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Chemical exfoliation is an attractive approach for the synthesis of graphene due to its low cost and simplicity. However, challenges still remain in the characterization of solution-processed graphene, in particular with atomic resolution. Through this work we demonstrate the x-ray pair distribution function as a novel approach to study solution-processed graphene or other 2D materials with atomic resolution, directly in solution, produced by liquid-phase and electrochemical exfoliations. The results show the disappearance of long-range atomic correlations, in both cases, confirming the production of single and few-layer graphene. In addition, a considerable ring distortion has been observed as compared to graphite, irrespective of the solvent used: the normal surface angle to the sheet of the powder sample should be less than 6°, compatible with ripples formation observed in suspended graphene. We attribute this effect to the interaction of solvent molecules with the graphene nanosheets.

Hybrid optical fibers have been widely investigated in different architectures to build integrated fiber photonic devices and achieve various applications. Here we proposed and fabricated hybrid microfiber waveguides with self-growing polymer nanofilms on the surfaces of microfibers triggered by evanescent field of light for the first time. We have demonstrated the polymer nanofilm of ∼50 nm can be grown on the microfiber with length up to 15 mm. In addition, the roughness of nanofilm can be optimized by controlling the triggering laser power and exposure duration, and the total transmission loss of the fabricated hybrid microfiber is less than 2 dB within a wide wavelength range. The hybrid polymer nanofilm microfiber waveguides have been characterized and their relative humidity (RH) responses have also been tested, indicating a potential for RH sensing. Our fabrication method may also be extended to construct the hybrid microfibers with different functional photopolymer materials.

Graphitic carbon nitride (g-CN) nanosheet is a potential material for sensing applications. The g-CN nanosheet films deposited on microfibers were first fabricated and employed for relative humidity (RH) optical sensing. The RH sensitivity of microfibers was significantly enhanced via g-CN nanosheet coating, the optical transmitted power of coated microfiber humidity sensor was changed ∼10.6 dB when the RH varied from 40% to 95%. In addition, fast response time of 0.43 s and recovery time of 0.87 s were demonstrated by monitoring human breathing. The g-CN nanosheet coated microfiber humidity sensor possesses excellent stability, repeatability, reversibility, and cost-effectivity. The experimental results validate that the microfiber combined with g-CN nanosheets is a promising platform for environmental and biological RH sensing applications.

Recycling urban tail water for ecological base flow and landscape use offers a reliable solution for the problem of water resource shortage. But the long-term direct discharge of urban tail water can aggravate the eutrophication of surface water based on the present drainage standard of sewage plant. It is of great significance to develop low-cost and low-energy ecological technologies as transitional region between urban tail water and surface water. In this study, a pilot-scale ecological bed coupled with microbial electrochemical system (EB-MES) was established to treat urban tail water deeply. The system was operated for 96 days from June to September. Average TN removal efficiency in EB-MES under the condition of submerged plant coupled closed-circuit MES could reach 59.0 ± 16.6 %, which was 82.7 % and 38.1 % higher than that of open-circuit EB-MES and MES without plants, respectively. Microbial community structure testing indicated that multiple nitrogen metabolic mechanisms occurred in the system, including nitrification, electrode autotrophic denitrification, anammox, simultaneous nitrification and denitrification, and aerobic denitrification, which results in better denitrification efficiency under tail water. Our research provided a novel ecological technology with advantages of high-efficiency, low-energy and low-carbon and verified the feasibility in pilot scale for application in the advanced treatment of urban tail water.

Particle-based delivery systems have emerged as a powerful platform in controlled drug release. In the present study, we developed a new inverse opal hydrogel microcarrier system composed of gold nanorods (AuNRs) for near-infrared light (NIR) activated drug delivery. AuNRs with a desired aspect ratio were prepared by a seed-mediated growth method. The inverse opal hydrogel microcarriers composited with AuNRs were synthesized by negatively replicating silica colloidal crystal beads (SCCBs). The NIR-thermo response of the microcarriers was due to the NIR photothermal heating effect of AuNRs and the thermo responsive volume transition of poly(N-isopropylacrylamide) (pNIPAM) hydrogel. It was found that the NIR-controlled reversible shrinking response of the microcarriers was ideal for the controllable drug release with real-time self-reporting color indication.

