Programming Single Quantum Dot Valencies Via DNA Caging

Quantum dots(QDs)are semiconductor nanocrystals with unique optical properties.QDs can be widely used as biological probes,shining brilliantly in biological imaging field.But the method using a single strand DNA as the template has a number of shortcomings.For exsample,DNA is uncontrolled.DNA sequence is single and bonding sites inaccuracy is inevitable.With the development of DNA nanotechnology,it provides powerful tools and methods to solve this problem.DNA nanotechnology uses DNA as the material,and designs complex multidimensional spatial structure with the accurate assembly of nanometer size through the base complementary pairing.Importantly DNA nanostructures can induce the synthesis and assembly of nanoparticles.Because DNA has the strict principle of complementary base pairing,a high degree of selectivity to assembly process,it can precisely control bonding sites of guests.To solve this scientific problem above,the quantum dots are functionalized by DNA nanotechnology,and the target of quantum dots surface modification with controllable number of DNA,various sequences and precise binding sites is achieved.This paper is mainly divided into several aspects: 1.We synthesized the water phase quantum dots and the gold nanoparticles with different and uniform sizes with DNA as the template which laid the foundation for the subsequent assembly construction.2.We synthesized the complexes of DNA nanometer three-dimensional structure encapsulated quantum dots by the two-step cooling method,and the morphological characterization of the structures was carried out in detail.As the same time we proved the integrity of the assembly by the FRET effect.3.We reassembled the specific sites of the gold nanoparticles to verify the superiority of quantum dot functionalization.