Photoactive compound-triplex-forming oligonucleotide linked gold nanoparticle as an artificial gene specific DNA cleaver assembly

We previously demonstrated the first DNA-nicking agent using PEG linked photoactive compound with gold nanoparticles (13nm). The DNA cleavage was greatly improved (10⁴ times) by nanoparticle conjugation compared to photoactive compound alone. However, the compound failed to recognize gene sequence and thus greatly limit their biomedical applications. In this study, we demonstrated the use of gold nanoparticles (13nm) conjugated triplex forming oligonucleotide (TFO) to selectively target gene(s) of interest. Gold particle enabled multiplexed targeting of selected genes while terminally conjugated photoactive compound exert the cleavage in response to light exposure. The targeting DNA cleaver was synthesized by self-assemble of 5'-end thiol modified TFOs on 13nm gold particles followed by coupling to photo-inducible DNA cleaver to the amino-group modified 3'-end of TFO. The Electrophoretic Mobility Shift Assays (EMSA) revealed sequence specific DNA binding of both TFO and TFO-nanoparticle probes. A successful double strand DNA cleavage at pre-designed site of the target sequence but not the control scrambled sequence was observed upon photo illumination. In conclusion, this study reported, the first time, an artificially assembled photo-inducible sequence specific double strand DNA cleaver. The double strand DNA cleavage was greatly enhanced by the use of gold particles as the carrier. A great potential for the development of improved gene manipulation strategy, recombinant DNA technology, treatment of infectious disease and gene therapy is anticipated.