Preparation Of Anti-biofouling Nanomaterials And Their Application For Whole Blood Detection

The presence of biofouling on the electrode surface of sensor during the direct detection of whole blood has hampered the progress of biomedical detection. While an electrochemical biosensor directly used in whole blood, the biofouling of electrode surface can be developed by platelet, fibrin and blood cell adhesion in the complex environment of whole blood media. And the biofouling of electrode surface will bring catastrophic damage to the electron transfer between biomolecules and electrode redox center. In this paper, novel polymeric-based micro-and nano materials with good anti-clotting properties will be designed, synthesized and utilized to inhibit the biofouling from whole blood formed on the electrode surface. The basic theoretical researches of polymer micro-and nano materials that including physico-chemical parameters, anticoagulant effect and mechanism, biocompatibility evaluation, the fixed efficiency of biological molecules and the effects of electrochemical performance will be investigated. The integration of the technologies, which include nanomaterial, anti-biofouling technology and biosensors, will have significant input to diagnostics and therapies of interest for human health. The main results can be concluded as follows:1. A novel electrochemical biosensor, which can be conveniently applied to veracious evaluate the level of blood glucose with the help of antibiofouling technology, was prepared and investigated. More details in preparing of polyurethane-Pluronic F127nanospheres (PU-F127NPs) and immobilizing glucose oxidase (GOx) on (PU-F127)/glass carbon electrode (GCE) were presented. And the electrochemical behaviors of the biosensor in whole blood were studied. The cyclic voltammetric results indicated that GOx immobilized on the PU-F127NPs exhibited direct electron transfer reaction, which led to stable amperometric biosensing for glucose with a detection limit of1.14×10-5M (S/N=3) in whole blood. The PU-F127NPs modified GCE also offered good anti-interference ability to ascorbic acid (AA) and uric acid (UA), especially when a detection potential of-0.49V was employed. The good stability and repeatability of this biosensor were also proved.2. Polypyrrole-Pluronic F127nanocomposites (PPy-F127NPs) with conducting and antibiofouling property were synthesized and used to construct the special glucose biosensor that can be applied in whole blood directly. The PPy-F127NPs were characterized by transmission electron microscopy (TEM), elemental analysis and UV-vis spectroscopy. The anti-biofouling property of PPy-F127NPs and glucose oxidase (GOx) structure variations on the PPy-F127NPs were investigated. The cyclic voltammetric results indicated that GOx immobilized on the PPy-F127NPs exhibited direct electron transfer reaction with a formal potential value (E0,) of-0.463V vs. SCE. Moreover, the biosensor had good electrocatalytic activity toward glucose with a wide linear range (0.2-20mM) and a low detection limit3.13×10-5±0.8×10-8M. The regression equation was I (μA)=(0.021±0.003) c (mM)+(0.439±0.004)(n=10, R2=0.9978). The glucose biosensor had a good anti-interference property towards AA and UA at their concentration encountered in blood. This idea and method will provide a promising platform foT the rapid development of biosensors that can be used in whole blood system directly for component detection of illness diagnosis.3. We have synthesized hyperbranched polyester nanoparticles with carboxylic acid functional groups (HBPE-CA NPs) and developed a label-free electrochemical aptamer biosensor using thrombin-binding aptamer (TBA) as receptor for the measurement of thrombin in whole blood. The indium tin oxide (ITO) electrode surface modified with HBPE-CA NPs was grafted with TBA, which has excellent binding affinity and selectivity for thrombin. Binding of the thrombin at the modified ITO electrode surface greatly restrained access of electrons for a redox probe of [Fe(CN)6]3/4-. Moreover, the aptamer biosensor could be used for detection of thrombin in whole blood, a wide detection range (10fM-100nM) and a detection limit on the order of0.90fM were demonstrated. Control experiments were also carried out by using bull serum albumin (BSA) and lysozyme in the absence of thrombin. The good stability and repeatability of this aptamer biosensor were also proved.4. HBPE-CA NPs were combined with chitosan wrapped around Au nanoparticles (CS-Au NPs) to prepare a novel and sensitive electrochemical immunosensor by adsorption of carcinoembryonic antibody (anti-CEA) on the (HBPE-CA)/CS-Au NPs modified GCE. Under the optimized conditions, the proposed immunosensor displayed a good amperometric response to carcinoembryonic antigen (CEA). Moreover, based on the antibiofouling study, the immunosensor could be used for detection of CEA in whole blood directly, a wide detection range (1fg·mL-1-107fg·mL-1) and a low detection limit of0.251fg·mL-1were demonstrated. Control experiments were also carried out by using AA, UA, human immunoglobulin G (IgG), BSA and glucose in the absence of CEA. The good stability and repeatability of this immunosensor were also proved. Importantly, the results of the detection of clinical whole blood specimens with the proposed immunosensor were well consistent with the data determined by enzyme-linked immunosorbent assay (ELISA) in serum samples.5. Polypyrrole-Pluronic F127-Au nanocomposites (PPy-F127-Au NPs) with conducting and antibiofouling property were synthesized and used to construct a novel electrochemical cytosenor that can be applied in whole blood directly. The PPy-F127-Au NPs were characterized by transmission electron microscopy (TEM), UV-vis spectroscopy and Fourier transform infrartd spectroscopy (FTIR). The anti-biofouling property of PPy-F127-Au NPs and cytotoxicity on PPy-F127-Au NPs were investigated. A novel electrochemical cytosenor was designed based on the specific recognition of KH1C12receptors and HL-60cell on the GCE surface modified with PPy-F127-Au NPs. Using human promyelocytic leukemia cells (HL-60cells) as model, the cytosensor could response down to89cells·mL-1with a linear calibration range from1.0×102to1.0×106cells·mL-1in whole blood, showing very high sensitivity.