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Rationale: Precise treatment of tumors is attracting increasing attention. Molecular probes simultaneously demonstrating the diagnostic signal and pharmacological effect in response to tumor microenvironment are highly desired. γ-glutamyl transpeptidase (GGT) is a biomarker with significantly up-regulated expression in the tumor area. We developed a GGT responsive near-infrared (NIR) nanoassembly for tumor-specific fluorescence imaging-guided photothermal therapy. Methods: The GGT responsive NIR probe was constructed by conjugating GGT-specific substrate γ-glutamic acid (γ-Glu) with cyanine fluorophore (NRh-NH2) via amide reaction. The resulting NRh-G spontaneously assembled into nanoparticles (NRh-G-NPs) around 50 nm. The NPs were characterized and the properties evaluated in the presence or absence of GGT. Subsequently, we studied fluorescence imaging and photothermal therapy of NRh-G-NPs in vitro and in vivo. Results: NRh-G-NPs, upon specific reaction with GGT, turned into NRh-NH2-NPs, showing a ~180-fold fluorescence enhancement and excellent photothermal effect recovery. NRh-G-NPs could selectively light up U87MG tumor cells while their fluorescence was weak in L02 human normal liver cells. The NPs also showed excellent tumor cell ablation upon laser irradiation. After intravenous injection into tumor-bearing mice, NRh-G-NPs could arrive in the tumor area and specifically light up the tumor. Following laser irradiation, the tumor could be completely erased with no tumor reoccurrence for up to 40 days. Conclusions: NRh-G-NPs were specifically responsive to GGT overexpressed in U87MG tumor cells and selectively lit up the tumor for imaging-guided therapy. Besides, the recovery of photothermal property in the tumor area could improve cancer therapy precision and decreased side effects in normal tissues.

Multimaterial fibers which integrate novel materials and/or structures into fiber configuration aim at developing multiple functionalities and high performance. Here, we demonstrate a kind of multimaterial fibers with crystalline GeSe core and K9 glass cladding by the molten core drawing method. The as-drawn fibers undergo a change in electrical conductivity when externally illuminated by an 808 nm HeNe laser. Furthermore, the Seebeck coefficient of the fibers is comparable with bulk GeSe, while the resistance is 3–4 magnitude lower than that. The results show that the GeSe core fibers have promising applications in optical switch and thermoelectric conversion field.

Bismuth selenide exhibits high thermoelectric performance, which is a promising candidate for thermal-electrical energy conversion. Here, Bi2Se3 core thermoelectric fibers with K9 glass cladding were fabricated by a molten core drawing method. The 50-μm-diameter Bi2Se3 core fibers exhibit an ultrahigh Seebeck coefficient of −150.85 μV/K. In addition, it has a high dimensionless figure of merit of 0.18 (at 300 K) and a long-term stability in air. The results indicate that the drawing approach is an effective way to fabricate high-performance and high-stability thermoelectric fibers, which will have potential application in fiber-integrated thermoelectric devices.

Non-invasive and accurate detection of copper is essential to elucidate its functions. Herein, we report a mitochondria-targeted near-infrared probe (NFL-TPA) for bioimaging of copper. The probe exhibits high sensitivity and selectivity for copper(I) with low detect of limit (14.4 nM). More importantly, the probe can monitor the level of copper(I) in mitochondria, and successfully detect the distribution of copper(I) in living mice by near infrared fluorescence (NIR) imaging in vivo and ex vivo. Furthermore, the probe could assess the therapeutic efficiency of d -penicillamine. Thus, the probe motivates the development of novel NIR platform for copper(I) detection and drug evaluation.

The target of this work is to survey the consequences of various B (B Fe, Co) sites of SmBO3 perovskite on crystal structure and ethylene glycol gas-sensitive properties. To this end, two samples based on SmFeO3 and SmCoO3 nanofibers with orthorhombic phase were prepared by a straightforward and efficient electrospinning technique and calcined at 700 °C. The XRD Rietveld refinements and tolerance factor (t) were implemented to research the crystal structure by the lattice parameters, size of B O B angles and t value, BET test shows that as-prepared two samples own different pore sizes, and XPS analyzes the composition and chemical state toward two samples, which indicates that more oxygen vacancies exist in SmFeO3 surface. Then, the gas-sensing performance of SmFeO3 and SmCoO3 nanofibers were compared at their optimal working temperature of 200 °C. The gas-sensing inquiries exhibit that the response of sensor based on SmFeO3 nanofiber (14.3) is almost 6.5 times higher than that of SmCoO3 (2.2) toward 100 ppm ethylene glycol. Finally, the sensing mechanisms of SmFeO3 and SmCoO3 nanofibers were also explained based on pore size, oxygen vacancy, lattice distortion and electrical conductance.

