Microfluidics and Lab-on-a-Chip for biomedical applicationsChapter 1: Introduction.

By Stanislas

CNRSUniversité de Lyon, FRANCEStansan International Group

CONTENT

Chapter 1: Introduction.

Chapter 2 : Basic principles of Microfluidics.

Chapter 3 : Basis of molecular biology and analytical tools.

Chapter 4 : Micromanufacturing.

Chapter 5 : Lab-on-a-Chip & applications.

Chapter 6 : Cancer diagnostics and monitoring.

WHAT IS « MICROSYSTEM » ?

MICROSYSTEM = microelectronic circuit + sensor(s) and/or actuator(s)

Any engineering system that performs electrical and « other » functions, with components in micrometer scale is a MICROSYSTEM. (1 µm = 1/10 of human hair)

MICROSYSTEM products may include :

● Micro sensors (pressure, acceleration, acoustic wave, biomedical, chemical, optical, radiation, thermal, etc.)

● Micro actuators (valves, pumps and microfluidics; micro-needles for blood sampling or drug injection,electrical and optical relays and switches;grippers, tweezers and tongs; linear and rotary motors, etc.)

MEMS = Micro Electro-Mechanical System

WHAT IS « MEMS » ?

This term is often used in USA and some other countries, even in connection to systems which do not contain mechanical parts in sensors and actuators.

e.g. BioMems, BioNems: MEMS/NEMS ‘bio’logical applications

In practice : MEMS = MICROSYSTEM

European Commission uses the abreviation MST for MICROSYSTEMSor microsystem's technology.

In this lecture we will speak about Bio-Microsystems

MICROSYSTEMS – contain parts in the scale of micrometersNANOSYSTEMS – contain parts in the scale of nanometers (<100 nm)

Size matters : scales, miniaturization

Microsystem as a Microsensor :

Example:

Miniaturised prssure sensors

Microsystem as a Microactuator :

Example:

Micro-motor

INTELIGENT MICROSYSTEMS :

Schematic diagram showing the main components of a biosensor. The biocatalyst (a) converts the substrate to product. This reaction is determined by the transducer (b) which converts it to an electrical signal. The output from the transducer is amplified (c), processed (d) and displayed (e).

What are biosensors?

A biosensor is an analytical device which converts a biological response into an electrical signal.

Biosensors sometimes are broadly defined as any device designed to gather biological information, such as the presence of a particular biomolecule, and convert it into an analytical signal. This report uses the stricter definition of biosensors used by The National Research Council (NRC), part of the U.S. National Academy of Sciences.

The NRC has defined a biosensor as a detection device that incorporates a) a living organism or product derived from living systems (e.g., an enzyme or an antibody) and b) a transducer to provide an indication, signal, or other form of recognition of the presence of a specific substance in the environment.

What are biosensors?

What is a "miner's canary"? The first bio-chemical sensor !

"Miner's canary" refers to the birds once used by miners to test the purity of the air in the mines. At least three birds would be taken underground by a group of miners. If any one bird showed signs of distress, it was taken as an indication that dangerously high levels of carbon monoxide existed. Today, miners use sophisticated sensing equipment instead of canaries.

Most Biosensors work on the principle of interactions between thebiomolecules in the sample and the analyte (usually in solution)in the sensor. Signal transduction is carried out by the sensing element, which may use a wide range of different techniques.

Biosensors - transduction

Some Events in the History of Biosensors

DiabetesDiabetes is a metabolic disorder, in which the pancreas underproduces or does not produce insulin. Because cells need insulin to absorb blood sugar (glucose) for their energy needs, the cells of people with diabetes suffer from a shortage of glucose, while glucose levels build up in the blood.

The disease is a major world health problem. It is estimated that there are over 150 million diabetics worldwide. Worse still, incidence of the disease has risen by an alarming 11% over the last five years, and a further doubling of new cases is predicted in the next 25 years.

There are three types of diabetes:

Type 1 Diabetes of the young. Approximately 10 % of diabetics have Type 1.

Type 2 Diabetes of older patients. 90 % of people with diabetes have Type 2.

Type 3 Gestational diabetes is a temporary condition that occurs during pregnancy. It affects 4 % of pregnancies with an risk of developing diabetes for both mother and child.

Glucose Biosensors

When left untreated or improperly managed, diabetes is one of the leading causes of death by disease.

Despite the many technological advances in biosensor and the introduction of many different biosensors, glucose biosensors still account for approximately 85% of the current world market, which has recently been estimated to be around $5 billion. There are, currently, over 40 blood glucose meters on the market.

The lion’s share of the market is shared between Roche Diagnostics, Lifescan, Abbott and Bayer.

Many transducers could be used for the measurement of glucose, but electrochemistry has dominated. This is partially historical, but the primary reason is that they offer suitable sensitivity, reproducibility and can be manufactured in great volumes at low cost.

A sensor for measuring the glucose concentration of a patient.

