WO1997004073A2

WO1997004073A2 - Covers for cell-culturing vessels

Info

Publication number: WO1997004073A2
Application number: PCT/IL1996/000052
Authority: WO
Inventors: Michael Inbar
Original assignee: Elbar Advanced Technology Ltd.; Ilan And Gavish Automation Services Ltd.
Priority date: 1995-07-19
Filing date: 1996-07-16
Publication date: 1997-02-06
Also published as: AU6368096A; IL114658A0; WO1997004073A3

Abstract

The present invention concerns a cover (11) for cell culturing vessels and a cell culturing vessel. The cover (11) or the vessel may transit between three positions: sealed (A) for transport purposes, open (C) for extracting or adding to the contents of the cell-culturing vessel; and a vented position (B) which allows communicating of the contents of the vessel with ambient air, for culturing or sterilization purposes, but eliminates contamination caused by gravitation fall of particles from above. The cover of cell-culturing vessels of the invention or the cell-culturing vessel itself may transit between the three positions by a single-handed manipulation.

Description

_ i _

COVERS FOR CELL-CULTURING VESSELS

FIELD OF THE INVENTION

The present invention concerns covers for cell-culturing vessels as well as cell-culturin *»s vessels.

BACKGROUND OF THE INVENTION

Cell-culturing is a key operation in microbiological laboratories and laboratories dealing with culturing of cells and tissue of higher organisms.

Multiple laboratory vessels are available today for culturing of cells, such as glass or plastic tubes, Erlenmeyer bottles, petri dishes etc.

A unique feature of laboratory vessels intended for cell-culturing as compared to other laboratory vessels is that, in addition to being able to be in a sealed position suitable for storage and transportation and an open position suitable for extraction from or addition to the contents of the vessel, the vessel is also capable of featuring an intermediate vented position. In this vented position the cells contained within the vessel are able to communicate with ambient air for consumption of essential gases and for disposal waste gases produced during metabolism. At the same time, the vented position is able to protect the contents of the cell-culturing vessel from contamination caused by fall of particles, especially microorganisms, into the vessel. Usually the vented position is obtained by constructing a cell- culturing vessel stopper made of cotton wool, which is shaped, with the aid of adhesive tape, to fit the opening of the vessel. The cotton wool enables passage of air through its pores while filtering out undesired particles such as contaminating microorganisms. Such cotton wool stoppers have to be constructed manually by each laboratory separately, and are not commer¬ cially available. Furthermore, manipulation of said cotton wool stoppers, for example, from the open to the closed position and vice versa is sometimes awkward, especially when the opening of the vessel is large requiring gripping by both hands.

Coverings, stoppers and caps which can be opened and closed with the use of one hand are known from various fields such as cosmetics, dentistry, etc. While most of the one-hand operated covers are used in cosmetics and for clinical utilities, some one hand manipulated caps or covers are also known for laboratory uses.

U.S. Patent 5,270,011 discloses a plastic reactor, for_. small quantities of liquid, having a cap which can be manipulated by using a single hand. This reactor, which is intended to hold various laboratory liquids, is not compatible for cell culturing, since it does not feature a vented position.

U.S. Patent 4,923,072 discloses a vial-type tube which has a stopper made of deformable material capable of preserving vacuum inside the tube which can be easily engaged with one hand. The vial is intended to be used for collection of various physiological fluids such as blood, and is not intended for culturing of cells, since it can transit between a sealed or open position and an intermediate vented position is not possible.

U.S. Patents 4,769,333 and 4,859,603 disclose a device for immunological assays comprising a container with a closure plate which can discharge fluid when an opening disc is displaced by the use of one hand. Usually the displacement of the disc cuts a specially formed nipple thus enabling flow of liquid from the container which means that the container is opened in an irreversible manner. This device is intended to hold liquids — J -

required for various immunological assays in a sealed position until use and then reverts only once to an open position enabling discharge of liquid.

