Bio-Rad Helios Gene Gun System User Manual
For Technical Service Call Your Local Bio-Rad Office or in the U.S. Call 1-800-4BIORAD (1-800-424-6723)
Helios Gene Gun
System
Instruction
Manual
Catalog Numbers
165-2431 and 165-2432
Warranty and Regulatory Notices
Warranty Statement
This warranty may vary outside of the continental United States. Contact your local Bio-Rad
office for the exact terms of your warranty.
Bio-Rad Laboratories warrants to the customer that the Helios Gene Gun System (catalog
number 165-2431 and 165-2432) will be free from defects in material and workmanship, and will
meet all performance specifications for the period of one year from the date of shipment. This
warranty covers all parts and labor.
In the event that the instrument must be returned to the factory for repair under warranty,
the instrument must be packed for return in the original packaging.
Bio-Rad shall not be liable for any incidental, special or consequential loss, damage, or
expense directly or indirectly arising from the use of the Helios Gene Gun System. Bio-Rad
makes no warranty whatsoever in regard to products or parts furnished by third parties, such
being subject to the warranty of their respective manufacturers. Service under this warranty
shall be requested by contacting your nearest Bio-Rad office.
The following items are considered customer-installable consumables: tubing, desiccant
pellets, and microcarriers. The battery, razor blade, O-rings, barrel liner, cartridge holders, and
syringe are replacement parts (see Section 9.2). These consumables and replacement parts are
not covered by this warranty and are warranted only to be free from defects in workmanship.
This warranty does not extend to any instruments or parts that have been subject to misuse, neglect, or accident, or that have been modified by anyone other than Bio-Rad, or that have
been used in violation of Bio-Rad instructions.
The foregoing obligations are in lieu of all other obligations and liabilities including negligence and all warranties, of merchantability, fitness for a particular purpose or otherwise,
expressed or implied in fact or by law, and state Bio-Rad’s entire and exclusive liability and
buyer’s exclusive remedy for any claims or damages in connection with the furnishing of goods
or parts, their design, suitability for use, installation or operation. Bio-Rad will in no event be
liable for any special, incidental or consequential damages whatsoever, and Bio-Rad’s liability
under no circumstances will exceed the contract price for the goods for which liability is claimed.
Bio-Rad is not responsible for any injury caused by the use of this instrument for purposes other
than those for which it is intended.
Regulatory Notices
Important: This Bio-Rad instrument is designed and certified to meet EN55011,
EN50082-1, and EN61010 requirements, which are internationally accepted electromagnetic compliance and electrical safety standards. Certified products are safe to use when operated
in accordance with the instruction manual. This instrument should not be modified or altered
in any way. Alteration of this instrument will result in the following:
Void the manufacturer’s warranty.
Void the regulatory certifications.
Create a potential safety hazard.
Note: This equipment has been tested and found to comply with the limits for a Class A
digital device, pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause
harmful interference to radio communications. Operation of this equipment in a residential area
is likely to cause harmful interference in which case the user will be required to correct the
interference at his own expense.
Patent License and Usage
Particle bombardment technology is covered by several patents which are held by
E. I. duPont de Nemours & Co. and Auragen, Inc. Particle bombardment may be used for
research purposes for gene delivery. Use of particle bombardment for commercial purposes
requires a commercial license from the appropriate patent holder. The Helios Gene Gun is
designed for research purposes only and is not intended for human or veterinary use. Licensed
only for research use.
