SAXS measurement of aggregate of DNA modified gold nanoparticles

DNA-modified gold nanoparticles exhibit a unique aggregation behaviour that they form aggregation with fully complementary DNA but do not with the terminal-mismatched DNA at certain concentration of added salts. We studied the aggregation structure of the nanoparticles by small angle X-ray scattering (SAXS). The results indicated that the gap between surfaces of gold nanoparticles is nearly two times as long as DNA in B-form. This suggests that the ends of completely double-stranded DNA (dsDNA) conjugated on gold nanoparticles contact or slightly interdigitate with each other in the aggregation structure.