Hua Chai

Bio: Hua Chai is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Biosensor & DNA. The author has an hindex of 6, co-authored 12 publications receiving 141 citations. Previous affiliations of Hua Chai include University of Science and Technology of China.

Bipedal DNA Walker Based Electrochemical Genosensing Strategy.

Abstract: DNAs are one of the most fundamental molecules for life. Quantification of specific sequences is of great importance for biological research and clinical diagnosis. In order to determine extremely low abundant DNAs, we herein develop a novel electrochemical genosensor taking advantage of a smart bipedal DNA walking machine. Magnetic nanomaterials are first employed to enrich target DNA. Strand displacement amplification initiated by target DNA is then designed on the surface of the nanomaterials, the products of which can be used to trigger bipedal DNA walking on the surface of an electrode. Benefiting from triple amplification, ultrahigh sensitivity is achieved for electrochemical analysis of DNA. More importantly, the proposed strategy opens a new avenue for employing the bipedal DNA walker for sensitive detection of various biomolecules with signal amplification.

Recent Progress in DNA Hybridization Chain Reaction Strategies for Amplified Biosensing.

Abstract: With the continuous development of DNA nanotechnology, various spatial DNA structures and assembly techniques emerge. Hybridization chain reaction (HCR) is a typical example with exciting features and bright prospects in biosensing, which has been intensively investigated in the past decade. In this Spotlight on Applications, we summarize the assembly principles of conventional HCR and some novel forms of linear/nonlinear HCR. With advantages like great assembly kinetics, facile operation, and an enzyme-free and isothermal reaction, these strategies can be integrated with most mainstream reporters (e.g., fluorescence, electrochemistry, and colorimetry) for the ultrasensitive detection of abundant targets. Particularly, we select several representative studies to better illustrate the novel ideas and performances of HCR strategies. Theoretical and practical utilities are confirmed for a range of biosensing applications. In the end, a deep discussion is provided about the challenges and future tasks of this field.

DNA Hairpins and Dumbbell-Wheel Transitions Amplified Walking Nanomachine for Ultrasensitive Nucleic Acid Detection.

Abstract: Nucleic acids, including circulating tumor DNA (ctDNA), microRNA, and virus DNA/RNA, have been widely applied as potential disease biomarkers for early clinical diagnosis. In this study, we present a concept of DNA nanostructures transitions for the construction of DNA bipedal walking nanomachine, which integrates dual signal amplification for direct nucleic acid assay. DNA hairpins transition is developed to facilitate the generation of multiple target sequences; meanwhile, the subsequent DNA dumbbell-wheel transition is controlled to achieve the bipedal walker, which cleaves multiple tracks around electrode surface. Through combination of strand displacement reaction and digestion cycles, DNA monolayer at the electrode interface could be engineered and target-induced signal variation is realized. In addition, pH-assisted detachable intermolecular DNA triplex design is utilized for the regeneration of electrochemical biosensor. The high consistency between this work and standard quantitative polymerase chain reaction is validated. Moreover, the feasibilities of this biosensor to detect ctDNA and SARS-CoV-2 RNA in clinical samples are demonstrated with satisfactory accuracy and reliability. Therefore, the proposed approach has great potential applications for nucleic acid based clinical diagnostics.

DNA-Functionalized Porous Fe3O4 Nanoparticles for the Construction of Self-Powered miRNA Biosensor with Target Recycling Amplification.

Abstract: Herein, we have developed an ultrasensitive self-powered biosensor for miRNA assay based on biofuel cells. The system is composed of indium tin oxide cathode and graphene oxide/gold nanoparticle/glucose oxidase anode. Redox probe of [Fe(CN)6]3– is entrapped inside porous Fe3O4 nanoparticles by DNA. However, in the presence of target miRNA, hybridization reaction occurs between miRNA and DNA, which initiates the release of [Fe(CN)6]3–. Moreover, duplex specific nuclease is further employed to trigger target recycling amplification. As a result, much more redox probes are released and the open circuit voltage is significantly increased. A “signal-on” self-powered biosensor for miRNA quantification is thus developed. The detection range is from 10 aM to 10 fM; meanwhile, the limit of detection is as low as 1.4 aM, which is superior to that in most reported methods. Therefore, the proposed biosensor is expected to be a powerful point-of-care tool for miRNA diagnostics, which may have wide applications in the ...

