Fabrication And Application Of Pillararenes And Gold Nanoparticles Functionalized Nanochannel

In nature,ion channels,that exist in living organisms serve as "smart" gates to ensure the transport of ions and the selectivity of specific target molecules;play key roles in maintaining normal physiological conditions.Because these biological channels are rather fragile and can function only when inserted in a lipid membrane,it is very hard to use them directly in man-made systems.Thereby,it is attractive to build solid-state nanochannels,which would exhibit similar properties to those of biological channels but would be stable in a variety of conditions.With the inspiration of examples from nature,the design and development of novel biomimetic synthetic solid-state nanochannels are becoming the focus of attention because,compared with their biological counterparts,they display several important advantages such as stability,robustness,tailorable surface properties,and flexibility in terms of shape and size.Designing smart nanochannels systems have emerged as possible candidates for mimicking the complex processes in living systems with strong stability and high selectivity and boosting the development of bioinspired intelligent nanomachines,remains a great challenging task for nanoscience.The response performance of these nanomaterials is based on the change in the ionic current generated by the interaction between the specific target molecule and ligands attached on the inner walls of the nanochannel.However,the majority of interaction processes are based on the noncovalent binding,such as hydrogen bonds,electrostatic interactions.Host-guest molecular recognition motifs,in particular,play a considerable role in the development of advanced supramolecular systems,functional nanodevices,sensors and drug delivery.Pillararenes,with its unique structure,good molecular recognition and versatile functionality characteristics,offer the possibility for their incorporation with high surface functionalization of gold nanoparticles by combining the characteristics of the two entities,expanding their application in the design and development of artificial responsive nanochannel materials which have strong stability and high selectivity compared with biological cells.The aim of this dissertation is to develop new strategies for preparing excellent building blocks for biomimetic nanochannel systems by the incorporation of water soluble-pillar[n]arenes and gold nanoparticles on the inner channel walls which act as binding sites for chiral drugs and monitoring their transport processes to achieve their enantioseparation for better understanding the functions of specific biological channels.The main content of the thesis is as follows:The first part of the work described the biomimetic photo-gating single conical nanochannel based self-assembly and disassembly of gold nanoparticles coated with water-soluble pillar[6]arene(WP6).Moreover,the reversible assembly of WP6 stabilized AuNP was constructed on nanochannels surface upon UV and visible light irradiation due to the photoisomerization of azobenzene with an excellent stability and reversibility.This system could bring more insight to nanoparticles surface engineering,thus employed in the development of recyclable AuNP with high efficiency and should readily improve and augment applications in smart nanofluidic systems,optical switches,controllable release,and biosensing devices.The second part of the research reported the use of modification-free single conical nanochannel method for enantioselective recognition of S-Naproxen by using N-acetyl-L-cysteine capped gold nanoparticles as a chiral selector has been described.The chiral discrimination is based on drug induced nanoparticle diastereoselective aggregation mechanism that blocks ion transport through the nanochannel.The high S-Npx selectivity can be achieved in both water and biological samples.This study is an important step toward mimic the process of chiral recognition in living organisms and can be applied for monitoring drug metabolism and biomolecules enantioselective transport.The third part of the study demonstrated that Glucose-functionalized-pillar[5]arene(GP5)modified-cylindrical nanoporous membrane is suitable to transport and separate two enantiomers of a chiral ibuprofen drug.These nanofilters were synthesized by attached a chiral receptor GP5 to the inner walls of the membranes via host-guest complexation that effect the chiral separations by transporting selectively one enantiomer which is specially interacts with GP5,relative to the other that has lower affinity for GP5.In this work,we presented a simple concept and straightforward strategy to provide a general approach for obtaining selectively permeable membranes for enantioseparation.