Various laboratory vessels which enable gas communication between the interior and the exterior of the vessel are also known. U.S. Patent 4,286,389 discloses an apparatus used in lyophiliza¬ tion procedures. The apparatus comprises a device for suspending a resilient stopper relative to a container during lyophilization in a manner which creates a space between the stopper and the container, permitting water vapor to escape from the container during the lyophilization procedure. Upon termination of the lyophilization, the stopper can be pushed into the container to seal the lyophilized products.

U.S. Patent 5,377,854 teaches of a stopper assembly for a test tube comprising an inner elastomeric stopper and an outer semi-rigid cap which assists in the manual manipulation of the inner stopper. The stopper is capable of being inserted halfway through the opening of the test tube, thereby creating a gap allowing gases, produced due to heating or chemical reactions, to escape the test tube. Subsequently the elastomeric stopper is inserted further into the tube to form a sealed position. The assembly concerns test tubes especially those used to hold noxious or hazardous substances and the semi-rigid cap is formed so as to avoid spilling of the contents of the tube when the inner stopper is half raised and the test tube is mishandled.

U.S. Patent 2,649090 discloses rubber stoppers for pharmaceutical vials that are lubricated by a silicone lubricant The stopper may be partially inserted into the vial so as to enable to evacuate air from the vial and then is pushed all the way into the vial in order to seal the vial under vacuum.

In U.S. 5,270,011 and 2,649,090 the vented position is created in order to enable vacuum formation in the vessel. In U.S. 4,923,072 the vented position is created in order to relieve excess gas pressure produced in the tube due to heating or chemical reaction. It would have been desirable to provide a cover for tissue- culturing vessels which, while being able to provide a vented position, wherein gases¹ transfer is possible and contamination by fall of particles is avoided, is also capable of being manipulated with the use of only one hand, thus freeing the other hand for various laboratory procedures.

SUMMARY OF THE INVENTION

The present invention provides covers for a cell-culturing vessel engageable with the vessel in one of three positions: a first sealed position, a second vented position wherein the interior of the vessel is in communi¬ cation with ambient air while contamination caused by gravitational fall of particles is essentially avoided, and a third open position enabling extraction from or addition to the contents of the vessel; wherein transition of said cover between each of said positions is carried out by a single-hand manipulation.

The covers are intended for cell-culturing vessels such as glass or plastic tubes, Erlenmeyers, glass bottles etc. The vessels are either used for culturing microorganisms such as bacteria, fungi, viruses, yeast or amoeba for various microbiological purposes, or for culturing cells or tissue cultures obtained from higher organisms, such as mammalian or plant cell cultures.

The covers of the invention may engage the cell-culturing vessel in a completely detachable manner, or may engage the vessel through a contacting region (such as a hinge, or flexible area) and in the latter case the covers may be an integral part of the vessel, for example, they may be both molded using a single cast.

The covers may engage the cell-culturing vessel directly, i.e. by insertion into the opening of the vessel, or may engage the vessel through mediation of various adapters, such as conical rings placed in the interior of the opening of the vessel, in order to enable one cover to fit into several openings of various sizes. In both cases the covers may be detachable, either from the vessel or the adapter or may be attached to the vessel or the adapter through contacting regions as described above.

Where the covers are intended for multiple usage they should be amenable for sterilization, for example by autoclave, and therefore made of autoclave-compatible materials such as plastic, rubber or latex. The covers may also be intended for disposable use and thus may be part of a sterilically produced unit comprising both a disposable cover and a disposable cell-culturing vessel. The material from which the covers are made is essentially gas impermeable, since the vented position is obtained by the special construction of the covers and not by the material from which they are composed.

