids for analysis. This partial action approach achieves the necessary DNA yield in a fraction of the time required for complete dissolution, significantly reducing processing time while maintaining adequate productivity for forensic applications.
3Loss of time
If automated systems are implemented for rapid extraction, then processing time is reduced, but device complexity increases
Solution Approach 1:
The extraction system uses a nested design where a disposable cartridge containing all extraction chambers and reagents is inserted into a simple automated instrument. The cartridge itself contains nested chambers for each processing step. This nesting allows complex extraction chemistry to be pre-packaged in a simple format that requires minimal sophisticated equipment, reducing overall device complexity while maintaining rapid automated processing.
Solution Approach 2:
The method employs disposable extraction cartridges that are pre-loaded with reagents and chamber structures. These single-use cartridges eliminate the need for complex cleaning, sterilization, and maintenance systems, reducing device complexity. The automated instrument simply loads, processes, and discards cartridges, achieving rapid processing without requiring maintainable complex systems.
4Device complexity
If simplified extraction protocols are used, then equipment requirements are reduced, but purification efficiency may be compromised
Solution Approach 1:
The extraction cartridge incorporates porous silica-based binding matrices in the DNA binding chamber. These porous materials provide high surface area for nucleic acid binding while allowing simple buffer flow through the cartridge. The porous structure enables efficient DNA purification through passive binding and washing without requiring complex equipment, maintaining purification reliability while reducing device complexity.
Solution Approach 2:
The method uses controlled changes in buffer composition (ionic strength, pH, chaotropic agents) to drive DNA binding, washing, and elution steps through the same cartridge. By changing buffer parameters rather than physical conditions, the system achieves reliable purification with simple isocratic elution, avoiding the need for complex gradient systems or sophisticated equipment while maintaining high purification quality.
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 generation of STR profiles from bone and tooth samples in under an hour and semen samples in under 30 minutes, reducing the need for specialized equipment and skilled labor, and facilitating sample-in to results-out processing.
Implementation Method 1
adding a demineralization buffer to the nucleic acid-containing material to obtain a mixture
Implementation Method 2
mixing the mixture vigorously
Implementation Method 3
separating the mixture to obtain a liquid supernatant
Implementation Method 4
degradation of any soluble DNA by nuclease treatment
Implementation Method 5
lysis of sperm cells by a sperm disruption agent (e.g. DTT or TCEP, other chemicals, or physical methods)
Data Source
AI summary
Disclosed are processes and kits for rapid nucleic acid extraction from a nucleic acid-containing material, such as a bone, tooth or semen sample. For bone and tooth process involves providing the nucleic acid-containing material in a form suitable for nucleic acid extraction, adding a lysis buffer to the nucleic acid-containing material to obtain a mixture, mixing the mixture in a manner equivalent for about 30 seconds or longer and separating the mixture by centrifugation to obtain a liquid supernatant. The liquid supernatant contains the extracted nucleic acids which can be used for analysis including STR profiling by conventional or rapid DNA analysis. For semen the processes and kits involve applying an appropriate amount of sperm disruptive agent.