Photothermal microscopy (PTM) is an emerging label-free optical microscopy technique that can image the photothermal property of single nanoparticles and single molecules. The image contrast relied on the sensitive detection of local temperature gradients and refractive index distribution associated with the photothermal effect of individual molecules or nanoparticles when it was illuminated with particular incident light. Since non-radiative relaxation is usually the dominant process for an excited molecule to return back to the ground state, photothermal properties are of more generalized significance compared to fluorescence. The past decade has witnessed the great growth and development of photothermal microscopy, mainly because of its advantages of label-free detection, high sensitivity and stability. Furthermore, this technique has received increasing attention in nano-science and life science, ranging from fundamental studies on molecule-photon interactions to promising applications in single cell imaging and bio-sensing. The review mainly describes the imaging principle, optical apparatus, technical concerns for performance optimization of PTM, and subsequently enumerates the important applications in live-cell studies and bioscience. In the last section, we provide perspectives regarding the major strength and challenges for the further development and applications of photothermal microscopy technology.

Contents
1 Introduction
2 Principle and apparatus of PTM
2.1 Imaging principle
2.2 Photothermal interference contrast (PIC)
2.3 Photothermal heterodyne imaging (PHI)
2.4 Performance optimization
3 Imaging single molecules and single nanoparticles
3.1 Plasmonic nanoparticles
3.2 Semiconductor nanocrystals
3.3 Carbon nanotubes
3.4 Organic molecules
4 Application
4.1 Photothermal probes for live cell imaging
4.2 Label-free imaging of biomolecules
4.3 PTM combined with other techniques
5 Conclusion and outlook

Upconversion nanoparticles (UCNPs) have been widely employed in biosensing, bioimaging, photodynamic therapy and drug delivery in the past ten years. Presently, upconversion nanoparticles are obtained via thermal decomposition, co-precipitation, and solvothermal methods with oleylamine or oleic acid as surfactants always have low size dispersity, strong luminescence and disperse well in nonpolar solvents like cyclohexane. However, these kinds of nanoparticles are normally covered by a layer of oleic acid or oleylamine molecules, and hence are not suitable for directly using in biological environments. The subsequent surface modification which can turn hydrophobic nanoparticles into hydrophilic ones is therefore required. These methods include ligand exchange, ligand oxidation, amphiphilic polymer coating, silica coating, and ligand removal and so on. This account throws a critical look at the methods for surface modification and functionalization that lead to UCNPs for use in aqueous media and discusses the advantages and disadvantages of these strategies.

Contents
1 Introduction
2 Surface modification
2.1 Ligand oxidation
2.2 Ligand exchange
2.3 Amphiphilic ligand coating
2.4 Ligand removal
2.5 Layer-by-layer assembly
2.6 Silica coating and silanization
3 Bioconjugation
3.1 Covalent conjugation
3.2 Electrostatic attraction
3.3 Van der Waals Bonding
3.4 Direct attachment of biomolecule to NP surface
4 Conclusion and outlook

DNA possesses characteristics such as excellent biocompatibility, biodegradation, molecular recognition ability, nanoscale controllability and programmability. In recent decades, DNA has taken on an assortment of diverse roles, not only as the central genetic molecule in biological systems but also as generic materials for nanoscale engineering. DNA hydrogel combines the characteristics both from DNA and hydrogel, such as controllable shape, high mechanical strength, materials delivery. The hydrogel formation includes chemical method based formation via covalent bond and physical method based formation via non covalent bond. DNA hydrogel can combine with perssad, molecule or DNA sequence which can be sensitive to incitant stimulating factor in order to expand the application of DNA hydrogel. DNA hydrogel can be sensitive to stimuli-response, such as pH, light, temperature and small molecules. These novel DNA hydrogels provide a natural bridge between nanotechnology and biotechnology, and this also leads DNA hydrogel to far-ranging real-world applications. Because of this, DNA hydrogel as a smart material has been widely used in biosensor, drug delivery, and three-dimensional cell culture. In this review, we summarize the classification of DNA hydrogel and then give the stimuli-response DNA hydrogel and its biological application. Also, the development prospect of DNA hydrogel is demonstrated.

