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The industrialization of microfluidic chips has long faced a practical tension: laboratory‑level prototypes tend to be costly, while designs intended for mass production often compromise on flexibility. In recent years, PCB‑based microfluidic solutions have drawn growing attention from researchers. This article introduces a PCB‑integrated electrochemical microfluidic array chip that uses PMMA (acrylic)夹具 as a clamping package, offering a relatively systematic overview of its structural design, material choices, and potential applications.
I. Structural Design
1. PCB Electrode Layer
The core of the chip is a green FR‑4 printed circuit board, on which a radial wiring layout leads to a circular array of individual working electrodes (labeled U17 to U33). The electrode surfaces are gold‑plated, taking advantage of gold’s chemical inertness and low impedance, making them suitable for electrochemical detection.
Each electrode has its own independent trace, allowing connection to a multi‑channel potentiostat. This enables parallel detection as well as droplet manipulation via electrowetting‑on‑dielectric (EWOD) or dielectrophoresis. The radial routing is a straightforward design choice—it shortens trace lengths and helps reduce crosstalk between adjacent electrodes.
2. Microfluidic Cavity Layer
Between the PCB and the top cover plate, a transparent PMMA (acrylic) sheet is sandwiched, with two independent microfluidic cavities etched into it. Three PTFE tubing ports are provided for sample inlet, waste outlet, and buffer solution flow, allowing liquid samples to be introduced.
The dual independent chambers offer the benefit of running two sets of experiments without cross‑interference, which is convenient for control experiments or parallel sample assays.
3. Packaging Clamp
The packaging consists of upper and lower transparent acrylic plates secured by stainless steel locking screws, achieving fluidic sealing through mechanical compression. This approach has several notable features: it does not require thermal bonding, thus avoiding potential heat‑induced damage to electrodes or channel structures; it is disassemblable, so the chip can be cleaned and reused after use; and the acrylic is transparent, allowing compatibility with inverted microscopes for optical observation.
II. Considerations on Material Selection
PCB electrodes offer relatively low fabrication costs for volume production, high precision in electrode array layout, and individually addressable channels—these characteristics make them a viable alternative to conventional ITO glass electrodes in certain contexts. For high‑throughput parallel experiments, the PCB approach shows a clear cost‑effectiveness advantage. The gold surface is well‑suited for biosensing and electrochemical voltammetry, which are mature application areas.
PMMA acrylic exhibits good chemical inertness and is compatible with aqueous buffers and some mild organic solvents. Its optical transparency supports fluorescence and bright‑field microscopy. The mechanically clamped structure means the chip can be disassembled, cleaned, and reused—a feature that may be particularly attractive for research groups with limited budgets.
The mechanical locking mechanism eliminates the need for adhesives, avoiding potential contamination of microchannels by glue residues. Assembly and disassembly are straightforward, and the clamp can accommodate different thicknesses of the microfluidic interlayer—if a different channel design is needed, only the middle layer needs to be replaced.
III. Typical Application Scenarios
Biosensing is one of the most direct applications. The multi‑channel parallel detection capability allows simultaneous electrochemical signal acquisition from proteins, nucleic acids, cellular metabolites, and small‑molecule biomarkers (e.g., glucose, dopamine).
Digital microfluidics (EWOD) —the radial electrode array can be employed for dielectrophoretic and electrowetting manipulation, enabling droplet sorting, mixing, and reactions.
High‑throughput drug screening can leverage the dual independent channels to collect electrochemical signals from both control and experimental groups in parallel, improving experimental efficiency.
Rapid environmental water quality testing—the multiple channels can concurrently measure heavy metals, organic pollutants, and other indicators.
IV. Key Design Features
In summary, the chip embodies several clear design priorities:
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Dual independent reaction chambers, free from mutual interference, suitable for parallel assays;
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Radial wiring shortens trace lengths, helping to reduce inter‑electrode crosstalk;
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A relatively large number of arrayed electrodes supports high‑throughput parallel data acquisition;
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Modular and disassemblable—the PCB electrode, microfluidic channel, and clamp can be individually replaced or maintained.
V. Supporting Equipment
Using this type of chip requires a multi‑channel potentiostat to read current or voltage signals from each electrode. For simultaneous optical monitoring, an inverted microscope can be placed beneath the chip to enable combined electrochemical and optical imaging.
Concluding Remarks
The PCB‑plus‑PMMA‑clamp approach essentially strikes a balance among cost, performance, and flexibility. It is neither a single‑use disposable chip nor a complex, expensive all‑glass device. For research that involves frequent protocol adjustments or aims to reduce long‑term operating costs, this modular, reusable design may be worth considering.
