Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or...
Reexamination Certificate
1999-12-16
2002-08-13
Chin, Christopher L. (Department: 1641)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
C422S050000, C422S051000, C422S068100, C422S082050, C422S082080, C422S186000, C422S186100, C435S287100, C435S287200, C435S287300, C436S501000, C436S518000, C436S526000, C436S514000
Reexamination Certificate
active
06432630
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods and apparatuses for detection, separation, sorting, and analysis of particles, such as cells, cell organelles, beads, molecules, such as Deoxyribonucleic acid (DNA), proteins, etc. in a fluid. In particular, the invention relates to particle separation by using different forces such as magnetic, electrophoretic, hydrodynamic and/or gravitational forces, e.g. for utilisation in flow cytometry, light microscopy, electrophoretic separation, magnetophoresis, etc.
BACKGROUND OF THE INVENTION
Flow cytometry is a well known technique that is used for high throughput measurements of optical and/or electrical characteristics of microscopic biological samples. Flow cytometry instruments analyse and isolate cells and organelles with particular physical, biochemical, and immunological properties.
Traditionally, cell sorting by flow cytometry (fluorescence activated cell sorting) has been the method of choice for isolation of specific cell populations by surface markers. However, cell sorting by flow cytometry suffers from several drawbacks, especially high dilution of desired cell sample, low speed and sterility problems. Furthermore, the equipment is very costly with high operation and maintenance cost, making the technique available only to a limited number of laboratories.
During the last few years, isolation of cells by antibody-coupled magnetic beads and carriers has been developed into a reliable tool for the isolation and characterisation of cell populations. Immunomagnetic cell separation, e.g. as commercially introduced by Dynal A/S and Miltenyi Biotec, has become an established method for cell analysis in clinical diagnostics. Due to the relatively low prize, this method is attractive in flow cytometry, especially in sorting of rare cellular events. For example, sorting of fetal cells contained in maternal blood sample provides a non-invasive alternative to prenatal diagnostic procedures, such as amniocentesis of cholionic villus sampling. Another rare event scenario is the detection of low concentration of cancer cells which has an important role in diagnosis of minimal residual disease and evaluation of appropriate therapies. Another medical application for cell sorting systems is the diagnosis of bacterial and viral diseases.
Although this method offers relatively inexpensive approach to sort rare cellular event, it adds considerable time onto the overall rare event detection and it does not offer the multiparameter analysis readily available with flow cytometry techniques. Existing techniques for magnetic separation are suffering from the low purity of the sorted cell fraction and the low recovery rate of the sorted cells. In most systems several washing steps have to be implemented into the separation procedure which then causes cell losses. Additionally small subpopulation of labelled cells cannot be directly isolated by existing magnetic separation techniques.
A good overview about fluorescence activated cell sorting procedures and magnetic activated cell sorting is given in Melamed et. al., “Flow Cytometry and Sorting, (Ed. Melamed et al., Wiley & Sons Inc., 1990).
SUMMARY OF THE INVENTION
Advances in microfabrication and microfluidic technologies continue to fuel further investigation into the miniaturisation of bioanalytical instruments and biochemical assays in general. The present invention relates to development of a low cost non-invasive diagnostic test method and devices for carrying out such tests that include measuring, monitoring, sorting and analysing samples containing particles, such as organic cells, microbeads, cell organells and macromolecules such as DNA. The present invention provides a cheap, fast and reliable method and devices for handling, sorting and analysis of such particles.
Separation may be performed according to various physical properties, such as fluorescent properties or other optical properties, magnetic properties, density, electrical properties, etc. According to an important aspect of the invention, particle separation is performed by aligning the particles in one row of particles in a micro flow channel so that particles can be treated individually.
Thus, it is an object of the present invention to provide a micro flow system and a method of particle separation having an improved efficiency of particle separation compared to the prior art.
It is another object of the present invention to provide a micro flow system and a method for particle separation in which cell lysis is minimised
It is yet another object of the present invention to provide an improved method for preparation of fluids containing particles for separation and analysis of the particles.
It is a still further object of the present invention to provide a micro flow system and a method for simultaneous separation of particles into a plurality of groups of particles.
It is a still further object of the present invention to provide a micro flow system including facilities for pre-treatment and/or post-treatment of a sample.
It is a still further objective of the invention is develop a system for separation and analysis of fetal cells in whole maternal blood samples using an integrated automated micro flow system. The system is designed by downscaling and combining different methods for handling, manipulation and analysis of biochemical samples. Thus, prenatal diagnostics by analysis of fetal cells separated from a whole maternal blood sample is an area, which can benefit from advances in miniaturisation.
It is another objective of the invention is develop a system for separation and analysis of cancer cells from a sample containing cancer cells and healthy cells using an integrated automated micro flow system. The system is also designed by downscaling and combining different methods for handling, manipulation and analysis of biochemical samples. Thus, cancer diagnostics by analysis of cancer cells separated from healthy cells is also an area which can benefit from advances in miniaturisation.
According to a first aspect of the invention the above and other objects are fulfilled by a micro flow system for separating particles, comprising a member having
a flow channel defined therein for guiding a flow of a fluid containing the particles through the flow channel,
first inlet means positioned at one end of the flow channel for entering the fluid into the flow channel,
first outlet means positioned at the other end of the flow channel for discharging the fluid from the flow channel,
the flow of the fluid containing the particles being controlled in such a way that one particle at the time passes a cross-section of the flow channel,
the member being positioned in a field that is substantially perpendicular to a longitudinal axis of the flow channel so that particles residing in the flow channel and being susceptible to the field across the flow channel are deflected in the direction of the field.
According to a second aspect of the invention the above and other objects are fulfilled by a method of separating particles, comprising the steps of
guiding a flow of a fluid containing the particles through a flow channel in such a way that one particle at the time passes a cross-section of the flow channel,
positioning the flow channel in a field that is substantially perpendicular to a longitudinal axis of the flow channel so that particles residing in the flow channel and being susceptible to the field across the flow channel are deflected in the direction of the field and thereby separated from the fluid.
According to a third aspect of the invention the above and other objects are fulfilled by a micro flow system for separating particles, comprising a member having
a flow channel defined therein for guiding a flow of a fluid containing the particles through the flow channel,
first inlet means positioned at one end of the flow channel for entering the fluid into the flow channel,
first and second outlet means positioned at the other end of the flow channel for discharging of fluid from the flow channel,
the flow of
Chin Christopher L.
Merchant & Gould P,C,
Scandinanian Micro Biodevices A/S
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