Table of Contents
Page
Section 1 General Safety Information....................................................................1
1.1 Helios Gene Gun Safety........................................................................................1
1.2 Pressurized Helium and Nitrogen Safety..............................................................1
1.3 Power Safety..........................................................................................................1
1.4 Ear and Eye Protection..........................................................................................2
Section 2 Introduction to Particle Delivery...........................................................2
2.1 Particle Delivery Technology ...............................................................................2
2.2 The Helios Gene Gun............................................................................................3
2.3 Operating Principle of the Helios Gene Gun System...........................................3
2.4 Requirements for System Operation.....................................................................4
Section 3 Product Description ................................................................................7
3.1 Packing List...........................................................................................................7
3.2 Identification of System Components and Controls.............................................8
Section 4 Setting up the Helios Gene Gun System.............................................12
4.1 Inserting the Battery into the Helios Gene Gun .................................................12
4.2 Connecting the Helios Gene Gun to a Helium Source.......................................13
4.3 Connecting the Tubing Prep Unit to a Nitrogen Source ....................................14
Section 5 Operation of the Helios Gene Gun System.........................................17
5.1 Quick Guide to Operation...................................................................................17
5.2 Preparation of System Components Prior to Bombardment..............................18
5.3 Particle delivery using the Helios Gene Gun......................................................23
5.4 Removing Used Cartridges, Depressurization, and Shut Down........................28
Section 6 Preparation of Mammalian Cell Targets............................................29
6.1 In vitro Delivery to Adherent Cells ....................................................................29
6.2 In vitro Delivery to Suspension Cultures............................................................30
6.3 in vivo Delivery to Epidermis .............................................................................31
Section 7 Optimization of Gene Gun Parameters..............................................32
7.1 Overview .............................................................................................................32
7.2 Parameters for in vitro Delivery..........................................................................34
7.3 Parameters for in vivo Delivery ..........................................................................35
Section 8 Troubleshooting.....................................................................................35
8.1 DNA/Microcarrier Preparation...........................................................................35
8.2 Cartridge Preparation ..........................................................................................35
8.3 Helios Gene Gun Operation................................................................................36
8.4 In Vitro and in Vivo Targeting ............................................................................36
Section 9 Product Information.............................................................................37
9.1 Helios Gene Gun System....................................................................................37
9.2 Spare Parts...........................................................................................................38
9.3 Specifications ......................................................................................................38
Section 10 Appendices .............................................................................................39
10.1 Precipitation of RNA onto Microcarriers ...........................................................39
10.2 Replacing the O-rings and Inner Sleeve on the Helios Gene Gun.....................40
10.3 Replacing the O-ring on the Tubing Prep Unit...................................................41
10.4 Replacing Tubing Cutter Razor Blade and Unit Disassembly...........................42
10.5 Cleaning and Sterilizing the Helios Gene Gun...................................................43
10.6 Testing Cartridges for Microcarrier Penetration and Density............................43
10.7 Quantitation of DNA in Cartridges.....................................................................45
10.8 References ...........................................................................................................46
10.9 Quick Guide ........................................................................................................47
Section 1
General Safety Information
Caution: In particle bombardment DNA-coated microparticles are accelerated to
velocities in excess of 1,000 ft/sec in order to penetrate the cell membrane and through multiple layers of cells in tissues and organs. In the Helios Gene Gun, this accelerating force is
supplied by a high pressure helium pulse. Numerous safety features have been designed into this
instrument to protect both the user and bystanders. The parts used in manufacturing the Helios
Gene Gun have been chosen because they are designed to work at the pressures required for operation and have a wide safety margin. General safety principles are indicated below. Specific
safety recommendations are indicated in the appropriate sections throughout the manual.
1.1 Helios Gene Gun Safety
Caution: While the Helios Gene Gun has a trigger button which is time-activated by
a safety interlock switch, accidental or unintentional discharge is still possible. Do not point
the gun at people. The Helios Gene Gun is for research use only.
Refer to Section 4.2 for connecting the Helios Gene Gun to a helium source, to Section 5.3
for use of the Gene Gun, and to Section 5.4 for depressurization and shut down of the Gene Gun.
1.2 Pressurized Helium and Nitrogen Safety
Caution: Although helium and nitrogen are neither toxic nor flammable, all gases
under pressure are potentially dangerous if used improperly. Always be sure pressurized tanks
are properly secured. This may be accomplished by placing the tank in a floor stand or by using
a wall-mounted or bench-mounted strap. Please follow the instructions provided with the
helium cylinder from the supplier and those that are applicable for your institution (see your
Site Safety Officer). Bio-Rad has supplied tubing, fittings, a control valve, and a pressure
regulator capable of safely handling the high pressure helium gas used in the Helios Gene
Gun. These components have been carefully selected and are the only parts to be used with
the Helios Gene Gun System.
Refer to Section 2.4 for a description of the helium and nitrogen gases required for the
Helios Gene Gun System.
1.3 Power Safety
Figure 1 shows the serial number certification label which is found underneath the
molded case of the Helios Gene Gun. This label provides the manufacturing data about the
instrument. This instrument is operational using a standard 9 volt battery. Change the battery only after detaching the Gene Gun from the helium hose.
Refer to Section 2.4 for a description of the battery required for the Gene Gun and to
Section 4.1 for information on replacing the battery in the Gene Gun.
