Applications of microfluidic systems in biomedical engineering felix chibuzo obi 20144610

APPLICATIONS OF MICROFLUIDIC SYSTEMS IN BIOMEDICAL ENGINEERING

PRESENTED BY FELIX CHIBUZO OBI (20144610)BIOMEDICAL ENGINEERING, MSc

Email: [email protected]

SUPERVISED BY ASSO. PROF. TERIN ADALI

FACULTY OF ENGINEERINGDEPARTMENT OF BIOMEDICAL

ENGINEERING

mailto:[email protected]

Presentation Outline• INTRODUCTION

• COMPONENETS OF A MICROFLUIDICS SYSTEM

• APPLICATION OF MICROFLUIDICS SYSTEN IN BIOSENSING

• APPLICATION OF MICROFLUIDICS IN MEDICAL DIAGONOSIS AND TREATMENT

• CONCLUSION

• REFERENCES

APPLICATIONS OF MICROFLUIDIC SYSTEMS IN BIOMEDICAL ENGINEERING, FELIX C. O. 2015 2

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 Presentation, we will concentrate on its Applications in Biomedical Engineering.



COMPONENETS OF A MICROFLUIDICS SYSTEM Microfluidics system typically consists of a micropump, micromixer,

valve, separator and concentrator. Among these components, micropumps and micromixers are the key components for microfluidic applications due to their actively functioning capability. The types of micropumps vary widely in terms of design and application but can be generally categorized into two main groups: mechanical and non-mechanical pumps. Conventional mechanical micropumps represent smaller versions of macrosized pumps that typically consist of a microchamber, check valves, microchannels and an active diaphragm to induce displacement for liquid transportation. Thermal bimorph, piezoelectric, electrostatic and magnetic forces, as well as shape memory mechanisms, have been utilized to actuate the diaphragm. These micropumps are relatively complicated, expensive, typically made by multi-wafer processes and difficult to be integrated with other systems such as integrated circuits (IC) for control and signal processing due to incompatible processes and structures. They generally have a large dead volume, leading to excessive waste of biosamples and reagents which are very expensive and precious in biological analysis, especially for forensic investigations. These micropumps typically have moving parts which lead to a high failure rate, low production yield in fabrication and poor reliability in operation.


These technologies are based on the manipulation of continuous liquid flow through micro fabricated channels. Actuation of liquid flow is implemented either by external pressure sources, external mechanical pumps, integrated mechanical micropumps, or by combinations of capillary forces and electro kinetic mechanisms.

Fig 1: A Micropump Fig 2: A Microvalve

APPLICATION OF MICROFLUIDICS SYSTEM IN

BIOSENSING• Microfluidic Systems have important application in

Biosensing which is an important part in Biomedical Engineering. The System typically consists of a set of fluidic operation units that allow different biomolecules to be detected and assayed in an easy and flexible manner. The chip-based platform has good integration with micro/nano-fluidic components and is capable of sampling, filtering, preconcentrating, separating, restacking, and detecting Biomolecules.

On the next Slide is a schematic diagram of the types of functional elements used for constructing such a microfluidic chip.



Fig 4. Schematic of one idealized total analysis device showing the various functions on a micro fluidic chip

Based on their flow type, microfluidic system can be categorized into two main types, continuous and discrete, details of these are reviewed in the subsequent Slides.

Continuous microfluidic system

Continuous-flow microfluidic operation is a promising approach because it is easy to implement and less sensitive to protein fouling problems. Continuous-flow devices are adequate for many well-defined and simple biochemical applications, and for certain tasks such as chemical separation, but they are less suitable for tasks requiring a high degree of flexibility or complicated fluid manipulations. These closed-channel systems are inherently difficult to integrate and scale because the parameters that govern the flow field vary along the flow path making the fluid flow at any one location dependent on the properties of the entire system. Permanently-etched microstructures also lead to limited reconfigurability and poor fault tolerance capability.



For Biosensing or diagnostic applications, the micro fluids involved are biomolecules or chemicals derived from biological tissues or body fluids. For the purposes of simple and point-of-care diagnostics, that sample is most likely blood, saliva, or nasal fluid. The preparative steps, including sample collection, metering and filtration, analyte enrichment, labeling and detection, are generally required prior to the diagnostic measurements. Recently advanced microfluidic systems not only provide elegant solutions to relieve the complexity of a Biosensing or diagnostic test, but also improve responsive speed and miniaturize the size of analysis equipment.