Contents
1 Introduction
2 Formation mechanism of DNA hydrogel
2.1 Chemical method based DNA hydrogel formation
2.2 Physical method based DNA hydrogel formation
3 Stimuli-responsive DNA hydrogel
3.1 pH-responsive DNA hydrogel
3.2 Photo-responsive DNA hydrogel
3.3 Temperature-responsive DNA hydrogel
3.4 Molecule-responsive DNA hydrogel
4 Applications
4.1 Biosensor
4.2 Drug delivery
4.3 3D cell culture
5 Conclusion and outlook

The up and down conversion technology can convert the infrared and ultraviolet light into the visible light in the range of 300~800 nm, which can solve the energy loss caused by spectral mismatch, and the absorption spectrum of the cell can be expanded to improve the light utilization and conversion efficiency. The rare earth ion is often used as the center ion of the up and down conversion materials because of the special structure of the energy level and the high luminous efficiency. In recent years, the center ion of up conversion is mainly Er³⁺, Tm³⁺and the sensitization center is Yb³⁺ with longer excited state lifetime. Tb³⁺, Eu³⁺ and Sm³⁺ have charge transfer absorption band in the ultraviolet region, which can be easily excited by ultraviolet light and the emission spectrum mainly located in the visible region, so they are often used as the center ion of down conversion.The host is usually fluoride and the materials with high crystallinity, small particle size and uniform distribution were prepared by hydrothermal method. At present, the research on up and down conversion applied to DSC is getting more and more important. In this paper, we mainly discuss the application of up and down conversion in DSC, and prospect the future development direction.

Contents
1 Introduction
2 Up and down conversion technology
2.1 Luminescence mechanism of up and down conversion
2.2 Host of up and down conversion luminescent materials
2.3 Preparation method of luminescent materials
3 Application of up and down conversion in dye sensitized solar cells
3.1 Energy loss in solar cells
3.2 Application modeling of up and down conversion in solar cell
3.3 Application of up and down conversion luminescent materials in DSC
4 Conclusion and outlook

Graphene is a one-atom-thick planar sheet of sp²-bonded carbon atoms densely packed together in a honeycomb hexagonal lattice. The exceptional structure endows graphene with excellent electrical, mechanical, thermal, and optical properties. Up to now, considerable efforts have been made to explore its application in varied areas, such as catalyst, battery, sensor and etc. Cellulose, one of the most abundant natural polymer on earth, is featured by non-toxicity, renewability, biodegradability and biocompatibility. The hydrophilicity and hydrophobicity, originated from the enriched O-H and C-H, respectively, have made cellulose an ideal candidate for the fabrication of graphene-based materials. So far, graphene/cellulose composites have shown great potential in the applications of transparent conductive flexible films, supercapacitors, drug delivery, UV-protection, sensors, absorbents and so on. In this review, we study the interaction between cellulose materials and graphene materials. Subsequently, the mixing technics, fabrication methods, and application of the graphene/cellulose composites are summarized. Finally, problems, such as dispersion of graphene in cellulose and production efficiency, hampering its up-scale application, have been pointed out.

Contents
1 Introduction
2 Interactions between graphene and cellulose
3 Mixing methods of graphene/cellulose composite
3.1 Solution mixing
3.2 Melting mixing
3.3 Others
4 Processing of graphene/cellulose composite
4.1 Regeneration of cellulose gel
4.2 Vacuum filtration
4.3 Solution coating
4.4 Dip and dry
4.5 Film transfer
4.6 Aerogel through freeze drying
5 Applications of graphene/cellulose composite
5.1 Thin film materials
5.2 Supercapacitors
5.3 Drug delivery
5.4 UV-protection
5.5 Sensors
5.6 Absorbents
5.7 Others
6 Conclusion

With the development of modern economy and industry, the environment problems are becoming increasingly serious. So the requirements of the novel adsorption/separation materials have become urgent. Electrospinning (ES) is a facile and effective technique to prepare continuous nanofibers and has a wide application prospect. Because the electrospun nanofibrous mat possesses the features of large surface area, controllable microstructure and chemical property, the ES technology is considered as a potential method to prepare novel adsorption/separation materials. This article has summarized the recent researches on fabricating and modifying the electrospun fibrous mat and illustrated its applications in air filtration, oil-water separation and heavy metal ion adsorption. The research prospects and directions of this rapidly developing field are also briefly proposed.