1
Fig. 1. Location of the instrument serial number label on the Helios Gene Gun.
1.4 Ear and Eye Protection
Caution: Expansion of gas from high pressure to low pressure produces a sound
wave, the intensity of which is a function of the gas pressure. The intensity of the sound generated by discharging the Helios Gene Gun is ~108 decibels (db) at 400 psi; sustained noise
levels of 85 db or brief noise levels of 110 db may lead to permanent hearing damage. Hearing
protection should be worn by all those in the immediate vicinity when discharging the Helios
Gene Gun. Earmuffs or ear plugs provide equivalent protection against hearing damage.
Refer to Section 2.4 for suggestions on ear protection. Eye protection should always be
worn when working with high pressure gases.
Section 2
Introduction to Particle Delivery
2.1 Particle Delivery Technology
Particle bombardment is a physical method of cell transformation in which high density,
sub-cellular sized particles are accelerated to high velocity to carry DNA into cells. The technique was first described as a method of gene transfer into plants (Klein et al., 1987, 1988;
McCabe et al., 1988) and subsequently shown to be applicable to mammalian experimental
systems (Zelenin et al., 1989; Yang et al., 1990; Williams et al., 1991). Because it does not
depend on specific ligand-receptors and/or the biochemical features of structural components
typically present on cell surfaces, particle-mediated gene transfer can be readily applied to a
variety of biological systems. Consequently, this procedure can be used to transform such
diverse targets as bacteria (Shark et al., 1991; Smith et al., 1992), fungi (Armaleo et al., 1990),
and intracellular organelles (Johnston et al., 1988; Boynton et al., 1988). Since it is a physical method of gene delivery, particle bombardment also overcomes physical barriers to
effective gene transfer, such as the stratum corneum of the epidermis and the cell wall of
plants. Particle bombardment is a convenient method for transforming intact cells in culture
since minimal pre- or post-bombardment manipulation is necessary. In addition, this technique is much easier and faster to perform than the tedious task of microinjection. Both
transient and stable expression are possible with particle bombardment. In addition to DNA,
RNA may also be transferred to cells by particle bombardment (Qiu, et al., 1996). Table 1 lists
some of the advantages of using particle bombardment for in vitro and in vivo transformation.
2
T able 1. Advantages of particle bombardment for
in vitro
and
in vivo
gene transfer.
• Easy to use, rapid, versatile gene delivery system
• Independent of target cell type
• Useful for both transient and stable expression
• Requires only small amounts of DNA
• No carrier DNA is needed
• Requires only small numbers of cells
• May obtain high levels of co-transformation
• Large DNA fragments may be transferred
• Direct intracellular delivery to many cells in the target area
• Applicable to both in vitro and in vivo transformation
• No extraneous genes or proteins are delivered
2.2 The Helios Gene Gun
The Helios Gene Gun is the second instrument in Bio-Rad’s particle delivery product
line. In contrast to the PDS-1000/He instrument where the overall size of the target to be
transformed is limited by the size of the chamber and the target tissue is subjected to a vacuum during bombardment, the Helios Gene Gun requires no vacuum and any target accessible
to the barrel can be transformed. Consequently, the Helios Gene Gun may be used in a much
wider variety of gene transfer applications and provides a tool for both in vitro and in vivo
transformations in the research lab. Essentially any type of cells which can be made accessible to its nozzle may be transformed.
Gene gun models have also been developed by Auragen, Inc., a Bio-Rad collaborator. Cell penetration, gene expression and other measures of performance vary with
the model of gene gun used. Users must be careful to select operating parameters
optimized for their particular model. The Accell®model used by Auragen Inc. may
include modifications to be included in the future Helios models. The current Helios
Gene Gun has been designed to serve a wide range of research uses.
