Chemical Research in Chinese Universities

Themed Issue on DNA Nanotechnology

FAN Chunhai

2020, 36(2): 0-0. doi:10.1007/s40242-020-1000-7

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Evolution of Artificial Base Pairs with Hydrogen Bond Complementarity

TIAN Jinmiao, CHEN Sikai, WANG Xiang, LI Juan

2020, 36(2): 151-156. doi:10.1007/s40242-019-0024-3

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Artificial base pairs, from the perspective of synthetic biology, are designed to contain the features of modularity, orthogonality, and manipulability. And the development of artificial base pairs has been endowed with responsibility to understand the biological process, improve the recognition capacity and stability of aptamers, and develop the nucleoside drugs, diagnosis, and drug delivery. In this review, we first gave a concise introduction of artificial base pairs based on their interaction modes including alternative hydrogen bonding, hydrophobic interaction, and metal coordination. Then we displayed the detailed information of artificial base pairs with hydrogen bonding interaction, and analyzed how the changes of their structures affect their functions. Subsequently, we highlighted the applications of functional artificial base pairs in aptamer discovery, diagnosis, and drug delivery. Finally, an insight into the remaining challenges and future perspective of the artificial bases was provided.

CRISPR-Cas System for RNA Detection and Imaging

CHEN Siyu, WANG Rujia, LEI Chunyang, NIE Zhou

2020, 36(2): 157-163. doi:10.1007/s40242-019-0030-5

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The system of clustered regularly interspaced short palindromic repeats(CRISPR) and CRISPR-associated endonucleases(Cas) have been widely used in gene editing, disease treatment, molecular diagnosis and chromosome imaging. On account of the programmable target recognition of CRISPR-Cas system and the specific targeting function toward RNA of type VI class II Cas proteins, CRISPR-Cas system has been deployed as RNA recognition and detection tools, exhibiting promising application potentials in the field of RNA detection and imaging. In this review, we summarize the latest research progresses as well as development prospects of CRISPR-Cas system in RNA diagnosis and live cell RNA imaging.

Artificial Nucleotide-containing Aptamers Used in Tumor Therapy

QIN Xinyuan, SU Yuanye, TAN Jie, YUAN Quan

2020, 36(2): 164-170. doi:10.1007/s40242-019-0033-2

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The high pharmaceutical cost and multi-drug resistance in tumor therapeutic agents hinder the further application of chemotherapy in tumor therapy. Artificial modified nucleic acid aptamers have the advantages of high binding affinity, programmability, and easy synthesis. Thus, the rational design of artificial modified aptamers is expected to provide a versatile platform for the optimization of chemotherapy agents. In this review, we summarize the modification strategies and the application of the artificial modified nucleotide-containing aptamers, aiming to provide a promising step toward aptamer-related chemotherapeutic agents.

Shape-controllable Synthesis of Functional Nanomaterials on DNA Templates

ZHU Jinjin, SHANG Yingxu, YU Haiyin, LI Na, DING Baoquan

2020, 36(2): 171-176. doi:10.1007/s40242-020-9035-3

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DNA nanotechnology enables precise organization of nanoscale objects with extraordinarily structural programmability. Self-assembled DNA nanostructures possess a lot of interesting features, such as designable size and shape, and structural addressability at nanometer scale. Taking advantage of these properties, DNA nanostructures could work as templates or molds for the controllable synthesis of functional nanomaterials, such as organic macromolecules, metallic or inorganic nonmetallic nanomaterials. In this review, we summarize the recent progress in the shape-controllable synthesis of functional nanomaterials on DNA templates. The potential application fields of these nanomaterials are also discussed.

DNA Nanostructures as Drug Carriers for Cellular Delivery

WU Na, ZHAO Yongxi

2020, 36(2): 177-184. doi:10.1007/s40242-020-9070-0

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Drug delivery systems have been widely developed for enhancing target activity and improving drug functions. Liposomes, high-molecular polymer, gold nanoparticles and carbon nanomaterials, etc., are all the candidates of drug carriers. However, immunotoxicity, heterogeneity and low solubility generally exist and hamper their applications. As a kind of biological materials, DNA has its unique advantages in biomedical applications, including excellent biological compatibility and programmability. DNA nanostructures have been proved to possess high cellular uptake efficiency, which sheds new light on DNA-based drug delivery system. In this review, we summarize the influence factors of DNA nanostructure internalization efficiency, including cell lines, and the size and the shape of DNA nanoparticles. Uniformity of DNA nanostructures in appearance and properties ensures the stability in research, which makes DNA carriers stand out from other nanomaterials. Next, we focus on the functionalization of DNA carriers, which endows DNA nanostructures with the potential to construct integrated drug delivery platforms. We also discuss the internalization pathways of DNA nanostructures and their fate in cells. The deeply understanding about the endocytic pathways provides new sight for the further design strategy on changing the transportation routes of DNA carriers in cells. Finally, the challenges in further applications are discussed, and suggestions are proposed.

