Electrowetting based conformal light sensing integrated digital microfluidic chip

Abstract

The present invention discloses a conformal light-sensing structure integrated digital microfluidic chip which can monitor a chemical reaction between droplets carrying different components in a digital microfluidic chip in real-time, in the detection application field of digital microfluidic biochemical detection on consumption for a low level sample. According to the chip disclosed by the present invention, on the basis of no change of a current structure and property of electrowetting, a subwavelength scale optical sensing structure is embedded between electrowetting adjacent electrode gaps; a co-planar conformal structure with a hydrophobic layer of the electrowetting structure is kept in structure; by detecting a change of a light-sensing structure light field which is caused by a small change in a refractive index occurring during a process of the droplets reaction, determination for composition and location of a microdroplet is realized. Compared with light sensing composed of a conventional capacitor, an electrical impedance sensor, an electrochemical sensor and a discrete element, the chip disclosed by the present invention has the advantages of being simple in structure, standard CMOS compatible process which is easier to integrate, low in cost and high in accuracy. In addition, a characteristic that a sensing structure is conformal with an electrowetting structure enables a sensing function to be added without reducing the electrowetting performance.

Description

technical field [0001] The invention relates to the technical field of biochemical detection of extremely low samples, in particular to a high-sensitivity, high-precision, full-chip conformal digital micro-flow optical sensing and detection system based on the electrowetting effect. Background technique [0002] The technology based on the principle of electrowetting (Electrowetting on Dielectric, EWOD) for the transmission, separation, and merging of discrete micro-droplets is called digital microfluidic technology (Digital Microfluidic, DMF). A typical digital microfluidic chip structure is usually composed of four parts: substrate, metal electrode, insulating layer and hydrophobic layer. By applying a certain voltage (AC or DC) to the electrowetting metal electrode, the liquid droplet close to the direction of the energized electrode The wettability changes and the contact angle decreases. When the applied voltage exceeds the threshold voltage of the electrowetting operat...

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Problems solved by technology

In 2013, Frederik Ceyssens et al. adhered two 125um optical fibers to the electrowetting electrode to realize the excitation and reception of light, and achieved the purpose of detection by detecting optical absorption and other characteristics. However, the adhesion of optical fibers and hydrophobic coatings requires strong Adhesive force, easy to damage the hydrophobic layer, and at the same time bring some obstacles to the movement of droplets

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