In vertebrates, the epidermal cells of the skin are the most obvious target (Yang et al.,
1990; Williams et al., 1991). In vivo experimental systems have targeted the skin for vaccination studies (Tang et al., 1992; Fynan et al., 1993; Eisenbraun et al., 1993), and wound
healing (Andree, et al., 1994), and cytokine gene therapy studies in mouse tumor models
(Sun et al., 1995; Keller et al., 1996; Rakhmilevich et al., 1996). In addition to skin, muscle
and internal organs, including liver, pancreas, spleen, kidney, etc., when appropriately exposed
surgically, can also be targeted in vivo (Yang et al., 1990; William et al., 1991; Cheng et al.,
1993). Using the Accell Gene Gun, both primary and established cultures of mammalian cells
have been transfected in vitro and ex vivo (Albertini et al., 1996; Mahvi et al., 1996;
Rakhmilevich et al., 1996). Additionally, transgenic expression of β-galactosidase, luciferase,
IL-12, granulocyte macrophage-colony stimulating factor and a nuclear papillomavirus protein has been demonstrated following in vivo transformation (Sundaram et al., 1996; Keller
et al., 1996; Rakhmilevich et al., 1996). Meristematic tissues and leaves are obvious target cells
for in vivo transformation of plants.
2.3 Operating Principle of the Helios Gene Gun System
The Helios Gene Gun System consists of all of the components needed to prepare DNAcoated microcarriers, coat the DNA-microcarrier suspension onto the inner surface of the
Gold-Coat™tubing, cut the tubing into cartridges which are used in the Helios Gene Gun, and
finally propel the microcarriers and their associated DNA into cells.
3
Prior to transfection, the plasmid DNA must be attached to the gold particles. This is accomplished by precipitation of the DNA from solution in the presence of gold microcarriers and the
polycation spermidine by the addition of CaCl2. The particles are then washed extensively with ethanol
to remove the water and resuspended in ethanol. Using the Tubing Prep Station, the DNA/microcarrier solution is coated onto the inner wall of Gold-Coat tubing and dried. The tubing is then cut into 0.5"
length cartridges using the Tubing Cutter. These cartridges, when inserted into the cartridge holder of
the Helios Gene Gun are the source of the DNA which enters the target cells by the helium discharge.
The Helios Gene Gun employs a high velocity stream of helium to accelerate gold particles
coated with plasmids or RNA to velocities sufficient to penetrate and transform cells, both in vitro
and in vivo (Figure 2). The discharge is initiated by pressing the trigger buttons which activates the
main valve, causing helium to travel down the bore of the particle delivery device. When the helium enters one of the bores of the cylinder containing the cartridge, the gold particles on the inside
of the tubing are pulled from the surface, become entrained in the helium stream, and begin to
pick up speed. Immediately past the acceleration channel, the barrel begins to open as a cone. The
slope of the cone causes the gas to be pulled outward, a process known as the Coanda effect (Reba,
1966), expanding the high pressure jet into a less destructive low velocity pulse, while the gold particles maintain a high velocity. The expansion also helps spread the microcarriers from their original
1/16" diameter to an area approximately 1/2" in diameter at the target site.
Fig. 2. How the samples are delivered. Helium gas is pulsed through the cartridge loaded with DNA-coated microcarriers. This pulse sweeps the microcarriers from the inside wall of the cartridge. As the microcarriers
enter the barrel liner they pick up speed in the acceleration channel then spread out as they travel down the
barrel; the increased cross-sectional area of the barrel from the acceleration chamber to the spacer also
moderates the helium shock wave so it is less intense when it reaches the target cells. The O-rings on each
side of the cartridge holder direct the flow of helium through the cartridge and the acceleration channel. The
spacer maintains optimal target distance and permits venting of the helium gas away from the target.
2.4 Requirements for System Operation
Selecting a Site for Operation
The Helios Gene Gun is a portable particle bombardment device. The range of its use is
limited by its requirement for a supply of pressurized helium and the 6 foot length of pressurized helium hose. When using the Gene Gun, only a small area is needed for setting down
the gun during an experiment, for loading the cartridges into the cartridge holders and exchanging cartridge holders during experiments. In addition, a clean and dry area is needed for
working with the tissue samples.
4
Preparation of the gold/DNA tubes used in the Gene Gun requires an area approximately 1 m2for the Tubing Prep Station, for manipulating the tubing, precipitating the DNA onto
the gold, and processing the tubing into cartridges. Additionally, the Tubing Prep Station
requires an electrical outlet and a tank of pressurized nitrogen for evaporating the ethanol from
the DNA-coated gold particles from the inner surface of the tubing.
User Supplied Components
Helium Supply
Only helium gas is to be used with the Helios Gene Gun. The low atomic weight of helium results in maximum gas expansion when the high pressure helium is released through the
valve opening and enters the cartridge at atmospheric pressure. Thus, sufficient acceleration
of the DNA-coated microcarriers is generated for penetration of the target cell membrane.
