Optically Activated Transistor Arrays for Microfluidic Cell Manipulation
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Solution Overview
Problem
Current microfluidic devices face challenges in efficiently generating localized electrokinetic forces to move micro-objects within the fluidic medium, which is essential for precise manipulation and processing of biological cells and particles.
Innovation Solution
The microfluidic device incorporates an array of transistor structures with both lateral and vertical bipolar transistors on a common conductor, where activating these transistors creates non-uniform electric fields to generate electrokinetic forces, enhancing the movement of micro-objects by directing a beam of light onto the base region of the transistor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional electrokinetic configurations are used in microfluidic devices, then the device structure remains simple, but the strength of localized electrokinetic forces is insufficient for effective manipulation of micro-objects
Solution Approach 1:
The base is segmented into multiple discrete transistor structures arranged in an array, each capable of being independently activated to generate localized electrokinetic forces at specific positions within the microfluidic device
Solution Approach 2:
Lateral and vertical bipolar transistors are merged into a single integrated transistor structure, where the lateral transistor connects the outer surface to a common conductor and the vertical transistor provides additional current flow path, together generating enhanced electrokinetic forces
2Measurement precision
If multiple electrode configurations are used to generate localized electrokinetic forces, then the force localization improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Traditional mechanical or electrical electrode configurations are replaced with optically-controlled transistor structures, where light activation of the transistor base regions enables precise spatial and temporal control of electrokinetic force generation without complex wiring or mechanical switching
Solution Approach 2:
The transistor structures provide dynamic control of electrokinetic forces through optical activation, allowing the system to adaptively generate forces at different positions and times by controlling which transistors are activated, rather than requiring fixed electrode configurations
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 configuration enables precise and efficient movement of micro-objects, such as beads and biological cells, within the fluidic medium by inducing localized electrokinetic forces, improving the manipulation and processing capabilities of microfluidic devices.
Implementation Method 1
activating a first of the transistor structures creates an electrokinetic force in the vicinity of the activated first transistor structure sufficient to move a nearby micro-object
Implementation Method 2
an optically-actuated electrokinetic configuration and, in particular, an optically-actuated dielectrophoresis (DEP) configuration
Implementation Method 3
activating a first of the transistor structures at a first of the regions of the outer surface of the base
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A microfluidic device can include a base an outer surface of which forms one or more enclosures for containing a fluidic medium. The base can include an array of individually controllable transistor structures each of which can comprise both a lateral transistor and a vertical transistor. The transistor structures can be light activated, and the lateral and vertical transistors can thus be photo transistors. Each transistor structure can be activated to create a temporary electrical connection from a region of the outer surface of the base (and thus fluidic medium in the enclosure) to a common electrical conductor. The temporary electrical connection can induce a localized electrokinetic force generally at the region, which can be sufficiently strong to move a nearby micro-object in the enclosure.