BRIEF DESCRIPTION OF THE DRAWINGS
Further objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of the presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings wherein
FIG. 1 illustrates the parts of the cell culture insert and their assembly in vertical section;
FIG. 2 illustrates the introduction of the insert in a tissue culture vessel in vertical section;
FIG. 3 shows an alternative embodiment of a cell culture insert placed in a culture vessel in vertical section;
FIG. 4 illustrates different possible height positions of the cell culture insert in a culture vessel in vertical section;
FIG. 5 is a perspective view of the parts of the cell culture insert;
FIG. 6 is a perspective view of the parts of the cell culture insert according to another embodiment; and
FIG. 7 is a perspective view of the parts of the cell culture insert according to one further embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Installation of the body, cell growth material and ring is represented in FIG. 1. The desired cell growth material 1, which can be a substrate for cells, such as film, foil, fibre, textile, membrane, mesh, or consist of cells, such as a self-supported tissue sample is placed on the ring 2, the body 3 is pushed into its place so that the ring 2 fits tightly enough around the outer wall of the body 3 at the lower part of the body in such a manner that it is in sliding engagement with the body with the margin areas of the material 1 between the inner surface of the ring 2 and the outer surface of the body 3. In this way the material 1 is secured on the body 3 so that it covers the lower opening of the body. The cell culture insert 4 is now ready for placement into the desired tissue culture vessel 5. The body has the general shape of a hollow cylindrical sleeve, having typically greater height than wall thickness that the sleeve will be positioned in vertical position inside the cell culture vessel. The horizontal cross-section of the sleeve is substantially circular, which is advantageous for inspection of the cells of the material 1, for example by microscope.
FIG. 2 shows the insertion of the sleeve-like body 3 together with the ring 2 and material 1 inside a cell culture vessel. The body has gripping means 7 extending sideways from the outer wall of the body 1. The gripping means 7 are able to retract elastically inwards so that the body can be inserted inside a cavity the cell culture vessel with its gripping means in friction contact against interior sidewalls of the cell culture vessel and kept in place by means of said friction contact. FIG. 2 further shows that the ring can be placed around the body so that it will lie entirely above the lower end of the body. The material 1 will thus be lowest in the assembled cell culture insert 4 and the material itself can thus be brought as close to the bottom of the cavity as possible, even in direct contact with the bottom if desired.
The apparatus for growing tissue cultures as shown in FIG. 2 includes a cell culture vessel 5 and the cell culture insert 4. Although only two wells in the cell culture vessel is shown, it should be appreciated that the cell culture vessel may have one, six, eight, twelve, twenty-four or some other number of wells, i.e. cavities, selected for the particular purpose for which the apparatus is used. The cell culture vessel can be a well-plate, also called multiwell plate, having a matrix of n×m wells in the fashion known per se. The wings are flexible and decrease their opening (extension sideways from the body) upon installation.
In FIG. 3 the body 3 is used to keep a hard block sample 6 in its place at the bottom of the tissue culture vessel (cavity of the vessel). In that case, the sample will be cut slightly smaller in size than the opening of the cavity of the tissue culture vessel 5. The sample 6 is placed on the bottom of cavity and the insert is pushed on top of it. For this purpose, it is possible to use the body 3 alone or the ensemble of the body and the ring 4. The hard block sample 6 can be porous to allow the growth of cells inside it. Although shown slightly above the bottom in FIG. 3, it will be appreciated that the sample 6 can be pushed down against the bottom of the vessel by the lower end of the body 3.
FIG. 4 illustrates the possibility to control the height of the cell culture insert 4 in the well, the material 1 and the ring 2 being omitted. Depending on the needs, the insert can be placed on the bottom of the well or heighten it up to the level of the upper surface of the tissue culture vessel 5. The adjustment of the height position is stepless, because the insert can slide with the gripping means 7 in friction contact with the inner wall of the well. The height of the insert 4 can thus be selected so that the cell growth material 1 fixed to it lies at optimum height for the purpose of cultivation of cells. If the assembly of the ring 2 and the sleeve-like body 3 has a total height lower that the inner height of the cavity (well) of the cell culture vessel 5, it can be placed totally inside the cavity so that a lid or plug can be used for closing the upper opening of the cavity, the closing means being thus able to be in contact with the upper edge of the cavity unobstructed by the cell culture insert 4.
FIGS. 5-7 show different designs of the cell culture insert.
