A new coccolith modified electrode-based biosensor using a cognate pair of aptamers with sandwich-type binding
Introduction
To deliver the high quality of life for individuals by providing decentralized diagnostics, the development of robust, cost-effective, and miniaturized electrochemical biosensor is essential. Notably, the modification of the electrode surface with the advanced materials has been known to be one of many ways to fabricate a highly sensitive and selective biosensor (Sarma et al., 2009, Sekretaryova et al., 2016, Walcarius et al., 2013).
Recently, there is growing interest in using biominerals produced by unicellular algae, a kind of marine organisms. The intricate 3D structures and delicate patterns of biominerals from marine organisms are the prominent features for diverse applications (Davis et al., 2013, Kröger and Brunner, 2014). Such ready-made inorganic marine structures can be utilized as promising materials in biosensors, photonic device or microfluidics, owing to characteristically unique nanometer-sized pores and channels inside (Mizukawa et al., 2015, Shen et al., 2017, Yu et al., 2010). Furthermore, the difficulty of producing the similar hierarchical structure of minerals makes marine-derived biominerals more attractive for applications.
Among biominerals, coccolithophores (coccoliths) are highly-structured microparticles with a lot of nano-sized pores and consisted with CaCO3 have several advantages, such as large surface to volume ratio, mechanical properties, and thermal stability (Skeffington and Scheffel, 2018). However, the coccoliths had received less attention due to their undesired properties which originate from calcite, such as low electrical conductivity, dissolution at low pH, and little functional groups (Volodkin et al., 2004, Skeffington and Scheffel, 2018). These limitations, however, could be overcome by coating the surface with metal or organic materials like silica.
Aptamers are well-known bioreceptors that can bind to a broad range of targets with high affinity and specificity. The unique properties like the ease of modification, thermal stability, and low-cost make aptamers promising molecular probes for a biosensor (Kim et al., 2016, Seo and Gu, 2017a). Especially, a pair of aptamers, like antibody-based sandwich assay, can also easily be used in a sandwich-format which will, in turn, improve the analytical performance and the reliability of the biosensor. However, there have been few studies about the cognate aptamer duo-based sandwich-type assays or biosensors, except for thrombin (Jo et al., 2017, Zhang et al., 2015, Zhang et al., 2018).
Recently, our research group reported a few successful developments of the cognate pair of aptamers (Nguyen et al., 2016, Park et al., 2014), including a cognate pair of aptamers (V1 and V49 aptamers) that binds to two different epitopes of the target, Vaspin (Raston and Gu, 2015). In this study, we report the development of a sandwich-type electrochemical biosensor using a cognate pair of aptamers utilized on the coccolith modified electrodeposited screen-printed gold electrode (CME-SPGE) for the first time. The coccolith, which is the CaCO3 shell of the Emiliania huxleyi, was used, and the Vaspin, which is known to be a biomarker protein related to type 2 diabetes in human (Blüher, 2012, Heiker, 2014), was used as a model target in this study. The morphological characteristics of the resulting electrodes were tested by scanning electron microscope (SEM) and energy dispersive spectrometer (EDAX). The electrochemical properties of the resulting electrode and the analytical performance of the successfully developed sandwich-type electrochemical aptasensor were evaluated by using cyclic voltammetry and chronoamperometry. To the best of our knowledge, this is the first report on the fabrication of coccolith modified electrode and its application in a cognate pair of aptamers-based sandwich-type electrochemical biosensor.
Section snippets
Materials
Potassium chloride, 6-Mercapto-1-hexanol, Tris(2-carboxyethyl) phosphine hydrochloride, potassium hexacyanoferrate(Ⅲ), sodium chloride, sulfuric acid, Gold(Ⅲ) chloride trihydrate, potassium nitrate, 3,3′,5,5′-Tetramethylbenzidine dihydrochloride (TMB) were purchased from Sigma-Aldrich and used without any additional purification. Avidin-HRP was purchased from Thermo Scientific and diluted with 1xPBS. The Vaspin binding aptamers were synthesized from GenoTech Corp. (Daejeon, Korea) with the
Results and discussion
The Scheme 1 illustrates the entire process in the preparation of the coccolith modified electrodeposited on the screen-printed gold electrode (CME-SPGE) and the use of it as a cognate pair of aptamer-based sandwich-type electrochemical aptasensor for the type 2 diabetes biomarker, Vaspin.
Since the coccolith has low electrical conductivity and little functional groups, we have overcome this limitation by using the gold sputtering process and electrodeposition to fabricate the electrode with the
Conclusion
In conclusion, we have successfully developed a sandwich-type electrochemical biosensor using a cognate pair of aptamers on coccolith modified electrodeposited screen-printed gold electrode (CME-SPGE). The CME-SPGE was characterized by SEM, EDAX, and cyclic voltammetry. By using a cognate pair of aptamers on CME-SPGE, the sandwich-type electrochemical aptasensor for Vaspin was successfully developed with high specificity and good sensitivity with a limit of detection of 298 pM With the
Acknowledgments
This work was supported by the Basic Core Technology Development Program for the Oceans and the Polar Regions of the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT (2015M1A5A1037055), and by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP) (No. 2016R1A2B3011422), and by a Korea University Grant. Also, we would like to thank Mr. Cheulmin Joe for his help in preparing the coccolith modified electrodeposited electrode.
References (32)
- et al.
Biosens. Bioelectron.
(2015) - et al.
Biosens. Bioelectron.
(2014) - et al.
Talanta
(2017) - et al.
Sens. Actuators B: Chem.
(2012) - et al.
Biosens. Bioelectron.
(2016) - et al.
Biosens. Bioelectron.
(2014) - et al.
Anal. Chim. Acta
(2013) - et al.
Biosens. Bioelectron.
(2009) - et al.
Biotechnol. Adv.
(2016) - et al.
Curr. Opin. Biotechnol.
(2018)
Biosens. Bioelectron.
Talanta
Sens. Actuators B: Chem.
Endocrine
Adv. Funct. Mater.
Anal. Chem.
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2023, BioelectrochemistryCitation Excerpt :The cognate pair of aptamers, have been used in a sandwich-type format to improve the reliability and sensitivity of the aptasensor in a signal-on format [50]. For instance, Gu’s research group reported a few successful developments in interacting with pairs of aptamers for different targets, such as viruses or proteins, and demonstrated their successful implementation in various biosensor platforms [35,48,51–53]. The physicochemical properties of the electrode surface significantly affect the efficiency of the biosensor [54].