Optics: measuring and testing – For light transmission or absorption – Of fluent material
Reexamination Certificate
1998-05-20
2001-01-16
Evans, F. L. (Department: 2877)
Optics: measuring and testing
For light transmission or absorption
Of fluent material
C356S039000, C436S164000
Reexamination Certificate
active
06175420
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an optical method and apparatus for use in an interactive cell processing system.
BACKGROUND OF THE INVENTION
Cell processing includes steps where cells or cell elements are treated with different process chemicals or are washed and then separated from a liquid phase. For example, when preparing frozen erythrocytes for transfusion, erythrocytes are separated from cryopreservatives and other blood components such as white cells, platelets and sub-cellular debris. The entire process must be performed under sterile conditions that minimize the risk of contamination. Furthermore, whole blood is separated into its various therapeutic components such as red blood cells, white blood cells, platelets and plasma which are later transfused. There are different cell processing systems that process biological cells in an automated or semi-automated way. These systems may use a controller connected to various sensors and valves for controlling the process and helping an operator to maximize the processing efficiency. However, these systems do not interactively adjust the process based on the amount or type of the processed cells or different processing conditions.
During the separation, for example, by expression of the processing fluid, it is desirable to accurately differentiate the supernatant (for example, a wash solution) from the harvested cells in order to avoid losing valuable cellular product into the expressed (and thereafter discarded) wash solution. Various optical detectors have been designed and described in the prior art. However, there are several features that needed to be resolved. For example, the means and location of the optic assembly housing can be problematic. A separate plastic cuvette is typically used to provide flat, parallel surfaces through which the object cells must pass. These flat surfaces minimize optical distortion but add a separate object, the cuvette, to the disposable set designed to contain the cells and washing reagents. This additional cuvette increases the complexity and requires an extra operator step during set up of the instrument, as this cuvette must be accurately positioned in the optical detector housing. Any operator interaction may potentially introduce an error. If the housing is located away from the centrifuge, such design leaves a length of tubing between its location and the centrifuge that is full of packed cells immediately after the first of the cells have been detected. These cells are typically lost to the waste supernatant of the next wash cycle. Finally, cell processing may involve separating one cell type from another (e.g., the buffy coat containing white blood cells and platelets must be separated from erythrocytes being prepared as packed red cells for transfusion; erythrocytes must be removed from bone marrow during the preparation of progenitor cells).
Therefore, there is a need for an optical sensor for use in an automated interactive cell processing system. Such optical sensor would need to have a practical design and would need to provide precise and reproducible data for different disposable elements, varying amounts of processed cells, different types of processed cells, or different operators and processing laboratories.
SUMMARY OF THE INVENTION
The present invention is a optical method and apparatus for characterizing a fluid transferred in a sterile manner during cell processing.
In one aspect, an optical sensor is used in an interactive cell processing system that includes a plurality of sensors arranged for monitoring and providing sensor data to a control module that directs processing of biological cells. The sensors including an optical sensor for characterizing a fluid transferred in a sterile manner during the processing. The optical sensor includes a light source, a light detector, a cuvette and a control circuit. The light source is connected to a control circuit and is constructed and arranged to emit light of at least one selected wavelength directed toward the fluid. The cuvette is constructed as a part of a fluid distribution manifold that includes several conduits for transferring the sterile fluid during the processing, wherein the cuvette is constructed and arranged to convey the fluid. The light detector is connected to the control circuit and is constructed and arranged to detect light that was emitted from the source and has interacted with the fluid flowing inside the cuvette. The control circuit is constructed and arranged to characterize the fluid in the cuvette based on the detected light.
The optical sensor may include one or several of the following features:
The light source and the light detector may be arranged in a transmission geometry. The light source, the light detector and the control circuit are enclosed in a housing. The housing is suitable for sterilization by gama rays or by other means.
The fluid distribution manifold includes an integral component constructed to be placed in close proximity to the housing and arranged to define uniquely the position of the cuvette relative to the light source and the light detector.
The cuvette is made of an optical material suitable for sterilization. The cuvette is made of an optical material suitable for sterilization using gama radiation. The cuvette and the fluid distribution manifold may be disposable.
The light source and the light detector are located in a sealed housing constructed and arranged for wet cleaning.
The light source includes a light emitting diode (LED) constructed and arranged to emit light of about 560 nm and about 640 nm. The light detector includes a silicon diode. The optical sensor is arranged to detect red blood cells in the fluid.
The control circuit is constructed to activate the light source and the light detector to perform repeated measurements over a short period of time to increase precision of the characterization. The control circuit is constructed to calibrate operation of the optical sensor after placement of the cuvette.
The optical sensor is further arranged to provide data to the control module to actuate re-distribution of fluids flowing in the conduits.
Another aspect is a method of characterizing a fluid transferred in a sterile manner in a conduit during processing of biological cells in a cell processing system. The method includes conveying the fluid in a cuvette during operation of a cell processing system, wherein the conveying includes distributing the fluid in a fluid distribution manifold that includes several conduits for transferring sterile fluid during the processing, and wherein at least one of the conduits is permanently connected to the cuvette. The method also includes emitting light of at least one selected wavelength generated by a light source; detecting light that was emitted from the source and has interacted with the fluid flowing inside the cuvette; and characterizing the fluid in the cuvette based on the detected light.
Another aspect is a method of controlling operation of a cell processing system comprising a control module, a processing module connected in a sterile manner by a set of conduits to a cell module and to a supply module for providing selected process chemicals, and a plurality of sensors providing process data to the control module also arranged to actuate a plurality of valves regulating flow of the cells and the chemicals in the conduits during the operation. The method includes processing biological cells in the processing module by employing process chemicals including saline; expressing the process chemicals from the processing module; transferring a flow the expressed process chemicals to a waste container via the conduits, wherein at least one of the conduits is permanently connected to and in communication with a cuvette. The method also includes emitting light of at least one selected wavelength generated by a light source; detecting light that was emitted from the source and has interacted with the fluid flowing inside the cuvette; characterizing the fluid in the cuvette based on the detected ligh
Barry Donald
Edwards Bruce H.
Fennelly Jeremy
Jorgensen Glen
Evans F. L.
Smith Zandra V.
ZymeQuest, Inc.
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