The present study illustrates the facile synthesis of silver nanoparticles capped with sulfur and nitrogen co-doped carbon dots (AgNPs@SNCDs) nanocomposites and their application towards the sensitive and selective detection of glutathione (GSH) using a spectrofluorimetry method. SNCDs were synthesized using solvothermal treatment of cysteamine hydrochloride and p-phenylenediamine. The as-fabricated SNCDs were then utilized as capping and stabilizing agents for the preparation of AgNPs@SNCDs nanocomposites using wet chemistry. The size of AgNPs@SNCDs nanocomposites was characterized to be ~37.58 nm or even larger aggregates. Particularly, the quenched fluorescence of AgNPs@SNCDs nanocomposites could be significantly restored upon addition of GSH, and the colour of its solution changed to some extent. The fluorescence intensity ratio of AgNPs@SNCDs nanocomposites at ~450 nm and 550 nm was directly proportional to the GSH concentration within the ranges 8.35-66.83 μM and 66.83-200.5 μM, and the detection limit was 0.52 μM. Furthermore various common organic molecules had no obvious interference in the detection mode. The proposed nanosensor was successfully applied for GSH assay in actual water samples.

Background Particle-based drug delivery systems (DDSs) have a demonstrated value for drug discovery and development. However, some problems remain to be solved, such as limited stimuli, visual-monitoring. Aim To develop an intelligent multicolor DDSs with both near-infrared (NIR) controlled release and macroscopic color changes. Materials and methods Microparticles comprising GO/pNIPAM/PEGDA composite hydrogel inverse opal scaffolds, with dextran and calcium alginate hydrogel were synthesized using SCCBs as the template. The morphology of microparticle was observed under scanning electron microscopy, and FITC-dextran-derived green fluorescence images were determined using a confocal laser scanning microscope. During the drug release, FITC-dextran-derived green fluorescence images were captured using fluorescent inverted microscope. The relationship between the power of NIR and the drug release rate was obtained using the change in optical density (OD) values. Finally, the amount of drug released could be estimated quantitatively used the structural color or the reflection peak position. Results A fixed concentration 8% (v/v) of PEGDA and 4mg/mL of GO was chosen as the optimal concentration based on the balance between appropriate volume shrinkage and structure color. The FITC-dextran was uniformly encapsulated in the particles by using 0.2 wt% sodium alginate. The microcarriers shrank because of the photothermal response and the intrinsic fluorescence intensity of FITC-dextran in the microparticles gradually decreased at the same time, indicating drug release. With an increasing duration of NIR irradiation, the microparticles gradually shrank, the reflection peak shifted toward blue and the structural color changed from red to orange, yellow, green, cyan, and blue successively. The drug release quantity can be predicted by the structural color of microparticles. Conclusion The multicolor microparticles have great potential in drug delivery systems because of its vivid reporting color, excellent photothermal effect, and the good stimuli responsivity.

In the present study we developed novel luminescent magnetic nanocomposites termed Fe₃O₄@polyaniline/carbon dots. First, Fe₃O₄ magnetic nanoparticles were prepared by the coprecipitation method. The nanoparticles were then coated with polyaniline using the in situ growth method to form Fe₃O₄@polyaniline nanohybrids, which were endowed with amino functional groups on the surface and avoided the aggregation of Fe₃O₄ nanoparticles. The X-ray diffraction pattern demonstrated that the crystalline phase of the Fe₃O₄ nanoparticles was an inverse spinel structure and was not changed in the Fe₃O₄@polyaniline nanohybrids. The saturation magnetization and the coercive force of the as-prepared Fe₃O₄@polyaniline nanohybrids measured by a vibrating sample magnetizer were 63.7 emu·g-1 and zero respectively, which indicated that the Fe₃O₄@polyaniline nanohybrids exhibited excellent superparamagnetism. The Fe₃O₄@polyaniline nanohybrids were conjugated with carbon dots, prepared from orange juice, via the amide bond between the amino groups on the surface of the Fe₃O₄@polyaniline nanohybrids and the carboxyl groups on the surface of carbon dots. The obtained luminescent magnetic nanocomposites Fe₃O₄@polyaniline/carbon dots showed good photoluminescent properties, which hinted that the nanocomposites have potential in drug tracing and magnetic targeted drug delivery. Finally, the anticancer drug methotrexate was loaded into the Fe₃O₄@polyaniline/carbon dots nanocomposites, forming a novel magnetic targeted drug delivery system. The results confirmed that the novel drug delivery system exhibited excellent drug-loading capability for methotrexate of ca. 70%, and emits strong fluorescence at the wavelength of 360 nm. An in vitro release experiment of the drug delivery system indicated that the cumulative release percentage of methotrexate was 17.2% in the phosphate-buffered saline (pH = 7.4) within 36 h.