Superparamagnetic nanoarchitectures for disease-specific biomarker detection

Abstract: The detection of clinically relevant disease-specific biomolecules, including nucleic acids, circulating tumor cells, proteins, antibodies, and extracellular vesicles, has been indispensable to understand their functions in disease diagnosis and prognosis. Therefore, a biosensor for the robust, ultrasensitive, and selective detection of these low-abundant biomolecules in body fluids (blood, urine, and saliva) is emerging in current clinical research. In recent years, nanomaterials, especially superparamagnetic nanomaterials, have played essential roles in biosensing due to their intrinsic magnetic, electrochemical, and optical properties. However, engineered multicomponent magnetic nanoparticle-based current biosensors that offer the advantages of excellent stability in a complex biomatrix; easy and alterable biorecognition of ligands, antibodies, and receptor molecules; and unified point-of-care integration have yet to be achieved. This review introduces the recent advances in superparamagnetic nanostructures for electrochemical and optical biosensing for disease-specific biomarkers. This review emphasizes the synthesis, biofunctionalization, and intrinsic properties of nanomaterials essential for robust, ultrasensitive biosensing. With a particular emphasis on nanostructure-based electrochemical and optical detection of disease-specific biomarkers such as nucleic acids (DNA and RNA), proteins, autoantibodies, and cells, this review also chronicles the needs and challenges of nanoarchitecture-based detection. These summaries provide further insights for researchers to inspire their future work on the development of nanostructures for integrating into biosensing and devices for a broad field of applications in analytical sensing and in clinic.

An overview to electrochemical biosensors and sensors for the detection of environmental contaminants

Abstract: Nowadays, environmental pollution is one of the major worldwide problems. There are various types of pollutants (i.e., organic, inorganic, and biological materials), which can contaminant water resources, land, and air. Therefore, there is a high demand to develop and design new devices for the detection and determination of various contaminants in the environment. In this regard, the chemical and biological sensors are interesting tools for environmental applications. Recently, different types of chemical and biological sensors, such as electrochemical, fluorescence, and mass-based (bio)sensors, have been developed through the studies of researchers in the many fields of science by chemists, chemical engineers, physicists, etc. Among the developed sensors and biosensors, the electrochemical ones have many advantages, including low cost, easy to fabrication and use, ability to miniaturization, and application in the point-of-demand. Furthermore, the electrochemical biosensors have been classified as the electrochemical immunosensors, aptasensors, and genosensors, which have high selectivity and sensitivity toward the proposed targets, with an emphasis on opportunities for further improvement in contaminants diagnostics and monitoring. Considering these conditions, the main approach of this review is on the electrochemical immunosensors, aptasensors, and genosensors, which have been applied in the determination of various contaminants, including organophosphorus, toxic hydrocarbons and organic compounds, heavy metals, and toxic anions and cations. The figures of merits of some important studies and related data such as LOD, LDR, and electrochemical methods, which have been used to determination of contaminants as well as the (bio)sensor design, are presented in the tables to further comparison and information.

Research Progress of DNA Walker and Its Recent Applications in Biosensor

Abstract: With the continuous development of DNA nanotechnology, researchers have focused increasing attention on the use of DNA molecules with diverse structural and functional properties to construct nanomachines. Among the various molecular machines, DNA walker is one of the most sophisticated DNA devices either in design or construction. Its key point is to drive the walking strand to move steadily and progressively along the tracks by the motor, and further to implement the generation and amplification of signals, cargo delivery, molecular computing and so on. This review provides a systematic and comprehensive overview of the design principles for DNA walkers with typical examples and in-depth discussion, as well as an exhaustive description of its application in the field of biosensors. Meanwhile, it also summarizes the performance advantages and challenges of DNA walker biosensors, thus offering a deepgoing discussion of the latest progress and future development trends in this new exciting area.