Preparation Of Surface-enhanced Raman Scattering Substrates For Functionalized Gold Nanoparticles And Its Application In Detection Of Disease Markers

Disease markers refer to the abnormal concentration of biomolecules in the body fluids of patients due to the disorder of the systematic metabolic process before or during the onset of disease.The measurement of the index can obtain the human health status and the degree of disease.Sensitive detection of disease markers is essential for the early detection,follow-up diagnosis and treatment,and prognosis evaluation of malignant diseases.Most of the clinical detection methods are complicated and time-consuming,and are usually accompanied by surgical operations,which require anatomical sampling of the diseased tissues,and difficult to detect in time in the early stage of the disease.Therefore,related researches on sensitive detection of disease markers have aroused great interest of scientific researchers.In recent years,surface-enhanced Raman spectroscopy(SERS)technology has been widely used in the detection of disease markers due to its high sensitivity,availability of molecular characteristic spectra,no sample pre-processing and rapid detection.SERS technology can not only satisfy the requirements of sensitivity,accuracy and specificity,but also realize simple and rapid noninvasive diagnosis.In this paper,using functionalized gold nanoparticles as the SERS substrate,two methods for the detection of disease markers have been successfully established,including hyaluronidase(HAase)and serotonin(5-HT).According to the concentration of HAase in the urine of patients with bladder cancer and the concentration of 5-HT in the serum of patients with carcinoid syndrome,relevant diseases can be clinically diagnosed.(1)A HAase detection method based on SERS technology has been established.Hyaluronic acid functionalized gold nanoparticles(HA-Au NPs)were synthesized as SERS substrates using a one-pot method,and malachite green(MG)was used as a SERS reporter for detecting HAase.The detection mechanism is based on HAase that can hydrolyze the HA on HA-Au NPs into hyaluronic acid oligomers,and decompose the originally HA-Au NPs into many smaller HA-Au NPs.The SERS substrate was disassembled,resulting in the weakening of the SERS signal at 1173 cm-1.Compared with other methods for the determination of HAase,this method is simple and efficient and the detection limit is 0.4 m U m L-1.The method is applied to the determination of HAase content in human urine,the spiked recovery rate is97.24-103.88% and the relative standard deviation(RSD)is less than 2.78%.The results show that the method can be used in the clinical diagnosis of bladder cancer.(2)A 5-HT detection method based on SERS technology has been established.Based on the fact that the amino and hydroxyl groups in 5-HT can react with dithiobis succinimidyl propionate(DSP)and N-acetyl-L-cysteine(NALC),respectively.Two functionalized gold nanoparticles DSP-Au NPs and NALC-Au NPs were synthesized with the Au-S bond and the mixed solution of these two functionalized Au NPs was used as the SERS substrate.DSP-Au NPs and NALC-Au NPs can specifically recognize 5-HT and effectively reduce the interference of biomolecules similar to5-HT in the experiment.The introduction of 5-HT will cause the functionalized Au NPs to aggregate,resulting in an increase in the SERS “hot spot” area and SERS signal.The 5-HT was quantitatively detected by calculating the change in the intensity of the SERS peak at 941 cm-1.The method has the advantages of low detection limit,high sensitivity and good selectivity.The detection limit is 0.15 nmol L-1.The method is applied to the detection of 5-HT content in human serum,the spiked recovery rate is 95.20-102.00%,and the relative standard deviation(RSD)is less than 2.81%.The results show that this method can provide a reliable experimental basis for the early diagnosis and treatment of carcinoid syndrome.