The Construction Of Cucurbit[7]uril And Gold Nanospheres Assembled Nanochannels For The Catalysis And Recognition Performance

Due to the limitation of the stability of biological channels,the design and development of artificial nanochannel materials has attracted more and more attention.Compared with biological materials,artificial nanochannels not only have stable physical properties,but also have adjustable shape and controllable surface chemical composition,thus exhibiting good biological properties.It provides a good research platform for the design and development of smart nanochannel systems.Cucurbit[7]urea（CB[7]）is an important member of the cucurbituril family,which can form inclusion compounds with a variety of guest molecules,which is beneficial for surface modification as a functional molecule.Gold nanospheres have received widespread attention due to their simple synthesis method,unique optical properties,good biocompatibility,and chemical stability.The electron-rich carbonyl oxygen at both ends of cucurbituril makes it easy for cucurbituril to be directly covalently attached to the gold surface,making cucurbituril attract much attention in the synthesis,assembly,catalysis and molecular recognition of nanoparticles.Accordingly,this thesis mainly focuses on the following work successively:1)Amino ferrocene molecules are designed and synthesized and introduced into the nano channel as receptors of CB[7].Through the cucurbit[7]urea and ferrocene host role to achieve the main body molecular modification,and gold nanoparticles were modified in the channel by the electrostatic interaction between cucurbit[7]urea and gold nanoparticles build the gold nanoparticles catalytic nano channel.The modification in the nano-channel was detected by picoammeter I-V current detection and X-ray electron spectroscopy（XPS）.Nitrobenzene reduction by sodium borohydride（Na BH₄）was used as a catalytic model reaction to investigate the catalytic performance of modified and unmodified nano-channels for this reaction.Moreover,¹HNMR was used to characterize the synthesis of guest molecules and the interactions between host and guest molecules.The experimental results proved that the nano-channels modified with gold nanospheres had obvious catalytic performance for the model reaction.In this work,the supramolecular main-guest system was introduced into the nano-channel,and the catalytic performance of the model reaction was studied.2)Based on the Au-S bond reaction between sulfhydryl-gold and the electrostatic interaction between cucurbituril and gold nanoparticles to construct layer-by-layer self-assembled nanochannel membranes,and explore the selective recognition of proteins by layer-by-layer assembled membranes.The assembly process and the assembled membrane were characterized by ultraviolet（UV）,contact angle（CA）,scanning electron microscope（SEM）,X-ray energy spectrum analysis（EDS）etc.And the selectivity and transmission of protein was detected by methods such as picoammeter I-V current detection.The experimental results prove that the nanochannels of the assembled membrane are selective for the transport of lysozyme.In addition,combined with the channel size of the theoretical calculation exploration,the mechanism was explored,indicating that the nanochannels of the assembled membrane have a stronger interaction with lysozyme,which will preferentially promote the transport of lysozyme into the assembled membrane.The transmembrane selectivity coefficients of lysozyme relative to bovine serum albumin and cytochrome C in the assembled membrane areα（Ly/BSA）=1.74,α（Ly/Cy C）= 1.79.Considering the special nature of isoelectric point,this work explored the influence of layer-by-layer self-assembled membrane control on protein transmission,and provided a theoretical basis for the complex biomolecular transmission system.3)Based on the previous work,firstly prepare smaller sodium citrate-modified gold nanosphere particles,and use transmission electron microscopy（TEM）and dynamic light scattering（DLS）to characterize the morphology and particle size of the prepared gold spheres.The characterization result is 8.14±0.67 nm.Then,we used gold nanoparticles of this size and cucurbit[7]urea to prepare layer by layer self-assembled film according to the method in the previous chapter.The selectivity to smaller amino acids of biomolecules was examined,and the effect of the assembled membrane on the transport performance of different amino acids was explored.The experimental results prove that the transmembrane selectivity coefficients of tryptophan relative to other amino acids in the assembled membrane areα（Trp/Leu）=2.16,α（Trp/Thr）=1.91,andα（Trp/Val）=2.23,Α（Trp/Pro）=2.34.