Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes

Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphenebased enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

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Graphene Based Electrochemical Sensors and Biosensors: A Review

MicroRNA: function, detection, and bioanalysis.

Signal amplification based on biofunctional nanomaterials has recently attracted considerable attention due to the need for ultrasensitive bioassays and the trend towards miniaturized assays. The biofunctional nanomaterials can not only produce a synergic effect among catalytic activity, conductivity and biocompatibility to accelerate the signal transduction, but also provide amplified recognition events by high loading of signal tags, leading to a highly sensitive and specific biosensing. Most importantly, nanoscaled materials are in direct contact with the environment, which permits them to act as chemical and biological sensors in single-molecule detection of biomolecules. In this tutorial review, we will focus on recent significant advances in signal amplification strategies combining the cross-disciplines of chemistry, biology, and materials science, and highlight some elegant applications of biofunctional nanomaterials as excellent electronic or optical signal tags in ultrasensitive bioanalysis. The biofunctional nanomaterials-based biosensing opens a series of concepts for basic research and offers new tools for detection of trace amounts of a wide variety of analytes in clinical, environmental, and industrial applications.

Signal amplification using functional nanomaterials for biosensing

As crystalline molecular materials, metal–organic frameworks (MOFs) have unique chemical and physical properties, such as ultrahigh porosity, tunable structure, and high thermal and chemical stability. These characteristics make MOFs suitable for use in gas storage, separation, catalysis, biomedical imaging and sensing. Precise chemical modifications can especially endow MOFs with specific functions and offer the possibility of designing a new generation of sensing devices. This article focuses on the design of functional MOFs and signal-transduction strategy, including optical, electrochemical, mechanical, and photoelectrochemical schemes, for analytical applications in detection of solvent molecules, metal ions, DNA, proteins, and other important biomolecules.

Design and sensing applications of metal–organic framework composites

A glucose biosensor based on direct electrochemistry of glucose oxidase immobilized on nitrogen-doped carbon nanotubes.

This work investigates the interaction of carbon nitride nanosheet (CNNS), a recently developed two-dimensional nanomaterial, with DNA and its fluorescence quenching mechanism on fluorophore labeled single-stranded DNA probes. The static quenching through the photoinduced electron transfer (PET) from the excited fluorophore to the conductive band of CNNS is identified. Utilizing the affinity change of CNNS to DNA probes upon their recognition to targets and the PET-based fluorescence quenching effect, a universal sensing strategy is proposed for design of several homogeneous fluorescence detection methods with short assay time and high sensitivity. This strategy is versatile and can be combined with different amplification tools for quick fluorescence sensing of DNA and extensive DNA related analytes such as metal cations, small molecules, and proteins. As examples, two simple fluorescence detection methods for DNA and Hg2+, one facile detection method coupled with Exo III-mediated target recycling for se...

Jianping Lei

Papers

MicroRNA: function, detection, and bioanalysis.

Signal amplification using functional nanomaterials for biosensing

Design and sensing applications of metal–organic framework composites

A glucose biosensor based on direct electrochemistry of glucose oxidase immobilized on nitrogen-doped carbon nanotubes.

Fluorescence quenching of carbon nitride nanosheet through its interaction with DNA for versatile fluorescence sensing.