Hybridization Chain Reaction-Based Electrochemical Biosensors by Integrating the Advantages of Homogeneous Reaction and Heterogeneous Detection

Abstract

The conventional hybridization chain reaction (HCR)-based electrochemical biosensors usually require the immobilization of probes on the electrode surface. This will limit the applications of biosensors due to the shortcomings of complex immobilization processes and low HCR efficiency. In this work, we proposed astrategy for the design of HCR-based electrochemical biosensors by integrating the advantages of homogeneous reaction and heterogeneous detection. Specifically, the targets triggered the autonomous cross-opening and hybridization oftwobiotin-labeled hairpin probes to form long-nicked dsDNA polymers. The HCR products with many biotin tags were then captured by a streptavidin-covered electrode, thus allowing for the attachment of streptavidin-conjugated signal reporters through streptavidin–biotin interactions. By employing DNA and microRNA-21 as the model targets and glucose oxidase as the signal reporter, the analytical performances of the HCR-based electrochemical biosensors were investigated. The detection limits of this method were found to be 0.6 fM and 1 fM for DNA and microRNA-21, respectively. The proposed strategy exhibited good reliability for target analysis in serum and cellular lysates. The strategy can be used to develop various HCR-based biosensors for a wide range of applications because sequence-specific oligonucleotides exhibit high binding affinity to a series of targets. In light of the high stability and commercial availability of streptavidin-modified materials, the strategy can be used for the design of different biosensors by changing the signal reporter and/or the sequence of hairpin probes.

Structure-Function Studies of Glucose Oxidase in the Presence of Carbon Nanotubes and Bio-Graphene for the Development of Electrochemical Glucose Biosensors

“…These devices present several advantages such as high sensitivity, fast response, and low cost of production. Electrochemical glucose biosensors can be fabricated by homogeneous or heterogeneous methods, depending on whether a nanomaterial interferes between the electrode and the enzyme that acts as the signal molecule [ 3 , 4 ]. The development of homogenous biosensors is simple, inexpensive, and exploits the adsorptive capacity and binding ability of the reactants towards the electrode; these biosensors surpass steric hindrance and improve enzymatic efficiency.…”

“…The development of homogenous biosensors is simple, inexpensive, and exploits the adsorptive capacity and binding ability of the reactants towards the electrode; these biosensors surpass steric hindrance and improve enzymatic efficiency. On the contrary, the fabrication of heterogeneous biosensors relies on the modification of the electrode with nanomaterials and the subsequent attachment of the enzymes; this way, nanomaterials serve as an effective electron transport between the signal molecule and the electrode, which endows these biosensors with high sensitivity, stability, and multiplexed detection [ 3 , 5 ]. The materials involved in various biosensing architectures aim to provide a suitable microenvironment for the immobilized enzymes to retain their activity, as well as an increased electron transfer between the redox center of the immobilized enzymes or the electroactive species involved in the analysis (mediators, enzyme reaction products, etc.)…”