At present, gas sensors have promising prospects in terms of gas monitoring. Heterostructure with high carrier transport property is an alternative strategy to enhance the gas sensitivity. Herein, we directly transformed ZnSn(OH)6 microspheres to obtain SnS2/ZnS heterostructures through a low-cost hydrothermal treatment. Hierarchical SnS2/ZnS flowerlike microspheres consisting of ultrathin nanoflakes subunits were successfully synthesized without any impurities. The more attractive finding is the great improvement of triethylamine gas-sensing properties of the SnS2/ZnS composite compared to the pure SnS2 at 180 °C. Especially, the proposed SnS2/ZnS sensor demonstrates ultrafast responding and recovering time (2/8 s) to 50 ppm TEA. Such significantly enhanced sensing properties can be ascribed to the merit of heterojunction and high specific surface area provided by flakes-assembled flowerlike structure. Moreover, the convenient synthetic route paves the way to the future design of various heterojunctions for diverse gas detection.

Pr-doped SnO2 hollow beaded tubular nanostructure was synthesized by electrospinning technique, accompanied by using carbon spheres as sacrificial templates. The crystalline phase, morphology, microstructure, and element composition of the samples were explored and analyzed. The gas sensitivity test results show that Pr-doped SnO2 sensor exhibits high response value, excellent selectivity and rapid response-recovery ability to ethanol at 200 °C. The sensor can effectively detect ethanol vapor as low as 2 ppm. Response/recovery time to 100 ppm ethanol are about 12 s/8 s, respectively. The possible enhancement mechanism caused by the synergistic effect of the unique nanostructure, the carbon templates, and Pr dopant are discussed. The research may provide a better design of ethanol sensors.

Tin selenide (SnSe) exhibits high thermoelectric (TE) performance, which is a promising TE candidate for thermal-electrical energy conversion. In this work, Sn-Se alloy core borosilicate glass-clad fibers with ∼94 μm core and ∼220 μm cladding in diameter were fabricated by a molten core drawing method. X-ray diffraction (XRD) showed the core to be highly crystalline and consist of SnSe and SnSe2 poly-crystal grains. Based on EPMA measurement, there exists an inter-diffusion process between the core and cladding ions during the fiber drawing. The Seebeck coefficient of the Sn-Se core is −151 μV/K. The electrical conductivity of the Sn-Se core is as high as 6.2 × 103 S/m, which is close to that of SnSe single crystals. The demonstration of fibers with TE core materials and the integration with the conventional fiber fabrication technique represents the first step in providing the building blocks for fiber-integrated TE devices.

Aerogels are usually synthesized from supercritical drying of wet-gels. High quality aerogels are usually characterized with high specific surface area (measured by BET method here) and high degree of polymerization of silicate (characterized by 29 Si NMR here). The quality of the aerogels depends highly on the quality of the corresponding wet-gels because the skeletal structure in the wet-gels changes only slightly in the supercritical drying process. Here we present a simple method to predict the quality of the desired silica aerogels before the supercritical drying. We found that the relative optical transmittance of the silica wet-gels at 500 nm had good linear correlation with the specific surface area and the degree of silicate polymerization in the corresponding aerogels. We can assess the quality and screen out the low-quality wet-gels from supercritical drying operation, and greatly reduce the cost for aerogel production.

A new type of thermally sensitive fibers with an antimony selenide (Sb 2 Se 3 ) core and phosphate glass cladding is demonstrated. The fibers were fabricated by a molten core method and maintained overall diameters ranging from 250 to 800 μm and core diameters of 35–200 μm. A 2.8 cm long Sb 2 Se 3 core fiber, electrically contacted to external circuitry through fiber end facets, exhibited a four orders of magnitude change in conductivity after the whole fiber was heated from 25 to 195 °C. In addition, the fiber exhibited enhanced photoconductivity under illumination. These results indicate that Sb 2 Se 3 core multimaterial fibers have promising applications in temperature sensing, optical switches and photodetectors.

In4Se3 exhibits high thermoelectric performance as a typical example of semiconductors, which is a promising thermoelectric candidate for energy conversion applications. Here, InSe alloy core thermoelectric fibers with glass cladding were fabricated by a reactive molten core drawing method. The as-drawn fiber core was found to be InSe crystals as evidenced by X-ray diffraction. The In4Se3 crystals were obtained in the fiber core by annealing the as-drawn fibers. The Seebeck coefficient of the In4Se3 core fibers (−347 μV/K) was enhanced by ∼85% compared with that of the as-drawn InSe core fibers (−189 μV/K). This work constitutes a proof-of-concept that thermoelectric materials can be incorporated into fibers, which have promising applications in fiber-based thermoelectric devices.