Copper-based metal–organic frameworks (MOFs) and their derivatives have been used for CO2 electroreduction; however, they still have obvious drawbacks like poor selectivity and durability. Here, Cu...

A simple biological strategy to couple intracellular irrelated biochemical reactions of staphylococcus aureus CMCC 26003 (S. aureus) with inorganic metal ions to synthesize cadmium selenide quantum dots (CdSe QDs) was demonstrated. Correspondingly, S. aureus as living matrices are internally generated and labeled with fluorescent QDs by the smart strategy. Several key factors in the process of biosynthesis were systematically evaluated. At the same time, ultraviolet-visible (UV-Vis), photo-luminescence (PL), inverted fluorescence microscopy and transmission electron microscopy (TEM) were utilized to study the characters of the as produced CdSe QDs. In addition, cytotoxicity and photostability of the QDs containing bacteria were also tested and evaluated as a whole. The results showed that intracellular CdSe nanocrystals had successfully formed in S. aureus living cells, which were less toxic, highly fluorescent and photostable. These fluorescent S. aureus bacteria were next applied as invading pathogens as well as fluorescent bioprobes for exploring the phagocytic behavior of THP-1-derived macrophage. Results proved that internal CdSe QDs labeling had no significantly adverse effects compared with the kind of infection reference, fluorescein isothiocyanate (FITC) stained S. aureus pathogen. Assuredly, the methods presented here provide researchers with a useful option to analyze the behavior of S. aureus as a type of infectious pathogen, which would also help understand the complex interplay between host cells and the invading bacteria on molecular level.

Understanding structural transformation of hexagonal boron nitride (h-BN) at elevated temperatures is critical to obtain 2D-h-BN through thermal exfoliation. Therefore, in situ x-ray diffraction data are collected from h-BN powders while subjecting them to a thermal cycle. The potential to define the structure order during temperature variations is revealed by using an index (I3D). It was revealed that no direct correlation with the degree of exfoliation of layered structure and the structural order change appeared during thermal cycling. Furthermore, particle size dependence of the structure order under elevated temperature is also mapped.

Macrophages eliminate and destroy invading bacteria and contaminants by engulfing them or secreting cytokines that trigger downstream immune responses. Consequently, impairment of the phagocytic functions of macrophages and/or suppressing their cytokine secretion are dangerous to organisms that rely on immune protection. Accordingly, exposure to environmental nanoparticles (NPs) that display immunomodulatory properties are serious. In this work, two types of NPs, i.e., mild-toxicity CuInS2 NPs and high-toxicity CdTe NPs, were used to evaluate the effects of NP exposure for macrophages. Following incubation for 24 h, THP-1-derived macrophage viability was assessed using an MTT method after exposing the THP-1 cells to different concentrations of CuInS2 or CdTe NPs. Phagocytosis assays demonstrated that both CuInS2 and CdTe NPs impair phagocytic activity toward Staphylococcus aureus (S. aureus). After pretreatment with CuInS2 and CdTe NPs at 4 μmol/L, THP-1 macrophages exhibited decreases in phagocytic ratio from ca. 32.9% to ca. 18.5% and 18.7%, respectively. Since the zeta potentials of intact and weathered CuInS2 NPs were distributed over a wide range from positive to negative, large quantities of intact and weathered CuInS2 NPs bore sufficient positive charge on their surfaces to induce membrane depolarization, thus theoretically providing electrostatic forces between S. aureus and THP-1, which could induce downstream intracellular events that increase phagocytosis. However, real time polymerase chain reaction arrays revealed that transcription of the pro-inflammatory factors IL-1β, IL-6, and TNF-α decreased while that of the anti-inflammatory factor IL-10 increased after treatment with CuInS2 NPs. Furthermore, transcription of TNF-α decreased while IL-10 increased after treatment with CdTe NPs. Thus, both kinds of NPs inhibited phagocytosis of S. aureus by THP-1 to some extent, confirming that immunosuppression can occur when macrophages are exposed to environmental NPs.

