A multi‐functional electrochemical sensing system using microfluidic technology for the detection of urea and creatinine

Abstract

This study presents a new microfluidic system capable of precise measurements of two important biomarkers, urea and creatinine, automatically. In clinical applications, high levels of these two biomarkers are early indicators of nephropathy or renal failure and should be monitored on a regular basis. The microfluidic system is composed of a microfluidic chip, a control circuit system, a compressed air source and several electromagnetic valves to form a handheld system. The microfluidic chip is fabricated by using micro-electromechanical systems and microfluidic techniques comprising electrochemical sensor arrays and polydimethylsiloxane-based microfluidic structures such as micropumps/micromixers, normally closed valves and microchannels. The microfluidic system performs a variety of critical processes including sample pretreatment, mixing, transportation and detection on a single chip. The experimental results show that the entire procedure takes approximately 40 min, which is much faster than the traditional method (more than 6 h). Furthermore, the total sample volume consumed in each operation is only 0.1 mL, which is significantly less than that required in a large system (5 mL). The developed automatic microfluidic system may provide a powerful platform for further clinical applications.

A Novel Potentiometric Sensor for Determination of Neurotoxinβ-N-Oxalyl-L-α,β-Diaminopropionic Acid

“…The ODAP-selective membrane sensor reached a steady-state rapidly (Table 1), and its detection limit was 1.15 × 10 −6  mol L −1 which is better than those in the literature [28, 30], as the lowest limit in the linear range was 8.0 × 10 −6  mol L −1 . The ODAP-selective membrane sensor presented in this work also exhibited a short response time less than 6 s better than those in the studies [28, 31], wider working concentration ranges 1.0 × 10 −1 to 8.0 × 10 −6  mol L −1 , and unfortunately short life span when compared to those of the sensors in other studies [29, 32, 33]. …”

A Portable Low-Power Acquisition System with a Urease Bioelectrochemical Sensor for Potentiometric Detection of Urea Concentrations

“…A comparison of the sensing performance for the present work and our previous work is listed in Table 3 . With an injection volume of 10 μL to a working volume of 50 μL whole serum, the linear calibration had a sensitivity of 1.59 ± 0.47 mV/log [M] for serum urea concentration, which was similar to [ 47 ]. The experimental results of the integrated device and sensor are summarized in Table 4 , while Table 5 compares the differences between the system proposed in the present work and the design described by Wang et al [ 40 ].…”

“…Moreover, the results confirm the successful measurement of urea concentrations by this portable device. We further compared the sensing results in this work with our previous work [ 47 ]. The major differences are listed as follows.…”

Microfluidic enzymatic biosensing systems: A review

“…Monomer solutions like 3,4-ethylenedioxythiophene (Nien et al, 2011), aniline and o-phenylenediamine (Cheng et al, 2006;Huang et al, 2011) or pyrrol (Blanco-Gomez et al, 2009;Huang et al, 2007) are mixed with an enzyme solution and brought into contact with the electrodes. By applying a constant current or a cyclic voltage sweep between the working and counter electrode for a few minutes, the monomer polymerizes on the electrode and entraps the enzyme.…”