Contents
1 Introduction
2 Preparation and modification of electrospun mats
2.1 Microstructure control of electrospun mat
2.2 Preparation of multi-component electrospun fibers
2.3 Surface modification of electrospun mats
3 Applications of electrospun mats as adsorption/separation materials
3.1 Air filtration
3.2 Oil-water separation
3.3 Heavy metal ion adsorption
4 Conclusion and outlook

Hydroxyl-terminated polybutadiene (HTPB) is a low molecular-weight telechelic liquid rubber. Because of its various advantages, such as low glass transition temperature, good transparency, low viscosity, hard volatilization, oil resistance, good processability, HTPB has a wide range of applications in military and civilian fields. The properties of HTPB are mainly influenced by its chain microstructure. The different synthetic methods produce HTPB with different microstructure, which will result in the large difference in the properties. In addition, the chemical modifications of C＝C double bonds in the main chain and hydroxyl groups in the chain ends lead to the formation of telechelic polymers with different molecular structure and various functional groups. After modifications, the different properties are endowed to HTPB and the application fields are also expanded. In this review, the research progress about the synthesis, chemical modifications and applications of HTPB is discussed in detail.

Contents
1 Introduction
2 Synthesis of HTPB
2.1 Free radical polymerization
2.2 Anionic polymerization
2.3 Ring-opening metathesis polymerization
2.4 Oxidolysis of polybutadiene
3 Chemical modifications of HTPB
3.1 Reactions with double bonds in the main chain
3.2 Reactions with hydroxyl groups in the chain ends
3.3 Reactions with carbon atoms at the terminal
4 Applications
4.1 Solid propellants
4.2 HTPB-based polyurethane
4.3 Block copolymers
5 Conclusion

Low molecular fluoropolymers have a special status in the defense industry as the important new functional materials. Meanwhile, as high-tech strategic materials, they have attracted more attention. Low molecular fluoropolymers, not only have excellent performance of traditional fluoropolymers, but also have irreplaceable characteristics. In the present study, the preparation, functionalization, and properties of low molecular fluoropolymers are reviewed. The study highlights the research progress in the preparation and functionalization methods. The properties of low molecular fluoropolymers are also summarized. Finally, the future development of low molecular fluoropolymers is prospected.

Contents
1 Introduction
2 Preparation methods of low molecular fluoropolymers
2.1 Copolymerization method
2.2 Oligomerization method
2.3 ITP method
2.4 Functional initiator method
2.5 Oxidative degradation method
3 Functionalization methods of low molecular fluoropolymers
3.1 Functional monomer method
3.2 Functional group transformation method
3.3 Functional monomer and group transformation method
4 Properties of low molecular fluoropolymers
4.1 Processing property
4.2 Physical property
5 Conclusion and outlook

Hierarchically porous aluminophosphate molecular sieves possessing both micropores and mesopores recently receive increasing interest because they can reduce diffusion limitations in the reactions involving bulky molecules. This paper mainly focuses on the latest development of synthesis, characterizations and catalytic applications of hierarchically porous aluminophosphate molecular sieves. According to the formation mechanism of hierarchical pores, the synthetic methods of the hierarchical structured aluminophosphate molecular sieves can be classified into four categories: hard template, soft template, nontemplated and post-synthesis method. The advantages and disadvantages of these synthetic methods are systematically compared with each other. From the point view of industrial application, the nontemplated and post-synthesis methods are more promising compared to other synthetic routes. In addition, various techniques characterizing the acid properties and pore textures of hierarchically porous molecular sieves are described, taking silicoaluminophosphate molecular sieve as an example. However, most of these measurements need to be performed on complex expensive instruments, and the process is time-consuming. Thus, to develop some facile and general characterization techniques is highly desirable.Finally, the catalytic applications of these hierarchically porous materials in three kinds of important reactions (such as alkylation reaction, isomerization reaction and methanol to olefins) are reviewed. The relationships between the catalytic performances and the properties of catalysts are analyzed in detail.

