GB2499372A

GB2499372A - Hypoxic Pressure Cell Culture Incubator

Info

Publication number: GB2499372A
Application number: GB1201161.5A
Authority: GB
Inventors: Kareem Salhiyyah
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-01-25
Filing date: 2012-01-25
Publication date: 2013-08-21
Also published as: GB201201161D0

Abstract

A hypoxic pressure chamber or incubator for cell culture comprises an air tight plastic box that has: at least one gas inlet; and a gas outlet, the gas outlet being closed with an adjustable one way valve (i.e. a check or pressure relief valve) that is configured to allow a desired increased pressure level inside the box (preferably up to 20 cm H2O, 49.82 mbar). Preferably, a medical positive end expiratory pressure valve (PEEP valve) is conveniently utilised as the one way valve and the incubator preferably portable. In some embodiments the incubator may comprise a more than one gas inlet, i.e. a tri-gas hypoxic incubator to allow culture gas mixing.

Description

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Hypoxic Pressure Chamber

Field of the Invention

The present invention concerns improvements in and relating to hypoxic pressure chambers and primarily to such chambers as are used in laboratories for cell culture.

Background of the Invention

Cell culture is a fundamental part of biological research. Different types of living cells can be grown in the laboratory under a controlled environment that mimics physiological conditions as much as possible. These conditions include temperature, humidity, concentration/ partial pressure of oxygen and other gases and concentrations of nutrients. The cells are most commonly cultured in cell culture plates that are held in incubators. A range of types of incubators are available and provide variable physiological conditions. Since different types of cells and experiment regimes may require differing conditions it is useful for the incubator to allow for adjustment of conditions and one of the most useful factors to be able to adjust in the incubator is the oxygen level. Whereas it is standard lab practice to culture cells under atmospheric conditions, the largest and most sophisticated incubators have been improved to have the ability to vary the level/ partial pressure of oxygen provided.

The known incubators generally fall into one of three size-related categories. Firstly, the largest ones, which are generally approaching room-sized (ie several square metres in floor area) often will have a sophisticated system that allows good gas control and with the ability to perform tasks from outside the chamber reaching into the chamber through sleeves (see Figure 1). These incubators are generally large enough to accommodate additional processing machines and tools inside such as, for example, mixers/ centrifuges.

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In a second category are medium size incubators - the size of a small domestic fridge and having a vertical array of shelves/ compartments like a fridge (see Figure 2). The medium size incubators are the commonest lab incubator. Some of the medium sized incubators can have oxygen control but the available ones generally have a limitation on the lowest level of oxygen that they can go down to (this is generally no lower than 2%) and there is large variability.

In a third category are the small incubators that are small boxes (eg glove box sized), normally substantially under one metre square floor area. The small incubators normally have little in the way of features and control, though there are some available on the market with limited adjustability. The advantages of these small incubators stemming from their compactness include that they can be used where space is limited and they can even be housed inside the standard, medium sized incubator and multiples of them may be used alongside each other or stacked, potentially allowing many different trials to be carried out within a given space. Additionally, unlike the larger incubators, small box incubators are readily portable. They can be readily moved from one place to another while maintaining gas composition.

Available small box incubators have a number of significant limitations that reduce their usefulness and appeal. Most notably, they generally depend on using a premixed gas and do not allow mixing of gases within them and most don't have an oxygen sensor, are too small and cannot control pressure.

Summary of the Invention

According to a first aspect of the present invention there is provided a hypoxic chamber or incubator for cell culture that comprises an air tight plastic box that has: at least one gas inlet; and a gas outlet, the gas outlet being closed with a one way valve that is configured to allow creating a desired pressure level inside the box.

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Particularly preferably the gas outlet valve is a PEEP valve (Positive End Expiratory Pressure valve). PEEP valves are traditionally used in medical resuscitator or ventilator apparatus for patients requiring assistance in breathing. The applicant has found that such valves, despite their substantial cost and design for specialised medical use can be used instead to extremely beneficial advantage in the construction of a compact cell culture incubator. A preferred PEEP valve used in the chamber is configured to achieve a pressure difference there-across of 0-20 cm H20, but valves of other pressure differential can be used also.

The box may have only one inlet to be used for premixed gas; or may have two or more inlets to be used to mix gases as required. The box is suitably connected to a gas sensor, eg an oxygen sensor or CO2 sensor, either directly or through a closed loop.

The hypoxic chamber can be provided in a wide range of sizes depending on need but is suitably of compact size and form corresponding to the 'small' readily portable chambers of the prior art. Preferred sizes are of a floor area of less than one square meter and preferably less than 0.5 square meters.

The hypoxic chamber of the present invention broadly speaking has all of the benefits of the existing available small incubators but for the first time provides a small portable hypoxic incubator that allows pressure control. The apparatus is simple and readily affordable and can be assembled using readily available PEEP valves. The apparatus permits various options in features such as size and number and type of inlets. The apparatus is versatile in configuration and allows the use of premixed gas or mixing of gases therewithin. The apparatus allows for varying the gases used and also allows the use of various gas sensors. The apparatus also allows real time measurement of oxygen concentration and pressure.

