Arpan Chakraborty

Bio: Arpan Chakraborty is an academic researcher from University of Calcutta. The author has contributed to research in topics: Biochip & Simple polygon. The author has an hindex of 4, co-authored 25 publications receiving 48 citations.

A technology shift towards triangular electrodes from square electrodes in design of Digital Microfluidic Biochip

Abstract: Digital Microfluidic Biochip (DMFB) is a ground-breaking invention in many areas of Microelectronics, Biochemistry, and Biomedical sciences. It is also known as ‘Lab-on-a-Chip’ for its performance as an alternative for laboratory experiments. Various types of diagnosis procedures are performed on it through a sequence of modular operations like sample preparation, mixing, and detection. Mixing is the most important operation of DMFB as the outcome of the experiment is almost dominated by mixing. A good mixing of corresponding sample and reagent gives proper result while an improper mixing leads to erroneous result, which may be the reason to discard the assay. So, our objective is the betterment of mixing operation. In this paper, we have proposed a design using equilateral triangular electrodes instead of square electrodes, maintaining all the constraints required to ensure safe droplet movement and other modular operations, while improvement of the mixing operation is the key design issue.

Fluid-level synthesis unifying reliability, contamination avoidance, and capacity-wastage-aware washing for droplet-based microfluidic biochips

Abstract: Production of correct bioassay outcome is the foremost objective in digital microfluidic biochips (or DMFBs). In high-frequency DMFBs, continuous actuation of electrodes leads to malfunctioning or even breakdown of the system. The improper functioning of a biochip tends to produce erroneous results. On the other hand, while transporting droplets, the residues may get stuck to electrode walls and cause contamination to other droplets. To ensure proper assay outcome, washing becomes mandatory, whose incorporation may delay the bioassay completion time significantly. Furthermore, each wash droplet possesses a capacity constraint within which the residues can be washed off successfully. Evidently, the design objectives possess a large degree of trade-offs among themselves and must be attacked to prepare an efficient platform. Here, the authors propose a complete fluid-level synthesis considering all the essential goals together instead of dealing with them in isolation. The presented approach effectively handles the trade-off scenarios and provides flexibility to the designer to decide the threshold of the individual optimisation objective leading to the construction of a good-quality solution as a whole. The performance is evaluated over several benchmark bioassays.

Design Optimization at the Fluid-Level Synthesis for Safe and Low-Cost Droplet-Based Microfluidic Biochips

Abstract: Droplet-based Digital Microfluidic Biochips (or DMFBs) are now being the prime platform for a number of point of care diagnostics, clinical studies, and sample preparations. Several design optimization methods exist at the fluid-level that automate the tasks of a DMFB. However, in high frequency applications, its performance heavily deteriorates in the order of degrading electrodes producing incorrect outcomes. Vague results may also be generated if cross contamination during droplet routing is not avoided. We define a DMFB to be safe if it is capable of handling reliability and also free from cross contamination. Alongside, as the fluid-level of DMFBs comprises several tasks that altogether introduces design cycles and leads to higher cost, a low-cost platform is urgently required. This paper proposes a fluid-level design for DMFBs that considers the above facts together. A graph model has been used to tackle them. An exact algorithm is presented. The obtained results are validated with several benchmarks.

A Capacity-Aware Wash Optimization for Contamination Removal in Programmable Microfluidic Biochip Devices

Abstract: Flow-based microfluidic biochips have emerged as a potential lab-on-chip platform for numerous biochemistry operations. Among various flow-based biochips, Programmable Microfluidic Devices (PMDs) receive much attention due to its capability of performing functionalities on a single platform with no hardware modifications. High precision control and production of correct outcomes are the urgent needs in the PMDs. While sharing the micro-channels, a fluid-flow may be contaminated by the residues stuck on the channel. Washing of the microchannels with buffer fluid is an immediate solution for safe execution of biochemistry. However, each wash fluid has a finite washing capacity and can wash only a limited number of contaminated spots. In this paper, we propose a wash optimization model that aims to remove all the contaminations while minimizing washing time and total capacity wastage. The effectiveness of the proposed approach has been evaluated considering a number of baseline methods and the previous works.

Triangulating a simple polygon in linear time

Abstract: We give a deterministic algorithm for triangulating a simple polygon in linear time. The basic strategy is to build a coarse approximation of a triangulation in a bottom-up phase and then use the information computed along the way to refine the triangulation in a top-down phase. The main tools used are the polygon-cutting theorem, which provides us with a balancing scheme, and the planar separator theorem, whose role is essential in the discovery of new diagonals. Only elementary data structures are required by the algorithm. In particular, no dynamic search trees, of our algorithm.

Advances in Testing Techniques for Digital Microfluidic Biochips

Abstract: With the advancement of digital microfluidics technology, applications such as on-chip DNA analysis, point of care diagnosis and automated drug discovery are common nowadays. The use of Digital Microfluidics Biochips (DMFBs) in disease assessment and recognition of target molecules had become popular during the past few years. The reliability of these DMFBs is crucial when they are used in various medical applications. Errors found in these biochips are mainly due to the defects developed during droplet manipulation, chip degradation and inaccuracies in the bio-assay experiments. The recently proposed Micro-electrode-dot Array (MEDA)-based DMFBs involve both fluidic and electronic domains in the micro-electrode cell. Thus, the testing techniques for these biochips should be revised in order to ensure proper functionality. This paper describes recent advances in the testing technologies for digital microfluidics biochips, which would serve as a useful platform for developing revised/new testing techniques for MEDA-based biochips. Therefore, the relevancy of these techniques with respect to testing of MEDA-based biochips is analyzed in order to exploit the full potential of these biochips.

Beyond high voltage in the digital microfluidic devices for an integrated portable sensing system

Abstract: Digital microfluidics (DMFs) show great potential in the fields of lab-on-a-chip applications for electro-chemical as well as biochemical sensing for decades. Various types of DMF devices have been demonstrated to improve their capabilities such as smaller device size for portability, higher reliability, and multi-purpose applications, etc. Among them, the electrowetting on dielectric (EWOD) is one of the most widely used mechanisms to manipulate droplets due to its good flexibility. On the other hand, the high-voltage application that required for EWOD-type DMF also limits the portability and dimension of the whole system. In this review, we discuss the DMFs which are powered by alternative sources other than electrical sources and evaluate their potential for future portable biochemical assays. Then, the demonstrations reported with the possibility beyond high voltage are discussed starting from lowering voltage requirement for EWODs to the unique methods using mechanical, optical, and energy harvesting to power DMF devices. Finally, the practical applications and prospective on the integrated multi-functional lab-on-a-chip applications are tackled.