Probing Soft Corona Structures of DNA-Capped Nanoparticles by Small Angle Neutron Scattering

Abstract

Soft corona structures of DNA-capped nanoparticles are crucial for their applications in diagnostics, gene delivery, and superlattice growth. While conventional X-ray techniques can only provide information on their inorganic cores, here we report substantial new insights of DNA corona structures within DNA-capped nanoparticles in this first study employing small angle neutron scattering (SANS). Using two 15-mer DNA strands with palindromic sequence and poly­(dT) sequence under high number density packing on gold nanoparticle surfaces, the influence of ionic strength and temperature on DNA corona structures and resultant hybridization has been investigated. Poly­(dT) sequences were found to maintain globular corona structures across a range of ionic strengths and temperatures, but the corona thickness decreased with increasing salt concentration and increased with increasing temperature. In contrast, palindromic sequenced DNA had globular corona structures in the absence of salt but quickly evolved into dimeric and multimeric structures under high ionic strength or under low annealing temperatures. The structural insights revealed by SANS can guide the design of tailor-made DNA corona structures for customizable designer materials and devices