Contents
1 Introduction
2 Synthesis of hierarchically porous aluminophosphate molecular sieves
2.1 Hard-template method
2.2 Soft-template method
2.3 Nontemplated method
2.4 Post-synthesis method
3 Characterizations of acid properties and pore textures
4 Catalytic applications of hierarchically porous aluminophosphate molecular sieves
4.1 Alkylation reaction
4.2 Isomerization reaction
4.3 Methanol (dimethyl ether) to olefins
4.4 Other reactions
5 Conclusion and outlook

Microcantilever biosensors based on atomic force microscope have the advantages of label-free, rapid, real-time, and high sensitivity detection features. Therefore, microcantilever biosensors can be applied in the fields of biomedicine, environmental monitoring, food production and military defenses. Microcantilever biosensors have become the focus of scientific research. In this paper, we review the working principle, excitation method and detection mechanism of microcantilever biosensors. Preview reviews about the microcantilever biosensors mainly focuse on the progress of applications, but lack of comprehensive and systematic introduction on detection methods. Herein, we not only systematically analyze eight detection methods, but also introduce several typical sizes, appearance and "heat mode" of microcantilever biosensors. So far, these have not been reported in literatures. In order to realize specific detection and improve sensitivity of microcantilever sensors, we summarize the surface modification methods of microcantilever sensors and review the latest applications of microcantilever biosensors. Furthermore, we introduce a new kind of self-actuating and self-sensing microcantilever biosensors. The prospective of microcantilever biosensors is also discussed in this paper.

Contents
1 Introduction
2 Microcantilever biosensors
3 The brief introduction of microcantilever beam
4 Microcantilever working mode
4.1 Dynamic working mode
4.2 Static working mode
4.3 Heat mode
5 Excitation methods of the microcantilever biosensors
6 Detection methods of the microcantilever biosensors
6.1 Optical lever
6.2 Optical interferometry
6.3 Piezoresistive method
6.4 Piezoelectric method
6.5 Capacitance method
6.6 Electron tunneling method
6.7 Other methods
7 Surface biofunctionalization
8 Application of the microcantilever biosensors
8.1 DNA hybridization detection
8.2 Pathogens detection
8.3 Protein detection
8.4 Small-molecular and drug testing
8.5 Biological warfare agent detection
8.6 Self-actuating and self-sensing microcantilever biosensors
9 Conclusion and outlook

Nanofibers have many promising applications as a main component of one-dimensional nanomaterials. Electrospinning technology is a facile and effective way to prepare nanofibers. However, the traditional preparation process only obtains non-aligned nanofibers, which significantly hinders their application. In recent few decades, many efforts have been focused on optimization of the preparation method, and well aligned nanofibers (ANFs) have been successfully obtained through improving spinning set-ups, collectors, and optimizing the separation section of nanofibers. Due to the absence of a systematic appraisal of ANFs, here a review of the preparation methods of ANFs based on electrospinning and their applications in tissue engineering regeneration, sensors, reinforced materials, sensors and energy devices, is present. Owing to the wide application of ANFs in tissue engineering regeneration, a detailed discussion is provided in that regard. In the field of energy, the application of ANFs in PEM fuel cells is focused. Finally, the challenges and outlooks for the development of ANFs are summarized.

Contents
1 Introduction
2 Electrospinning technology
3 Fabrication of electrospun ANFs
3.1 Improved collector methods
3.2 Magnetic assistance mothod
3.3 Conjugate spinneret electrospinning method
3.4 Centrifugal electrospinning method
3.5 Near-field electrospinning method
3.6 Multiple collectors method
4 Applications of electrospun ANFs
4.1 Tissue engineering
4.2 Sensors
4.3 Reinforced materials
4.4 Energy
5 Conclusion and outlook

Quaternary ammonium compounds (QACs) used as cationic surfactants have been ubiquitously detected in water, sediment, sludge, etc. QACs residue can be examined highly at several hundreds or even thousands of mg/kg (dry weight, dw) in sludge particularly. Because of their high surface activity and moderate-high toxicity, QACs can cause toxic effects on fish, aglae, bacteria, daphnids, etc. at relatively low concentrations. Furthermore, QACs significantly influence the bioavailability and mobility of the other coexisting pollutants in environment. The environmental problems of QACs have attracted a great attention in devoloped countries, however, little literature is available in China. Therefore, this paper reviews the pollution source, analytical methods, pollution status, fates and toxic effects of QACs in environment. The currently existing problems and trends are also discussed. We hope that this review will provide valuable reference for the enviromental researches on QACs in China.

