Simultaneous Detection Of Free And Total Prostate Specific Antigen Using Dual Channel Surface Plasmon Resonance Based On Gold Nanoparticles Signal Amplification

Abstrat:cancer (PCa) has been the most common illness and the second primary cause of cancer mortality following lung cancer for the masculinity in most developed countries. A series of researches have proved that the serum prostate-specific antigen (PSA) is the most useful tumor marker for the diagnosis recurrence of treatment of prostate cancer. The only detection of prostate specific antigen can result in misdiagnosis for the clinical diagnosis of prostate cancer, especially in the grey zone where density of prostate specific antigen ranges from4to10ng·mL-1. The ratio of free PSA to total PSA, possessing prostate cancer specificity, was reviewed as the most useful tool used to discriminate the prostate cancer from benign prostate hyperplasia. SPR technology, with the advantages of low detection of limit, label-free, little sample consumption and real-time monitor, has been used widely in the field of drug screening, detection of foods, environmental monitoring and clinical diagnosis of critical illness. The gold nanoparticles were applied to amplify detection signal as it owns good biocompatibility. The drawbacks that SPR can not detect directly low content of small molecules can be surmounted through combination with gold nanoparicles. The paper established a new method used to detect f-PSA and t-PSA simultaneously with the advantages of high sensitivity and low limit of detection of SPR, signal amplification using gold nanoparticles, and the specific binding between antigen and antibody. Magnetic nanoparticles are widely applied to field of biomedical as the features of magnetic orientation, biodegradation, bioaffinity, and active groups. We used chemical method to synthetize Fe3O4@Au nanoparticles, whose diameter is about30nm and dispersibility is good as the picture of TEM showed.The main results were shown as below:(1) Synthesitized a kind of20nm gold nanoparticles with good dispersibility, which were coated by PSA antigen can be used as probe to amplify signal in the detection.(2) Explore the detection of f-PSA and t-PSA by direct detection, enzyme-linked immunosorbent assay, and competitive inhibition respectively. T-PSA can be detected directly as its relative high content in serum and big molecular weight. The linearity of t-PSA ranges from1to20ng·mL-1, and that of f-PSA is0.05to0.4ng·mL-1. Lastly, the detection of serum samples provide thresholds value of f/t of22.4%and16.6%for benign prostate hyperplasia and prostate cancer separately. The obtained thresholds approach the values of25%and17%reported in papers, which provides a new method to diagnose prostate cancer and discriminate prostate cancer from benign prostate hyperplasia in grey zone.(3) Fe3O4nanoparticles with small diameter were prepared by coprecipitation with the tetramethyllammonium hydroxide as stabilizer. Then the Fe3O4nanoparticles work as nucleus; Au atoms, from HAuCl4reduced by sodium citrate, coat Fe3O4nanoparticles to form Fe3O4@Au magnetic nanoparticles. The morphology was characterized by UV-Visible spectroscopy and TEM. At last we obtained the optimal experimental conditions, and Fe3O4magnetic nanoparticles with uniform particle size distribution and good dispersity were synthesized.