The covers engage, either directly or through the adapter, the cell-culturing vessel in one of the following three positions: sealed, vented or open. In the sealed position, the interior of the vessel is essentially isolated from ambient surroundings. This position is usually used when the vessel is stored and/or transported and the covers of the invention may comprise in addition locking means to ensure maintenance of the sealed position. The vented position, which is used either during the cell-culturing phase or during sterilization of the vessel by autoclave or by noxious gases, such as ethylene oxide, enables the interior of the tissue-culturing vessel to be in communication with ambient air. Said communication is required to facilitate gas transfer between the interior and exterior of the vessels required for survival and culturing of cells, for relief of excess pressure produced by autoclave sterilization or for the purpose of sterilization by noxious gases. Such gas transfer may be achieved simply due to diffusion and no difference in pressure between the interior and the exterior is required therefor. The cover is able to protect the interior of the vessel from contamination caused by gravitational fall of particles from above, especially contamination caused by fall of microorganisms. Such vented, but contamination-protected position, is achieved by positioning the cover in a manner that creates an air path, wherein the air enters from a gap formed between the cover and the vessel, which air path is not straight, i.e. does not extend essentially perpendicular to the bottom of the vessel. Alternatively, a perpendicular air path may be used where its upward facing opening is protected by overhanging projections.

The open position enables extraction from, or addition to, the contents of the vessel. The open position is used when performing various laboratory operations such as: adding cells, adding or exchanging growth media, extracting samples of cells or growth media, adding nutrients etc. Transition of the cover from one position to the other is carried out by a single hand manipulation, thus freeing the other hand for various laboratory operations such as holding a pipetter for adding or extracting liquids from the interior of the vessel, etc.

Said single handed manipulation complies with sterility require- ments, so that transition from one position to the other is carried out without any contact between the hand of the user and the inside of the vessel, the rims of the vessel at the mouthpiece region through which liquid is poured, or with parts of the cover which arc to face the inside of the vessel.

The single handed manipulation of the cover can be carried out in various manners. For example, the cover may contain engaging means suitable for one finger, such as a small handle, a protrusion or a depression, all capable of serving as a grip for one or more fingers (usually the index finger), while the remaining fingers usually grasp the vessel near its opening in order to provide support. The cover is transitioned between its various positions by engaging the finger with said gripping means and lifting or lowering the cover in case of completely detachable cover, or opening, closing, rotating or tilting the cover along the contacting region in case of an attached cover.

In order to achieve the vented position, the cover in the above examples comprises in addition supporting means which arc able to space the edges of the cover from the rims of the vessel, while the projecting edges of the cover protect the opening of the vessel from contamination caused by gravitational fall of particles from above. By a single hand manipulation, said spacing action of the supporting means is eliminated, for example by placing the supporting means inside the vessel so that the edges of the cover are in tight contact with the rims of the vessel or of the adapter in order to provide the tight sealed position.

An example of such supporting means arc a plurality of spaced spikes arranged at the circumference of the cover made of a resilient material. Said spikes arc present within the neck of the tissue-culturing vessel when the cover is in the scaled position, enabling tight contact between the edges of the cover and the rim of the vessel or the adapter. When the cover is halfway raised, the spikes frictionally engage the inner surfaces of the neck of the bottle or the adapter and thus support the cover in a semi-raised position, allowing air passage thereinbetween, while holding the cover so that its projecting edges protect the opening of the vessel from fall of particles from above.

Another example of such supporting means arc one or more protrusions, on the edges of the cover. When the cover is in the sealed position the protrusions are placed inside the opening of the vessel, thus enabling a tight contact between the edges of the cover and the rims of the vessel. When the protrusions arc dislocated from the inside of the vessel and placed on the rims of the vessel, the edges of the cover arc slightly raised from the rims of the vessel, thus creating a gap allowing air flow while the projecting edges of the cover protect the vessel's opening from contamination by fall of particles from above The cover can also be composed of a rotatable body, such as a cylinder, a sphere, or a segment of a sphere, which is then placed either directly in the mouth of the vessel or within a socket which is then placed in the mouth of the vessel. The rotatable body bears a hole. Manipulation between the various positions is carried out by rotating the rotatable body so that the hole is completely aligned with the opening of the vessel to form the open position, or is completely facing the walls of the vessel, in order to form the sealed position. The vented position is created by rotating the rotatable body, so that its opening is in an intermediate position between the open and the closed positions, in a manner that a small air passage is created by partial blockage of the hole with the walls of the vessels, said small opening is protected from direct fall of particles from above by overhanging projections which are either part of the cover or part of the rims of the vessel.

