Microfluidic Sample Collection Device with Magnetic Mixing
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Solution Overview
Problem
Conventional methods for capturing and processing biological samples, such as saliva, face challenges in ensuring the correct sample volume, secure containment, efficient mixing, and contamination-free nucleic acid extraction and amplification, particularly in point-of-care settings where user error and contamination risks are high.
Innovation Solution
A collection device with a diluent blister and magnetic capture particles, along with a microfluidic cartridge and extraction tube, ensures secure sample handling and automatic mixing, preventing user interference and contamination, and facilitates efficient nucleic acid extraction and amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sample collection methods are used, then users can obtain samples, but it is difficult to ensure the correct sample volume and secure containment
Solution Approach 1:
The collection device is divided into separate functional components: a collection chamber for sample intake, a diluent chamber for reagent storage, and a mixing chamber for processing. This segmentation allows each component to be optimized for its specific function, ensuring accurate sample volume control while maintaining ease of use through modular assembly
Solution Approach 2:
The diluent and capture particles are pre-loaded into the collection device in controlled amounts during manufacturing. This preliminary action eliminates the need for users to measure or add reagents manually, ensuring correct sample volume and reagent ratios while simplifying user operation to merely adding the biological sample
2Reliability
If manual mixing is used, then users can mix sample with components, but mixing may be interrupted by user error or inadequate mixing
Solution Approach 1:
The collection device incorporates a magnetic mixing mechanism where magnetic capture particles are manipulated by an external magnetic field to dynamically mix with the sample. This dynamic mixing approach ensures complete and consistent mixing without manual intervention, while the magnetic field application remains externally controlled rather than requiring complex internal mechanical structures
Solution Approach 2:
Magnetic fields serve as an intermediary mechanism to induce mixing between the sample and capture particles. The magnetic field acts as a non-contact mediator that drives the magnetic beads to move and mix with the sample, achieving reliable mixing without direct mechanical contact or complex internal mixing mechanisms
3Reliability
If conventional extraction methods are used, then nucleic acid can be extracted, but contamination risk increases at extraction and analysis stages
Solution Approach 1:
The collection device merges sample collection, reagent storage, mixing, and nucleic acid extraction into a single integrated system. The extraction tube is directly connected to the collection chamber, allowing the sample to flow directly into the extraction reagents without intermediate transfer steps. This merging eliminates multiple handling opportunities that could introduce contamination while maintaining rapid processing through streamlined fluid flow
Solution Approach 2:
The magnetic capture particles are selectively extracted from the sample matrix using magnetic field separation. This extraction method allows capture particles bound to target nucleic acids to be separated from the liquid sample phase, concentrating the target while preventing contamination from other sample components. The magnetic separation occurs within the integrated device without requiring open manipulation
4Reliability
If multiple components are stored separately, then components can be preserved, but ensuring they mix adequately at the right stage increases complexity
Solution Approach 1:
Reagents and capture particles are pre-loaded into the device in their stable, separate compartments during manufacturing. The diluent is stored in a sealed chamber and capture particles are pre-mixed with stabilization agents in their storage location. This preliminary preparation maintains component stability during storage while the device structure guides their automatic mixing at the appropriate stage of sample processing
Solution Approach 2:
The device structure enables sequential mixing of components at different stages: first the diluent mixes with the biological sample, then capture particles are introduced and mix with the diluted sample, and finally extraction reagents are added. This periodic, staged mixing approach ensures each component mixes adequately at the right time while the integrated design maintains relatively simple structure through natural fluid flow
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
The solution enables rapid, accurate, and contamination-free nucleic acid extraction and amplification, suitable for point-of-care use by both medical and non-medical professionals, with the collection device ensuring adequate sample preparation and the microfluidic cartridge facilitating efficient processing and analysis.
Implementation Method 1
capture particles such as magnetic beads can also be housed with the diluent within the diluent blister
Implementation Method 2
a heat-deformable extraction tube
Implementation Method 3
configured for carrying out thermocycling for amplification and detection of nucleic acid
Data Source
AI summary
A collection device for a biological sample to capture target compounds such as viruses or other pathogens or particles for testing from within the sample and move the captured target compound to a separate chamber for subsequent processing. The collection device can include an openable substance blister including capture particles located in a cup interior. Capture particles can attract and bind the target compounds from the sample. An extraction tube extracts any nucleic acid from the target compound for storage or subsequent amplification and testing to confirm presence of known microorganisms. The extraction tube can comprise a heat-deformable material and can be connected to a microfluidic cartridge for further processing of nucleic acid including, amplification and detection. The microfluidic cartridge includes valves and a plurality of chambers for amplification.