Single Molecular Analysis of the Interaction between Aspirin and DNA

The interaction between aspirin and double-stranded DNA was studied by using magnetic tweezers and atomic force microscope,respectively.When the concentration of aspirin was 2×10-4 mol/L,the B-A conformation transition of the DNA was observed via single molecular force spectrum of magnetic tweezers,and results showed the persistent length decreased from 52 to 25 nm.The folding and condensation of DNA induced by aspirin was observed using AFM,it was found that the binding number of single circle DNA molecules and aspirin increased with aspirin concentration increasing,and finally condensed into the morphologies of bar or globular.Meanwhile,the authors measured the particle size of complex after the interaction of DNA and aspirin and found the particle size decreased from 135 to 56 nm when the aspirin concentration increased from 2×10-6 to 2×10-4 mol/L.According to experimental results,the phenomenological model of DNA conformation change induced by aspirin was built.