Nanopatterns Constructed By Biomolecules And Their Applications For Replica Molding

"Nanofabrication" is the process of making functional structures with arbitrary patterns in nanoscale, which is currently defined to be less than 100 nm. Although commercial-scale production have already been realized for conventional nanofabrication based on photolithography and scanning beam lithography, these techniques are limited by the factors such as high capital and operating costs.Unconventional nanofabrication is based on those techniques including molding, embossing, printing, scanning probe lithography, edge lithography, and self assembly which are now only confined to research fields. This kind of nanofabrication may offer more alternatives to photo lithography used in manufacturing now and has the potential to be the ultimate, low-cost method for nanomanufacturing.An important field of unconventional nanofabrication is to make use of organic materials to replicate nanoscale patterns or masters by a set of techniques. Then these patterns are transferred into different materials by molding, embossing, or printing. With further studies on the polymers material, the polymer materials that are capable of replicating at the molecular scale come into existence. And at the same time the masters used for molding also come diverse. This dissertation mainly focuses on the replicated capability of nanopatterns formed by bio-molecules. TheλDNA and the short peptide (GAV-9) were mainly used to form mask bio-nanopatterns. Atomic force microscope (AFM) was used to investigate the topography of the master and its polymer replicas.In most cases the features of the mold has to be imaged as well as the corresponding reverse position of the replica in soft lithography. So it is important to relocate and re-relocate the interested pattern. In this dissertation, we developed two new methods based on AFM for reposition and re-reposition nanopatterns. The experiment results showed that the replica reversed position corresponding to the master can be relocated easily and efficiently.This dissertation investigated replica molding techniques using nanopatterns formed by DNA on the modified mica surface as master. DNA molecule was stretched on the modified mica surface by using molecular combing method. Then, the DNA nanopatterns were replicated by PDMS and h-PDMS. We found that DNA could be replicated, while the replica resolution in PDMS was not satisfied.GAV-9, NH2-VGGAVVAGV-CONH2, a peptide consisting of hydrophobic amino acid residues, is a conserved consensus of three neurodegenerative disease-related proteins:α-synuclein, amyloid-βand prion. ZHANG etc in our lab found that GAV-9 peptides could grow into nanostructures on mica by a special "standing up" manner of epitaxial growth. In this dissertation, GAV-9 filaments nanopatterns were prepared on the bare mica surface. After master being cleaned and blew with the nitrogen gas, the nanopatterns were successfully replicated into h-PDMS and then remolded to PU surface. The height of final nanopatterns in PU was measured lower than that of former GAV-9 nanofilaments master.In summary, the nanofilaments self assembled by short peptide can be successfully replicated or remolded with polymers such as PDMS and PU, meanwhile more works should be done to realize replicating based on nanopattern masters formed by single DNA molecules. It shows that this new method combining "top-down" and "bottom-up" is possible and has potential for nanofabrication. The development of these techniques is directed by the deep research on the polymer materials, the molecular nanopatterns formation mechanism and the interaction between the polymer and biomolecule masters.