Contents
1 Introduction
2 Sources of QACs in environment
3 Analytical methods
3.1 Sample extraction and purification
3.2 Sample analysis
4 Pollution status and fates of QACs in environment
4.1 QACs in water
4.2 QACs in sewage sludge and sediment
4.3 QACs in soil and agricultural crops
4.4 Fates of QACs in environment
5 Toxicity of QACs
6 Conclusion and outlook

Defect-free monolayer graphene with excellent shielding performance is impermeable to O₂ and H₂O molecules, which can protect metal against corrosion and hence is considered to be the thinnest known coating for corrosion protection. Based on the great potential of graphene in the field of metal corrosion protection, this paper systematically summarizes the graphene anticorrosion films, graphene/organic anticorrosion coatings and graphene-conductive polymer/organic anticorrosion coatings. The existing problems of graphene anticorrosion films and well-dispersed graphene in polymer coatings are also discussed. Finally, the future development of graphene based anticorrosion coatings is prospected.

Contents
1 Introduction
2 Graphene anticorrosion films
3 Graphene/organic anticorrosion coatings
4 Graphene-conductive polymer/organic anticorrosion coatings
5 Summary and outlook

Pharmaceuticals and personal care products (PPCPs) as emerging organic contaminants are mostly chiral compounds. They are usually consumed as racemic compounds or single enantiomers. Biological degradation process can lead to stereoselective enrichment of enantiomer of chiral PPCPs. Due to the difficulties in chiral separation and quantification of enantiomers in the complex environmental matrices, their environmental behavior study has been limited. Enantioselective biodegradation and ecotoxicity of chiral PPCPs tend to make their potential environmental behavior and risk more complicated. Recently, enantiomeric selectivity of chiral PPCPs in environment has gradually caused attention of environmental researchers in developed countries, such as Europe, North America and Japan. Effort has been devoted in studying enantiomeric selectivity of environmental behavior and effect about chiral PPCPs. However, in China, there are very few related studies. It is necessary to carry out more related studies. Consequently, this paper reviews chiral signature of PPCPs, analytical methods, environment behavior and effect selectivity of chiral PPCPs, as well as their potential application in pollution source apportionment. Limitation of current research on environmental behavior and effect of chiral PPCPs is also discussed. The prospect of environmental study on chiral PPCPs in the future is also proposed.

Contents
1 Introduction
2 Manufacture and use of chiral pharmaceuticals
3 Chiral signature of PPCPs
4 Analytical methods of chiral PPCPs
5 Occurrence and environment behavior of chiral PPCPs
6 Toxicological effects of chiral PPCPs
7 Application in source analysis
8 Conclusion and outlook

Zero valent metal (ZVMs) has been the most interesting point for the treatment of environmental pollutants and zero valent iron (ZVI) is the most representative. In recent years, zero valent aluminum (ZVAl), another kind of ZVMs, is starting to be paid more attention due to its lower redox potential than ZVI (E⁰(Al³⁺/Al⁰)=-1.662 V, E⁰(Fe²⁺/Fe⁰)=-0.44 V) and its amphoterism characteristic (the reaction pH can be extended to alkaline range). At present, the research mainly focuses on the oxidation system of ZVAl/O₂/H⁺ and the reduction system of ZVAl/anaerobic. And the former has garnered particular attention by in-situ producing hydrogen peroxide to form Fenton-like oxidation reaction. The studies of ZVAl-based oxidation or reduction technology have found that organic contaminants such as phenolics, azo dyes, organic halide, and inorganic contaminants such as Cr(Ⅵ) and As(Ⅲ), can be effectively removed. And some auxiliary means such as ultrasonic, microwave, plus polyoxometalate (POM), Fe²⁺ have effective influences on this technology. In this review, the reaction mechanism and the latest research progress of oxidation and reduction systems based on of ZVAl are summarized and prospected. Not like ZVI, ZVAl as the most abundant metallic element in the earth's crust, don't have the problem of producing the precipitate under high pH condition. And it is believed that ZVAl based oxidation or reduction technology will be more widely used in water treatment with the gradual solution of the restricted factor of the surface oxide film.

Contents
1 Introduction
2 Oxidative removal of pollutants by ZVAl
2.1 ZVAl/O₂/H⁺ system
2.2 Assisted ZVAl/O₂/H⁺ system
2.3 Bimetallic system
3 Reductive removal of pollutants by ZVAl
3.1 ZVAl direct reduction pollutants
3.2 Bimetallic system
4 Conclusion and outlook