1. How fast do the microparticles travel?
2. Can I shoot myself?
3. Why is gold used for the microcarriers?
4. Why is helium used in the Helios Gene Gun?
5. What grade of helium is used with the Helios Gene Gun?
6. Why is nitrogen needed and what grade (purity) is required?
7. What grade/quality of ethanol is needed for coating gold microcarriers?
8. Why is polyvinylpyrrolidone (PVP) used in cartridge preparation?
9. Can the Barrel Liner be cleaned? Using what methods?
10. What is the normal battery life for the Helios Gene Gun?
11. How is the Biolistic Purchase Agreement processed?
12. What is the optimum size range of DNA that can be coated onto gold particles for Biolistic Gene Gun delivery?
13. What Size Microcarrier Particles are recommended for DNA Vaccination with the Helios Gene Gun?
14. What's the difference between the Helios Gene Gun and the PDS-1000He?

Q.     How fast do the microparticles travel?
A.     To velocities in excess of 1,000ft/sec in order to penetrate the cell membrane and several layers of cells. [Top]

Q.     Can I shoot myself?
A.     The Helios Gene Gun has a trigger button that is time-activated by a safety interlock switch, but accidental or unintentional discharge is possible and the Gun should never be pointed at yourself or another person. For particles to penetrate the skin the gun would have to be within several millimeters of the skin surface. [Top]

1. Spherical for an even coating of DNA
2. inert/non-toxic
   1. DNA attached to the gold is not degraded. Cartridges prepared with DNA-coated gold are stable and can be stored for up to 1 year under proper conditions of low humidity.
   2. Gold is not toxic to cells - this is important since the particle remains in the target
3. dense (19g/cc) to achieve momentum sufficient to penetrate the cells controlled sizes gold particles may be produced in the size range useful for transformation of several cell types (0.5 - 3 µ in diameter) [Top]

Q.     Why is helium used in the Helios Gene Gun?
A.     The low molecular weight of helium permits the most rapid expansion of the gas inside the barrel once the valve is opened. This maximizes microcarrier acceleration for delivery into target cells. [Top]

Q.     What grade of helium is used with the Helios Gene Gun?
A.     Compressed helium of grade 4.5 (99.995%) or higher must be used. Lower grades may contain contaminating material, which can obstruct gas flow within the system, as well as contaminate the biological sample. [Top]

Q.     Why is nitrogen needed and what grade (purity) is required?
A.     Compressed nitrogen of grade 4.8 (99l998%) or higher is required for cartridge preparation using the Tubing Prep Station. Nitrogen is used because it is relatively inexpensive and provides a water-free atmosphere for evaporating the ethanol from the DNA or RNA/gold complexes inside the Gold-Coat tubing. [Top]

Q.     What grade/quality of ethanol is needed for coating gold microcarriers?
A.     Completely dehydrated, 100% ethanol must be used for both nucleic acid precipitation and coating the gold inside the Gold-Coat tubing. Uneven gold distribution inside the tubing is the result of water in the sample or the tubing. [Top]

Q.     Why is polyvinylpyrrolidone (PVP) used in cartridge preparation?
A.     PVP serves as an adhesive for the gold/nucleic acid complexes to the inner wall of the Gold-Coat tubing. [Top]

Q.     Can the Barrel Liner be cleaned? Using what methods?
A.     The Ryton plastic can be autoclaved or sterilized with ethanol. Make certain the Barrel Liner is dry prior to use. [Top]

Q.     What is the normal battery life for the Helios Gene Gun?
A.     The 9V battery is rated for 1000 continuous discharges. Once the cartridge holder is removed, the Gene Gun will automatically turn off after 3 minutes. [Top]

Q.     How is the Biolistic Purchase Agreement processed?
A.     The signed original Purchase/Demonstration Agreement must be on file in the Hercules, CA office prior to shipment of a unit. The Agreement is also required if the unit is to remain in a user's lab on loan for demonstration purposes. Only one Agreement is needed per user/laboratory. Faxed copies of signatures are not legally valid, so we recommend that the signed original document be delivered to the address noted on the form by overnight courier service (DHL, Fed X) for efficient processing and shipment. [Top]

Q.     What is the optimum size range of DNA that can be coated onto gold particles for Biolistic Gene Gun delivery?
A.     Large Plasmids or naked DNA up to 20-25kb works well in Biolistics. Cosmids, YAC's and other larger DNA vectors can suffer from shearing during the precipitation and "shooting" of the gold particles. [Top]

Q.     What Size Microcarrier Particles are recommended for DNA Vaccination with the Helios Gene Gun?
A.     Highest immune responses have been achieved using 1.6µm gold microcarriers. This is due to largest DNA load per particle, and optimal particle penetration depth. [Top]

Q.     What's the difference between the Helios Gene Gun and the PDS-1000He?
A.     Both instruments deliver DNA and RNA carried on micron-sized gold particles into a wide variety of cells using pressurized helium, i.e.the Biolistic process. The Helios Gene Gun is a hand-held instrument which is made for in vivo transfection into animal or plant tissues in a 2cm diameter target area. The PDS-1000He is an in vitro benchtop instrument that has a vacuum sample chamber for more controlled particle delivery into animal or plant cell culture or tissues over a 9cm diameter target area. [Top]