Discrete microfluidic system

Droplet-based microfluidic systems are currently an emerging area of microfluidic research. One of the most popular means is to inject multiple laminar streams of aqueous reagents into an immiscible carrier fluid and therefore to induce flow instability instantly for forming the droplets. There are several distinctive advantages based on droplet-based microfluidic systems. First, the systems promise a new high-throughput technology that enables the generation of microdroplets in excess of several thousand per seconds. In addition, parallel and serial in-vitro compartmentalization is possible with this technology. The reagents are confined inside the droplets in water-in-oil (w/o) emulsions and reagent transport occurs with no dispersion. This unique feature enables chemical reaction indexing, thereby facilitates many chemical reactions in a highly organized manner.



Furthermore, fast mixing can occur within minute volumes of microdroplets (nanoliter to femtoliter range) due to the short diffusion distance and chaotic mixing within droplets with the use of twisting channel geometries by stretching, folding, and reorienting fluid. Another feature is that the variation of the channel dimensions can regulate the droplet volumes and decrease volumes anything up to 109 times compared to the smallest assays in conventional microtiter plates. With a control of flow rate, the reagent concentrations can be modified accordingly. It is the confluence of the aforementioned unique features and the ability to regulate and manipulate the droplet motions to split, merge, and sort that has revolutionized our ability to control fluid/fluid interfaces for use in fields ranging from material.

APPLICATION OF MICROFLUIDIC SYSTEMS IN MEDICAL DIAGONOSIS AND TREATMENT

Another interesting application of Microfluidic Systems in biomedical engineering is in point-of-care diagnosis. Targeted biological cells are separated from other substances in a sample. Conventionally, cells can be separated in a fluidic suspension, based on size, density, electrical charge, light-scattering properties, and antigenic surface properties. Separating cells according to these metrics requires complex technologies and special equipment. Techniques such as centrifuging, fluorescence activated cell sorting, electrophoresis, chromatography, affinity separation and magnetic separation are used. Microfluidic solutions have been successfully engineered to either integrate into the above techniques, or to function as a standalone device to execute sample preparation tasks.



A typical example is the use of microfluidic filtration device for spermato-genetic cell sorting to support IVF (In Vitro Fertilization) and ICSI (intracytoplasmic sperm injection) processes. In certain cases of male factor infertility, a single viable spermatogenic cell can be retrieved from a biopsy pellet and be directly injected into an oocyte. The biopsy pellet contains a variety of tissues and a range of germ cells from all orders of maturity. These process of finding viable cells for intracytoplasmic sperm injection can be time consuming, requiring hours of intensive work involving manually mincing the pellet, successive cell separation cycles through centrifugation, and individual cell discrimination. The germ cells become smaller as they mature, beginning as a large round spermatogonion of 16~18µm and ending as a small and slender spermatozoon of 4~6µm. Using this characteristic, one can aim to divide the spermatogenic cells into different mature categories according to their sizes in a fast and efficient manner.


Fig 5. Microfluidic Chip used in Sperm Analysis

CONCLUSION Microfluidics is both a science and a technology

and it offers a great deal of revolutionary capabilities for the future. It is in its infancy and a great deal of work need to be done before it can be claimed to be more than an active field of academic research. However, the fundamentals of the field are very strong: much of the world’s technology requires the manipulation of fluids, and extending those manipulations to small volumes, with precise dynamic control over concentrations, while discovering and exploiting new phenomena occurring in fluids at the micro scale level, must, ultimately, be very important.



What requirements must be fulfilled for Microfluidics to become a major new technology? Will it live up to the high hopes experienced at its conception? As a field, the problems it faces are common to those faced by most fields as they develop. The fact that Microfluidics has not yet lived up to its early expectations is not a surprise, the reasons for the rate at which it has developed are both characteristic of new technologies, and suggestive of areas in which to focus work in the future. With more funding and more intensive Research, Microfluidics System will become a useful tool not just in Biomedical Engineering but in a lot of other Applications.

REFERENCES• Dr Xianghong Ma, “Microfluidics and Biomedical

Applications” (UK: Aston University, 2015) http://www.azonano.com/article.aspx?ArticleID=2926

• Davenport, A., Ronco, C., Gura, V. and Beizai, M., et

al. (2007) A wearable haemodialysis device for patients with end-stage renal failure: A pilot study. Lancet, 370, 2005-2010. http://dx.doi.org/10.1016/S0140-6736(07)61864-9

• George M. Whitesides “The origins and the future of

Microfluidics” (Nature Publishing Group, 2006) • Wikipedia, The Free Encychopedia “Microfluidics”

https://en.wikipedia.org/wiki/Microfluidics


http://www.azonano.com/article.aspx?ArticleID=2926

http://www.azonano.com/article.aspx?ArticleID=2926

http://dx.doi.org/10.1016/S0140-6736(07)61864-9





Applications of microfluidic systems in biomedical engineering felix chibuzo obi 20144610

Health & Medicine

Transcript of Applications of microfluidic systems in biomedical engineering felix chibuzo obi 20144610