Fabrication Of Functionalized Cross-scale Micro/Nano-fluidic Chips Utilizing UV-TPP Lithography

In biological tissues,cells are constantly changed under the influence of mechanical and chemical signals imposed by their environment.More and more evidences show that environmental mechanical signals may cause the changes of the chromatin threedimensional conformation,for sometime,they can even destroy the integrity of DNA molecules.Therefore,the study of mechanical signals regulating mechanism on the threedimensional conformation of DNA molecules is very important for understanding cell life activities.In this paper,the femtosecond laser Two-Photon Polymerization(TPP)direct writing technology is applied in the fabrication of multi-scale nanometer channel array and a tapered nanometer channel with gradually changing dimensions.Furthermore,combined with Ultraviolet(UV)lithography technology,the nanochannel array is coupled with the valvecontrolled microchannel.Finally,a cross-scale micro-nanofluidic chip,which can be used to manipulate DNA molecules and generate high-precision mechanical signals,has beensuccessfully fabricated.Then,the chip is applied in the mechanical environment simulation of the cell nucleus to deeply study the regulation of Pico-newton(p N)level tensile force on the three-dimensional nanostructure of DNA molecules.The results prove that the mechanical signal does not depend on the mechanical signal pathway and it directly regulates the transcriptional behavior of cells.In this paper,the characterization by scanning electron microscope and atomic force microscope shows that the width of the multi-scale nano-channel array processed by femtosecond laser two-photon direct writing technology is in the range of 100 nm to 500 nm.The smallest end of the tapered nano-channels with gradient is smaller than 200 nm.Based on the prepared functionalized cross-scale micro-nanofluidic chip,this paper carried out an experimental study on the regulation of DNA molecules by mechanical signals.The regulation effects of different mechanical signals generated by multi-scale nanochannel arrays on DNA molecules are investigated.It is found that,the DNA molecule,which tolerates three-dimensional conformational changes under the action of equivalent mechanical signals,will bestretched to different lengths.On the other hand,in the 300 nm channel,the nuclear factor NF-?B(Nuclear factor-kappa B)and the nano-restriction structure are used together to construct mechanics signal environment.By investigating the regulation of DNA molecules by the mechanical signals,which is transmitted to the chromosome through the cytoskeleton,it is found that the nuclear factor NF-?B and nanorestriction structure have a synergistic effect on the mechanical regulation of DNA molecules by affecting the transcription factor on the DNA molecule.In summary,based on the UV-TPP technology,this paper constructs a cross-scale micronano fluidic chip which can generate high-precision pico-Newton-scale mechanical signals.The chip is appropriate inthe mechanical environment in the nucleus simulation.The effects of mechanical signals on the three-dimensional conformation of DNA molecules is investigated in detail.The regulatory role,preliminary exploration of the mechanism of mechanical signals regulating the three-dimensional conformation of DNA molecules in the process of cell transcription is studied and discussed in this paper.It is of great significance for understanding the regulatory role of mechanical environmental signals on life activities.