The present invention also concerns a cell-culturing vessel capable of transition between three positions: a first sealed position, a second vented position wherein the interior of the vessel is in communi- cation with ambient air while contamination caused by gravitational fall of particles is essentially avoided, and a third open position enabling extraction from or addition to the contents of the vessel; wherein said transition is carried out by a single-hand manipulation.

The tissue-culturing vessel according to the invention comprises an opening region made of a deformable material, such as rubber or latex. By applying force to the deformable opening region, for example by a squeezing action of a single hand, the deformable material deforms and the vessel assumes its open position. The vented position is created by allowing the vessel to assume its native unpressurcd form and protecting the air path created between the rims of the vessel from contamination by fall of particles, by use a protecting member such as a clasp which overshadows the opening of said air path. The sealed position is obtained by pressing together tightly the deformable rims of the vessel, for example with the aid of a clasp. The cell-culturing vessel of the invention may be composed entirely from said deformable material or may be composed of an essentially rigid material, and only by the opening region (such as the region of the neck of a bottle) is made of said deformable material.

The cell-culturing vessel of the invention, may be in a disposable form, or may be adapted for repetitive use. In the latter case, it should be composed of a material capable of being sterilized, for example by an autoclave. The invention will now be further illustrated with reference to some specific, non-limiting drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic representation of a completely detachable cover of the invention engaged with the vessel in a sealed (A), vented (B) or open (C) positions;

Fig. 2 shows a schematic representation of an attached cover of the invention engaged with the vessel in a sealed (A), vented (B) or open (C) positions;

Fig. 3 shows a schematic representation of a cock-type valve cover of the invention engaged with the vessel in a sealed (A), vented (B) (top view (B ')) or open (C) positions;

Fig. 4 shows a schematic representation of a hemisphere-segment cover of the invention engaged with the vessel in a sealed (A), vented (B) or open (C) positions;

Fig. 5 shows a schematic representation of a cover of the invention engageable with an adapter in a sealed (A), vented (B) or open (C) positions; Fig. 6 shows another schematic representation of an attached cover of the invention engaged with the vessel in a sealed (A), vented (B) or open positions; and

Fig. 7 shows a schematic representation of the tissue-culturing vessel of the invention in the sealed (side view (A), front view (A')), vented (side view (B), front view (B')) or open (side view (C) front view (C ')) positions.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Figure 1 shows one embodiment of the cover of the invention 11.

The cover comprises a circular flat top 12 attached to a conical stopper 13. To the middle of the flat top 12 is attached a handle in the shape of an upright positioned ring 14, the size of which is suitable for inserting a finger

(for example an index finger) therethrough. The circumference of conical 10

stopper 13 holds a plurality of spaced spikes 15 which serve as supporting means and are somewhat resilient.

Transition from one position to the other is carried out by inserting a finger through handle 14 and raising or lowering the cover while the remaining fingers hold the bottle in the neck region for support. The sealed position (A) is obtained by placing cover 11 inside the neck of vessel 16, so that stopper 13 is in contact with the inner walls of the vessel, while resilient spikes 15 are present within the neck of the vessel so that an airtight seal is provided, shown enlarged in (A'). The vented position is obtained by placing cover 11 halfway through the neck of vessel 16 so that while the opening is covered by the projecting edges of flat top 12, which is larger in diameter than the diameter of opening of vessel 16, to avoid contamination due to gravitational fall of particles from above, the interior of the vessel is vented by ambient air passing through multiple gaps between the spikes 15 as shown in (B) and enlarged in (B'). Opening of the vessel is obtained by completely lifting the cover as shown in (C). The finger (usually the index fingers) remains within ring 14 when cover 11 is detached from vessel 16 while the remaining fingers grasp the neck of the vessel, so that reversion back to the closed or vented position is achieved simply by lowering again the index finger.

