Novel SERS Nanoprobes For Measurement Of Nitric Oxide And Hyaluronidase

In recent years,surface-enhanced Raman scattering（SERS）has become one of the most accurate methods for biological and chemical analysis because of its unique advantages in specificity,selectivity and sensitivity.With the continuous development and improvement of SERS substrates,SERS has presented unique application potential in many fields such as chemistry,material science,analytical science,surface science and biomedical research,etc.These exciting results have led to the development of SERS-based biomedical sensing research for higher clinical diagnostic applications and real-time detection applications.Therefore,based on the unique advantages of SERS applied in the field of biosensing,to development of a simple and highly sensitive biomedical sensing detection method as the starting point,this paper mainly carries out the following two works:（1）Au-Ag alloy/porous-SiO₂ core/shell nanoparticle-based surface-enhanced Raman scattering nanoprobe for ratiometric imaging analysis of nitric oxide（NO）in living cells.In this chapter,AuAg@p-SiO₂NPs is used as the SERS substrate,3,4-diaminothiophenol（DABT）as the NO-reactive recognition molecules adsorbed on the surface of gold-silver alloy nanoparticles by Au-S bond to form of DABT-AuAg@p-SiO₂NPs SERS nanoprobe.When DABT reacts with NO,a new Raman scattering peak at around 804 cm^-1will appear,while the Raman scattering peak at 1064 cm^-11 remains unchanged.Thus,quantitative detection of NO can be achieved based on the ratiometric peak intensity of I₈₀₄/I₁₀₆₄.This nanoprobe possesses excellent biocompatibility and chemical stability,superior SERS enhancement capacity and good signal reproducibility.To the best of our knowledge,this is the first report of a porous SiO₂-coated Au-Ag alloy nanoparticle and ratiometric strategy-based SERS nanosensor to be used for the detection of NO in living cells.（2）A novel surface-enhanced Raman scattering-based ratiometric approach for hyaluronidase assay in urine.4-mercapto benzonitrile（TBN）and 4-mercapto benzene-acetylene（TPA）have the Raman signal peaks at 2220 cm^-11 and 1974 cm^-1,respectively,and are located in the cell Raman silencing region.Firstly,the strong positive charges gold nanorods SERS nanoprobe modified by TBN（TBN-AuNRs）and the electrically neutral gold and silver alloy SERS nanoprobe modified by TPA（TPA-AuAgNPs）were prepared.A novel ratiometric SERS sensing ensemble based on the electrostatic interaction between cationic AuNRs and polyanionic hyaluronic acid（HA）was constructed by mixing the two kinds of nano-probes,which was used for the analysis and detection of hyaluronidase（HAase）.In the presence of HAase,HA is degraded and TBN-AuNRs are not agglomerated.In the absence of HAase,the TBN-AuNRs agglomerate with HA,and the Raman signal of TBN is enhanced,while the Raman signal of TPA-AuAgNPs remains unchanged all the time,thus achieving ratio detection of HAase.Compared with other nano-sensors,the ratiometric SERS sensing ensemble we constructed has such characteristics as simple,sensitive,and good signal reproducibility,and the detection range is 5-70 U/mL,which can better distinguish the level of HAase in the urine of healthy and cancer patients.