Preparation Of Micro-nano Fluidic Chips By Photolithography And Their Application In Testing Instruments

The micro-nano flow control chip technology is an emerging technology and is a cross discipline that includes biology,chemistry,physics and other disciplines.Its manufacturing method involves semiconductor manufacturing.Combined with optical detection,it can be applied to disease diagnosis,environmental monitoring,and drug screening.Unique observations can be obtained by using the characteristics of fluids existing at the micrometer scale and nanometer scale.This article introduces the microfluidic channel and the nano-fluidic channel separately:(1)Making a microfluidic chip suitable for optical microscope system,and the main methods used for making micro-channels include photolithography method to make SU-8 channel positive mode.The SU-8 thickness is 100 micrometers.A PDMS micro-channel was fabricated by a plastic method.A PDMS solution was prepared at a ratio of prepolymer and a curing agent of 10:1,and a PDMS solution was bonded to a gold film by an oxygen plasma treatment to produce a complete channel,Which is 100 ?m×100?m×5 mm.When modified with oxygen plasma,the principle of modification is studied.The content of C,O,Si in PDMS before and after modification and the fitting of Si peaks after modification are described.It is concluded that the presence of SiOx on PDMS surface after oxygen plasma treatment makes PDMS hydrophilic.Using the microfluidic chip to detect polystyrene nanoparticles of different sizes,the light intensity image of the nanoparticles can be obtained,and the size of the nanoparticles can be inversely derived based on the bright field light power of the image.(2)Fabricating nano-chambers adapted to the ultrafast frozen electron microscopes,and fabricating nano-chambers by using photolithography,dry etching using sulfur hexafluoride,and wet etching using potassium hydroxide the window confirms that a 30 nm silicon nitride film can form a self-supporting film,and a gold intermediate layer is formed by peeling negative metal.The thickness of the intermediate gold film is 100 nm,and the two upper and lower chips are bonded together by a gold-silicon bonding method to form a cavity.In the chamber,the chamber chip unit on the silicon wafer was finally separated by a laser cutting method to fabricate an independent chamber chip having a size of 2.6 mm×2.6 mm.Using this nano-chamber to observe ferritin molecules in solution in ultrafast frozen electron microscope,independent protein molecules can be clearly observed and the dynamic changes of protein molecules can be seen.