18 TH INTERNATIONAL CONFERENCE ON COMPOSITE MATERIALS Gold Nanoparticle modified PVA/GOx Biocomposite Membranes via Electrospun for Biosensor Applications C.M. Wu 1 *, S.L. Lin 1 , H.G. Chiou 1 , Y.C. Weng 2 , C.Y. Ho 1 , W.H. Huang 1 1 Department of Fiber and Composite Materials, Feng Chia University, Taichung, Taiwan 2 Department of Chemical Engineering, Feng Chia University, Taichung, Taiwan * Corresponding author (cmwu@fcuoa.fcu.edu.tw) Keywords : Electrospun, Poly(vinyl alcohol), Glucose biosensor, Immobilization, Gold nanoparticles Abstract and transducer type reaction [2]. Glucose biosensor This study successfully combined the advantages of is an important development for biosensor, and it electrospun technology, gold nanoparticles and also has an extensive application from blood glucose electrochemical biosensor to produce a sensor to food analysis. Then, the stability of high-sensitive glucose biosensor. We prepared the enzymes is crucial for the fabrication of biosensors. biocomposite electrospun nanofiber membranes by A number of techniques have been used for the electrospun a solution of PVA, GOx and Gold immobilization of enzymes on different substrates to nanoparticles. SEM image showed the membrane improve the enzymatic activity and stability [3]. was a nanoporous structure; TEM image indicated Poly (vinyl Alcohol) (PVA) is one of electrospun that gold nanoparticles were well dispersed in polymer materials because it has good hydrophilicity, nanofiber; The results of FT-IR showed that GOx high mechanical strength and flexibility. Recently, exist in nanofibers. With the addition of gold there were many systematic studies about the effect nanoparticles, the sensitivity of PVA/GOx/Au fiber of molecular weight, the solution PH value and membrane was much higher than other samples, and small molecule additives etc. on PVA electrospun the 50ppm of nanoparticles was the best proportion behavior [4-6]. These studies have made the in this experiment. manufacturing method of PVA electrospinng nanofibers become developed. Besides, PVA has 1 Introduction excellent film-forming and biocompatibility, and Electrospun technology is a manufacturing that is considered an appropriate matrix for enzyme technique that extracts continuous fibers from immobilization [7]. The enzymes can be polymer solutions or melts under a strong immobilized on PVA matrix by different methods electrostatic field. The jet flow which is ejected from (cross-linking with aromatic tri-isocyanates, gamma the tip of Taylor Cone can extend to a long distance, or UV irradiation etc.). However, because of the thereby obtaining a super-fine fiber. Fibers compaction and low-conductivity of the membrane, manufactured using this method possess smaller it is adverse for the substrate to infiltrate into the diameter, high specific surface area and great enzyme membrane and for the electrons to transfer porosity. Due to these excellent properties, the fibers between the enzyme membrane and the electrode[8]. can be applied as filter material, biomedical Characteristics of gold nanoparticles such as high applications, biosensors, photoelectric components, surface-to-volume ratio, high surface energy, ability and reinforced composite materials [1]. Moreover, it to decrease distance between glucose oxidase (GOx) is reported recently that the composite fabrics of and electrode, and the functioning as drug carrier prepared by electrospun have chance of electron-conducting pathways between redox protein healing the retinal damage. and the electrode surface, have been claimed as Biosensor is a device which is combined reasons to facilitate electron transfer between GOx immobilized biorecognition element with transducer. and electrode surfaces [9]. It can monitor chemical substances on the inside or This study combined the advantage of electrospinng, outside of organism by translating them into a gold nanoparticles and electrochemical biosensor in transducer signal after a coupling of the biochemical order to produce a high-sensitive glucose biosensor.
