Genotoxic Effects of Tungsten Microparticles Under Conditions of Biolistic Transformation

Improvement of DNA/Metal Particle Adsorption in Tungsten-Based Biolistic Bombardment; Alkaline pH is Necessary for DNA Adsorption and Suppression of DNA Degradation

“…To date, the mechanism of DNA/metal adsorption has not been studied in detail, so that the nature of this adhesion is poorly understood (Buchowicz and Krysiak 2003). We disclosed that DNA/tungsten adsorption occurred when the pH value of DNA coating mixture was maintained at 9.4 or more, regardless of a kind of buffer ( Fig.…”

“…Sanford et al (1993) referred previously to catalysis of tungsten on DNA cleavage, but the data for that was not presented in their article. The mechanism of tungsten catalysis regarding DNA cleavage has not been proven yet; however, free radical species are not likely involved in this phenomenon because radical scavengers such as EDTA and ascorbate do not affect DNA (Krysiak et al 1999a;Buchowicz and Krysiak 2003).…”

“…First, they are much less expensive than alternatively used gold particles. In fact, the price of tungsten particles (per gram) is less than onehundredth of that of gold particles purchased from Bio-Rad Laboratories Inc. Second, tungsten particles can penetrate target tissues for a desired depth with minimal mechanical injury because of their very high specific gravity and extreme hardness, in addition to their irregular shape (Buchowicz and Krysiak 2003). The tungsten particles, however, have several disadvantages for genetic transformation, including the cleavage of adhered DNA to the particle; oxidation of its own surface, which possibly affects DNA binding; cell toxicity against certain types of organisms; and medium acidification due to their chemical property as a Lewis acid (Russell et al 1992;Sanford et al 1993).…”