Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving nucleic acid
Patent
1998-05-22
2000-10-31
Horlick, Kenneth R.
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving nucleic acid
435 71, 4352832, 536 243, 536 2431, 536 2432, 359368, 250282, 2504581, 204452, C12Q 168, G01N 3353, C12M 100, G02B 2100, B01D 5944
Patent
active
061400483
DESCRIPTION:
BRIEF SUMMARY
FIELD OF INVENTION
The present invention concerns a system for distinguishing at least two types of groups of molecules having different fluorescent characteristics that are bound to analyte molecules. The system performs differentiation using time-resolved fluorescence measurement and includes a light source that exposes a first sample volume to light that is suitable for exciting the at least two types of molecular groups to fluorescence. The system also includes a detector for detecting fluorescence radiation emitted from a second sample volume that at least partially overlaps the first sample volume, and a control unit that is designed to activate the light source for a time interval T.sub.1 and, after time interval T.sub.2 has passed, to activate the detector for a time interval T.sub.3. According to this system, the illumination and detection of emitted fluorescence radiation is performed at least 1,000 times per millisecond, the detector signals recorded with a recording unit during time interval T.sub.3 are evaluated with an evaluation unit, and the signal behavior over time during time interval T.sub.3 is used to determine which of the at least two groups of molecules is contained in the overlapping sample volume.
The present invention belongs to the field of chemical analysis based on detection of excited fluorescence radiation. Analytical methods of this nature have a very broad array of potential applications, although biochemistry has recently become one of the most significant applications. In particular, fluorescence radiation can be employed in order to sequence nucleic acids, as described in EP-B-0 157 280, for instance. This sequencing method produces cloned DNA strands which are broken down into fragments, the termini of which contain the fluorescently-labelled bases A, G, C, and T. Apparatuses are also known in the prior art that are described in U.S. Pat. No. 5,252,834, for instance, with which undesired background radiation can be blocked by properly coordinating the timing of the excitation light and the detected fluorescent light. The apparatus described in U.S. Pat. No. 5,252,834, however, is complex and utilizes spectral analysis of the emitted fluorescence radiation in order to identify analyte molecules.
In EP-A-0 563 998, a method for detecting biomolecules is described that is based on time-resolved laser spectroscopy. The method described here is based on the fact that the molecules to be detected are labelled with various fluorescent dyes that emit fluorescence for different lengths of time. The duration of the fluorescence signals are distinguished from each other by means of time-resolved fluorescence spectroscopy, and the emitted fluorescence is detected after the excitation light in order to suppress background radiation.
The methods and devices of the prior art described are based on the fact that there is a large number of molecules having the same fluorescence characteristics, which makes it possible to detect and characterize the fluorescent molecule. In order to accomplish this, the concentration of molecules must either be sufficiently high, or a sample volume of sufficient size must be exposed to light. Both of these methods, which are designed to capture fluorescent light from a large number of molecules, have a disadvantage in that the ensemble of molecules does not necessarily have to be homogeneous, i.e., molecules having different fluorescent characteristics may be detected. If the fluorescence radiation is evaluated based on the duration of the fluorescence, the ensemble of molecules under consideration will be assigned a common and, therefore, averaged, duration of fluorescence. This can result in the assignment being incorrect or the results being misinterpreted. Moreover, the methods of the state of the art have a disadvantage in that the presence of just a few molecules of one type can make it impossible to reliably assign them to a group of molecules due to statistical signal fluctuations and low signal intensities.
SUMMARY OF THE INVENTION
These di
REFERENCES:
patent: 4877965 (1989-10-01), Dandiker et al.
patent: 4923819 (1990-05-01), Fernandez et al.
patent: 5039219 (1991-08-01), James et al.
patent: 5252834 (1993-10-01), Lin
patent: 5323008 (1994-06-01), Studholme et al.
patent: 5418371 (1995-05-01), Aslund et al.
patent: 5498324 (1996-03-01), Yeung et al.
patent: 5674743 (1997-10-01), Ulmer et al.
patent: 5871906 (1999-02-01), Dyer et al.
Bush et al Analytical Biochemistry vol. 202, pp. 146-151, 1992.
Muller Ralph
Sauer Markus
Zander Christoph
Horlick Kenneth R.
Roche Diagnostics GmbH
Siew Jeffrey
LandOfFree
System for distinguishing fluorescent molecule groups by time re does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for distinguishing fluorescent molecule groups by time re, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for distinguishing fluorescent molecule groups by time re will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2049801