Modulation Of Metal Deposition Morphologies By DNA Origami Templates

Metal nanomaterials have been widely used in catalysis,optics,electronics,biosensing,and other fields,which are closely related to their excellent physical and chemical properties.However,their physical and chemical properties depend on their morphology,size,and chemical composition.The concept of DNA（Deoxyribonucleic Acid）metallization provides a new idea for the controlled preparation of metallic materials.However,due to the type and shape of DNA templates,the metal morphologies that can be fabricated are limited.DNA nanotechnology has evolved into a highly innovative and widely used field in recent years.DNA origami has unique structural programmability and site addressability to precisely organize nanoscale materials at atomic and molecular levels.DNA origami as a template has unique advantages in controlling the morphology of nanomaterials,especially guiding the synthesis of metal nanomaterials,which provides more possibilities for the preparation of metal nanostructures with rich morphology and excellent properties using DNA metallization methods.In this paper,a series of studies have been carried out on the synthesis of metal nanostructures regulated by DNA origami templates.The specific research content is as follows:1.By combining DNA origami with electrochemical deposition technology,a DNA origami template is used to regulate the electrochemical deposition of metals to prepare single metal nanostructures with specific morphology.Firstly,by taking advantage of the addressability of DNA origami,a single DNA strand at a specific position in the triangular origami was extended.After annealing and assembly,the extended strand was anchored on the DNA origami to form the designed template pattern.Then,the metal salt solution and the origami template are mixed,and metal ions are enriched in the extended chain due to electrostatic or coordination interactions.Finally,electrochemical deposition using the potentiostat method was carried out and metal ions were reduced on the extended chain to obtain metal nanostructures conforming to the designed morphology.Characterized by atomic force microscopy（AFM）,scanning electron microscopy（SEM）,and energy dispersive spectroscopy（EDS）,the results showed that single metallic silver,copper,gold,and iron nanostructures with specific morphologies were successfully fabricated by the above methods.2.Based on the above fabrication of single metal nanostructures with specific morphologies based on DNA origami templates,this section further explores the use of DNA origami templates to regulate the electrochemical deposition of poly metals to fabricate nanoalloys and core-shell structures with specific morphologies.Cu-Fe and Ag-Cu alloys were fabricated on DNA origami templates by exploring suitable electrochemical co-deposition conditions and reducing the mixed metal salt solution,a strategy that theoretically yields alloys with any metal component with similar deposition conditions.In addition,Ag and Cu were deposited on the DNA origami template successively by controlling the deposition potential using a step-by-step electrochemical deposition strategy to prepare Ag/Cu core-shell structure.The core-shell structure can be used as a protective circuit coating structure,which provides a new idea for nanoscale circuit fabrication.3.DNA origami templates regulate metal plasma nanostructures.The Bowtie structure template was formed by annealing and assembly of DNA single strands at specific positions in rectangular origami.After adding Au Cl₄^-containing reaction solution,the Bowtie-type plasmonic gold nanostructures were obtained by electrochemical deposition.In this section,two gold Bowtie structures with different sizes and two different spacings were prepared,respectively.This study provides a new approach for the controlled fabrication of plasmonic metal nanostructures.4.The potential of DNA origami as a template to guide the synthesis of metal nanoarrays was explored.Firstly,we explored the conditions under which DNA origami templates were densely laid on the mica surface to form a single-molecule layer origami array.Then,the potential of fabricating metallic Cu arrays on densely laid DNA origami templates was explored using chemical deposition.This study preliminarily demonstrates the possibility of fabricating metal nanoarrays using this method,which provides a new approach for fabricating metal nanoarrays.