Screen Printed Carbon Electrodes Sensor for Viral DNA Isothermal Amplification Real-Time Measurement
Authors: Kim Hyo Eun , Schuck Ariadna , Kim Yong-Sang 
Published: July 2021

Recombinase polymerase amplification (RPA) is a gene amplification technology that amplifies template DNA with isothermal(37-42℃) using three core enzymes – a recombinase, a single-stranded DNA-binding protein (SSB) and strand-displacing polymerase. Recently RPA sensors with an electrical analysis function using an electrochemical measurement method have been reported. This RPA technique and electrical measurement method is suitable for low-cost, rapid, miniaturization and POC system development.
Amperometric detection is an electrochemical detection method with various advantages that make it suitable biosensors. Amperometric detection system can be easily integrated with the Screen-printed Carbon Electrodes (SPCEs) sensor without the need for complicated additional equipment for optical detection. For this reason, the size of the sensor can be reduced to microchip size, which makes it possible to use point-of-care due to low-cost disposable chips and potable equipment [1]. The optical method which the detection of the fluorescence intensity of the target sample is important. However, amperometric detection omits pretreatment process of the sample such as purification extraction of samples and fluorescent staining for detection [2]. These features allow the device system to be miniaturization and rapid detection for use in lab-on-a-chip or point-of-care applications [3].
Modified AuNP SPCEs is proposed for on-chip amperometric detection of RPA isothermal amplification for viral DNA. AuNPs were first electrodeposited on SPCEs. The AuNPs was carried out in 1.0 M NaNO3 solution containing 0.25 mM HAuCl4 using amperometric 0.70V for 10,100 and 500 seconds at the scans of 0.10 V·s−1. After electrodeposition, the AuNPs modified SPCEs were rinsed with water to remove the deposited materials.
The surface characterization of this the AuNP-modified SPCEs was shown in Fig. 1(a) using cyclic voltammetry measurement from -0.2V to 0.4V for 3 cycles at the scan rate of 0.10 V·s−1. It was observed that the AuNP was deposited on SPCEs by amplified redox peak.
Fig.1. Measurements of the CV of the different printed sensors: (a) Stability of SPCEs; (b) After electrodeposition.

References

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Figure 1