Figure 2 shows another embodiment of the cover of the invention 21. The cover is attached to vessel 26 through hinge 22. The cover 21 is in the form of a cap 23 having a handle 24 attached thereto, which is suitable for engagement with the finger of the user. The edge of cap 23 comprises an extending lip which bears a depression 25, shown enlarged in (A') and (B'). Depression 25 corresponds to protrusion 27 present at the rim of vessel 26, shown enlarged in (A') and (B')- Such a protrusion is normally present at the rims of many tissue culturing vessels such as Erlenmeyers but can be especially constructed for the purpose of engagement with the cover of the invention. The sealed position is obtained by sliding the lip of the cover (having depression 25) over protrusion 27. This is possibly due to the slightly resilient properties of the lip bearing of the cover. The vented position (B) is obtained by dislocating protrusion 27 from depression 25, to allow air to communicate with the interior of the vessel through a gap formed between the edges of cap 23 and the rims of the vessel. The overhanging edges of cap 23 are able to protect the opening of the vessel from contamination due to gravitational fall of particles from above. The open position (C) is obtained by moving the cover 21 so that it is completely separated from the vessel except in the hinge region. The force required for transition from one position to another may vary, for example in order to ensure that the vented position does not revert, due to mishandling, to the sealed position, a somewhat larger force is required to push protrusion 27 into depression 25 than the force required to disengage said protrusion and depression.

Figure 3 shows yet another embodiment of the cover of the invention 31 comprising a rotatable cylinder 32 shown separately at the right-hand bottom side of the Figure. The cylinder is placed within the opening of the vessel to form a cock-type valve. A hole 33 spans cylinder 32 and a small handle 34 constitutes gripping means, by which the cylinder is rotated within the socket by the use of one or more fingers. The sealed position (A) is obtained by rotating the cylinder 32 so that the hole 33 completely faces the wall of the vessel. The open position (C) is obtained by rotating the hole 33 of cylinder 32 to be completely aligned with the opening of vessel 36. The vented (B) position is obtained by placing the cylinder 32 in an intermediate position between (A) and (C) so that a small opening is created allowing air passage therethrough. Contamination due to fall of particles from above is avoided due to small overhanging projections 37 extending from the rims of the vessel towards the center of the opening shown in top view in (B'). These projections overshadow the region of the small opening in the vented position, so that the air path is protected by said projections 37. Fig. 4 shows yet another embodiment of the invention, wherein the cover 41 comprises a sphere-segment 42 which is essentially a hemisphere. Hemisphere 42 comprises a hole in the shape of half an ellipse 43. The hemisphere segment is present within a rounded construct which forms the neck and opening region of vessel 46. Extending peφendicular to opening 43 is a handle 44 which can be moved by one finger. Handle 44 carries, essentially perpendicular thereto, a surface 45 which when the cover is in the vented position is able to overshadow all of the part of hole 43 which is not facing the walls of the vessel. Surface 45 is constructed essentially in the shape of half a moon. Surface 45 carries two protrusions defining therebetween depression 47. In the open (C) position hole 43 is completely aligned with the opening of the vessel 46. In the scaled position (A) the handle 44 is tightly touching the wall of vessel 46 and depression 47 is placed beyond the rim of the vessel to provide a tight seal as shown enlarged in (A')- In the vented position (B) shown enlarged in (B') depression 47 is placed on the rim of the vessel, thereby creating a gap 48 through which air may pass. Surface 45 which overshadows hole 43 eliminates the fall of particles from above.

