Development of an Internet of Things Based Electrochemical Microfluidic System for Free Calcium Detection

Abstract

This paper represents the design, fabrication, and implementation of an Internet of Things (IoT)-based electrochemical microfluidic system for free calcium concentration detection with a 3D printing technique. Free calcium solutions with desired concentrations between 0 and 40 µM can be obtained. The solutions were used to calibrate the system by using an impedance analyzer for monitoring the impedance change to determine the operating frequency. Continuously, an IoT enabled point of care device was used for real-time detection and to send signals to the cloud for sharing. The relationship between the concentration and reactance are y = −1.3812Lgx + 0.9809 at a wavelength of 450 Hz, with an R 2 of 0.9719. We measured the calcium concentration changing from 39.8 µM to 1.35 µM (nearly real-time) by the PoC device and showed the concentration changes resulting with time on the cell phone app. The results depicted in this paper provide a strong platform for the precise and real-time monitoring of different biomedical samples. Appl. Sci. 2018, 8, 1357 2 of 15 and sophisticated laboratory systems into friendly home-use devices [15][16][17]. Different applications had been achieved, especially in the fields of clinical diagnostic and environmental monitoring. This is because of their low cost, ease of use, reliability, and portability [18][19][20][21][22][23][24]. Moreover, some PoC devices can carry out real time testing which can produce results rapidly. By this way, patient-care can be improved with less costs and treatment can start more quickly [25,26].Wireless transmissions and cloud servers enable transferring and sharing the measured data while being connected with the monitored patient, which enhances the functionalities of the sensing systems [27,28]. It is powered by the Internet of Things (IoT) concept, where all the connected objects that surround us can exchange data over a network. IoT-enabled smart devices and health services can reduce the diagnostic cost, provide real-time information to the house physician, and provide important health information without any mobility of the patient, therefore increasing their quality of life and the efficiency [26,29].In this paper, we devised the use of silicon-based sensors integrated into the microfluidics system with 3D printing. IoT techniques were used to store and transmit the data to end-users. One of the prominent biomedical applications was where free calcium iron solutions were measured in different concentrations. Commercial calcium buffer solutions were used to calibrate the system. The determination of free calcium is very important in human and veterinary pathology and in dairy chemistry [30][31][32].

Design Configuration of Water Quality Monitoring System in Surabaya

“…Water usages and leaking monitoring was necessary to be monitored for ensuring the high-quality water was well distributed [23,24]. As for fluid level and viscosity, it was not considered for water quality monitoring as its application was for chemical solution in medical andindustrial application [6,7,14].…”

“…Therefore, the IoT methodology was the most prominent method to be implemented [26]. That was because it could realize an integrated water quality monitoring by combining many kinds of respective sensor, thus build a sensor network to collect data for assessing the water quality in real time [14]. The IoT also provided a remote-online monitoring, therefore the monitoring could take place in a remote area such as in a catchment area [27].…”

“…However, the main concern of liquid in that area was not the tap water, but another liquid such as chemical solution which directly contribute to the area. For instance, in medical environment, the IV content monitoring in a saline bag [6] and chemical content such as calcium threshold in a solution which unnecessary for medicine [14]. On the other hand, the viscosity of an oil is necessary to be monitored in industrial environment because the oil was used regularly for the machinery [7].…”

“…The mineral content in a solution was monitored because there might be some toxic mineral or unwanted mineral included. The solution which was contaminated with unnecessary mineral might not suitable for patient's consumption [14]. On the other hand, the viscosity of an oil was monitored to ensure the industrial machine could work optimally by using the monitored oil as a grease [7].…”

Fabrication and Analysis of Polydimethylsiloxane (PDMS) Microchannels for Biomedical Application

“…Diverse parameters of microfluidic devices like fluid flow time, temperature, flow rate, flow velocity, pressure drop, density and viscosity can be monitored and examined using IoT devices. These devices can be used potentially for analysis and detection for specific applications [1][2][3][4]. The schematic of IoT controlled microfluidic system is shown in Figure 1.…”