Heavy metal cadmium (Cd) has drawn tremendous comcern due to its rigorous environmental and health hazards. Herein, we have presented an efficient and economical strategy for the removal and recycling of hazardous Cd ions using microalgae cells as the bioreactors. Remarkably, the green bio-platform for the bioproduction of CdSe nanoparticles (NPs) was developed depending on their orderly regulated and sustainable cellular environment. The biofabricated CdSe NPs manifested favorable photoluminescence properties, and presented well monodispersed spherical morphology and certain crystallinity structure with mean size of smaller than 7 nm. Especially, the fluorescence “turn off” sensing system based on the CdSe NPs was established to detect Hg2+. The nanosensor enables the quantitative analyses of Hg2+ with a linear range of 0–2.0 μM and a detection limit of 0.021 μM. Furthermore, it was preliminarily speculated that the reducing biomolecules in the algae cells could be involved in the formation of CdSe NPs. This work not only provides new insights into the removal and recycling of hazardous Cd ions, but also brings a promising route for biosynthesis of CdSe NPs.

Quantum dots (QDs), as a kind of novel nanomaterial, have the extensive applications in various fields, inevitably leading to increasing risks for the ecological environment. The mobilization of cadmium including metal smelting and subsequent machining for multifarious applications has caused the release of cadmium element into the environment. In this study, we evaluated the potential toxicity of a novel nanoparticle material CdSe QDs, using two green algae Chlorella pyrenoidosa and Scenedesmus obliquus. The impact of CdSe QDs and cadmium ions on algae and the sensitivity of the two algae on target compounds were also considered and compared. Our results showed the algal growth rates and chlorophyll content decreased with increasing exposure concentrations and durations. Moreover, the glutathione levels were decreased while the activities of superoxide dismutase increased, exhibiting their pivotal functions in defeating toxic stress. The increment of malondialdehyde levels revealed that the stresses of CdSe QDs and cadmium ions were contributed to the occurrence of oxidative damage. Our study also indicated that the impact of CdSe QDs was stronger than that of cadmium nitrate and the algal response was also species-specific. In addition, the TEM photographs of the algal ultrastructure showed the presence of surface attachment and uptake of QDs.

A novel self-assembly phenomenon triggered by Zn2+ of Cu-In-S quantum dots with aggregation-induced emission effect was presented in this paper. Hydrophilic Cu-In-S quantum dots with aggregation-induced emission effect were successfully prepared. They were monodisperse spherical nanoparticles with the diameter of 2.8 ± 0.4 nm and had weak fluorescence in aqueous solution. However, the solution emitted strong fluorescence after addition of Zn2+. The results of TEM and SEM indicated the monodisperse quantum dots self-assembled into 3D networks of Cu-In-S quantum dots-Zn2+, which hindered the motion of quantum dots. Besides, the Zn2+ in the mixture passivated the surface defects. The phenomenon also proved by florescence lifetime and XPS. Thus the radiation decay decreased and followed by strong fluorescent emission. Interestingly, the degree of aggregation was proportional to the amount of Zn2+ and the fluorescent intensity. Based on this interesting phenomenon, a novel metal enhanced fluorescent nanosensor for detecting Zn2+ was established. The results demonstrated the proposed method had a good selectivity and linearity in the concentration range of 0–800 nmol L−1 with a limit of detection of 1.99 ppb. These results showed a promising future in the field of metal-enhanced fluorescent probes of the Cu-In-S quantum dots.