SWNT - single-walled carbon nanotubes

CNT based Field Effect Transistor for Glucose Detection

Example of Home Blood Glucose Monitor

The main biosensors products sold by Roche are the Accu-Chek blood glucose monitoring systems. Accu-Chek Active is one of the fastest meters in the market, requiring just 5 seconds to obtain a reading. It features an automatic on/off function, a 1 µl blood sample requirement, 200 value memory storage (with times and dates, 7 and 14 day averaging and an underdosing monitor that detects when insufficient blood has been applied.

Ion-Selective Field Effect Transistors (ISFETs)

Enzyme membranes are coated on the ion-selective gates of these Field Effect Transistors, responding to the electrical potential change via the current output. Thus, these are potentiometric devices although they directly produce changes in the electric current. The main advantage of such devices is their extremely small size (<< 0.1 mm2) which allows cheap mass-produced fabrication using integrated circuit technology.

Ion-Selective Biosensor which Use Deformable Centilaver.

Medical Telesensors

A chip on your fingertip may someday measure and transmit data on your body temperature. An array of chips attached to your body may provide additional information on blood pressure, oxygen level, and pulse rate. This type of medical telesensor, which is being developed at ORNL for military troops in combat zones, will report measurements of vital functions to remote recorders. The goal is to develop an array of chips to collectively monitor bodily functions.

These medical telesensors would send physiological data by wireless transmission to an intelligent monitor on another soldier's helmet. The monitor could alert medics if the data showed that the soldier's condition fit one of five levels of trauma. The monitor also would receive and transmit global satellite positioning data to help medics locate the wounded

Biosensors printed directly onto clothing

Joseph Wang and colleagues at the University of California San Diego, La Jolla have devloped a method for printing biosensors directly onto clothing. To form the sensors, Wang screen-printed carbon electrode arrays directly onto the elastic bands of mens' underwear. The tight contact and direct exposure to the skin allows hydrogen peroxide and the enzyme NADH, which are both associated with numerous biomedical processes, to be monitored using the sensor.

Inteligent Biosensor devices :

sensor + control +actuator

The global market for biosensors and other bioelectronics is projected to grow from $6.1 billion in 2004 to $8.2 billion in 2009, at an AAGR (average annual growth rate) of about 6.3%.

Learning From the Experiences in Microelectronics

invention of transistors by three Nobel Laureates, W.Schockley, J. Bardeen and W.H. Brattain of Bell Laboratories in 1947.

concept of Integrated Circuits (IC) in 1955, and the production of the first IC few years later by Jack Kilby of Texas Instruments.

Moore’s law (1964) - number of transistors per chip doubles every 1.5-2 years

ICs have made possible for miniaturization of many devices and engineering systems in the last 50 years.

Integrated circuits: Example-Pentium 4TM

1959: Richard Feyman says, “There is plenty of room at the bottom.”

1969: Westinghouse creates the “Resonant Gate FET.”

1970s: Bulk-etched silicon wafers used as pressure sensors (micromachining technologies...).

1982: Kurt Petersen published “Silicon as a Structural material.”

1980s: Early experiments in surface- micromachined polysilicon. Micromachining leverages the micro-electronic industry in late 80s.

1990s: Introductionof new materials (piezoelectric, piezoresistive, poly-Si ...).

Learning From the Experiences in Mechanical Microsystems and Microfabrication

Micro/nano fabrication: it is a process used to construct physical objects with dimensions in the micro/nano-metre to millimeter range.

Micro/nano objects or devices are comprised of a range of miniature structures, including moving parts (cantilevers and diaphragms), static structures (flow channels and wells), chemically sensitive surfaces (proteins and cells) and electrical devices (resistors and transistors).

In contrast to planar microelectronic devices, micro/nanosystemns contains ALWAYS 3-dimmensinal objects.

WHAT IS « MICRO/NANOFABRICATION » ?

Microfabricationby physical-chemical

processes

Traditional Manufacturing

by machine tools

Evolution of Microfabrication

● There is no machine tool with today’s technology can produce microsystem components of the size in the micrometer scale (or in mm sizes).

● The microfabrication techniques originally developed for producing integrated circuit (IC) components can help.

● The complex geometry of microsystem components can only be produced by various complex physical-chemical processes.

● Despite the fact that many microelectronics technologies can beused to fabricate silicon-based MEMS components, microsystemsengineering requires the application of principles involving multidisciplines in science and engineering (new materials and new technologies).

● Team effort involving multi-discipline of science and engineering is the key to success for any microsystem industry.

Micro Cars(Courtesy of Denso Research Laboratories,

Denso Corporation, Aichi, Japan)

A micro gear-train (Sandia National Laboratories)

Mechanical microsystems : accelerometers, pressure sensor, microphone...

A mechanical sensor as a part of CMOS integrated systems

High complexity of MEMS elements possible (multi-functional sensing) together with advanced electronic detection/signal processing.