Nucleic Acid Nanoprobes for Biosensor Development in Complex Matrices

DENG Mengying, LI Min, MAO Xiuhai, LI Fan, ZUO Xiaolei

2020, 36(2): 185-193. doi:10.1007/s40242-020-9073-x

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Nucleic acid probes in living organisms play an essential role in therapeutics and diagnosis. Through the imaging and sensing of nucleic acid probes in complex biological matrices, a variety of diseases-related biological process, pathogenic process, or pharmacological responses to a therapeutic intervention have been discovered. How-ever, a critical challenge of nucleic acid probes applied in complex matrices lies in enhancing the stability of nucleic acid probes, especially when it suffers from nuclease degradation and protein adsorption. In order to enhance the application of nucleic acid nanoprobes in complex matrices, great efforts have been devoted to improving the stability of probes operated in complex media, including construction of nucleic acid nanoprobes with nuclease resistance and protein adsorption resistance, sample pretreatment, anti-biofouling and signal correction. In this review, we aim to summarize recent advances in the stability of nucleic acid nanoprobes in complex matrices, including the methods of enhancing the stability of probes or signals, and the application of nucleic acid nanoprobes for disease diagnosis.

Fluorescence Signal Amplification Strategies Based on DNA Nanotechnology for miRNA Detection

LI Tao, DUAN Ruilin, DUAN Zhijuan, HUANG Fujian, XIA Fan

2020, 36(2): 194-202. doi:10.1007/s40242-019-0031-4

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In this review, the most recent progresses in the field of fluorescence signal amplification strategies based on DNA nanotechnology for miRNA are summarized. The types of signal amplification are given and the principles of amplification strategies are explained, including rolling circle amplification(RCA), catalytic hairpin assembly (CHA), hybridization chain reaction(HCR) and DNA walker. Subsequently, the application of these signal amplification methods in biosensing and bioimaging are covered and described. Finally, the challenges and the outlook of fluorescence signal amplification methods for miRNA detection are briefly commented.

DNA Nanotechnology on Live Cell Membranes

YANG Linlin, MIAO Yanyan, HAN Da

2020, 36(2): 203-210. doi:10.1007/s40242-020-9036-2

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Recent developments in DNA nanotechnology have brought various nanoscale structures, devices and functional systems for different applications. As biological barriers with significant functions, cell membranes provide direct interfaces for studying cellular environment and states. So far, DNA nanotechnology engineered on live cell membranes has advanced our fundamental understandings of DNA nanomaterials and facilitated the designs of novel sensing, imaging and therapeutic platforms. In this review, we highlighted strategies and outcomes of using DNA nanotechnology on cell membranes towards various biomedical applications, including biosensing, imaging, cellular function regulations and targeted cancer therapy. Furthermore, we also discussed the challenges and opportunities of DNA nanotechnology on cell membranes towards broader applications.

Programmable Assembly of DNA-protein Hybrid Structures

LI Xue, YANG Donglei, SHEN Luyao, XU Fan, WANG Pengfei

2020, 36(2): 211-218. doi:10.1007/s40242-019-0038-x

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DNA is the genetic information carrier for most known living organisms on Earth, while proteins are the functional component that carry out most biological processes. Many natural machineries are DNA-protein hybrid complexes to cooperatively and efficiently conduct sophisticated biological tasks. It has drawn increasing interest to the research field to construct artificial DNA-protein hybrid structures towards a variety of applications including biological studies, nanofabrication, biomedical research, etc. In this regard, here in this report we reviewed the up-to-date progress on making DNA-protein hybrid structures, with a particular focus on DNA nanotechnology-enabled programmable assembly of DNA-protein hybrid structures.

