Automated Electrowetting-Based Digital Microfluidic Chips for Next-Generation Sequencing and Sample Preparation

For identifying and characterizing unknown pathogens next-generation sequencing (NGS) technology is a prominent tool, but its usefulness in time-critical biodefense and public health applications is currently limited by the lack of fast, efficient, and reliable automated DNA sample preparation methods like automated multiplexing technique which use for switching the electrode voltage, the deciding threshold voltage, used for clinical diagnostic to protect the cell from damage and avoiding the cross talk between electrodes because of electrostatic effect to maintain droplet on proper track. We efforts to address those limitations to enhance the system performance for digital microfluidic (DMF) platform to function as a fluid distribution hub, which enabling the integration of multiple subsystem modules into an automated NGS library sample preparation system. DMF platform using an Electrowetting on dielectric (EWOD) bead assay to achieve an efficient DNA recovery. EWOD helps in discretizing the flow and hence it is called as Digital microfluidic (DMF). DMF technology offers a platform for Lab-on-a-chip (LoC), which is concerned with the design of micro total analysis system (µTAS) for chemical and biological applications. This emerging technology combines electronics with biology to open new application areas such as point-of-care diagnosis, on-chip DNA analysis, and automated drug discover

Design and Simulation of Microfluidic Passive Mixer With Geometric Variation

Microfluidic designs are advantageous and are extensively used in number of fields related to biomed ical and biochemical engineeri ng. The objective of this paper is to perform numerical simulations to optimize the design of microfluidic mixers in order to achieve optimum mixing. In the present study, fluid mixing in different type of micro channels has b een investigated. Numeric al si mulations are performed in order to understand the effect of channel geometry parameters on mixing p erformance. A two dimensional “ T shaped ” passive microfluidic mixer is restructured by employing the rectangular shaped obstacles in the chan nel to improve the mixing performance. The impact of proper placement of obstacles in the channel is demonstrated b y applying the leakage concept. It has been observed that, the channel design with non - leaky obstacles (i.e. without leaky barriers) has presented better mi xing performance in contrast to channel design with leaky obstacles (i.e. leaky barriers) and channe l design without obstacles. The mixing occurs by virtue of secondary flow and generation of vortices due to curling o f fluids in the channel o n account of t he presence of obstacles. This passive mixer has achieved complete mixing of fluids in few seconds o r some milliseconds , which is certainly acceptable to utilize in biological applications such as cell dynamics, drug scre ening , toxicological screening and others

Digital Microfluidic (DMF) devices based on electrowetting on dielectric (EWOD) for biological applications

Microfluidic devices have been used in various applications including automated analysis systems, biological applications like DNA sequencing, antigen-antibody reactions, protein studies, chemical applications, single cell studies, etc. Microfluidic devices are primarily categorised into two types. First are continuous microfluidic devices. These devices consist of predefined microchannels, micro-valves, and syringe pumps. Fluid is continuously flowing in these channels. The second type is digital microfluidic platforms. In this type, MXN array of electrodes is patterned on non-conducting substrate. Fluid is discretized to form tiny droplets. These droplets are transported, mixed and split using external electric field. Digital microfluidic devices are configurable as there are no permanently etched channels. Also, they have high throughput. Multiple reactions can be performed on the same platform at the same time. The time taken to complete one reaction is less compared to the continuous devices. Thus they help in faster analysis. These devices are controlled by electrical field and thus unlike continuous devices, digital microfluidic devices are free from mechanically moving parts. Digital microfluidic devices may suffer from charge accumulation due to electrostatic forces. Also, voltage levels applied play an important role. The applied voltage has to be enough to move droplets but should not cause electrolysis of the liquid used. Also voltage switching time between electrodes and frequency applied are important. These parameters can change the mixing quality. In this work, 2D simulations of droplet manipulation due to voltage application, transport and mixing are carried out. Also digital microfluidic device is designed and fabricated to carry out biological mixing experiments

Acoustophoretic microfluidic device for high throughput DNA sequencing

Modern DNA sequencing technique is a cumbersome, expensive and vast lab process and our aim is the miniaturization of the huge lab process which brought about the inception of the device known as “lab-on-a-chip” (LOC). Acoustophoresis is the ultrasound-induced control of the motion of particles in the microfluidic channel which is rapidly becoming a popular technology in the modern LOC devices. The factors that affect particle motion in the channel on application of acoustic wave are mainly volume of particle, compressibilities and densities of particle and medium and the acoustic pressure applied which depends on the acceleration of the piezo- crystal. Acoustophoretic transport can be modeled by Continuity equation, Navier-Stokes equation, and Convection – Diffusion equation. The resonant frequency of piezo- crystal corresponding to maximum pressure or acceleration, depends on the piezo- material, size and voltage applied to it. The present study focuses on the optimization of acoustic parameters and simulation of particle transport using COMSOL