Fig. 5 shows a still further embodiment of the invention wherein cover 51 is engaged with adapter 56, which adaptor is then inserted in the neck of the cell-culturing vessel. Cover 51 is attached to the adapter through hinge 52. The cover comprises an inner part 55 in the shape of a conical ring which is enagageable with the inner surface of the adapter. Cover 51 carries handle 54, which serves as gripping means for one finger as well and depression 53 which aids in closure of the cover as will be explained hereinbelow. At the region facing the hinge, cover 51 is constructed having a step-like appearance having two steps 57 and 58. Adapter 56 comprises around its ring protrusion 59 engageable both with the inner surface of step 57 and of step 58. In the sealed position (A) step 57 is placed over protrusion 59 so that inner part 55 is in tight contact with the inner surface of the rims of the adapter. In order to case achievement of the sealed position, a finger may be placed in depression 53 pushing the cover downward. The vented position (B) is achieved by placing a finger beneath the overhanging edge 50 of the cover and lifting the cover so that step 58 rests on top of protrusion 59. In such a position air may pass through the gap between the cover and the adapter while the opening is protected by the overhanging edges of cover 51. The open position (C) is obtained by engaging a finger with handle 54 and tilting the cover. In order to avoid accidental closure of the cover, when in the vented position, transition of the cover from engagement of protrusion 59 and step 58 forming the scaled position, requires some force, as described above.

Adapter 56 can have slightly conical surfaces, so it may fit into various vessels ha ing different opening diameters, depending on the depth of insertion into the vessel.

Fig. 6 shows yet another embodiment of the cover of the invention 61 engaged to vessel 66 by hinge 62. Cover 61 comprises handle 64 serving as gripping means for one finger. At the circumference of cover 61 is a protrusion 63 shown enlarged in a side view in (B'). In the sealed position (A) protrusion 64 is placed within the rim of the vessel. The open position (C) is obtained by engaging a finger with handle 64 and moving cover 61 at the plane parallel to the bottom of the vessel. The vented position (B) and (B') is obtained by dislocating protrusion 63 from the inside of the vessel and placing the protrusion on the rims of the vessel 66. A gap is thus created between cover 61 and vessel 66 enabling air passage. The overhanging edges 65 of the cap shown enlarged in B' protect the opening of the vessel from contamination caused by the fall of particles from above.

Fig. 7 shows the vessel of the invention. (A) (B) and (C) are a side view of the vessel and (A') (B') and (C) are front views of the vessel which is turned 90° in respect to the side view. The vessel comprises an opening region 71 and a body region 76 which may both be composed of a deformable material such as resilient plastic or only the opening 71 may be composed of said deformable material while the body region 76 is made of a more rigid material.

The rims of the vessel 73 are in the shape of two lips, which when no pressure is applied collapse to touch each other leaving a small opening. The vessel comprises in addition an elongated clasp 75 attached to the vessel through contacting region 72 made of a thin layer of the material of the vessel which thin layer cause it to be flexible, and comprises in addition a handle 74.

In the un-pressured vented position (B) and (B') (shown enlarged in (B")) rims 73 collapse, leaving a small elongated opening thereinbetween allowing air passage. Elongated clasp 75 rests on rims 73 but is spaced therefrom, so that air may enter through the gap between the rims and the clasp, while contamination caused by fall of particles from above is avoided, due to the protective action of the overhanging clasp. The sealed position (A) and (A') (shown enlarged in (A")) is obtained by forcing the elongated clasp down so that it clasps together tightly the resilient rims of the vessel creating a tight seal. The open position (C) and (C) is obtained by gripping with one finger, handle 74 and completely rotating clasp 75 along the contacting region 72 simultaneously squeezing with the remaining fingers the resilient opening region 71, so that the rims of the vessel part from each other as in opening of a resilient spectacle's case.

Claims

CLAIMS:

1. A cover for a cell-culturing vessel engageable with the vessel in one of three positions: a first sealed position, a second vented position wherein the interior of the vessel is in communication with ambient air while contamination caused by gravitational fall of particles is essentially avoided, and a third open position enabling extraction from or addition to the contents of the vessel; wherein transition of said cover between each of said positions is carried out by a single-hand manipulation.

