Curvature-Induced Base Pair Slipping Effects in DNA-Nanoparticle Hybridization

摘要

Experiments are presented that suggest DNA strands chemically immobilized on gold nanoparticle surfaces can engage in two types of hybridization, one that involves complementary strands and normal base pairing interactions and a second one assigned as a “slipping” interaction, which can additionally stabilize the aggregate structures through non-Watson Crick type base pairing or interactions less complementary than the primary interaction. The curvature of the particles appears to be a major factor that contributes to the formation of these “slipping” interactions as evidenced by the observation that flat gold triangular nanoprism conjugates of the same sequence do not support them. Finally, these “slipping” interactions significantly stabilize nanoparticle aggregate structures, leading to large increases in Tms and effective association constants as compared with free DNA and particles that do not have the appropriate sequence to maximize their contribution.