New SERS Probe Design, Paper-based Chip Platform Construction And Application

The surface-enhanced Raman scattering(SERS)technology has the advantages of diversified test modes and flexible application methods.In this paper,two aspects are studied,one is the design and application of SERS tag,and the other is the application research of paper-based SERS chip technology.In recent years,SERS tags have developed extremely rapidly.A typical SERS tag consists mainly of three parts: a metal nano-enhanced substrate,a Raman reporter,and a protective shell.Among them,the nano-enhanced substrate and reporter molecules have higher attention,while the research on the shell layer is weaker,but the shell layer is very sensitive to the sensitivity and stability of the bioanalysis process.Therefore,a novel SERS probe,polystyrene(PS)shell SERS probe,was designed and synthesized.The PS-coated SERS tags show satisfactory sensitivity,monodispersity,biocompatibility and excellent structural stability under many demanding conditions.It is a commercially valuable tool that shows great promise in bioanalysis and medical diagnostics.Recently,the developed paper chip technology is a cost-effective detection technology that is easy to operate and easy to transport.It was quickly combined with SERS to form a SERS paper chip technology for the detection of contaminants.Based on a variety of SERS measurement principles,this experiment builds an integrated,high-throughput detection SERS paper chip,combined with a portable Raman test instrument,for typical explosives TNT,pesticide chlorpyrifos,heavy metal mercury ions and cadmium ions,etc.Contaminants are analyzed and tested.Achieve high sensitivity and rapid testing of typical contaminants.It provides a promising platform for functional and flexible detection of samples.The concrete contents of this thesis are as follows:Chapter one: The related contents of surface-enhanced Raman mechanism,surface-enhanced Raman probe,surface-enhanced Raman paper chip technology and surface-enhanced Raman technique are introduced.Chapter two: The synthesis and application of the novel SERS tag are introduced in detail.The preparation method is simple,and the PS shell layer is coated on the bare SERS tag by polymerization.First,the Raman reporter molecules are adsorbed on the surface of the noble metal nanoparticles to form SERS nanoparticles,and the PS shell layer is grown in situ by polymerization.The synthesized tags are versatile and can encapsulate both thiolated and non-thiolated reporter molecules;they can also coat the cores of various substrates(gold nanospheres,nanoflower nanorods and gold nanostars)while The sensitivity of the SERS probe is not lost.The stability of the tag is then detected in various environments,and finally the probe is used for cell and bioimaging studies,which also exhibits a strong and stable signal.Chapter three: The construction and application of SERS paper chip technology are introduced in detail.An integrated SERS paper chip with high throughput detection characteristics was constructed.Combined with portable Raman test instruments,different detection principles are used to detect a variety of pollutants: typical explosives TNT,pesticide chlorpyrifos,heavy metal mercury ions and cadmium ions.The measurement technology based on SERS paper chip has the following advantages: under the action of noble metal nanoparticles,the Raman signal of the molecule can be increased by tens of thousands of times,and the trace analysis can be performed;the Raman spectrum is characterized by strong contrast with the standard spectrum.It can quickly characterize the sample to be tested;requires less sample,no complicated sample and pretreatment,and improves the detection limit.