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The use of microfluidic devices for conduction of biomedical research and creation of clinically useful technologies has numerous advantages. Such devices reduce reagent consumption, allow a higher control for mixing and sample manipulation, can integrate and automate multiple assays in parallel and facilitate their imaging and tracking for detection with high precision.
Microfluidics is the technology that works with the fluid flow inside a set of channels whose diameter is in micrometers. Microfluidic devices must have the capabilities of manipulation of the nanoliter to the picoliter volume liquid inside the devices. One of the main characteristics of the devices powered by microfluidic technology is that, it should have at least one channel with dimensions less than one mm.Fluids containing blood cells, protein, bacterial cell suspensions and buffers required for mixing are commonly used in channels of microfluidic tools. The application of microfluidic devices to conduct biomedical and biochemical research has several advantages. Compared to traditional laboratory process, microfluidic technologies offers a fewer amount of reagent consumption, much higher portability, simultaneous execution of different operations and detection of results with much higher precision.
Powered by the fast advancement of micro-fabrication technology, Microfluidic biochip also known as lab-on-chips emerges as a new set of tools as a replacement of traditional laboratory process for biomedical applications. The rapid improvement semi-conductor field and areas of biochemistry in 1980 onwards, set the platform for the advancement of the biochip technology in large scale in 1990 onwards.
The early generation of biochip is known as continuous flow based biochip where chips were built with a number of micro-channels etched into silicon, glass or polymer substrate known as PolyDiMethylSiloxane (Verpoorte & Rooij, 2003).
These connected micro-channels form a network where actuators were involving to controlling the flow of fluids. Micro-valves along with the actuators were involved to perform required fluid operations like pumping, monitoring, mixing and monitoring biochemical environment (Nguyen & Wereley, 2002; Hu, Tsung, & Chakrabarty, 2014).
These channels are connected together to form a network and the flow through such channels were controlled through actuators and microvalves to perform the necessary fluidic operations like mixing, pumping, sorting and monitoring of the biochemical environment.These continuous flow based biochip did offer less flexibility, narrow reconfigurability and limited fault tolerance.
To overcome all above mentioned problems, a new generation of biochip has emerged where instead of continuous liquid flow, liquid droplets has been used (Pollack, Fair, & Shenderov, 2000). This new generation of biochip is termed as digital microfluidic biochips (DMFBs).
This new technology offers advantages such as individual droplet manipulation, reagent isolation, higher reconfigurability and support array based procedures compatible with biomedical and biochemical applications (Pollack, Fair, & Shenderov, 2000; Cho, Moon & Kim, 2003).
Figure 1. Top view of a DMFB (Bhattacharya, Roy & Rahaman, 2017)