Compressed helium of grade 4.5 (99.995%) or higher should be used; lower grades may
contain contaminating material which can obstruct gas flow within the Helios Gene Gun as
well as contaminate the biological sample. A helium tank pressurized to 2,600 psi [approximately 5 ft (1.7 m) high, 291 cu ft standard in the United States] is recommended, although
a smaller tank [~2.5 ft (~0.8 m) high] may be used. Follow all safety instructions provided by
the helium supplier for helium tank installation.
The helium pressure regulator (supplied) has a CGA 580 female fitting (standard in the United
States) for attachment to the user-supplied helium tank. An adaptor to this fitting may be required
outside of the United States. Contact your local Bio-Rad office for information on the helium pressure regulator adaptor requirements in your location. The regulator supplied with the Helios Gene
Gun is the only one that should be used with this instrument because of its three safety features: (1)
a self-venting valve that permits decreasing the pressure in the Helios Gene Gun System in the
event of battery failure or when it is necessary to reduce the pressure during an experiment; (2) an
over-pressure relief valve that prevents the helium pressure in the Helios Gene Gun System from
being adjusted above 700 psi ± 10%; and (3) a check valve that shuts off pressure if the helium hose
is disconnected while the system is still pressurized (Note: a check valve is also present at the
female connector of the helium hose where it connects to the Gene Gun to shut off pressure to the
gun if it is disconnected while the system is still pressurized.) Refer to Section 4.2 for proper use
of the helium regulator and to Section 5.4 for a description on shutting down the Gene Gun System.
A user supplied 10" or 12" (~25 cm) adjustable wrench or a 1 1/8" open end wrench is
required for attachment of the helium regulator to the helium tank.
Nitrogen Supply
Compressed nitrogen of grade 4.8 (99.998%) or higher is required for cartridge preparation using the Tubing Prep Station. Nitrogen is used for this purpose because it is relatively
inexpensive and provides a water-free atmosphere for evaporating the ethanol from the
DNA/gold sample inside the tubing. As with the helium tank, the nitrogen tank should be
properly secured on a floor stand or with a strap for safety.
A nitrogen regulator must be attached to the tank. A single stage regulator with an output gauge
that registers a maximum of 30 psi is recommended since an output pressure of no more than
1–2 psi is needed to produce the 0.4 liters per minute (LPM) flow rate necessary for using the Tubing
Prep Station. A regulator especially designed for this use, including a self-venting valve, an overpressure relief valve, and a hose barb for attaching the nitrogen hose is available from Bio-Rad
(catalog number 165-2425). Other regulators which are adjustable to give a low pressure output
may also be used. Manufacturers of regulators include Victor and Matheson; examples of regulators which may be used include Victor Model No. SR250A-580 and Matheson Model No. 3537-580.
Large scientific supply houses (e.g., VWR, Fisher, CMS, etc.) are also good sources for regulators.
The nitrogen line provided for use with the Cartridge Prep Unit is 3/16" diameter Tygon tubing.
5
Battery
One battery is provided with the Helios Gene Gun System. Under normal use, it should
provide approximately 1,000 discharges. For maximum life, only alkaline batteries should
be used.
Laboratory Equipment
The following materials should be available before beginning any work with the Helios system.
Ultrasonic cleaner (e.g., Fisher FS3, Branson 1210)
Vortex mixer
Analytical balance
Microfuge
Peristaltic pump capable of pumping 5–8 ml/min (e.g. Bio-Rad Econo Pump,
catalog number 731-8140)
1.5 ml microfuge tubes
20 µl, 200 µl, and 1,000 µl micropipettors and tips
5 ml and 10 ml pipettes and pipettors
Lab timer
Ear protection (e.g., VWR catalog number 56610-728 (earmuffs) or catalog number
56610-680 (ear plugs)
1 1/8" open end or 10" or 12" (~25 cm) adjustable wrench
Helium tank (grade 4.5 or higher)
Nitrogen tank (grade 4.8 or higher)
Nitrogen regulator (e.g., Bio-Rad, catalog number 165-2425)
Scissors
Marking pen
Laboratory reagents
The following chemicals will be needed for coating plasmid onto the gold and for preparing
the tubing:
Gold microcarriers
Polyvinylpyrollidone, MW = 360,000
100% ethanol (e.g., Spectrum Chemical, catalog numberET-107; it is extremely important
that this be free of water; an unopened bottle should be used daily)
Spermidine (e.g., Sigma, catalog numbers S-0266 or S-4139)
Calcium chloride (CaCl2)
Plasmid DNA (for most applications, this should be at a concentration of ~1 µg/µl)
Plasmid DNA of high purity suitable for the Helios Gene Gun can be obtained through
use of any of Bio-Rad’s Quantum Prep®Plasmid Prep kits.