DNA Nanotechnology-based Biocomputing

YIN Jue, WANG Junke, NIU Renjie, REN Shaokang, WANG Dexu, CHAO Jie

2020, 36(2): 219-226. doi:10.1007/s40242-020-9086-5

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With silicon-based microelectronic technology pushed to its limit, scientists hunt to exploit biomolecules to power the bio-computer as substitutes. As a typical biomolecule, DNA now has been employed as a tool to create computing systems because of its superior parallel computing ability and outstanding data storage capability. How-ever, the key challenges in this area lie in the human intervention during the computation process and the lack of platforms for central processor. DNA nanotechnology has created hundreds of complex and hierarchical DNA nanostructures with highly controllable motions by exploiting the unparalleled self-recognition properties of DNA molecule. These DNA nanostructures can provide platforms for central processor and reduce the human intervention during the computation process, which can offer unprecedented opportunities for biocomputing. In this review, recent advances in DNA nanotechnology are briefly summarized and the newly emerging concept of biocomputing with DNA nanostructures is introduced.

Characterization of 3D DNA Assemblies Using Cryogenic Electron Microscopy

WANG Mingyang, DUAN Jialin, DAI Lizhi, XIN Xiaodong, WANG Fangfang, LI Zheng, TIAN Ye

2020, 36(2): 227-236. doi:10.1007/s40242-020-9107-4

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DNA nanotechnology utilizes DNA double strands as building units for self-assembly of DNA nanostructures. The specific base-pairing interaction between DNA molecules is the basis of these assemblies. After decades of development, this technology has been able to construct complex and programmable structures. With the increase in delicate nature and complexity of the synthesized nanostructures, a characterization technology that can observe these structures in three dimensions has become necessary, and developing such a technology is considerably challenging. DNA assemblies have been studied using different characterization methods including atomic force microscopy (AFM), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). However, the three-dimensional(3D) DNA assemblies always collapse locally due to the dehydration during the drying process. Cryogenic electron microscopy(cryo-EM) can overcome the challenge by maintaining three-dimensional morphologies of the cryogenic samples and reconstruct the 3D models from cryogenic samples accordingly by collecting thousands of two-dimensional(2D) projection images, which can restore their original morphologies in solution. Here, we have reviewed several typical cases of 3D DNA-assemblies and highlighted the applications of cryo-EM in characterization of these assemblies. By comparing with some other characterization methods, we have shown how cryo-EM promoted the development of structural characterization in the field of DNA nanotechnology.

Conjugated Polymer Nanomaterials for Phototherapy of Cancer

FU Xuancheng, BAI Haotian, LYU Fengting, LIU Libing, WANG Shu

2020, 36(2): 237-242. doi:10.1007/s40242-020-0012-7

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Due to the excellent properties including high specificity, low side-effect and good biocompatibility, conjugated polymer nanomaterials have been served as efficient anticancer reagents in the past decades. According to the developed anticancer systems based on conjugated polymer nanomaterials, it could be summarized into three main cancer therapy strategies:photodynamic therapy(PDT), photothermal therapy(PTT) and combination therapy. In this mini review, we provide a brief introduction to three different cancer therapy modes, their mechanisms and potential biological applications. Furthermore, some perspectives on the further development of conjugated polymer nanomaterials are proposed in the territory of anticancer precision medicine.

Construction of pH-Triggered DNA Hydrogels Based on Hybridization Chain Reactions

LI Yujie, CHEN Jie, DONG Yuanchen, LIU Huajie, LIU Dongsheng

2020, 36(2): 243-246. doi:10.1007/s40242-019-0034-1

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As a novel type of bio-functional material, DNA hydrogels have attracted more and more attention due to their successful applications in 3D cell culturing and tissue engineering for the designable and programmable responsiveness. Herein, we have developed a pH-triggered DNA hydrogel based on a clamped hybridization chain reaction(C-HCR). In this system, a DNA switch was designed, which can release the initiator strand in a controllable way via the formation of the C-G·C⁺ triplex under the pH stimuli. While the pre-gelation solution is stable in neutral environment, the C-HCR will trigger the sol-gel transition as the pH decreased to 5.0. This strategy has endowed the DNA hydrogel with good controllability for triggering, which also shows potential in intellectual responsiveness to certain stimuli.