2. A cover according to Claim 1 engageable with the vessel through the mediation of an adapter.

3. A cell-culturing vessel capable of transition between three positions: a first sealed position, a second vented position wherein the interior of the vessel is in communication with ambient air while contami- nation caused by gravitational fall of particles is essentially avoided, and a third open position enabling extraction from or addition to the contents of the vessel; wherein said transition is carried by a single-hand manipulation.

4. A cover according to Claims 1 or 2, which is detachable from the vessel or the adapter comprising gripping means suitable for one finger and wherein said single-hand manipulation is carried out by engaging one finger with said gripping means and lifting or lowering the cover, while the other fingers support the vessel.

5. A cover according to Claim 4, wherein said engaging means is a ring-shaped handle attached in an upright orientation to the center of the cover.

6. A cover according to Claims 1 or 2 attached to the vessel through a hinge comprising gripping means suitable for one finger and wherein said single hand manipulation is carried out by engaging one finger with said gripping means and opening or closing the cover, while the other fingers supports the vessel.

7. A cover according to Claim 6, wherein said opening and closing is obtained by moving the cover at the plane essentially parallel to the bottom of the vessel.

8. A cover according to Claim 6 wherein said opening is obtained by moving the cover at a plane essentially perpendicular to the plane of the rim of the vessel.

9. A cover according to any one of Claims 4 to 8, comprising supporting means which are able to space the edges of the cover from the rims of the vessel or the adapter, thereby forming the vented position of the cover, said space is eliminated by a single hand manipulation to bring the edges of the cover to tight contact with the rims of the vessel, thereby creating the sealed position of the cover.

10. A cover according to Claim 9, wherein the supporting means are a plurality of resilient spikes spaced at the circumference of the cover and extending toward the bottom of the vessel when the cover is in the closed or vented positions, said spikes frictionally engage the opening of the vessel or the adapter so as to space the cover from the rims of the vessel or adapter allowing air passage thereinbetween, when the cover is in the vented position, and are completely inserted into the vessel or the adapter when the cover is in the sealed position.

11. A cover according to Claim 9, wherein the supporting means comprise at least one protrusion on the edge of the cover extending downward when the cover is engaged with the vessel, said sealed position is obtained by placing said at least one protrusion within the opening of the vessel and said vented position is obtained by placing said at least one protrusion on the rim of the vessel or the adapter, thereby spacing the cover from the vessel.

12. A cover according to Claims 1 or 2, placed within the opening of the vessel or the adapter, comprising a rotatable body bearing a hole; said transition between positions is carried out by rotating the body within the opening of the vessel, the open position is obtained by aligning said hole with the opening of the vessel, the closed position is obtained by placing said hole to completely face the walls of the vessel and said vented position is obtained by placing said hole in an intermediate position between the closed and open positions.

13. A cover according to Claim 12, wherein said rotating body is a segment of a hemisphere, comprising a surface overhanging the opening of the vessel so that when the cover is in the vented position, said surface protects the contents of the vessel from contamination caused by fall of particles from above.

14. A cover according to Claim 12, wherein said rotating body is a cylinder.

15. A vessel for use in conjunction with the cover of claim 14, comprising two protrusions projecting from the rims inward, said protrusions capable of protecting the openings formed between the walls of the vessel and the rotating body of the cover from fall of particles from above when the cover is engaged with the vessel in the vented position.

16. A cell culturing vessel according to claim 3, wherein at least the opening region of the vessel is composed of deformable material, the deformable rims of the vessel are in a collapsed form when no pressure is applied; said vessel further comprising an elongated clasp attached through a contact region to the vessel; said scaled position is obtained by forcing the clasp on the deformable rims thereby creating a tight seal, said vented position is obtained by unclasping the deformable rims and placing the elongated clasp on said rims in a spaced manner so that said clasp overhangs the opening between the deformable rims, eliminating contamination caused by fall of particles from above; and said open position is obtained by rotating the clasp along the contact region and applying pressure to the deformable opening region by a squeezing action, thereby spacing the rims from one another.

17. A cover according to Claim 1, substantially as hereinbefore described.

18. A cell-culturing vessel according to Claim 3, substantially as hereinbefore described.