Sensitive Immunosensor With Dual Signal Amplification Strategy For Sensing Of Biomarkers

Biomarker is a class of markers related to cell growth and proliferation,which has been proposed with the development of immunology and molecular biology technology in recent years.It has important significance in disease prediction and evaluation,diagnosis and efficacy judgment.The higher sensitivity and selectivity of biomarker detection has attracted increasing attention from researchers,and has become a research hotspot in the field of bioanalysis in recent years.Miniaturized immunosensors,such as those based on optical fibers and capillary,which have the advantages of low reagent consumption,fast analysis speed,simple operation,easy miniaturization and automation,etc.which has made them develop rapidly in recent years.The main limitation is the low detection sensitivity due to the inherent one-dimensional cylindrical geometry of optical fibers and capillary tubes.This could be the major barrier that limit further applications of immunosensors for detecting biomarkers with low content.This article focuses on the research and application of ultra-sensitive capillary immunosensors and optical fiber immunosensors based on the dual signal amplification strategy around the development of highly sensitive miniaturized immunosensors.The main research work is divided into the following two parts:1.We developed a promising capillary immunosensor by combining porous-layer surface modification and streptavidin-biotin-peroxidase nano-complex signal amplification to improve the detection sensitivity.Via an in situ biphasic reaction,we prepared an innovative surface modification-mediated porous layer open tubular(PLOT)capillary and combined with streptavidin-biotin-peroxidase nano-complex signal amplification(SA)system to prepare a promising PLOT-SA capillary immunosensor.In combination with chemiluminescence immunoassay analysis method,which was successfully applied to the quantitative analysis of procalcitonin(PCT)in clinical human serum samples.The results indicate that the proposed PLOT-SA-sensor is capable of measurements of PCT with large detection range,ultra-high sensitivity and extremely low LOQ,which could be attributed to the advantages of both porous-layer surface modification and streptavidin-biotin nano-complex signal amplification.Compared to a bare-capillary sensor,the response of the PLOT-sensor can be increased by 20 times.Our studyprovides a robust and universal approach,of which the principal application fields are ultra-sensitive and reliable sensing various trace targets in clinical diagnosis,food safety,environmental monitoring,and so on.2.We developed a highly sensitive PLOT-SA-chemiluminescence optical fiber immunosensor by surface modification combined with signal amplification strategies.Via an in situ biphasic reaction,we prepared an innovative surface modification-mediated porous layer open tubular(PLOT)capillary and combined with streptavidin-biotin-peroxidase nano-complex signal amplification system to prepare a promising PLOT-SA-chemiluminescence optical fiber immunosensor.In combination with chemiluminescence immunoassay analysis method,which was successfully applied to the quantitative analysis of hepatitis B surface antigen(HBsAg)and hepatitis B e antigen(HBeAg)in clinical human serum samples.Under the optimized experimental condition,the optical fiber immunosensor enhanced the sensitivity of HBsAg and HBeAg detection by about 4.8 and 6.7 times,respectively,and has a wide range of antigen concentration detection.The sensor has been successfully applied for determination of PCT in human serum samples with satisfactory accuracy and excellent stability and reproducibility.