PARR Acid Disruption Bombs

PARR Acid Disruption Bombs

4635 and 4639 shown

CELL DISRUPTION BY NITROGEN DECOMPRESSION

A rapid and effective way to:

Homogenize cells and tissues
Release intact organelles
Prepare cell membranes
Release labile biochemicals
Produce uniform and repeatable homogenates without subjecting the sample to extreme chemical or physical stress.

A WIDELY ACCEPTED METHOD

Cell disruption by rapid decompression from a pressure vessel has been used for many years by investigators who wanted to overcome the limitations imposed by other cell disruption procedures. Although the technique is not new, interest in the decompression method and many new applications for it have grown rapidly in recent years following the introduction of convenient pressure equipment such as the Parr Cell Disruption Bomb.

MANY APPLICATIONS

The nitrogen decompression method is particularly well suited for treating mammalian and other membrane bound cells. It has also been used successfully for treating plant cells, for releasing virus from fertilized eggs and for treating fragile bacteria. It is not recommended for untreated bacterial cells, but this restriction can be eliminated by using various pretreatment procedures to weaken the cell wall. Yeast, fungus, spores and other materials with tough walls do not respond well to this method.

HOW IT WORKS

The principle of the method is quite simple. Large quantities of nitrogen are first dissolved in the cell under high pressure within a suitable pressure vessel. Then, when the gas pressure is suddenly released, the nitrogen comes out of the solution as expanding bubbles that stretch the membranes of each cell until they rupture and release the contents of the cell.

WHY IT IS SO EFFECTIVE

It's a gentle method. Although sometimes referred to as 'explosive decompression,' nitrogen decompression is actually a gentle method for homogenizing or fractionating cells since the chemical and physical stresses that it imposes upon the sub-cellular components are held to an absolute minimum. It is much more protective of delicate enzymes and organelles than ultrasonic and mechanical homogenizing methods. In fact, it compares favorably to the controlled disruptive action obtained in a TFE and glass mortar and pestle homogenizer, but it does the job faster and more uniformly, with the added ability to treat large samples quickly and conveniently.

There is no heat damage. While other disruptive methods depend upon friction or a mechanical shearing action that generates heat, the nitrogen decompression procedure is accompanied by an adiabatic expansion that cools the sample instead of heating it.

In addition, the entire cycle can be conducted at low temperature by pre-chilling or by operating the bomb in an ice bath. The bomb can also be filled with ice to keep the sample cool during the processing period.

There is no oxidation. The blanket of inert nitrogen gas that saturates the cell suspension and the homogenate offers excellent protection against oxidation of any labile cell components. Although other gases: carbon dioxide, nitrous oxide, carbon monoxide and compressed air have been used in this technique, nitrogen is preferred because of its non-reactive nature and because it does not alter the pH of the suspending medium. In addition, nitrogen is preferred because it is generally available at low cost and at pressures suitable for this procedure.

Any suspending medium can be used. The suspending medium can be chosen for its comparability with the end use of the homogenate and without regard for its adaptability to the disruptive process. This offers great flexibility in the preparation of cell suspensions and produces a clean homogenate that will not require intermediate treatment to remove contaminates which might be introduced when using other disruption methods.

Each cell is exposed only once. Once released, subcellular substances are not exposed to continued attrition that might denature the sample or produce unwanted damage. There is no need to watch for a peak between enzyme activity and percent disruption.

The product is uniform. Since nitrogen bubbles are generated within each cell, the same disruptive force is applied uniformly throughout the sample, thus ensuring unusual uniformity in the product. Cell-free homogenates can be produced.

IT'S EASY TO APPLY

Use any sample size. Cell disruption by this method is independent of sample size or concentration. Any size sample from a few cc's to five hundred can be treated equally well in a Parr Cell Disruption Bomb with excellent recovery of the starting material. In addition, a wide variety of materials can be treated with the opportunity for scale-up work where labile cell components or organelles are involved.

Easy to control. The degree of cell fractionization is easily controlled by adjusting the nitrogen pressure. High pressures that dissolve large quantities of nitrogen within the cell usually produce total homogenization. Or, moderate pressures can be employed to reduce the disruptive forces and thus release nuclei, active mitocondria and other organelles intact. Operating conditions can also be adjusted to homogenize suspensions of subcellular components such as nuclei and mitochondria that are normally difficult to disrupt because of their small size.

Special skills are not required. The few simple steps required to operate the Parr bomb are easily learned. After operating conditions have been established, uniform and repeatable results can be obtained from run to run, usually within less than twenty minutes-even with large samples.

Parr stainless steel bombs for processing cell suspensions by the nitrogen decompression method are made in several sizes with full opening heads and self sealing closures which can be handled easily on any laboratory bench without special tools or fixtures. Each bomb has two valves and a pressure gage: one valve for charging with nitrogen and the other for withdrawing the homogenate and discharging it through an attached delivery tube. All of the fittings as well as the bomb itself are made of stainless steel with polished surfaces for good corrosion resistance and freedom from contamination. The individual parts are easily cleaned and can be thoroughly sterilized.

