Direct nanomaterial-DNA contact effects on DNA and mutation induction.

Area of Science:

• Nanomaterial science
• Molecular toxicology
• Genetics

Background:

• Nanomaterial toxicity is recognized, but underlying mechanisms remain unclear.
• Understanding direct nanomaterial-DNA interactions is crucial for assessing genotoxicity.

Purpose of the Study:

• To investigate the direct interaction between nanomaterials and naked DNA.
• To elucidate the genotoxic effects of nanomaterials on DNA and bacterial cells.

Main Methods:

• Exposure of naked plasmid DNA to carbon nanotubes (CNTs) and tungsten trioxide (WO₃) nanoplates in dry and wet conditions.
• Analysis of DNA damage using gel electrophoresis and fluoro-spectrometry.
• Assessment of bacterial mutations in Escherichia coli (E. coli) after DNA transfer.

Main Results:

• Nanomaterial contact induced DNA strand breaks (single and double) and bacterial mutations.
• DNA damage escalated exponentially with contact time, particularly rapid in wet conditions.
• Carbon nanotubes exhibited higher genotoxicity than WO₃ nanoplates.
• Surviving bacteria showed high mutation rates (nearly 100%), with transversion mutations dominating, influenced by contact conditions (guanine in wet, cytosine in dry).

Conclusions:

• Direct nanomaterial-DNA contact can cause significant DNA damage and mutations, potentially leading to adverse health outcomes.
• Wet contact conditions enhance nanomaterial genotoxicity compared to dry conditions.
• Findings highlight a potential mechanism for nanomaterial genotoxicity and caution against their use in DNA delivery applications.