Solution for Mass Production of High-Throughput Digital Microfluidic Chip Based on a-Si TFT with In-Pixel Boost Circuit

Abstract

As one of the most popular research hotspot of lab-on-chip, digital microfluidic (DMF) technology based on the principle of electrowetting has unique advantages of high-precision, low cost and programmable control. However, due to the limitation of electrodes number, the throughput is hard to further upgrade. Therefore, active matrix electrowetting-on-dielectric (AM-EWOD) technology is a solution to acquire larger scale of driving electrodes. However, the process of manufacturing of AM-EWOD based on thin-film-transistor (TFT) is complex and expensive. Besides, the driving voltage of DMF chip is usually much higher than that of common display products.In this paper, a solution for mass production of AM-EWOD based on amorphous silicon (a-Si) is provided. Samples of 32 × 32 matrix AM-EWOD chips was designed and manufactured. A boost circuit was integrated into the pixel, which can raise the pixel voltage up by about 50%. Customized designed Printed Circuit Board (PCB) was used to supply the timing signals and driving voltage to make the motion of droplets programmable. The process of moving, mixing and generation of droplets was demonstrated.The minimum voltage in need was about 20 V and a velocity of up to 96 mm/s was achieved. Such an DMF device with large-scale matrix and low driving voltage will be very suitable for POCT applications.

Thin-film transistor arrays for biological sensing systems

“…The device adopted polycrystalline silicon instead of amorphous silicon to achieve higher carrier mobility. In 2021, Qin et al from Nanjing University demonstrated an AM-DMF chip based on a-Si:H [62]. The pixels of the 32 × 32 matrix feature an integrated boost circuit that can raise the pixel voltage up by 50%.…”

“…Reprinted, with permission, from [56]. (b) Layout and pixel schematics of the AM-DMF chip based on 3T2C.Reproduced from[62]. CC BY 4.0.…”

Laser-induced graphene-based digital microfluidics (gDMF): a versatile platform with sub-one-dollar cost

“…Very recently, an emerging DMF device based on thin film transistors (TFTs) has also been reported. [27][28][29] Typically, it involves an active matrix of thousands of electrodes, with each electrode able to be addressed individually. Such features have promptly made the TFT-based DMF device a very hot topic, which has gained extensive interest in recent years.…”

Research progress of electrode shapes in EWOD-based digital microfluidics

“…For the portable DMF platform, it may cause large volume, and the operation of multiple droplets is troublesome. Some researchers have used large-scale electrode arrays to improve the chip's ability to control droplets in parallel, 35,36 which helps to synchronize the experiment and shorten the experimental period. It is an essential direction for the development of DMF, 37 and facilitates high-throughput analysis on the DMF chip.…”