5. Metal Nanoparticles as Glucose Sensor

Diabetes, a metabolic disorder, has become a major health problem in the world. According to WHO report, the number of patients is projected to 300 million in 2025. Therefore, the need of glucose detection is extremely important to the patients suffering from diabetes. Glucose oxidase (GOx) has been extensively used to construct amperometric biosensors for glucose detection owing to its high selectivity and sensitivity to glucose. However, GOx-based biosensors suffer from a stability problem due to the fundamental feature of enzymes. Therefore, it requires a need for enzyme-free glucose sensors. During last two decades, considerable attention has been paid to develop enzyme-free electrodes. Precious metals, metal alloys, and metal nanoparticles are extensively studied for advancement of non-enzymatic glucose sensors. Therefore, the need of a cost-effective, sensitive, and reliable enzyme-free glucose sensor is in great demand. In recent years, noble metal nanoparticles have found immense interest by researchers due to their potential in label-free forms of biological and chemical sensors. The high capability of these sensors is due to the novel properties of noble metal nanostructured arrays, for instance, high surface to volume ratio, localized surface plasmon resonance, excellent conductivity and anomalous transmission, and reflection of light. The amperometric technique is most widely used tool in the sensing of glucose. On the other side, some LSPR sensors are also reported which showed good sensitive to the changes in refractive index occurring at a metal/dielectric interface. Some researchers also studied fiber-optic-based glucose sensor which was based on the attenuated total reflection phenomenon. Enzymatic and non-enzymatic sensors of silver, gold, and copper nanoparticles are discussed in details in the chapter. The fabrication of glucose sensors has also been discussed with keeping in view the interest of the researchers. The objective of this chapter is to cover the bare and modified/composites of metal nanoparticles as glucose sensor. The most recent as well as conventional fabrication methods are discussed in detail. The linearity range and limit of detection of the glucose sensors are described in detail to justify the fabrication process. The chapter will provide in-depth review of metal nanoparticles-based glucose sensors which would be beneficial to all researchers, scientists, engineers, and students who are in direct contact of developing and using glucose sensors. It is hoped that the chapter will bridge the common gap between the research literature and standard textbooks. The material in this chapter emphasizes on developments of sensitive, rapid, and cheap systems for identification of glucose. The fabrication techniques of metal nanoparticles as glucose sensor are also studied in connection with different methodologies like SPR, SERS, electrochemical, and paper based devices.