Microfluidic Device for Uniform Bacterial Culture Distribution
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Solution Overview
Problem
Current fluidic devices for determining the susceptibility of bacterial cultures to antimicrobial drugs are labor-intensive, prone to errors due to manual filling, and suffer from gas bubble interference, which affects the accuracy of minimum inhibitory concentration (MIC) determination and heteroresistivity analysis.
Innovation Solution
A multi-layer microfluidic device with a top layer containing an injection opening and a fluid distribution system, ensuring equal distribution of bacterial cultures across wells, minimizing gas bubble formation, and allowing for controlled growth conditions, thereby enhancing the accuracy of MIC determination and other optical analysis processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual filling of wells is used, then device complexity is reduced, but manufacturing precision and reliability deteriorate due to labor intensity and error-proneness
Solution Approach 1:
The fluid distribution system automatically distributes fluid from a single injection opening to multiple wells without manual intervention. The system uses passive fluidic principles where fluid injected into the distribution system automatically flows through channels to fill all wells, making the system self-servicing and eliminating the need for complex automated liquid handling robots while ensuring precise and equal filling of all wells.
2Ease of manufacture
If manual filling is used, then device complexity is reduced, but productivity deteriorates due to labor intensity and time consumption
Solution Approach 1:
The invention merges the fluid distribution function into the device structure itself by integrating a distribution system with multiple channels that simultaneously deliver fluid to all wells. This allows a single injection action to fill multiple wells at once, dramatically increasing throughput compared to manual well-by-well filling, while keeping the device structure relatively simple and manufacturable.
3Measurement precision
If multiple wells are used for analysis, then measurement precision is improved through parallel testing, but object-generated harmful factors worsen due to gas bubble formation and mutual contamination
Solution Approach 1:
The invention extracts and removes gas bubbles from the system by providing dedicated vent openings that allow bubbles to escape from the distribution channels and wells. This prevents bubbles from interfering with optical measurements while maintaining the benefits of multiple parallel wells for improved measurement precision and statistical reliability.
4Productivity
If fluid is injected into multiple wells simultaneously, then productivity is improved, but manufacturing precision deteriorates due to volume variations between wells
Solution Approach 1:
The distribution system is designed with channels of equal length and equivalent hydraulic resistance leading to each well, creating equipotential conditions that ensure equal fluid distribution to all wells simultaneously. This passive fluidic design uses pressure equilibrium to automatically balance the fluid volume delivered to each well, eliminating the need for complex active control mechanisms while achieving both high productivity and precise volume uniformity.
Data Source
AI summary
The invention relates in a first aspect to an improved fluidic device for determining a property of a microbe. The device comprising a bottom layer comprising a plurality of light-transmissive wells; and a top layer comprising an injection opening and a fluid distribution system. Each of said plurality of distribution channels has: essentially the same channel length between the inlet end and the outlet end; and essentially the same channel volume. The invention relates in a second aspect to a use of the device for determining a susceptibility of a microbe, preferably a bacterium, to an antimicrobial drug.