Surface Acoustic Wave Immunosensorbased On Anau-nanoparticles-decoratedgraphene Fluidic Channel For CA125 Detection

As one of the important tumor markers,CA125 plays an important role in the screening and clinical detection of ovarian cancer,cervical cancer,breast cancer and colorectal cancer.Early detection of CA125 can effectively avoid the risk of cancer.In recent years,the detection of immunosensors in cancer has attracted more and more attention.With the continuous improvement of people's requirements for quality of life and medical quality,it is becoming more and more important to develop new immunosensors with more portability,lower energy consumption,simple operation,sensitive response and rapid response recovery.In this paper,a 203.5 MHz surface acoustic wave(SAW)immunosensor based on gold nanoparticles graphene fluid tube was designed.The sensor was used for the immunoassay of CA125 antigen,and the level of CA125 in human serum samples was actually measured.Firstly,graphene is prepared on tantalum wire by chemical vapor deposition,and the tantalum wire is extracted to obtain graphene microtubules.Gold nanoparticles are modified on the inner wall of the graphene tube by electrochemical multi potential step method to construct gold/graphene tube fluid channel.The structure of gold nanoparticles and graphene can combine well with biological proteins.A fluid channel test box is constructed using gold/grapheme tube.A delay line SAW immunosensor is composed of the fluid channel test box and a delay line type SAW device.Secondly,the optimal conditions for constructing a reliable and high-performance delay line SAW immunosensor are studied in detail.Specifically,the optimal conditions for quantitative detection of CA125 were determined by optimizing deposition time of grapheme tube,antibody concentration,antibody incubation time,and antigen incubation time.CA125 was detected by delay line immunosensor in buffer with p H 7.4.The experiments show that the sensitivity of the immunosensor can reach-0.00861 MHz(log(m U m L^-1)^-1)in the low concentration range of CA125(0.1 m U ML^-1?300 m U ML^-1)and the detection limit is less than0.02207 m U m L^-1.In addition,the immunosensor shows good repeatability,specificity,reproducibility and long-term stability.Finally,the content of CA125 antigen in human serum was actually tested by using the SAW immunosensor.The recovery ranged from 91.1%to 101.2%,and the relative standard deviation was less than 5%.The application value of the SAW immunosensor in clinical immunodetection was verified.