Bacillus amyloliquefaciens containing intracellularly biosynthesized cadmium selenide (CdSe) quantum dots (QDs) was used as a fluorescent bioprobe. Several parameters in the QD biosynthesis process were systematically optimized. The optimized protocol for producing high-quality CdSe QDs in B. amyloliquefaciens features mild synthetic conditions, good reproducibility, short reaction time and high yield. This process shows promise for the mass production of QDs by bacterial matrices. The resultant fluorescent B. amyloliquefaciens containing intracellular CdSe QDs was used as a bioprobe for the simple detection of copper (II) ions in blood plasma. The selective permeability of the bacterial cell membrane along with the protection provided by a protein envelope on the QD surface prevented interference by other components of blood plasma, resulting in the accurate determination of Cu2+. Using the copper addition method, the content of Cu2+ in human blood plasma samples was determined to be 15.6–18.5 μmol/L, consistent with atomic absorption spectroscopy results. The technique developed here shows potential for the simple determination of Cu2+ in plasma with excellent selectivity and good sensitivity.

Targeting to obtain better water solubility and stability and less aggregation-caused quenching effects of quantum dots, two kinds of thiol molecules, glutathione and L-cysteine, were firstly united to offer stabilizing ligands for aqueous synthesized CdS quantum dots, which exhibited sensitive aggregation-induced emission properties. Fluorescent intensity of the CdS quantum dots was enhanced about 5 folds by simple solvent exchange from water to 90 vol% PEG200. Restriction of intramolecular motions in an aggregate state was probably the main cause of the phenomenon. At the same time, fluorescent intensity of CdS quantum dots in the presence of zinc ions was able to be enhanced about 2.2 folds. Based on the researches, a handy metal enhanced fluorescent probe for detecting zinc ions was established. And the detection limit was 0.58 μmol/L. Zinc ions as a bridge among CdS quantum dots to form aggregates limited motions of CdS quantum dots to a certain extent and simultaneously enhanced their fluorescence emission intensities. Meanwhile, activation of surface states of CdS quantum dots also led to emission enhancement. Both of the two factors together contributed to the fluorescence enhancement and ultimately to the sensitivity to zinc ion sample detection.

Copper-based metal-organic frameworks (MOFs) and their derivatives have been used for CO

Graphitic carbon nitride nanosheets deposited on microfibers for relative humidity sensing is first demonstrated with high sensitivity. Fast response time of 0.43 s and recovery time of 0.87 s are characterized. © 2020 The Author(s)

As endocrine disrupting chemical, 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) is widely distributed in water environment with a high detection rate. 6-hydroxy-2,2′,4,4′-tetrabromodiphenyl ether (6-OH-BDE-47) and 6-methoxy-2,2′,4,4′-tetrabromodiphenyl ether (6-MeO-BDE-47) are two main derivatives of BDE-47. To explore the aquatic risk of BDE-47 and its derivatives, the effects of them and their ternary mixture on the reproduction, growth, energy allocation, and neurological and antioxidant responses of Daphnia magna were monitoring during different exposure periods, i.e., daphnids exposed to compounds for 21 days or pre-exposed to compounds for 14 days and then recovered 7 days in clean water. In general, in 21-day test, reproductive parameters of exposed daphnids were significantly stimulated, and the growth and enzymatic activities of super oxidase dimutase (SOD), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) were significantly depressed by the single- or mixture compounds. In (14 + 7)-day test, the levels of body length, number of living offspring per female and the enzyme activities recovered to some degree. However, after 7 days of recovery in pollution free medium, the reproductive parameters and enzymatic activities of D. magna were unable to restore control values. These results showed that D. magna has a tendency that the energy allocated to reproduction was greater than that to grow after exposure. The energy distribution of D. magna occurred autonomously after being exposed, which can make it better adapt to environmental changes. Moreover, based on the behavioral and enzymology indicators of D. magna, the spider chart's application in the characteristic analysis of function indicators of D. magna implied that SOD, GPx and AChE could become sensitive biomarkers for different exposure periods. Those findings enable us to better understand BDE-47 and metabolites, and are conducive to better take measures to solve the pressure it brings.