Catalog
Number Description
732-6100 Quantum Prep Plasmid Miniprep Kit, 100 preps
732-6120 Quantum Prep Plasmid Miniprep Kit, 20 preps
732-6130 Quantum Prep Plasmid Maxiprep Kit, 10 preps
732-6150 Quantum Prep HT/96 ClearVac Plasmid Miniprep Kit,
2 x 96 preps
6
Section 3
Product Description
3.1 Packing List
The Helios Gene Gun System (see Figures 3 and 4) is shipped with the following components. If items are missing or damaged, contact your local Bio-Rad office.
Helios Gene Gun Kit
Instruction manual
Warranty card (please complete and return)
Helios Gene Gun
5 cartridge holders
5 barrel O-rings
5 barrel liners (four plus one installed in Gene Gun)
9 volt battery
Cartridge extractor tool
Helium hose assembly
Helium regulator
Tubing Cutter and 10 razor blades
Tubing Prep Station (see Figure 4)
Tubing Prep Unit (base, tubing support cylinder and power cord)
Nitrogen hose [12 ft, (~4m), Nalgene tubing 8000-0030, 3/16" ID, 5/16 " OD]
3/16" barb-to-male Luer-Lok fitting
10 cc syringe sleeve
5 O-rings, Tubing Prep Station
2 1/8" barb-to-male Luer fittings
5/64” Allen wrench
Syringe Kit
5 10 cc syringes
5 1/8" barb to female Luer fittings
1 syringe adaptor tubing [silicone, 5ft, (~2.6 m), 0.104" ID, 0.192" OD]
Optimization Kit
Gold-Coat Tubing [50 ft, (~26 m)]
1.6 µ gold microcarriers, 0.25 g
1.0 µ gold microcarriers, 0.25 g
0.6 µ gold microcarriers, 0.25 g
Polyvinylpyrrolidone, 360,000 MW (0.5 g)
5 desiccant pellets (store tightly sealed)
5 cartridge collection/storage vials
Note: If any of the system components (Helios Gene Gun, Tubing Prep Station, Tubing
Cutter, Helium Regulator, or Helium Hose) are dropped, check them for proper operation
before use.
7
Fig. 3. Major components used for sample delivery with the Helios Gene Gun.
Fig. 4. Components of the Tubing Prep Station.
3.2 Identification of System Components and Controls
Helios Gene Gun
The locations front and back refer to the barrel end and LED display end of the Helios
Gene Gun, respectively. The locations left and right refer to the left and right sides of the
Gene Gun from the viewpoint of the user holding the device. Top and bottom refer to the
side of the gun that the cartridge holder is on and the side of the gun that the helium hose
connects, respectively (see Figure 5).
8
Fig. 5. Components and controls on the Helios Gene Gun.
Gene Gun Controls Description
Cylinder Lock Controls movement of the barrel pin. The cylinder lock is
spring-loaded; its natural position is in the backward (locked)
position so the barrel pin is inserted in the hole in the cartridge
holder; this keeps the cartridge holder in its proper position for
firing. Moving the cylinder lock forward disengages the barrel
pin from the cartridge holder to permit removing the cartridge
holder from the gun. Moving the cylinder lock forward and to
the right latches the cylinder lock to permit removal of the
cartridge holder; however, to prevent damage to the O-rings,
the cartridge holder should only be removed after compressing
the cylinder advance lever (see below).
Safety Interlock Switch Switch that must be held down to permit the trigger button to
be operational. Once this switch is depressed, the trigger button
is functional for 30 sec; the LED ARMED display flashes
quickly during this time. If the trigger button is not pressed
within the alloted time, this safety interlock switch must be
released and pressed again to re-activate the trigger button.
Trigger Button Controls the flow of helium gas through the Gene Gun. This switch
activates the solenoid, momentarily (for ~40 msec) opening the main
valve, and permitting helium to enter the cartridge and barrel. The
trigger button is only active for 30 sec after the safety interlock switch
is depressed.