FIG. 5 shows an insert 4 where the body 3 has a plurality of gripping means 7 distributed at even intervals around the outer periphery of the body 3. The gripping means 7 are in form of vertical ridges protruding from the outer wall of the sleeve. Their elasticity inwards is ensured by cutout portions or notches extending from the upper edge of the sleeve and terminating midways of the sleeve. The cutout portions or notches limit tongues that comprise said ridges and that can slightly bend inwards to allow the elastic movement of the gripping means. The lower part of the sleeve has a smaller diameter so that the ring 2 can be fitted around the body 3 in position, where the ring 2 does not extend radially beyond the gripping means 7 in horizontal direction.
FIG. 6 shows an insert 4 where the gripping means 7 are in the form of elastic wings that extend obliquely from the relatively rigid outer wall of the sleeve and are slightly curved. The wings are able to bend inwards so that they can fulfil the function of elastic gripping means. The ring 2 has on its upper surface short pins or knobs that help to keep the material 1 in place when the body is pushed down into the ring 2. In this embodiment of the insert, the ring 2 also has a smaller outer diameter that the outermost diameter of the body 3 defined by the wings. At the lower part of the body 3 there are cutout portions or notches starting from the lower end of the sleeve to increase the elasticity of the sleeve in this zone so that the ring 2 could be more easily placed around it.
FIG. 7 in turn shows an insert 4 where the gripping means 7 are formed of elastic arcuate portions of the sleeve wall that are left between cutout portions or notches in the sleeve wall and diverge slightly conically in upward direction. Radially extending wings situated centrally of the cutout portions or notches serve to stiffen the body 3. The lower part of the body 3 has a smaller diameter and the ring 2 has cutout portions to facilitate its installation around the lower part of the body 3.
The culture vessel where the insert is located includes a base comprising a number of wells each comprising an inner side wall closed at the bottom by wall and open at the top end. The base is typically transparent and may be, for example, molded of polyvinylchloride or polypropylene. For viewing of the cell culture by microscope it is important that at least the bottom of the cavity is transparent.
It can be seen that the body 3 of the cell culture insert 4 has a varying outer diameter which is largest in the area of the gripping means 7. This will leave areas between the gripping means for adding or withdrawing substances between the body and the inner wall of the cavity into or from the cavity.
While in the foregoing paragraphs the details of the culture vessel illustrated are described, it is to be appreciated that the vessel itself does not form part of the present invention, and the cell culture insert of the present invention may be sized to fit and be used with other culture vessels or like receptacles. However, the combination of a cell culture insert and the vessel, containing also the material for cell growth, forms part of the present invention. According to one embodiment, a vessel having a plurality of cavities, of which at least some or all are provided with a cell culture insert together with a cell culture substrate can be provided ready for the customer.
The cell culture insert can be delivered to the customer without a cell culture substrate, which can be selected by the customer when using the insert for cell culture purposes. Alternatively, the cell culture substrate can be pre-assembled in the insert which is thus delivered together with the substrate to the customer.
As practitioners-in-the-art will understand, the cell inserts of the invention may be comprised of simple moldable parts which may be mass produced from a variety of materials, including, for example, polyethylene, polystyrene, polyethylene terephthalate, and polypropylene.
As to the material for the cell culture substrate, it can be made of synthetic and natural biomaterials including but not limited to polylactides, polyglycolides, poly-d,l-lactides, polyethylene oxides, polyepsilon caprolactones, chitosan, collagen, starch, bioglass, hyaluronic acid, tyrosine, tricalciumphosphate, hydroxyapathite, polyurethane, alginate and fibrin, and polypropylene and their copolymers, including mixtures of the above-listed materials. The cell culture substrate can be in the form of foil, fiber, textile, membrane, mesh, block, foam, or plate. Especially in case of blocks held on the bottom of the culture vessel, they can be of tricalciumphosphate or hydroxyapathite. The block can also be made of fibers or foam which form a porous felt-like or sponge-like porous structure. As can be seen from the above listing, the materials can be biodegradable or stable.
The material in connection with the insert can be tissue itself of human or animal origin, such as amniotic membrane, bone, soft tissue or cornea. The membrane can be used in the same way as the material 1 in FIGS. 1, 2 and 5-7, i.e it spans the lower opening of the sleeve. The bone, soft tissue and cornea can be used in the same way as the block in FIG. 3, that is, held against the bottom by the sleeve.
Patent Application
20080076170
