Microwell device

#This invention relates generally to microfluidic devices, and in particular, to a microwell device for isolating a fluid, such as an analyte, into very small volumes.

#Techniques for studying single cells have become indispensable in cell biology for their ability to identify characteristics and behaviors that would otherwise be hidden using population averaged measures. As single-cell techniques continue to develop, these techniques have the potential to significantly impact many different areas of study. For example, the study of virus infections and virus-host interactions are particularly well-suited for such techniques. Virus infections are generally rapid and dynamic events that exhibit high levels of heterogeneity stemming from multiple sources. Thus, at any given time during an infection, different cells can respond with phenotypically different behavior and progress at different times and rates, making it difficult to use average readouts to make inferences concerning the sequence or timing of infection events or for relating changes in one biological measure to another.

#The most basic advantage of single cell data for addressing these challenges is the ability to categorize a heterogenous group of individual cells into cohorts or subpopulations with similar individual characteristics to explore the potential relationship of those characteristics to heterogenous outcomes. In other words, the heterogeneous system behavior can be leveraged to learn more about important cellular characteristics. The most prominent example of this is the use of flow cytometry, where multiple fluorescent tags or reporters can be simultaneously quantified for each cell in a population of thousands to provide exquisite, quantitative insight into the presence and nature of subpopulations. However, this powerful tool is often difficult to apply in the area of virology given the danger of contamination and production or aerosolized virus on shared flow cytometry equipment. Flow cytometry is also typically limited to endpoint analysis. Although many other single cell techniques have been developed such as droplet-based microfluidics and microfluidic flow traps, sandwiched microwells (SMAs) offer an attractive alternative with respect to flexibility, throughput, cost, and required expertise for operation. Further, SMAs offer the capability to observe single cell behavior over time.

#The drawings furnished herewith illustrate a preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will be readily understood from the following description of the illustrated embodiment.

#In the drawings:

#FIG. 1 is an exploded, isometric view of a microwell device in accordance with the present invention in an initial configuration;

#Referring to FIG. 1, a microwell device for use in the method of the present invention is generally designated by the reference numeral 10. In the depicted embodiment, microwell device 10 includes plate 11 defined by first and second ends 12 and 14, respectively; first and second sides 16 and 18, respectively; and upper and lower surfaces 20 and 22, respectively. It can be appreciated that plate 11 of microwell device 10 may have other configurations without deviating from the scope of the present invention. Further, it is contemplated for plate 11 to be fabricated from a gas permeable material so as to facilitate cellular growth and development, as hereinafter described. However, other materials are contemplated as being with the scope of the present invention.

#Upper surface 20 of plate 11 includes a plurality of microwell regions 24 formed therein. Each of the microwell regions 24 are identical in structure, and as such, the following description is understood to describe each of the microfluidic regions. Each microwell region 24 is a defined by a barrier. By way of example, the barrier may take the form of a generally circular channel, designated by the reference numeral 26, extending about center 27. FIG. 2. It can be appreciated that channel 26 can have other configurations without deviating from the scope of the present invention. As best seen in FIGS. 2-3, channel 26 is defined by generally circular, radially inner wall 28 and generally circular, outer wall 30, which are generally perpendicular to upper surface 20. Inner and outer walls 28 and 30, respectively, are interconnected by lower wall 32 extending between the lower ends thereof. It is contemplated for channel 26 to have a depth preferably in the range of 200 to 1000 micrometers and a volume in the range of 2 to 75 microliters.

#Microwell region 24 further includes recess 34 centered at center 27. In the depicted embodiment, recess 34 has a generally circular cross section. However, it can be appreciated that recess 34 can have other configurations without deviating from the scope of the present invention. By way of example, recess 34 is defined by a generally circular wall 36. Wall 36 is generally perpendicular to upper surface 20 and is radially spaced from center 27. Recess 34 terminates at lower wall 38 such that recess 34 has a depth in the range of 200 to 1000 micrometers and a volume in the range of 0.025 to 3.5 microliters.