Split multi-well plate and methods

#This invention relates generally to the field of testing systems and methods, and more particularly to systems and methods for transport or permeation testing. In one particular aspect, the invention provides systems and methods for culturing cells onto a membrane and then using the membrane to simulate an epithelial cell layer, such as the cells which form the inner lining of a human intestine or blood vessel. In this way, transport or permeation tests may be performed using the membrane.

#In humans, ingested food passes from the stomach to the small intestine where proteins, fats, carbohydrates and other nutrients are absorbed and distributed into circulation for use in various organs and cells throughout the body. The small intestine is about five to six meters in length and has an extremely large surface area for absorbing nutrients and other materials. The interior of the small intestine includes the mucosal epithelium which comprises small fingerlike projections called villi which protrude into the intestine and provide the nutrient absorption surface.

#For a variety of reasons, it is desirable to study and evaluate how various chemicals which are orally ingested into a human will be absorbed into the blood stream through the intestinal wall. Such evaluation can be useful in, for example, drug testing to determine how various drugs will be absorbed into the blood stream. Transport of various substances through other types of epithelial cells can also be useful in therapeutically treating patients.

#FIG. 1 is a perspective view of an exemplary testing device according to the invention.

#FIG. 2 is a more detailed view of the device of FIG. 1 taken along lines 2--2.

#FIG. 3 is a perspective view of a divider of the tester of FIG. 1 having a plurality of membranes for dividing wells into separate chambers.

#The invention provides systems, devices and methods for testing and evaluating the transport or permeation of various substances through a layer of cells, and particularly epithelial cell layers, including those found in blood vessels throughout the body, arteries, the intestine, and the like. Although useful in a wide variety of simulation applications, the invention will find use in modelling intestinal permeation of drug-like compounds.

#According to the invention, mammalian-based cells are seeded on a membrane while the membrane is in a generally horizontal orientation. Such an orientation is preferably employed to facilitate attachment of the mammalian-based cells to the membrane. The membrane is then inserted into the wells of a multi-well plate, preferably in a generally vertical orientation, to divide the wells into separate chambers, such as a receptor chamber and a donor chamber. In some cases, however, it may be desirable to have the membrane inserted horizontally or at an incline. Vertical orientation of the membrane is advantageous in that it allows for a more efficient use of the space within the wells. In this way, a larger membrane surface may be provided to enhance the sensitivity of the system. Further, by optimizing the size of the membrane, smaller well sizes may be used while still providing an adequate transport interface. Once the membrane is inserted, various substances may be introduced into the donor chambers where they will permeate through the cells on the membrane into the receptor chambers. The permeation rate may be determined by measuring the concentration levels over time in both the donor chambers and the receptor chambers. In this way, a scientist will be able to evaluate the permeation of various substances through the cells in order to model how the human body will absorb such substances.

#The system of the invention will preferably employ a cell culture device which maintains cells in a tissue culture media until the cells are ready to be seeded onto the membrane. Preferably, the cells will be mammalian-based cells and the membrane will preferably be constructed of a porous material, such as polytetrafluroethylene (commonly referred to as teflon), polyethylene, PCT, polycarbonate, or the like. For convenience of handling, the membranes will preferably be operably attached to a divider. In addition to facilitating handling of the membranes, the divider will preferably also encompass or frame the periphery of the membranes with a raised edge to constrain the growth of the cells to the membrane. In this way, growth of the mammalian-based cells onto the membrane will be facilitated. Use of such a divider is further advantageous in that it may be employed to horizontally orient the membranes when growing the cells on the membrane.