DESIGNS FOR LARGE AND SMALL SAMPLES

These bombs are made in five different sizes to accommodate samples ranging from 0.5 mL to 5 liters, The maximum charging capacity for each bomb is limited to two-thirds of the internal volume of the vessel, but smaller samples can be treated in any of these bombs by simply placing the sample in a beaker or test tube and positioning it under the dip tube within the bomb.

The 4635, 920 mL, bomb is the general purpose model with a capacity for treating samples ranging in size from a few milliliters up to 600 mL.

The 4639, 45 mL, bomb is designed specifically for small samples from 30 mL down to less than one milliliter. It has a tapered bottom that drains directly into the discharge valve, ensuring complete recovery of all of the sample.

The larger bombs, 4636, 4637 and 4638, are intended for large volume applications. Users are urged to run preliminary experiments in the 4635 bomb to confirm the suitability of the procedure before scaling up to these larger sizes.

PARR CELL DISRUPTION BOMBS

Catalog Number	Internal Volume	Maximum Sample Size	Maximum Working Pressure, psig	Inside Diameter Inches	Inside Depth Inches
4635	920 mL	600 mL	2200	3.75	5.1
4636	1850 mL	1200 mL	2200	3.75	10.1
4637	1 gallon	2.5 liters	2200	6.00	8.6
4638	2 gallon	5.0 liters	2200	6.00	17.2
4639	45 mL	30 mL	2200	1.5	2.25

EASY ACCESS TO BOMB CHAMBER

Each of these bombs, except the small 45 mL size, has a split-ring closure -an exclusive Parr design which allows the bomb to be opened or closed easily without disturbing any of the fittings or connecting lines attached to the head. In this closure two rings sections slide into place from the sides of the bomb to lock the head in position while a self-sealing O-ring maintains a tight seal at all pressures. The ring sections are secured by a steel retaining band that is raised from the bottom of the bomb and anchored with a single, hand-tightened screw.

On the small, 45 mL bomb, a firm closure is obtained by simply turning down a knurled cap until it is hand tight. No wrenches or fixtures are required.

SAFETY PROTECTION

All Parr Cell Disruption Bombs are designed to accommodate the full 2000 psig available from a commercial nitrogen cylinder. If higher pressures should accidentally develop, the 920 mL and larger bombs are protected by a safety rupture disc which will burst at approximately 3000 psig, well below the pressure at which any parts of the bomb would fail. A 3000 psi pressure gage and a 3000 psig rupture disc are standard but other gages and discs with lower pressure ratings can be furnished on special order.

INCLUDES NITROGEN FILLING CONNECTION

An 1831 nitrogen filling connection furnished with each bomb provides all of the fittings needed to fill the bomb from a commercial nitrogen cylinder. The 1823 connection consists of a control valve with a standard CGA-580 coupling for attachment to a nitrogen cylinder, a tank pressure gage and a flexible Nylon pressure hose for connection to the bomb inlet valve. Extra O-rings for the bomb head are included with each bomb.

CUSTOM MODIFICATIONS

Most cell disruption procedures can be handled readily in the 920 mL, 4635 bomb with its customary fittings and attachments, yet applications may arise in which it will be desirable to modify a bomb to meet special requirements. It initial studies show a need for modifications, the user can return any bomb to the factory for such changes or additions as may be needed. Changes sometimes requested include:

Multiple sample capacity. Up to three additional dip tubes and discharge valves can be installed in any bomb (except the 45 mL size). With these additional outlets and appropriate sample holders, as many as four samples can be processed independently and simultaneously in a single unit.

Special valves. Valves with either larger or smaller orifices can be provided. Users processing large quantities of materials that have a tendency to plug the orifice of the standard throttling valve may want to substitute either a larger needle valve or a ball valve to permit faster flow rates or to avoid stoppage. Fine metering valves with smaller orifices and very precise control capabilities may be helpful when treating samples that must be processed under very exact and repeatable conditions. Such valves may also be desirable when working with very small samples.

Size conversion. Since cylinders for the 920 and 1850 mL bombs are interchangeable and both bombs use the same head and closure, any user of a 4635 bomb can increase the capacity of his unit to the 4636 size by simply purchasing a deeper cylinder (599HC2) and a longer diptube (591HC2). A similar conversion can also be made from the one gallon bomb to the two gallon size for users interested in vaccine production or in similar large volume applications. These larger vessels can also be equipped with vigorous internal agitators to speed equilibrium times when processing large volumes of material.

Inquiries concerning any of these modifications should be directed to the factory.

Orders for these bombs should specify the catalog number and internal volume of the bomb as shown in the table below. Each bomb will be made of an AISI 300 Series stainless steel and equipped with a 0-3000 psi pressure gage and 1831 nitrogen filling connection, unless other construction and other fittings are specified.

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