The saturable absorption properties of molybdenum tungsten disulfide (MoWS2) near 1.6 μm were investigated. Passively Q-switched Er:YAG laser at 1645 nm with a home-made MoWS2 as saturable absorber was realized. Under an absorbed pump power of 10.75 W, a maximum average output power of 1.62 W was achieved with a pulse duration of 1 μs at a repetition rate of 43 kHz, corresponding to a pulse energy of 37.7 μJ.

Hypochlorite (OCl–), an essential part of reactive oxygen species (ROS), plays a crucial role in cellular redox balance. OCl– has been shown to be implicated in many physiological and pathological processes, including liver injury and cancer. Exploitation of fluorescent probes for the OCl– helps to reveal its function in the genesis and progression of the aforementioned diseases. Here we propose an easy-to-fabricate coumarin-based fluorescent probe incorporated with an aryl dihydrazide linker for highly specific detection and biological imaging of OCl– in living cells and tissues. The p-nitrophenyl-modified dihydrazide-linked coumarin derivative (Cou-dhz-Ph-NO2) was screened from a series of candidate molecules and served as a “turn-on” probe with a low background fluorescence interference due to the nitro-group-based quenching on the coumarin fluorescence. The Cou-dhz-Ph-NO2 probe showed high selectivity and fast response with excellent linear relationship for detection of OCl–. A specific OCl–-responsiv...

Currently, the bio-immobilization methods displayed great potential for the removal and recycle of highly toxic metals depending on their gentle and orderly regulated cellular environment. Herein, we have presented a facile and eco-friendly strategy for bio-immobilizing cadmium (Cd) ions and to harvest CdSe quantum dots (QDs) using microalgae cells as bio-reactors. The production process has good environmental benefits for recycling hazardous Cd metal. The biosynthesized CdSe QDs exhibited superior optical properties, good water-solubility, high crystallinity structure, and were monodispersed sphere nanoparticles with approximate range of 5–6 nm in size, clearly comfirmed by the inversed fluorescent microscope, Ultraviolet-visible, photoluminescence, transmission electron microscopy analyses and so on. Owning to their fluorescence quenching effect, the as-obtained CdSe QDs could be deemed as an effective fluorencent nanoprobe for imatinib detection. The linear range for imatinib was calculated to be from 10.43 μg mL−1 to 417.30 μg mL−1 with a low detection limit of 0.014 μg mL−1. More strikingly, the possible formation mechanism of CdSe QDs in algal cells was preliminarily speculated that could be related with the intracellular GSH, which could provide new insights for the possibility for environmental transformation of poisonous metals to fluorescent QDs.

Multilayer molybdenum ditelluride (MoTe2) nanosheets were prepared by liquid-phase exfoliation (LPE) method. A YAG-based MoTe2 saturable absorption (SA) was consequently fabricated. The MoTe2-SA was employed in a passively Q-switched Ho,Pr:LiLuF4 laser at 2.95 μm. Under the absorbed pump power of 3.8 W, an average output power of 90 mW was achieved. The shortest pulse duration of 670 ns was generated with an output power of 73 mW and a repetition rate of 76.46 kHz, corresponding to a pulse energy of 0.95 μJ.

Although 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47), 6-hydroxy-2,2′,4,4′-tetrabromodiphenyl ether (6-OH-BDE-47) and 6-methoxy-2,2′,4,4′-tetrabromodiphenyl ether (6-MeO-BDE-47) clearly disrupt the endocrine system, current knowledge of their single and/or mixture toxicities on other behaviors of aquatic organisms remains limited. In the present study, Daphnia magna was used to investigate the single and mixture toxicities of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 as measured by inhibition of feeding during exposure and post-exposure periods. Additionally, the biochemical performance, i.e., the activities of super oxidase dismutase (SOD), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) of the test organism was studied to investigate the potential mechanisms of the toxicity of the target compounds. The three target compounds produced an obvious depressive effect on feeding behavior during the exposure period, and the effect increased with increasing concentrations. D. magna was most sensitive to 6-OH-BDE-47. The toxicity of the ternary mixture showed an obvious concentration-dependent effect, whereas the binary mixture toxicity showed the characteristics of hormesis. During the post-exposure period, overcompensation occurred, indicating a short-term effect of the target compounds on D. magna. Additionally, significant changes occurred in neurological responses, indicating that these compounds might have neurobehavioral toxicity in D. magna. The decrease in oxidative stress enzymes (SOD and GPx) indicated that the antioxidant response of D. magna was destroyed.