Effects of Molecular Crowding on G-Quadruplex-hemin Mediated Peroxidase Activity

LIU Lu, LIN Jingfang, SONG Yanling, YANG Chaoyong, ZHU Zhi

2020, 36(2): 247-253. doi:10.1007/s40242-020-0018-1

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The concentration of macromolecules in cells can reach up to 50-400 mg/mL. They occupy 40%(volume fraction) of the whole cellar space, known as molecular crowding. The diluted solution condition in vitro is different from the crowded physiological condition in vivo. Therefore, the simulation of the physiological condition is necessary for obtaining the reliable results. It has been reported that G-quadruplex can bind to hemin to enhance its catalytic function for generating oxygen radicals, which can oxidize the lipids, proteins and DNA, thus leading to the damage of cells and tissues. In this paper, we chose PEG400 as molecular crowding reagent to simulate the molecular crowding environment in vivo. The catalytic characteristics of G-quadruplex-hemin complex in H₂O₂-ABTS system have been investigated[ABTS=2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)]. The results showed that the binding affinity of G-quadruplex and hemin was decreased with the increasing of PEG400 concentration. They even lose their binding affinity in the presence of 40% PEG400. As a result, the peroxidase activity of G-quadruplex-hemin also reduced. Therefore, in physiological condition, hemin might not bind to G-quadruplex and it might not be the main reason to cause the damages of cells and tissues.

Multivalent Aptamer-modified DNA Origami as Drug Delivery System for Targeted Cancer Therapy

CAO Mengyao, SUN Yueyang, XIAO Mingshu, LI Li, LIU Xiaohui, JIN Hong, PEI Hao

2020, 36(2): 254-260. doi:10.1007/s40242-019-9273-4

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In spite of great development in nanoparticle-based drug delivery systems(DDSs) for improved therapeutic efficacy, it remains challenging for effective delivery of chemotherapeutic drugs to targeted tumor cells. In this work, we report a triangle DNA origami as targeted DDS for cancer therapy. DNA origami shows excellent biocompatibility and stability in cell culture medium for 24 h. In addition, the DNA origami structures conjugated with multivalent aptamers enable for efficient delivery of anticancer drug doxorubicin(Dox) into targeted cancer cell due to their targeting function, reducing side effects associated with nonspecific distribution. Moreover, we also demonstrated that the multivalent aptamer-modified DNA origami loading Dox exhibits prominent therapeutic efficacy in vitro. Accordingly, this work provides a good paradigm for the development of DNA origami nanostructure-based targeted DDS for cancer therapy.

A Triode-like Enzyme-free Catalytic Circuit with Junction Fuel

LUO Tao, WANG Xiaojing, FAN Sisi, LIU Yan, CHENG Jin, TANG Linlin, SONG Jie

2020, 36(2): 261-267. doi:10.1007/s40242-019-0025-2

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Target detection circuits have been previously designed, which are propelled by conventional PCR, isothermal amplification and strand-displacement reaction. These detection circuits obtain the target signal via the replication of the target strand, the aggregation of the signal particles or the branch migration. Here we constructed a triode-like enzyme-free catalyst strand-displacement circuit for target DNA detection. The target strand triggered the reaction and released the fluorescence signal strand circularly through branch migration. However, the main challenge of strand-displacement reaction is the signal leakage. Therefore, we designed a double strand structure "junction fuel", which was used to increase the binding energy across the displacement process. Ultimately, the leakage of the system obtained stable inhabitation due to the junction fuel strand. The limit of detection of the system was as low as 0.11 nmol/L and the gain of the system was as high as 28-fold(the concentration of target was 50 nmol/L). Furthermore, the process of the system was visualized vividly in the reaction curve through the kinetic simulation implemented, which suggests that the combination of the kinetic simulation and the experiment exhibits a promising prospect towards the use of strand-displacement circuit in analytical, diagnostic application and synthetic biology.

Self-assembly of DNA Nanostructures via Bioinspired Metal Ion Coordination

WANG Congli, DI Zhenghan, FAN Zetan, LI Lele

2020, 36(2): 268-273. doi:10.1007/s40242-019-0028-z

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Despite a growing interest in DNA nanomaterials, their simple synthesis remains a challenge. A simple and general strategy for constructing DNA-based nanomaterials by metal ion coordination is reported. The metal-DNA nanoparticles(NPs) could be synthesized with DNA molecules of diverse sequence and various metal ions of intrinsic property, resulting in multifunctional NPs with the combined advantages of both inorganic and DNA building blocks. It is demonstrated that the hybrid metal-DNA NPs could be engineered for magnetic resonance and luminescence imaging, encapsulation of multifarious nucleic acids with controlled ratio, and co-assembly with small drug molecules. Furthermore, because these metal-DNA NPs exhibited enhanced cellular uptake compared to free synthetic DNA, they hold potential for applications in diagnostics and therapeutics.