18 TH INTERNATIONAL CONFERENCE ON COMPOSITE MATERIALS In electrospun technology, our laboratory had made 101 Series, Kd scientific, USA). The syringe pump a self-assembled electrospun device, and we also was connected to a Teflon tube and the tube was found the best electrospun parameter of PVA. We attached to a plain-stitch spinneret acting as the used the established electrospun technology and spinneret. An electrostatic controller (LGC-300 prepared PVA nanofiber membranes instead of series, Taiwell, Taiwan) connected to the collector, traditional films, and we expect that nanoporous and a ground wire connected to the spinneret. The structure could improve the sensitivity of glucose applied voltage was 25KV, and the working distance biosensor. Moreover, we used the characteristics of was 18cm in the electrospinning system. gold nanoparticles to increase the efficiency of 2.3 Analysis electron transfer. The morphology of PVA/GOx film and PVA/GOx 2 Experimental fiber was characterized by a variable vacuum 2.1 Material scanning electronic microscope (VVSEM, S3000, Hitachi, Japan). The transmission electron Poly (vinyl Alcohol) with 98~99% hydrolyzed, and microscopy (TEM) images were obtained by JEOL a molecular weight of 146,000-186,000 was 200CX. The chemical composition was verified by purchased from Sigma-Aldrich. The concentration Fourier transform infrared spectroscopy (FTIR-8300, of the prepared PVA solution was 7wt%. Glucose Shimadzu, Japan). The thickness of PVA/GOx film oxidase (G7141, Sigma-Aldrich) was 153,100 and PVA/GOx fiber was measured by alpha step units/G and solid. The disodium Hydrogen (Surfcoder Model ET-3000, Kosaka Laboratory Ltd., Phosphate 12-water (ECHO Chemical CO.) and Japan). The measurement was performed using a Sodium Hydrogen Phosphate Dehydrate (ECHO scan length of 1 mm, scan speed of 0.05 mm/sec, Chemical CO.) were used for phosphate buffer and stylus contact pressure of 5 × 10 -7 kg. solution. Dextrose Anhydrous (D(+)-Glucose) was purchased from ECHO Chemical Company. Gold 2.4 Electrochemical Measurements nanoparticle solution with 10~100nm and 1000ppm In this study, the electrochemical measurement of was purchased from Lihochem Inc. glucose biosensor was three-electrode system with 2.2 Preparation potentiostat (CH Instruments Electrochemical Analyzer). Ag/AgCl was used as reference electrode PVA/GOx film: We dipped the Pt electrode in a was, and platinum foils were used as working 200U/ml PVA/GOx solution to form a coating film. electrode and counter electrode. The working After film-forming, the PVA/GOx film was potential was 0.8V. The PBS (phosphate buffered cross-linked with glutaraldehyde solution. solution, 0.1M and PH6.8) is a buffer solution PVA/GOx fiber: We prepared the biocomposite containing disodium hydrogen phosphate 12-water electrospun nanofiber membranes on the Pt and sodium hydrogen phosphate dehydrate. All electrode by electrospun a solution of PVA and GOx. electrochemical reactions were in the solution. After electrospun, the electrospun PVA/GOx nanofiber membranes were cross-linked with 3 Results and Discussion glutaraldehyde solution. 3.1 The morphology of electrospun PVA/GOx PVA/GOx/Au fiber: We prepared the biocomposite fiber membrane electrospun nanofiber membranes on the Pt electrode by electrospun a solution of PVA, GOx Fig.2 was the deposited configuration of electrospun and gold nanoparticle solution. After electrospun, PVA/GOx fiber membrane on Pt electrode. The the electrospun PVA/GOx/Au nanofiber membranes electrospun PVA/GOx fiber formed a white were cross-linked with glutaraldehyde solution. micro-transparent membrane on Pt electrode. In order to examine the physical morphology of 2.2 Electrospun electrospun PVA/GOx fiber membrane, we must use This experiment used a self-assembled electrospun SEM and TEM to observe the membrane. device, as Fig.1 shown, and an injection spinneret Fig.3(a) showed the SEM image of PVA/GOx film. (0.008ml/min) powered by a syringe pump (Model The coating film was compact, and it was not a
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