Electrochemical detection of protein by using magnetic graphene-based target enrichment and copper nanoparticles-assisted signal amplification

Abstract

In this paper, we propose a new method for protein detection by making use of magnetic graphene for enrichment and separation of the targets and duplex DNA-templated copper nanoparticles for amplification of electrochemical signals. Because the binding of the target protein (e.g. folate receptor) and small molecule (e.g. folate) can protect complementary DNA (cDNA) from exonuclease III-catalyzed degradation, duplex DNA from the hybridization of probe DNA and cDNA can act as the template for the formation of copper nanoparticles (CuNPs). Afterward, CuNPs-coated DNA can be enriched on the surface of magnetic graphene through the 3'-overhanging end of probe DNA, and then separated from the reaction mixture with the aid of magnet. As a result, copper ions released from acid-dissolution of CuNPs can catalyze the oxidation of o-phenylenediamine (OPD) by dissolved oxygen, resulting in an amplified electrochemical response. Our method can sensitively detect target protein over a wide linear range and with a low detection limit of 7.8 pg mL(-1), which can easily distinguish the targets even in complex serum samples. Therefore, this method may be promising for the clinical diagnosis of protein biomarkers by changing the recognition elements in the future.

Rapid and ultrasensitive detection of microRNA by target-assisted isothermal exponential amplification coupled with poly (thymine)-templated fluorescent copper nanoparticles

“…Also, they exhibit excellent non-toxicity and biocompatibility, which can meet the criteria to be applied in the various bioassays [28,29]. Considering these advantages, poly (thymine)-templated fluorescent CuNPs have been utilized as a promising fluorescent nanoprobe in various bioassays [30][31][32][33][34][35][36]. In this work, we developed a rapid and ultrasensitive method to detect target miRNA with combining the advantages of both TAIEA and fluorescent CuNPs.…”

Functional Magnetic Graphene Composites for Biosensing

“…Moreover, numerous toxins and pesticides could also cause severe environmental and safety issues. By using acetylcholinesterase (AChE) magnetic graphene nanocomposites (Fe 3 O 4 /GO/AChE MNCs), Liang et al fabricated a replaceable on-chip enzymatic microreactor for electrochemical detection of dimethoate [55]. As shown in Figure 2, Fe 3 O 4 /GO/AChE MNCs could be flushed out easily and quickly based on magnetic separation properties of the composites.…”

Sequence-Independent DNA Adsorption on Few-Layered Oxygen-Functionalized Graphene Electrodes: An Electrochemical Study for Biosensing Application

“…Graphene comprises a single layer of graphite in which carbon atoms arrange themselves in a 2D hexagonal lattice with metal-like charge carrier properties [1,2]. The interfacial properties of graphene interface, e.g., charge transport, can be easily and sensitively modulated by interactions with biomolecules [3][4][5], Therefore, single and multilayered graphene and its derivatives (i.e., graphene oxide and reduced graphene) have been widely exploited as sensing platforms to detect DNA [6][7][8], proteins [9][10][11][12], and small molecules [13] using a variety of detection methods including optical [6,13], scanning probe [10], electrical [7,8], and electrochemical techniques [9,11,12].…”