International Journal of Scientific & Engineering Research Volume 3, Issue 8, August-2012 1 ISSN 2229-5518 IJSER © 2012 http://www.ijser.org Synthesis and Characterization of Fe 2 O 3 Nanomaterials using HVPC Growth Technique for Glucose Sensing Application Donna Marie B. De Mesa, Gil Nonato C. Santos, Reuben V. Quiroga Abstract - This study investigated the capability of the grown Iron Oxide nanoparticles (NPs) for faster glucose detection. Horizontal Vapor Phase Crystal (HVPC) Growth Technique was utilized in the synthesis of Iron Oxide NPs from 99.99% purity Magnetite – Iron Oxide (Sigma- Aldrich) bulk material. Different parameters were varied such as the growth environment (without external magnetic field, with external magnetic field), size of the sealed tube (10cm, 12cm, 14cm), growth temperature (1000 C, 1100 C, 1200 C) and dwell time (8hr, 9 hr, 10 hr). Scanning electron Microscope (SEM) and Energy Dispersive X-ray (EDX) confirmed that the Iron Oxide nanowires and almost uniform size nanoparticles approximately 50nm in diameter were formed utilizing the optimum parameters such as 1000 C growth temperature, 8 hours dwell time, 12 cm size of sealed tube and the presence of external magnetic field in the growth environment. The application of the external magnetic field enhanced the Superparamagnetic (SPM) property of the grown Iron Oxide NPs above the Curie temperature. The net magnetic moment determined the direction of magnetic force of attraction present in the grown NPs. Particles to particles- chain assembly were observed in which some NPs were interconnected forming nanowires/ agglomerated nanowires in the vapor - solid phase nucleation. The magnetic field also lessened the effect of gravity which aligned the formation along the field. Glucose oxidase (GOx) and chitosan have been immobilized by physical adsorption onto electrode with Iron Oxide NPs. Amperometric – electrochemical circuit setup was used to determine the glucose sensing ability of the modified electrode with iron oxide NPs while varying some factors such as glucose concentration, applied DC potential and electrolyte solution. At α = 0.05, since F(27.52; 54.48) > FC(3.29; 4.49), two - way ANOVA reveals that there was a significant difference between the current responses while varying the electrolytes for different modified electrodes. Among the modified electrodes, G/FeO/CH/GOx and SS/FeO/GOx showed highest sensitivity and longest limit of detection correspondingly. The correlation coefficients (ave. r = 0.74; 0.99) indicates that there was a linear relationship between the response current versus varying concentrations and applied DC potential. Iron Oxide NPs integrated in modified electrode in an amperometric- electrochemical circuit also showed low detection limit (0.008mM), fast response time (<5s), usage repeatability (≈20 times) and longest detection limit range of 0.008mM to 32mM. Based on the results, modified electrode with Iron Oxide NPs showed high surface reaction and catalytic activity, large surface-to-volume ratio and strong adsorption ability that are beneficial in the immobilization of glucose oxi dase. The Iron Oxide NPs’ magnetic property was considered in the modification of the electrode for Amperometric- Electrochemical circuit for glucose sensing application since the magnetic field reinforces the attraction of the particles to the electrode’s surface. Keywords - Iron Oxide Nanomaterials, Horizontal Vapor Phase Crystal (HVPC), glucose sensing application, amperometric glucose sensing, biosensing applications ——————————  —————————— 1 INTRODUCTION Diabetes is one of the most alarming diseases worldwide. In the article entitled “Diabetes Warning” at the Inquirer.net (2008), Dr. Philip S. Chua mentioned that the victims of diabetes are expected to grow from 246 million to 380 million by year 2025 based from the report of the International Diabetes Institute in Australia. One way to prevent diabetes is through proper monitoring of the glucose concentration in the body. A person can still develop diabetes if the glucose levels in the bloodstream are not carefully regulated due to its building up in the blood instead of going to the cells (Mongillo, 2007). There are numerous ways used in monitoring glucose concentration. Some researchers today integrate nanotechnology in medical applications. “There’s a plenty of room at the bottom,” a talk presented by Feynman not knowing that it did become the central point in the field of nanotechnology long before anything related to the word “nano” had emerged (Ashby et al., 2009). Nanotechnology is the research and development of materials, devices, and systems that exhibit physical, chemical, and biological properties at dimensions ranges from 1 to 100 nanometers which are expected to bring lighter, stronger, smarter, cheaper, cleaner, and more durable products (Mongillo, 2007). Some of the major applications of the nanotechnology are energy storage, production, and conversion, agricultural productivity enhancement, water treatment and remediation, drug delivery systems and disease diagnosis and screening. Since then, many researches had materialized in the study of nanomaterials and one of these is the iron oxide nanomaterials that was utilized in disease diagnosis and screening. Iron Oxide nanoparticles (NPs) have attracted extensive interest due to their magnetic properties and their potential applications in many fields. Even though cobalt and nickel are highly magnetic materials, they have limited applications due to their susceptibility to oxidation and toxicity. Some of the applications of Iron Oxide NPs include multi-tera bit storage device, catalysis, sensors, and a platform for high-sensitivity biomolecular magnetic resonance imaging (MRI) for medical diagnosis and therapeutics. In the review “Biosensor fabrication based on metal oxide nanomaterials,” magnetite (Fe3O4) iron oxides nanoparticles and thin films structures have potential ———————————————— Donna Marie B. De Mesa, Master of Science in Physics, De La Salle University-Manila, Philippines. E-mail: Donnamarie.demesa@dlsu.edu.ph Gil Nonato C. Santos, Doctor of Philosophy in Materials Science, Professor, De La Salle University-Manila, Philippines. E-mail: santosg@dlsu.edu.ph Reuben V. Quiroga, Doctor of Philosophy in Physic, De La Salle University-Manila, Philippines. E-mail: quirogar@dlsu.edu.