An Effective Design and Simulation for Microfluidic Passive Mixing with Geometric Variation

[Abstract not available

Advanced Microfluidic Mixing Device for the Study of Macromolecule Dynamics

[Abstract not available

Electrowetting and Droplet Transport in Digital Microfluidic Chips for Mixing Applications

Microfluidics- based biochips have varies applications like high throughput analyses, DNA sequencing, automated drug discovery, real time bio-molecular recognition, parallel immunoassays, single cell studies and protein RNA interaction and environmental toxicity monitoring. Based upon the fluid flow pattern microfluidic based devices can be categorized in two types. They are continuous flow microfluidic device and discrete flow microfluidic device or digital microfluidic. The continuous flow uses permanently etched microchannels, micro-pumps, and micro-valves for the application such as mixing, splitting, and transportation. In contrast to this discrete type flow uses array of electrodes, voltage to controlled droplet independently for the same application

In-vitro antioxident and free radical scavenging activity of Alternanthera sessilis

The present study was aimed to evaluate the antioxidant activity of A.sessilis plant extracts in different solvents. The antioxidant activity was studied by phosphomolybdate method and DPPH method. In phosphomolybdate method the highest activity was shown by methanolic extract (12.044 mM of ascorbic acid eqvt/gm of sample). The highest radical scavenging activity by DPPH method was found in methanol extracts (IC 50 587.093µg/ml). Ferrous chelating activity, superoxide radical scavenging activity, nitric oxide radical scavenging activity was found high in acetone, acetone and methanol extracts respectively. Total Flavonoids and crude phenolics were found to be 0.370 mg/gm dry wt. and 1.529 mg/gm dry wt. respectively. The antioxidant activity increases with increase in the concentration. This study indicates that A.sessilis is a potential source of natural antioxidant

Primary temporal bone angiosarcoma: a case report.

We present a rare case of temporal bone angiosarcoma diagnosed in a 26-year-old female patient at 36 week of pregnancy. The patient was referred with a 2 months history of left otalgia and tinnitus with a tender swelling above the mastoid. Cranial imaging studies showed a 7 x 5 x 4 cm hypervascularized mass located in the left middle fossa with lysis of the temporal bone and extension to the subcutis. After the baby was delivered by caesarean section, the patient entered the oncology protocol. Selective embolization of the feeding vessels was followed by gross total surgical resection using a combined supra- and infra-tentorial approach. Pathological findings were those of a poorly differentiated, highly malignant sarcoma with a large epitheloid component and immunohistochemical evidence of endothelial differentiation (CD31, Factor VIII related antigen, CD34), consistent with an angiosarcoma with epitheloid features. No extra-cranial tumor was found after extensive staging. The patient received adjuvant radiotherapy followed by a course of chemotherapy consisting of 6 cycles of paclitaxel. At 15 months follow-up, she developed multiple distant metastasis to a left postauricular lymph node and to the lungs and ribs. The patient was given a second line chemotherapy using doxorubicine and ifosfamide. Despite an initial good response, she died with metastatic disease 26 months after diagnosis. We present a rare case of primary temporal bone angiosarcoma and report our experience with a multimode therapeutic approach combining surgery, radiotherapy and chemotherapy.Peer reviewe

Combined effects of a third-generation bisphosphonate, zoledronic acid with other anticancer agents against murine osteosarcoma

Bisphosphonates (BPs) are widely used to treat bone diseases and also appear to possess direct antitumour activity. We have previously reported that third-generation BPs such as zoledronic acid (ZOL) and minodronic acid (YM529) synergistically augment the effects of anticancer agents in various cancer cells. Recently, we have also reported the antitumour effects of YM529 on murine osteosarcoma cells. As YM529 has not been clinically available, we herein focused on the anti-osteosarcoma effects of ZOL which is clinically available. In addition to ZOL alone, we evaluated the concurrent or sequential combined effects of ZOL with other anticancer agents against murine osteosarcoma cell lines. ZOL showed almost same anti-osteosarcoma activity compared with YM529 and more sensitive growth inhibitory effects against osteosarcoma cells than normal cells. Moreover, ZOL acted synergistically in vitro when administered concurrently with paclitaxel (PAC) or gemcitabine (GEM), not only in wild-type osteosarcoma cells but also in P-glycoprotein (P-gp)-overexpressing osteosarcoma cells, which were much less sensitive against each anticancer agent. Furthermore, 24 h of ZOL pretreatment significantly augmented the sensitivity of doxorubicin (DOX), PAC or GEM against osteosarcoma cells. These findings suggest that combined administration of ZOL with other anticancer agents may improve the osteosarcoma treatment