MEMS as a part of CMOS integrated systems

1st level packaged microsystems & smallest commercialised unit Example of inkjet (microfluidic microsystem)

Total market for microsystems in 2009

Microfluidics deals with the behavior, precise control and manipulation of fluids that are geometrically constrained to a small, typically sub-millimeter, scale. Typically, micro means one of the following features:

small volumes (nl, pl, fl) small size

It is a multidisciplinary field intersecting engineering, physics, chemistry, microtechnology and biotechnology, with practical applications to the design of systems in which such small volumes of fluids will be used. Microfluidics emerged in the beginning of the 1980s and is used in the development of inkjet printheads and in the beginning of 1990s for bio-chemical analysis. DNA chips, lab-on-a-chip technology, micro-propulsion, and micro-thermal technologies.

WHAT IS « MICROFLUIDICS » ?

To date, the most successful commercial application of microfluidics is the inkjet printhead.

Advances in microfluidics technology are revolutionizing molecular biology procedures for enzymatic analysis (e.g., glucose and lactate assays), DNA analysis (e.g., polymerase chain reaction and high-throughput sequencing), and proteomics. The basic idea of microfluidic biochips is to integrate assay operations such as detection, as well as sample pre-treatment and sample preparation on one chip.

An emerging application area for biochips is clinical pathology, especially the immediate point-of-care diagnosis of diseases.

In addition, microfluidics-based devices, capable of continuous sampling and real-time testing of air/water or food samples for biochemical toxins and other dangerous pathogens, can serve as an always-on "bio-smoke alarm" for early warning.

MICROFLUIDICS - key application areas

Inkjet head ejection

Thermal inkjet headsThermal head eject droplets on the top of the

printhead (Roofshooter) or on the side (Edgeshooter)

Inkjet head device manufacturers

Annual issued US patents by topic area

Annual Microfluidics and Microsystem publications across all journals

WHAT IS « Lab-on-a-Chip » ?

Lab-on-a-Chip are devices that integrate multiple laboratory functions on a single chip of only millimeters to a few square centimeters in size and that are capable of handling extremely small fluid volumes down to pico liters.

Lab-on-a-chip devices belong to the family of MICROSYSTEMS.

Lab-on-a-chip devices are sometimes called "Micro Total Analysis Systems" (µTAS).

Lab-on-a-chip concept extends the simple sensor functionality and includes the integration of pre-treatment steps, additional cleaning and separation steps towards a complete laboratory analysis.

Lab-on-a-Chip devices emerged in early 1990s (Manz, A., 1990,Sensors & Actuators B Chem., B1, 1-6, 244)

Lab-on-a-Chip are Microfluidic Devices

Real-time PCR ;detect bacteria, viruses and cancers.

Immunoassay ; bacteria, viruses, cancers based on antigen-antibody reactions.

Dielectrophoresis : detecting cancer cells and bacteria.

Blood sample preparation ; can crack cells to extract DNA.

Cellular lab-on-a-chip for single-cell analysis.

Lab-on-a-chip technology may soon become an important part of efforts to improve global health, particularly through the development of point-of-care testing devices.

Many researchers believe that LOC technology may be the key to powerful new diagnostic instruments. The goal of these researchers is to create microfluidic chips that will allow healthcare providers to perform diagnostic tests such as immunoassays and nucleic acid assays with no laboratory support.

Examples of LOC Applications

The detection of protein cancer markers will be obtained here by the integration on the Chip of the following blocks :

The most general block diagram of the Chip for the detection of molecular cancer markers is the following :

Lab-on-a-Chip : Possible Functional Blocks

MULTIDISCIPLINARY FIELD

Miniaturization

Few cm 2

small laboratory which uses Labs-on-a-Chip = very big laboratory

Lab-on-a-Chip >>>> towards “point of care application”

E-coli Germ detection chip, which combine target cell capture, cell preconcentration and purification, cell lysis, DNA multiplication and

electrochemical detection.

Example of a Lab-on-a-Chip

Lab-on-a-Chip

Miniaturization Makes Engineering Sense !!!

• Small systems tend to move or stop more quickly due to low mechanical inertia.It is thus ideal for precision movements and for rapid actuation.

• Miniaturized systems encounter less thermal distortion and mechanical vibration due to low mass.

• Miniaturized devices are particularly suited for biomedical and aerospace applications due to their minute sizes and weight.

• Small systems have higher dimensional stability at high temperature due to low thermal expansion.

• Smaller size of the systems means less space requirements.This allows the packaging of more components in a single device.

• Less material requirements mean low cost of production and transportation.

• Ready mass production in batches.

Market breakout for 1st level packaged microsystems

Market breakout for 1st level packaged microsystems

3 products make 70% of the market in 2009– Read-Write (RW) heads– Inkjet heads– MEMS displays

3 other products making each over $1 billion in 2009– Pressure sensors– RF MEMS– Inertial sensors

12 emerging or niche products each < $100m in 2009

Lab-on-a-Chip, Microreaction, chip cooler, inclinometers, MEMS memories, MEMS fingerprints, liquid lenses, microspectrometer, wafer probes, micro-mirrors for optical processing, micro-pumps, micromotors, chemical analysis systems.

Forecasted Growth of Microsystems

Wireless Capsul Endoscope

Back to the Future

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