Engineering a Floxuridine-integrated RNA Prism as Precise Nanomedicine for Drug Delivery

PAN Gaifang, MA Yuan, ZHANG Jiao, GUO Yuanyuan, DING Fei, GE Huan, LI Qifeng, ZHU Xinyuan, ZHANG Chuan

2020, 36(2): 274-280. doi:10.1007/s40242-019-0049-7

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Herein, we report a geometrically well-defined prism assembled by two floxuridine(F) integrated RNA strands as a precise nanomedicine for chemodrug delivery. Owing to the similarity between chemotherapeutic F and uridine(U), all uridines in the component RNA strands are replaced by F during their in vitro transcription syntheses. By specifically designing their sequences, F-containing S-shape tiles with the single-stranded loops are constructed and then further assemble into the RNA prism through T-junction interactions and sticky-end cohesions. The present study demonstrates that the F-integrated RNA prism can serve as an efficient platform for chemodrug delivery and anticancer treatment. We believe that the study would help the future development of RNA-based nanomedicine in various applications.

Increasing the Solubility of a Hydrophobic Molecule with Thymine-like Face by DNA via Supramolecular Interaction

SHI Peijun, ZHANG Zhe, LIU Mingchun, SUN Teng, HE Xiaoyan, MAO Chengde, FANG Liang, ZUO Hua

2020, 36(2): 281-284. doi:10.1007/s40242-020-9063-z

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Poor water-solubility of hydrophobic drugs greatly hampers drug design and creats delivery problems. The traditional way to improve the solubility is to add hydrotropes or excipients to supress aggregations. Here, a novel mechanisim has been proposed based on supramolecular interactions and demonstrated with a small molecule, pyromellitic diimide(PD). This compound contains thymine-like ‘face’ and can interact with adenines through Watson-Crick and Hoogsteen hydrogen-bonding. Given the high water solubility of polyadenines[poly(A)], it is expected that poly(A) will greatly increase the PD solubility. Indeed, such an increased solubility was confirmed by ultraviolet-visible spectroscopy(UV-Vis) and polyacrylamide gel electrophoresis(PAGE) analysis. We believe that this strategy could be used to improve the solubility of other similar hydrophobic molecules.

pH-Responsive Reversible DNA Self-assembly Mediated by Zwitterion

DONG Yuhang, PAN Xiaorui, LI Feng, YANG Dayong

2020, 36(2): 285-290. doi:10.1007/s40242-020-9067-8

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pH-Responsive DNA assembles have drawn growing attentions owing to their great potential in diverse areas. However, pH-responsive motifs are limited to specific DNA sequences and annealing is usually needed for DNA assemblies; therefore, sequence-independent pH-responsive DNA assembly at room temperature is highly desired as a more general way. Here, we propose a reversible pH-responsive DNA assembly strategy at room-temperature using zwitterion, glycine betaine(GB), as charge-regulation molecules. The reversible assembly and disassembly of DNA nanostructures could be achieved by alternatively regulating the acidic and basic environments in the presence of GB, respectively. In an acidic environment, carboxylate group in GB was protonated and GB was positively charged, which facilitated to shield the inherent electrostatic repulsion of DNA strands. Molecular simulation showed that the newly formed carboxyl group in protonated GB could form hydrogen bonds with bases in DNA to promote the assembly of DNA strands. In a basic solution, carboxylate group in GB was deprotonated and GB was neutral, thus inducing the dissociation of DNA assembly.

Handheld Aptasensor for Sandwiched Detection of Chloramphenicol

YU Mintong, XIA Tian, BAI Wanchen, JI jinyu, WANG Huan, HUANG Yaqi, DENG Shengyuan, MA Kefeng, SU Yan, WAN Ying