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Brief Description of the Drawings

A preferred embodiment of the present invention will now be more particularly described, solely by way of example, with reference to the accompanying drawings in which:

Figure 3 is a perspective view of the preferred embodiment of the invention comprising a plastics cell culture incubator box; and

Figure 4 is a perspective view of the preferred embodiment of cell culture incubator box as viewed from above and with the lid of the box removed.

Description of the Preferred Embodiment

Referring to Figures 3 and 4, the illustrated preferred embodiment comprises a plastics box 1 that is moulded of a suitable plastics, such as polypropylene and is here shown as being an assembly of an open-topped tub base part 1a and a mating lid part 1b to close down over the open top of the tub 1a and seal in the content to be incubated in a gas-tight manner. The box 1 is cuboidal being rectangular in plan but with rounded corners. The tub part 1a of the box 1 has four sidewalls of equal height that terminate at their upper end in a rim that sealingly co-operatively engages with the rim of the lid 1b in use, there being a gasket/ elastomeric seal means 2 fitted at the interface between the tub's rim and the mating rim of the lid 1 b.

The box 1 has at one end two separate gas inlets 3a, 3b for introducing different gases into the chamber of the closed box 1. The two separate gas inlets 3a, 3b each have a respective one way gas valve for introducing gas into the box 1 and to allow two different gases or gas compositions to be separately introduced and mixed together in the chamber. The first of the gas inlets 3a suitably serves to deliver oxygen into the box 1 while the second of the gas inlets 3b suitably serves to deliver a mix of nitrogen and carbon dioxide. The selected balance between those gas supplies determines the hypoxic level in the box 1.

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At the other end of the box 1 is a first outlet 4 with a PEEP valve 5 demountably fitted to it and a second valve-sealed outlet port 6 to which an Oxygen sensor 7 is shown fitted to sense the oxygen concentration within the chamber of the box 1 in use. The sensor 7 is demountable from the valve-sealed outlet port 6. The port 6 may have a valve (eg a Schrader type of valve or similar) to open only when a gas sensor 7 capping the outlet port 6 is securely fitted in place. The sensor 7 could be configured to sense a number of different gases or the sensor 7 may be swapped with other gas sensors when required.

The PEEP valve 5 on the first outlet 4 is adjusted for use and set to a selected setting for defining and maintaining the target pressure within the sealed box 1. The valve 5 has a return spring/ resilient biasing means that may be adjusted in position to alter the biasing force that it exerts to close the valve 5. Once the PEEP valve 5 is set for the target pressure and the box 1 is filled with gases through the inlets 3a, 3b any excess pressure above target pressure is relieved through the PEEP valve 5. The mixed gas composition within the chamber of the box 1 may be intermittently or continuously monitored by the oxygen sensor 7 to adjust for consumption of oxygen by the cell culture. The operator or a feedback loop can re-balance the gases in the chamber by feeding further oxygen into the chamber as required.

In preferred embodiments the capacity of the box 1 may be from 1 to 10 litres but in other embodiments it may be up to 80 litres. The operably achievable hypoxic oxygen levels of the box 1 may be down from 20.9%, or atmospheric oxygen level to as low as 1 % or even 0.1 %.

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Claims

1. A hypoxic pressure chamber or incubator that comprises a gas/ air tight plastic box that has: at least a first gas inlet; and a first gas outlet, the first gas outlet being closed with an adjustable one way valve that is configured to allow creating a desired pressure level inside the box.

2. A hypoxic pressure chamber or incubator as claimed in claim 1, wherein the first gas outlet valve comprises a PEEP valve (Positive End Expiratory Pressure valve).

3. A hypoxic pressure chamber or incubator as claimed in claim 1 or 2, wherein the box has two or more gas inlets to be used to mix gases as required.

4. A hypoxic pressure chamber or incubator as claimed in claim 1, 2 or 3, wherein the box is connected to a gas sensor either directly or through a closed loop.

5. A hypoxic pressure chamber or incubator as claimed in claim 4 wherein the box is connected to an oxygen gas sensor.

6. A hypoxic pressure chamber or incubator as claimed in any preceding claim wherein the box is an assembly of an open-topped tub base part and a mating lid part to close down over the open top of the tub 1a and seal in the content to be incubated in a gas-tight manner.

7. A hypoxic pressure chamber or incubator as claimed in claim 6 wherein the tub part of the box has a rim that sealingly co-operatively engages with the rim of the lid in use, there being a gasket/ elastomeric seal means fitted at the interface between the tub's rim and the mating rim of the lid.

8. A hypoxic pressure chamber or incubator as claimed in claim 4 wherein the box has a valve-sealed outlet port to which the gas sensor is demountably fitted in use.

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9. A hypoxic pressure chamber or incubator as claimed in any preceding claim wherein the hypoxic chamber is a compact portable box of a floor area of less than one square meter.

10. A hypoxic pressure chamber or incubator as claimed in any preceding claim wherein the first outlet valve is configured to achieve a pressure difference there-across of 0-20 cm H20.

11. A hypoxic pressure chamber or incubator as claimed in any preceding claim wherein the box is configured to be operable to achieve an oxygen content as low as 1 %.

12. A hypoxic pressure chamber or incubator as claimed in claim 12 wherein the box is configured to be operable to achieve an oxygen content as low as 0.1%.

13. A hypoxic pressure chamber substantially as hereinbefore described with reference to the accompanying drawings.