Cylinder Advance Lever A multi-functional lever which is spring-activated by pulling the
lever backwards. When inserting or removing a cartridge holder,
pull back and hold in the cylinder advance lever; this moves the
barrel liner forward to provide additional room for maneuvering
the cartridge holder. After discharging the microcarriers from one
cartridge, pull back and release the cylinder advance lever; this
ratchets the cartridge holder, bringing the next cartridge into firing
position—the number visible on the very top of the cartridge rim
indicates the active sample position.
9
Push Bar A metal bar that ratchets the cartridge holder from one position
to the next when the Cylinder Advance Lever is pressed. Move
this bar to the left (outward) prior to inserting a cartridge
holder to provide additional room for maneuvering the cartridge
holder.
LED Display An 11 light display.The display is normally off; inserting a
cartridge holder in the Gene Gun and advancing to position 1
activates the display. The left-most 7 LEDs act to indicate charging and ready status of the gun. After each firing of the gun and
at reset, the CHARGING LEDs turn-on in bargraph fashion,
left-to-right, throughout the 5 second charging time. Once the
Gene Gun is fully charged, the CHARGED LED will flash, indicating the safety interlock switch can be pressed. Upon pressing
the safety interlock, the ARMED LED’s sequentially flash.
When the trigger is pressed during the 30 sec armed period, the
gun fires and the FIRED LED turns-on for 1 sec. The change
bargraph then operates as described. The last light indicates
battery status : good battery (steady green light) or low battery
(flashing red light). The Gene Gun can be fired when the green
light is illuminated. If the battery is low, neither the safety interlock switch or the trigger button is active and an alarm will beep
three times every 15 sec.
Tubing Prep Station (see Figure 6)
Tubing Prep
Unit Controls Description
3 Position Switch Located on the motor housing and controls rotation of the tubing
support cylinder. At position (I), the tubing support cylinder turns
continuously at 30 revolutions per minute (rpm). At position (II),
the tubing support cylinder rotates only while the switch is
depressed. At position (O), no rotation occurs and the unit is off.
Flow Meter Registers the rate of nitrogen flow in liters per min (LPM) into the
tubing support cylinder. The valve on the flowmeter is used to
control the rate of nitrogen flow.
Tubing Support Cylinder A 28" aluminum cylinder with an opening on the right side
leading to a channel which holds the Gold-Coat tubing. The
left side of the channel has a replaceable O-ring into which the
tubing must be inserted. The tubing support cylinder can be
removed by pushing it to the right/left to compress the spring
which holds it in position.
Tubing Cutter (see Figure 7)
An instrument for rapid preparation of cartridges from Gold-Coat tubing. It cuts the tubing into
the exact length and shape required by the Gene Gun.
Tubing Cutter Part Description
Arm A spring-loaded piece that holds a razor blade (used for cutting
the tubing). The razor blade is held in place by the locking knob
on the lock block.
Base The support for the arm. It positions a storage vial under the
tubing channels so that the cut tubing pieces fall into the vial.
10
Fig. 6. Components and controls on the Tubing Prep Station, fully assembled.
Fig. 7. The Tubing Cutter.
Cartridge Extractor Tool (see Figure 8)
A 12-prong tool for removal of tubes from the cartridge holder. One prong is longer than
the others so it can be easily inserted into one of the bores of the cartridge holder to orient the
remaining 11 prongs.
11
Fig. 8. Cartridge Holder and Cartridge Extractor Tool.
Section 4
Setting up the Helios Gene Gun System
4.1 Inserting the Battery into the Helios Gene Gun
The electrical system of the Helios Gene Gun is powered by a 9 volt battery. Under normal use, this should provide sufficient energy for 1,000 shots. The battery compartment is in
the base of the handle near the attachment fitting for the helium hose (Figure 9).
To insert the battery, first remove the battery cover by sliding it toward the front of the
Gene Gun. Slide the battery into the opening as shown in Figure 9. The battery must be oriented with the positive terminal toward the front of the Gene Gun indicated by the "+" symbol
inside the battery compartment. (Note: If the battery is inserted correctly, a tone will be audible for ~5 sec and the battery status LED will light; if the battery is inserted backward, the
electrical system will not operate and the Helios Gene Gun will be non-operational.) The battery is held in place by the battery cover.
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