DESIGN AND IMPLEMENTATION OF HARDWARE ARCHITECTURE OF PORTABLE TESTING PLATFORM FOR URIC ACID BJOSENSORS

• Main Author: Reivan Banjarnahor, Christian
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/79448
• Institution: Institut Teknologi Bandung

The electrochemical biosensors that have been tested are of the amperometric and voltammetric types which use 3 electrodes for the transducer: Reference Electrode (RE) for voltage reference for the three electrodes, Counter Electrode (CE) to create a closed loop so that current can flow, and Working Electrode (WE) as a recognition site for the reaction to take place. The electrochemical reaction in this type of electrochemical biosensor is initiated signal called afaradaic current where the magnitude of the current has a correlation with the intrinsic properties of the analyte, such as the concentration value. These flows require an instrument to pe,form readings and processing so that the data can be converted into useful information that is used for characterizing analytes and even estimating concentrations of analytes. The instrument is the main piece of portable test platform hardware known as a potentiostat. The electrochemical biosensor tested was a screen-printed carbon electrode (SPCE) uric acid biosensor with a Gold Nanospike (AuNS) modification. The absence of a portable test platform that has been tried on uric acid biosensors is the basis.for selecting the tested biosensors. In thisJznal project book, the discussion is also limited to the design and implementation of the hardware architecture, which is based on the potentiostat as the main circuit, from the designed portable test platform. Hardware design is carried out in a modular manner so that further development and signal tracing/or staged testing purposes can be more easily carried out. The designed hardware provides several advantages such as the existence of a Programmable Gain Ampl[fier (PGA) to realize the current range selection feature, the existence of a noise filter at low frequencies using an order 4 Sal/en-Key lowpass filter with a cutoff frequency o.f850 Hz, as well as protection against overstresslunderstresson the input of analog to digital converter. The designed instrument uses power from a rechargeable battery so the design also includes an automatic recharging system and separation of power lines. Communication between hardware and software for data transfer using Bluetooth serial. The instrument is able to maintain connectivity up to a distance of about 4 meters from the smartphone. The final dimensions of the tool are 83 mm x 78.3 mm x 32.6 mm and it weighs approximately 51 grams, including battery and casing. The hardware is then calibrated by testing Ohm's law on a dummy cell model in the.form qf a resistor with.fairly high precision. The results show that the accuracy of the designed hardware is quite good as indicated by the J-V curve which shows good linearity and produces a negligible offset. A comparison of the pe,formance of instruments designed with commercial product gives the highest and lowest relative accuracy of 97.193% and 85.072%, respectively. Finally, the tool was used to apply Cyclic Voltammetry (CV) electrochemical analysis to uric acid samples with a concentration range of 0.1 mM - 2 mM and it was found that the current reading by the instrument was good enough, indicated by low noise. In terms of performance and portability, the hardware has provided satisfactory results. However, the total power of 2.5 W consumed by the device means that 1500 mAh battery can only lastfor 2.5 hours before recharging. Development needs to be done in the future to reduce power consumption so that the duration of use of the tool can be prolonged.