Studies On Fabrication And Detection Of Dot Array Sers Sensor Chip Based On Localized Plasmon Resonance

The rapid development of China’s economy has promoted the continuous improvement of people’s living standards.At the same time,consumers are also increasingly concerned about food safety and health.However,the current food safety situation in China still faces the problems of coexistence of various hazardous ingredients such as mycotoxin pollution,illegal additives,excessive antibiotics and the high detection limit of the equipment.Therefore,Therefore,it is of great significance to develop a fast and high-throughput food safety detection device.As a detection technology with ultra-high sensitivity and single molecule recognition,surface-enhanced Raman scattering（SERS）technology is widely used in many fields such as food ingredient detection and biomedicine.Limited by the instability of traditional nanomaterials and the short-range effect of the surface-plasma-enhanced areas,the fabrication of ultra-highly sensitive,stable and controllable SERS substrates has always been a hot and difficult research focus in the application of SERS spectroscopy.Based on this,the thesis fabricated a large-area,highly ordered and high SERS effect nano-gold dot array chip combining microsphere lithography and plasma magnetron sputtering technology.The chip has the advantages of high sensitivity,good stability,easy to fabricate and low cost.Due to the good biocompatibility of nano-gold,the chip can also be coupled with DNA,protein and specific antibodies,etc.It has potential application value in the field of material composition detection and interface chemistry,which provides a reference for the innovative fabrication of SERS substrates.First,gold nanorods（Au nanorods,AuNRs）,gold nanocrosses（Au nanocrosses,AuNCs）,gold nanospheres（Au nanospheres,AuNPs）,and gold nanostars（Au nanostars,AuNSs）were synthesized respectively,and their morphology and optical properties were characterized.Then microsphere lithography and magnetron sputtering technology were used to fabricate micro-nano hole arrays by depositing aluminum film on the glass substrate,and the effect of the time of depositing aluminum on the hole size was investigated.The results showed that the time of aluminum plating had a great impact on the size of the chip substrate hole.The size of the hole decreased as the time of aluminum plating increased.Based on the synthesized nanomaterials and chip substrates,optimization of the fabrication methods and performance studies on the dot array chip were carried out.The four kinds of nanoparticles were self-assembled into the array holes by the method of cleaning charge and the electrostatic adsorption method,respectively.And then the regularly assembled nano-gold dot array chips were obtained after removing the aluminum film.The nano-gold dot array chips were characterized by SEM.The results showed that the interface of the AuNPs and AuNSs dot array chips fabricated by electrostatic adsorption method were cleaner and tidier,and the array units were more complete,which was superior to the AuNRs and AuNCs dot array chips fabricated by the method of cleaning the charge.A series of AuNPs and AuNSs dot array chips were fabricated based on the electrostatic adsorption method,and the effects of different Si O₂ microspheres size and different aluminum plating time on the two nano-gold dot array chips were investigated.The results showed that the dot gap of nano-gold dot array chips was increased as the increase of the size of SiO₂ microspheres,and the dot size of the nano-gold dot array chips was decreased as the extension to the aluminum plating time.In addition,the research revealed that the size of the dots of the nano-gold dot array directly affected its SERS performance.In order to investigate the SERS effect of two kinds of nano-gold dot array chips,SERS spectroscopic testing and mapping imaging detection were performed on AuNPs and AuNSs dot array chips fabricated by electrostatic adsorption using R6G as a Raman probe molecule.The thesis investigated the SERS performance of different nano-gold dot array chips from following three aspects:the morphology of gold nanoparticles,the size of SiO₂ microspheres and the time of aluminum plating.The results showed that using 4μm SiO₂ microspheres as the template,the AuNPs array chip with aluminum plating for 90 min had the best SERS performance,with an EF value of 1.14×10¹⁰.Then the thesis carried out SERS spectroscopic detection of the illegal additive rhodamine B in food based on the AuNPs array chip.The results showed that the detection limit of rhodamine B can be as low as 10^-77 mol/L.This result suggested that the nano-gold dot array chip had good detection sensitivity.In addition,in order to investigate the biological and chemical synthesis activity of the nano-gold on the dot array chip,an“ON-OFF”DNA probe was constructed on the AuNSs dot array chip.The results showed that the gold nanoparticles on the Au NSs dot array chip can be coupled with sensing probes such as DNA to design template molecules and maintain their good biological activity.It showed that the chip also had broad application prospects in the field of biosensing.