Quantitative measurement of sugar concentration using in house fabricated microgap biosensor

Sugar is carbohydrate sweet-flavoured substance that composed of carbon, oxygen and hydrogen. It is an important component to provide sweet taste in food. Besides, it also provides immediate energy to complete daily routine life. However, uncontrolled amount of sugar can lead to serious health complications and diseases such as Hypoglycemia (low sugar in blood), syndrome X, diabetes and heart disease. Low amount of sugar in bloodstream may cause nausea and dizziness. Besides that, it also can be used as sensor to detect the amount of sugar in beverages. Here, sugar is used as a reference measurement to test the functionality of the device before testing it in real life using glucose samples. In future, real urine samples will be used to measure concentration of glucose in diabetic patients. In this paper, sugar concentration measurement based on microgap biosensor is fabricated by using conventional photolithography process. Silicon was used as the substrate material and followed by layers of Silicon dioxide (SiO2), Polysilicon, Titanium (Ti) and Gold (Au). Chrome mask were used to transfer pattern of microgap and contact pads onto the silicon substrate. The device design has been optimised to achieve few performance factors that includes accuracy, sensitivity, response time and fabrication cost. A number of sugar concentrations were prepared by diluting it with DI water for measurement process by electrical characterization. In this work, studies and analysis were conducted based on different concentration of sugar on constant sized microgap and based on different size of microgap structure on constant sugar concentration. As the result, the experiment has been successfully yielded a high sensitive microgap sensor and the lowest detected sugar concentration sample is 0.0245gml^-1. This method of biosensing provides a very simple and promising detection technique for any kind of biomolecules that includes proteins, DNA, enzymes, antibody and antigen.