2020, 36(2): 291-295. doi:10.1007/s40242-020-9076-7

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Chloramphenicol(CAP) is an antifungal agent approved for use in aquarium. However, CAP residue imparts serious adverse effect on human health as well as the ecology. Thus, keeping track of CAP in aquatic products and its environmental metabolites are of great importance. Herein, we developed a novel and neat electrochemical aptasensor for the detection of simulated CAP residual in a sandwich fashion. The screen-printed carbon electrode was employed as the sensing platform and electrodeposited with peculiar nanogolds to enhance the electrochemical performance. For the specific recognition of such small target, a pair of chloramphenicol-binding aptamers, the primary Apt1 and the secondary Apt2, were tailored as an artificial single-chained antibody couple, of which the thiolated Apt1 stood on the coated working substrate to capture the analyte, while the biotinylated Apt2 rallied the signal output. In the presence of CAP, Apt1 at the lower place cooperated with the upper Apt2 pinched CAP together. After that, the reporter avidin-conjugated horseradish peroxidase associated atop the mounted biotin labels, resulting in an electrocatalytic amplification. In whole, this modular biosensing construction would set a paradigm not just for practicable checkpoint quarantine or point-of-care testing, but potentially adaptable for technological fusion with "Internet Plus" and "Internet of Things".

Reconfigurable Plasmonic Nanostructures Controlled by DNA Origami

LONG Qipeng, YU Hanyang, LI Zhe

2020, 36(2): 296-300. doi:10.1007/s40242-020-9078-5

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Precise surface functionalization and reconfigurable capability of nanomaterials are essential to construct complex nanostructures with specific functions. Here we show the assembly of a reconfigurable plasmonic nanostructure, which executes both conformational and plasmonic changes in response to DNA strands. In this work, different sized gold nanoparticles(AuNPs) were arranged site-specifically on the surface of a DNA origami clamp nanostructure. The opening and closing of the DNA origami clamp could be precisely controlled by a series of strand displacement reactions. Therefore, the patterns of these AuNPs could be switched between two different configurations. The observed plasmon band shift indicates the change of the plasmonic interactions among the assembled AuNPs. Our study achieves the construction of reconfigurable nanomaterials with tunable plasmonic interactions, and will enrich the toolbox of DNA-based functional nanomachinery.

Programmable and Reversible Regulation of Catalytic Hemin@MOFs Activities with DNA Structures

LIU Shuo, YANG Mingjie, GUO Weiwei

2020, 36(2): 301-306. doi:10.1007/s40242-020-0110-6

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Metal-organic frameworks(MOFs)-based nanozyme plays an important role in biosensing, therapy and catalysis. In this study, the effects of single-stranded DNA(ssDNA) with programmable sequences and its complementary DNA(T_DNA) on the intrinsic peroxidase-like activity of hemin loaded MOFs(UiO-66-NH₂), denoted as hemin@UiO-66-NH₂, were investigated. The hemin@UiO-66-NH₂ exhibited improved catalytic activity compared with free hemin. However, the catalytic activity is inhibited in the presence of ssDNA, as ssDNA can be adsorbed by MOFs and therefore protected the active sites from contact with substrates. Upon the addition of the T_DNA, double-stranded DNA(dsDNA) was formed and detached from the MOFs, resulting in the recovery of catalytic activity. Sequentially adding ssDNA or its complementary DNA strands can achieve the reversible regulation of the catalytic activity of MOFs nanozymes. Moreover, the DNA hybridization-based regulation was further applied to a cascaded catalytic system composed of the nanozyme, hemin@UiO-66-NH₂, and glucose oxidase. These nanozyme based programmable and reversibly regulated catalytic systems may have potential applications in future smart biosensing and catalysis systems.

Ultrasensitive Detection of Hepatitis C Virus DNA Subtypes Based on Cucurbituril and Graphene Oxide Nano-composite

JIANG Ping, LI Yifei, JU Ting, CHENG Wenbo, XU Jianhua, HAN Kun

2020, 36(2): 307-312. doi:10.1007/s40242-020-9111-8

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Infectious of hepatitis C viruses(HCVs) lead to hepatic fibrosis, cirrhosis even hepatoma. Developing rapid and sensitive diagnostic method for HCV is of great importance. Based on the host-and-guest interaction between cucurbit[7]uril(CB[7]) and methylene blue(MB), a CB[7]-graphene nano-composite(CB[7]-N₃-GO) is raised for the electrochemical detection of HCV DNA. The method is able to linearly detect the HCV nucleic acid in the range of 0.2-10 nmol/L with detection limit as low as 160.4 pmol/L. The proposed detection strategy is able to discriminate the 1b and 6k subtypes of HCV and has a prospective potential in the blood screen for HCV in clinical diagnosis.

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