Recently, fluorescent carbon dots as optical sensors have drawn tremendous attention due to their attractive optical properties. Herein, we have presented a facile and economical approach to fabricate nitrogen and sulfur co-doped carbon dots (N, S co-doped C-dots) for the temperature and erlotinib sensing applications. The N, S co-doped C-dots, synthesized by one-step hydrothermal treatment of D-glucose and cysteamine hydrochloride, manifested superior optical performances, good water-solubility, and remarkable fluorescence thermosensitivity. When considered as a temperature sensor, the N, S co-doped C-dots owned significant reversibility, high sensitivity, and good linearity. Moreover, based on the inner filter effect (IFE), the nanoparticle-based sensor displayed a wide linear range of 0.33-13.33 μg mL−1 (R2 = 0.998) and provided an exciting detection limit of 0.027 μg mL−1 for quantifying erlotinib. More strikingly, the C-dots sensing system could commendably resist the interference from potential foreign substances, and achieved satisfactory recoveries, which indicated the excellent selectivity and sufficient accuracy of the sensor for real sample analyses. As a simple and effective optical nanosensor, the proposed N, S co-doped C-dots hold admirable promise to broaden the applications in pharmaceutical analysis and others fields.

A novel fluorescent sensor for the ratiometric detection of biothiols, such as cysteine (Cys) and glutathione (GSH), was developed. This sensor was based on the system composed of fluorescent silver nanoclusters stabilized by single-stranded DNA (DNA–Ag NCs) and Hg2+. The Ag NCs we synthesized had two fluorescence emission peaks, red and green. The red peak was strongly quenched by Hg2+ while the green peak showed a concomitant increase in fluorescence intensity in the presence of Hg2+. In contrast, when biothiols were added to the DNA–Ag NCs–Hg2+ system, there was an increase in the intensity of the red emission peak and a decrease in the intensity of the green emission peak because of the robust Hg–S interaction. By employing the ratio of the DNA–Ag NCs–Hg2+ system's red to green fluorescence emission intensity as a function of biothiol concentration, we obtained satisfactory detection limits and linear relationships of Cys and GSH. Cys and GSH were detected at concentrations as low as 1.59 nM and 2.88 nM, respectively. The capability and potential for practical applications of this method were also demonstrated by detecting biothiols in human serum samples.

In this study, we present a facile one-step solvothermal strategy for the fabrication of sulfur–nitrogen co-doped carbon dots (SNCDs) using p-phenylenediamine and cysteamine hydrochloride as the precursors. The as-prepared SNCDs possess well monodispersed and nearly spherical morphology, and present favorable optical performances encompassing strong yellow-green fluorescence and excitation wavelength-independent fluorescence behavior with the maximum excitation/emission wavelength at 420/550 nm. More strikingly, the emission of SNCDs is effectively quenched by hypochlorous acid (HOCl/ClO−), whereas the SNCDs–HOCl aggregate can be released by zinc(II) ions (Zn2+) causing a fluorescence enhancement/recovery process. As such, we designed a SNCD-based fluorescence “off–on” nanosensor for HOCl and Zn2+ detection. The “turn off” mode enables the quantitative analysis of HOCl with a linear range of 0.18–4.22 μM and a detection limit of 0.021 μM. And the quantitative range for Zn2+ detection based on the “turn on” process is from 8.41 to 84.12 μM with a detection limit of 0.30 μM. Moreover, the fluorescent nanoprobe was applied for the assay of HOCl/ClO− and Zn2+ in water samples with satisfactory recovery values and in MCF-7 cell imaging with negligible autofluorescence, indicating its promising application potential in chemical, environmental and biological systems.

