The effect of single-walled carbon nanotubes on DNA replication and the shape of DNA strands

Single-walled carbon nanotubes (SWNTs) can be thought of as a vector of medicines or other molecules. Furthermore DNA molecules work as a dispersing agent preventing SWNTs bundling. So it is necessary to fully understand the effect of SWNTs on DNA replication. SWNTs can protect DNA strands under high temperature though denature experiment. SWNTs can increase the yield of PCR products by two-step PCR and improve the reaction efficiency of DNA polymerase in a short extension time. The rpsL fidelity test showed that the error rate of PCR products in the control group was 5.3×-10 −6, the error rate in the experimental group was only 2.4×- 10 −6. The potential binding between SWNTs and genomic DNA was investigated by atomic force microscopy. After being cultured together with nanomaterials, E. coli cells were harvested and subjected to genomic DNA isolation. After SWNTs was added in the E. coli culture for 10 hours, the isolated genomic DNA had some brightened region that was supposed to be SWNTs-bound sequences. The brightened region had a height close to 10 nm, and was thought the binding area of SWNTs. The free state of DNA changed to a condensed form in the cells. The strong interactions between SWNTs and DNA suggested SWNTs significantly influence DNA behavior in vivo. The binding could disturb DNA replication, and thus may potentially interfere with DNA damage and repair, and introduce changes of biological activities of genes.