Synthesis,Assembly Of DNA-Guest Molecular Hybrids And Their Morphology Regulation Mediated By Host-Guest Interaction Of Cyclodextrin

Due to the stimuli-responsiveness,smart DNA nanomaterial is one of the important functional nanomaterials in nanotechnology and biomedicine.The construction of DNA-organic molecular hybrids has promoted the rapid development of DNA nanomaterials.These amphiphilic DNA-organic molecular hybrids can self-assemble into various regular assemblies,such as spherical micelles,vesicles,nanofibers,etc.Meantime,cyclodextrin as a macrocyclic host molecule,possesses good water solubility,non-toxic and harmlessness.Cyclodextrin can include hydrophobic molecules or groups with matching shapes and sizes.These host-guest inclusion compounds and the related nanomaterials have a wide range of applications in the fields of biomedicine and food.Herein,we intend to study the assembly behavior of different kinds of hydrophobic guest molecules after covalent modification of DNA,and further study the morphology regulation through the host-guest interaction of cyclodextrins.Here,we mainly carried out two parts of work: Firstly,the guest molecule azobenzene(Azo)was conjugated to DNA to obtain the DNA-Azo hybrid.It was proved by dynamic light scattering(DLS)and transmission electron microscopy(TEM)that DNA-Azo hybrids can self-assemble into spherical diameter of about 20 nm micelles in aqueous solution.Further the influence of the host-guest interaction of cyclodextrin(α-CD,β-CD)on the DNA-Azo assembly behavior was explored.It was found that the spherical micelles dissociated after adding an excessive amount of the main host(α-CD or β-CD);Moreover,based on the photo-responsiveness of azobenzene,the spherical micelles can also be dissociated under the irradiation of ultraviolet light.Secondly,on the basis of the above work,a perylenebisdiimide(PDIIOL),with a larger hydrophobic volume and rigid structure,was designed to conjugate with DNA to obtain DNA-PDIIOL hybrid through solid-phase synthesis.It is proved by dynamic light scattering(DLS)and transmission electron microscopy(TEM)that the DNA-PDIIOL hybrids formed spherical micelles of about 20 nm in the water phase.The influence of the host-guest interaction of cyclodextrin(α-CD,β-CD)on the DNA-PDIIOL assembly behavior was further explored.It was found that after adding excess host molecules(α-CD and β-CD)to the system,the spherical micelles were transformed into nanofibers,and the reversible control of the morphology was achieved by adding competing guests.Furthermore,it is proved that both spherical micelles and nanofibers can realize the directional arrangement of gold nanoparticles through the loading experiment of gold nanoparticles.The nano-assemblies constructed by DNA-guest molecular hybrids have the characteristics of excellent biocompatibility,addressability and sequence programmability,and have potential applications in targeted drug therapy and other fields;In addition,the reversible regulation of morphology based on the role of host and guest interaction also has important potential applications in the field of controlled release of drugs.