| Use of biosensing techniques to detect the meaningful bio-markers for the accurate and rapid diagnosis of clinical diseases as well as for the field screening and mass monitoring of the epidemic diseases has been a novel, attractive and hot topic in the current medical studies. Some immunoassay systems were established for human thymidine kinase1 (hTK1) detection. The immunoassay not only provides an accurate and reproducible method for evaluating hTK1 protein levels in various types of samples (serum and tissue), but is also faster, more convenient than radio labeled assay. Moreover, problems associated with the storage, handling, and use of radioactive materials are completely avoided. Our method was expected to be a useful probe for biochemical and immunohistochemical determinations of hTK1, which can be used in the clinical immunoassay.(1) We developed a fluorescence enhancing immunoassay for hTK1, using magnetic nanoparticles (MNPs) as the biomolecular immobilization mediator. The horseradish peroxidase labeled hTK1 monoclonal antibody (HRP-Ab) competitively reacts with the free hTK1 in the detection solution and the bound hTK1 on MNPs. After separated by a magnetic field, the bound HRP-Ab on MNPs catalyzes the oxidization of 3-(p-hydroxyphenyl)-propionic acid (HPPA) to form a fluorescent dimmer product, 2,2'-dihydroxybiphenyl-5,5'-dipropionic acid, leading to an enhanced fluorescent signal at 407 nm which is inversely proportional to the hTK1 concentration. The hTK1 can be linearly determined in the range of 0.01-1 ng/mL and the detection limit reaches 0.008 ng/mL. The hTK1 concentrations of several live cancer patient and normal human serum samples were well evaluated by the developed fluoroimmunoassay. This new immunoassay system is simple, fast, and sensitive for the detection of hTK1, offering a promising alternative method that can be extended to detect other biomarker molecules and has broad potential applications in clinical disease diagnosis.(2) Using Nano Au and chitoan nanocomposite (Nano Au - Chit) layer as the immobilizing mediator layer, a new electrochemical immunosensor was propored for hTK1. The structure and electrochemical characteristics of the Nano Au– Chti nanocomposite layer were studied, and the results showed that Nano Au - chitoan nanocomposite layer possessed excellent ability of electron transfer. The activity and stability of hTK1 on the surface of biosensor were also be effectively retained. The hTK1 concentration can be linearly detected in the range of 0.5-10 ng/mL, and the detection limit reaches 0.22 ng/mL.(3) A new scaning electrochemical immunoassay was deceloped for the detection of hTK1. hTK1 was first immobilized on the Au plate. The immobilized hTK1 on the Au plate and the free hTK 1 in the detection solution reacted with the horseradish peroxidase labeled hTK1 monoclonal antibody (HRP-Ab). HRP catalyzed the oxidation of hydroquinone (H2Q) to generate p-benzoquinone (BQ), which was detected by SECM. In this study, the optional experimental conditions were investigated for the detection of hTK1. Under the selected conditions, the immobilized hTK1 spots were scanned and the SECM images were obtained.
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