Microfluidic chamber assembly for mastitis assay

Abstract

The present invention relates to a device and method for the detection of mastitis or other disease from a body fluid of a mammal for example from cow's milk. The device and method relates to a wedge microfluidic chamber for using a minimal amount of fluid and being able to use the device to observe leukocytes in a mono-layer for the purpose of disease detection, cell counts or the like.

1 - 3 . (canceled) 
   
   
       4 . A microfluidic chamber assembly comprising:
 a) a wedge base;   b) a wedge top having a first top edge and an opposite second edge positioned on the base such that the first top edge is in an elevated configuration and the second edge is resting on the base such that it forms a wedged shaped chamber sufficient for cell differential determination;   c) a cut out well positioned to add liquid to a top portion of the wedge at the first top edge;   wherein the wedge top is secured to the base in the elevated position in a manner that it does not move during normal use and wherein at least one of the top or base is optically transparent.   
   
   
       5 . A chamber assembly according to  claim 4  wherein there are two or more chamber assemblies on the wedge base. 
   
   
       6 . A chamber assembly according to  claim 4  wherein the chamber further comprises a leucocyte observation colorant positioned in the chamber. 
   
   
       7 . A chamber assembly according to  claim 4  wherein the first top edge is elevated by means of a wedge forming device. 
   
   
       8 . A system for detecting disease in milk comprising:
 a) a microfluidic chamber assembly comprising:
 i. a wedge base; 
 ii. a wedge top having a first top edge and an opposite second edge positioned on the base such that the first top edge is in an elevated configuration and the second edge is resting on the base such that it forms a wedged shaped chamber sufficient for cell differential determination; and 
 iii. a cut out well positioned to add milk to a top portion of the wedge at the first top edge;
 wherein the wedge top is secured to the base in the elevated position in a manner that it does not move during normal use and wherein at least one of the top or base is optically transparent; 
 
   b) a leucocyte observation colorant positioned within the chamber; and   c) a reader for automatically performing a leukocyte differential on a milk sample placed in the well and reporting the results of the differential.   
   
   
       9 . A system according to  claim 8  wherein the reader is programmed to take the results of the differentiation and determine one or more from the group consisting of:
 a) stage of a disease;   b) an indication for determining whether to do cultures;   c) an indication as to the likelihood that disease will get better;   d) an early warning of mastitis in peri-partum or early lactation;   e) a differentiation between a high SCC due to lactation and a high SCC due to intra-mammary infection; and   f) confirmation of the presence of mastitis.   
   
   
       10 . A method for performing a leukocyte differential assay on a milk sample comprising:
 a) adding a milk sample to a microfluidic chamber assembly comprising:
 i. a wedge base; 
 ii. a wedge top having a first top edge and an opposite second edge positioned on the base such that the first top edge is in an elevated configuration and the second edge is resting on the base such that it forms a wedged shaped chamber sufficient for cell differential determination; and 
 iii. a cut out well positioned to add milk to a top portion of the wedge at the first top edge;
 wherein the wedge top is secured to the base in the elevated position in a manner that it does not move during normal use, wherein at least one of the top or base is optically transparent and wherein there is a leucocyte observation colorant positioned within the chamber; 
 
   b) enumerating and calculating the leukocytes in the milk containing chamber into sub-populations;   c) deriving a differential count of the leucocyte sub-populations.   
   
   
       11 . An assay according to  claim 10  wherein there are one or more chambers on each base. 
   
   
       12 . An assay according to  claim 10  wherein the assay is used to determine the presence of mastitis in the milk. 
   
   
       13 . A method according to  claim 10  wherein the assay is performed in an automatic reader wherein a differential is performed by the reader on a milk sampler placed in the microfluidic chamber and the chamber placed in the reader.