A hybrid self-growing polymer microtip is firstly proposed and fabricated as an ultracompact fiber-tip Fabry-Perot interferometer (FPI) with enhanced figure of merit (FoM). The hybrid microtip FPI is based on a sharp polymer microtip grown on an ultraviolet (UV) cured polymer film at the fiber end, which has exhibited significant interferometric visibility with high fringe contrast up to 30 dB in the reflection spectra. Using this tiny FPI, an optical fiber relative humidity (RH) sensor with the enhanced FoM of ∼ 0.95/%RH was demonstrated, which is ∼30 times higher than the previous optical fiber-based humidity sensors, and the achieved sensitivity is high enough to perform real-time human breath observation. Furthermore, the humidity sensor exhibited excellent performance in monitoring human breath with fast response time of ∼ 0.6 s. This new type of photonic microtip RH sensing element has shown advantages of compactness, flexibility, fast-response and high sensitivity, which provides a promising platform for potential applications in environmental and biological RH sensing, especially in a restricted space environment.

Microstructured optical fibers (MOFs) have attracted intensive research interest in fiber-based optofluidics owing to their ability to have high-efficient light-microfluid interactions over a long distance. However, there lacks an exquisite design guidance for the utilization of MOFs in subwavelength-scale optofluidics. Here we propose a tapered hollow-core MOF structure with both light and fluid confined inside the central hole and investigate its optofluidic guiding properties by varying the diameter using the full vector finite element method. The basic optical modal properties, the effective sensitivity, and the nonlinearity characteristics are studied. Our miniature optofluidic waveguide achieves a maximum fraction of power inside the core at 99.7%, an ultra-small effective mode area of 0.38 µm2, an ultra-low confinement loss, and a controllable group velocity dispersion. It can serve as a promising platform in the subwavelength-scale optical devices for optical sensing and nonlinear optics.

Compared to Bisphenol A (BPA), current knowledge on the spatial distribution, potential sources and environmental risk assessment of other bisphenol analogues (BPs) remains limited. The occurrence, distribution and sources of seven BPs were investigated in the surface water and sediment from Taihu Lake and Luoma Lake, which are the Chinese shallow freshwater lakes. Because there are many industries and living areas around Taihu Lake, the total concentrations of ∑BPs were much higher than that in Luoma Lake, which is away from the industry-intensive areas. For the two lakes, BPA was still the dominant BPs in both surface water and sediment, followed by BPF and BPS. The spatial distribution and principal component analysis showed that BPs in Luoma Lake was relatively homogeneous and the potential sources were relatively simple than that in Taihu Lake. The spatial distribution of BPs in sediment of Taihu Lake indicated that ∑BPs positively correlated with the TOC content. For both Taihu Lake and Luoma Lake, the risk assessment at the sampling sites showed that no high risk in surface water and sediment (RQt < 1.0, and EEQt < 1.0 ng E2/L).

The anticancer drugs are getting increasing attention as an emerging contaminant in the aquatic environments. In the present study, feeding behavior of the rotifer Brachionus calyciflorus under the impact of anticancer drug imatinib was evaluated. Traditional toxicological studies usually focus on dose-effect relationship at a given exposure time, while ignore the possible impact after the exposure. Thus, how the impact varied in the post-exposure and re-exposure was also considered in the present study. The feeding depression of the rotifers was attributed to the increased concentration of imatinib. Although the filtration and ingestion rate of the rotifers recovered to a certain extent after the exposure, the significant feeding inhibition still persisted even if the exposure was ended. In the re-exposure period, the feeding behavior was less depressed than those of the exposure period, which implied that rotifers might develop a tolerance to the same toxics. The activities of acetylcholine esterase (AchE) and the levels of reactive oxygen species (ROS) in rotifers were also detected. Imatinib inhibited the activities of AchE in the exposure and re-exposure while ROS levels increased significantly in the re-exposure period. Our present study provided an integrated assessment the potential environmental risks of imatinib at a new perspective.