When the method of particle bombardment was developed, the first gene guns used a powder charge to propel the DNA coated metal microparticles into the cells of organisms. Here is a report by the head of gene gun hardware technology, Dr. Johnson on one of these early and now obsolete models of the gene gun. It's a real piece of gene gun history.
Gene Gun by DuPont
A.D. Johnson, 5 Mar 2024
This is a first-impression description of the gene gun that was brought to CCL March 3 2024.
It is a very early version of DuPont ‘bioloistics’ devices: it uses a .22-caliber rifle cartridge to generate pressure to accelerate microparticles. The explosion is triggered by an electrical circuit and fires into a chamber through a burst disc. The chamber is evacuated by a vacuum pump through two ports.
The gene gun consists of two steel enclosures: it is well-engineered and skillfully machined. The left chamber is a pump with (I assume) an exhaust port on the front and two tubes connecting the vacuum pump to the acceleration chamber on the right, closed by a plastic door with O-ring seals. On top of the acceleration chamber is the gun consisting of a cartridge chamber and a box containing the firing mechanism. Mounted on the side of the vacuum pump is a box with a push-button. This box is wired to the
top of the firing mechanism, so I assume it fires a solenoid that extends the firing pin so that it strikes the cartridge and triggers the release of energy.
Cartridge chamber into which is inserted a 22-caliber shell.
Burst-disc holder that is mounted on a shelf in the vacuum chamber
The legend says that this is a biolistic DuPont gene gun model BPG
This machine represents an important piece of history. The design was developed by geneticist Dr. John C Sanford working with Edward Wolf and Theodore Klein in 1983 and was purchased from them by DuPont. The history is documented in papers available through Google scholar. Here is a link to a memoir by Dr. Sanford.
http://www.ask-force.org/web/Bt/Sanford-Biolistic-2000.pdf
Project GRFT is fortunate to have physicist Alfred David Johnson, PhD on board as part of our small but excellent team. He has built 2 helium powered gene guns for project GRFT to use in the transformation of rice to express griffithsin, a method based on the research of Evangelia Vamvaka, PhD.
Dr. Johnson has solid background in particle physics. He is the founder, director, and president of TiNi Alloy Company. With his company he did extensive research in shape-memory alloys for practical applications. He has several patents on his discoveries (one of which went up to the planet Mars).
Prior to founding TiNi Alloy Company, Dr. Johnson was employed as a physicist at Lawrence Berkeley Laboratory. Accomplishments include software for bubble chamber experiments of Luis Alvarez and pattern recognition and track reconstruction programs for the magnetic detectors at Stanford Linear Accelerator Center in which the charmed particles were first discovered. As a member of the SLAC-LBL collaboration he coauthored numerous papers in high-energy physics.
Because of Dr. Johnson's diligent hard work we now have the pipeline in place to transform rice using particle bombardment.
Deep gratitude!
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