Microfluidic dynamic system for biological fluids viscosity measurements (original) (raw)

A biodynamic microsystem for fluids viscosity measurements

Journal of Physics: Conference Series, 2006

The purpose of this research was to model, design and fabricate a biodynamic analysis microsystem required for determination of various molecular transport properties of the biological fluids. In order to achieve this, a lab-on-a-chip device was fabricated. The microfluidic system developed satisfies the objectives for the study of microcirculation and characterization of cell rheological properties, functions and behaviour. The measurement principle of the viscosity of biological fluids is based on the detection of the rotation of a polysilicon gear-wheels system. The gear-wheels have external diameters of 250 μm, 200 μm, 160 μm and 3 μm thickness. The micromachining process combines the undercut and refill technique with pin-joint bearing permitting the fabrication of bushings that were used to elevate the rotor away from the silicon surface. The testing of the microfluidic dynamic system was performed using electromagnetic micropumps and magnetic controllers. Each device was fabricated by silicon micromachining technology and tested to obtain the specific characteristics.

Manipulation and Flow of Biological-Fluids in Straight Channels Micromachined in Silicon

Clinical Chemistry

Analysis of minute sample volumes is a major analytical challenge that requires an understanding of fluid flow in microstructures. Accordingly, flow dynamics of biological fluids and cell suspensions in straight glass-capped silicon microchannels (40 to 150 m wide, 20 and 40 m deep) were studied. We demonstrated that these microstructures are appropriate components for microfluidic analytical devices. Different fluids were easily manipulated in the microchannels, and measurements of flow rate as a function of pressure for whole human blood, serum, plasma, and cell suspensions revealed non-Newtonian behavior. By means of micromachined filters (5 m) located in channels, blood cells and microparticles were effectively separated from nanoliter-sized samples, clearly indicating the future role of microstructures for a variety of analytical purposes.

Characterisation of microfluidic devices

2002

Silicon micromachining techniques have enabled the fabrication of a wide range of microfluidic components and systems. Given the small volumes of liquid and low flow rates involved, the accurate characterisation of such systems presents a challenge. To date many of the measurements have been performed manually; this is both time consuming and prone to inaccuracies. This paper describes an automated measurement technique and presents results for a surface micromachined valve.

APPLICATIONS OF MICROFLUIDIC SYSTEMS IN BIOMEDICAL ENGINEERING

INTRODUCTION Microfluidics is the science and technology of systems that process or manipulate small (10–9 to 10–18 litres) amounts of fluids, using channels with dimensions of tens to hundreds of micrometres. Its first Application is in analysis, in which it offer a number of useful capabilities which include the ability to use very small quantities of samples and reagents, and to carry out separations and detections with high resolution and sensitivity. Using Microfluidics in this Application greatly reduced cost and time of analysis. Microfluidics is a compound word, Micro meaning small size and fluidic, gotten from fluid (Liquid or Gas) thus to a layman, Microfluidics is the playing around with small Liquids or gases. Microfluidics offers fundamentally new capabilities in the control of concentrations of molecules in space and time. As a technology, Microfluidics seems almost too good to be true: it offers so many advantages and so few disadvantages. But it has not yet become widely used. Microfluidics systems are devices in which low volumes of fluids are processed to achieve multiplexing, automation, and high-throughput screening. Such Devices emerged in the early 80s and have been used in the development of inkjet printheads, DNA chips, lab-on-a-chip technology, micro-propulsion, and micro-thermal technologies. It deals with the behavior, precise control and manipulation of fluids that are geometrically constrained to a small, typically sub-millimeter scale. Microfluidics systems typically comprises of active (micro) components such as micro pumps and micro valves. Micro pumps supply fluids in a continuous manner and can be used for dosing. Micro valves determine the flow direction or the mode of movement of pumped liquids. Often processes which are normally carried out in a lab are miniaturized on a single chip in order to enhance efficiency and mobility as well as reducing sample and reagent volumes. Microfluidics Systems have a broad range of Application but in this Pepar, we will concentrate on its Applications in Biomedical Engineering.

Innovative Design and Modeling of a Micropump: A Microfluidics Application

2012

An electroosmotic micropump is a device capable to be used as a source of hydraulic pressure from the application of small voltages. Due to the absence of mobile parts and because it allows the movement of fluids, the micropump has became into an essential component of micro-laboratories (labs-in-chip). The labs-in-chip have important applications in medicine in the early detection of diseases like cancer or tuberculosis. The physical laws modeling a micropump are those of fluid mechanics (Navier-Stokes eqs.), as well as the diffusion equation for current density. The velocity of the fluid and the electric field are related by means of the Helmholtz-Smoluchowski equation, which is used to set certain boundary conditions. This paper presents three innovative designs of a micropump that effectively produce hydraulic pressure. Furthermore, proven scientific studies are referenced in order to validate the mathematical method and to make a comparison, highlighting the advantages of the proposed designs.

Microfluidics chip design analysis and control

Journal of Mechatronics and Artificial Intelligence in Engineering

Micro-Electro-Mechanical Systems (MEMS) is an integrated electromechanical system where the feature size and operating range of the components are on a micro-scale. Unlike traditional mechanical processing, the production of the MEMS device uses semiconductor manufacturing, which includes surface microprocessing and bulk microprocessing, which can be compatible with an integrated circuit. These devices or systems have the ability to detect, control, activate, and create macro-scale effects. In this study, a 3-channel microfluidic channel design was realized by using the SolidWorks program, which is a 3D design program, to realize a microfluidic chip design. The preliminary physical tests and investigation of this microfluidics were made using the Comsol Multiphysics program and necessary time-dependent pressure tests. In this study, it is aimed to understand the pressure and speed values of the microfluidic chip according to the analysis. As a result of the analysis, it was found that the microfluidic chip has a maximum pressure of 6.1 Pa and a speed of 2.36×10 14 mm/s.

Microfluidics and Microfabrication

2010

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Microfluidics: from Engineering to Life Sciences

Current Nanoscience, 2012

This interdisciplinary view of microfluidics at the interface with life sciences starts with presentation of the advantages and challenges presented by microfluidic devices. The forces important for flow in microchannels are discussed and special emphasis is placed on electrokinetic effects. The laws and principles governing flow in microchannels are compared to those important in macroflow and experimental methods used to measure flow in microchannels are introduced. Because flow in microchannels is laminar, for many applications there is need to enhance mixing and different ways to achieve this are presented herein. Due to the important influence of surface interactions for microfluidics, the materials used to manufacture microchannels are very important in flow control. A separate section discusses glass, silicon-based materials, and newer soft polymers used in microfluidic devices and the connection between their structure and the properties they impart to the flow. The field in which there are already numerous commercially available microfluidic devices is biotechnology. Some applications are discussed in a separate section. Lab-on-a-chip devices, due to their importance, are presented in a separate unit. Future directions of research in this interdisciplinary field are briefly discussed.

Application and Manufacturing of Microfluidic Devices: Review

IJMER

Abstract:Micro fluidic devices are gaining increasingly popularity owing to their many advantages. Microfluidics varies in terms of forces operating from other domains as well as from macro-scale fluidic devices. Effects which can be omitted on a macro scale are dominant when fluid dynamic faces the issue of scale. With the recent achievement in the biotechnology, microfluidic devices promise to be a big commercial success. To have a better understanding of the various types of microfluidic devices, their application areas, basic design and manufacturing issues, a brief review is carried out and reported in this paper. Few devices and their applications are discussed.