Solution-processed organo-lead halide perovskites have emerged as promising optical gain media for tunable coherent light sources. The lasing performance is generally determined by the as-synthesized crystal quality. Noble metal nanostructures have been widely utilized to enhance optical responses due to their unique property of localized surface plasmon resonance. Herein, we report a simple method to enhance the near-infrared amplified spontaneous emission (ASE) performance of MAPbI3 polycrystalline films by solution-processing a PMMA spacer layer and an Au NR-doped PMMA top layer on perovskite thin films. As a result, the ASE threshold of the triple-layer perovskite film was significantly reduced by around 36% and the ASE intensity increased by 13.9-fold, compared to the pristine film. The underlying mechanism was attributed to the combined effects of surface passivation by PMMA and plasmon resonance enhancement of Au NRs. The passivation effect results in suppressing the nonradiative recombination and prolonging excited state decay, which have been investigated by transient absorption and pump–probe measurements. The plasmon effect is systematically studied through distance-dependent and spectra-dependent plasmon enhanced emission. The perovskite films with PMMA and Au NR coating showed great stability for 180 min under intense pulse laser continuous irradiation. The improved ASE performance still remained after leaving the film under the atmosphere for more than one month. We have successfully demonstrated a highly stable and sustained ASE output from MAPbI3 films under pulse laser excitation. This study provides a general approach for exploring plasmonic nanostructures in combination with polymers in the development and application of low-cost solution-processed semiconductor lasers.

Accurate detection of HOCl with high sensitivity and high selectivity is essential to elucidate its functions in health or disease states. Herein we propose a new fluorescence HOCl probe (NFL-S) by combining reasonable design strategies and dye screening methods. The probe NFL-S has fast response rate, excellent sensitivity (LOD = 35.0 nM) and outstanding selectivity toward HOCl. It has been successfully applied to detect endogenous HOCl produced by RAW264.7 cells, and further applied to oxidative stress imaging in a mouse arthritis model. Therefore, the probe NFL-S is highly promising to be useful for biological tool to disclose the roles of HOCl in different physiological and pathological contexts.

A convenient two-step hydrothermal method was used to prepare unique hierarchical MoS2/ZnO composites composed of porous microspheres and nanosheets. The gas sensing properties of MoS2/ZnO composite sensor was investigated. Compared with pure MoS2, the MoS2/ZnO composite sensor shows a remarkably increased response of 23.57 to triethylamine (TEA). In addition, the much shorter recovery time for MoS2/ZnO sensor is a sharp contrast to the terribly bad desorption ability of pure MoS2. The prepared MoS2/ZnO gas sensor can achieve a recovery rate of over 90 % after 134 s without using auxiliary means. The composite material also presents strong anti-interference ability and outstanding selectivity. The excellent sensing performances of MoS2/ZnO composite sensor may be attributed to the n-n composite heterojunction and the abundant diffusion channels originated from the unique microstructure. Our research work may provide a valuable strategy for preparing high-performance TEA sensor with low-cost.

Highly rare earth ions (RE-ions) doping phosphate glass fiber makes it possible to obtain high gain and high output power per unit length. However, high concentrations of RE-ions will cause concentration quenching and crystallization during the conventional rod-in-tube fiber drawing process. In this work, highly Er 3 + /Yb 3 + co-doped multi-component phosphate glasses were prepared by the melt-quenching method. Through thorough investigation of 1.53 μm luminescent properties of the glasses, optimal RE-ions were ascertained. The Er 3 + and Yb 3 + doping concentrations reach as high as 13.77 × 10 20 and 2.295 × 10 20 ions/cm 3 , respectively. Then the silicate-clad highly Er 3 + /Yb 3 + co-doped phosphate core multimaterial fibers were successfully fabricated by a molten core method. The multimaterial fibers have a large refractive index difference and good interface between the phosphate glass core and silicate glass cladding. An intense 1.53 μm emission was obtained from the multimaterial fiber. The results indicate that the highly Er 3 + /Yb 3 + co-doped multimaterial fibers are promising in applications that require high gain and high power from a short piece of active optical fiber.

We report the visible up-conversion, near to middle infrared luminescence, and energy transfer mechanism of Er 3+ /Ho 3+ co-doped barium gallo-germanate glasses under 980 and 1550 nm excitations, respectively. The 2.0 μm emission lifetime of the present glass is as high as 5.67 ms with the corresponding energy transfer efficiency of 70.0% from Er 3+ : 4 I 13/2 to Ho 3+ : 5 I 7 when pumped by 980 nm laser diode. In addition, the enhanced 2.0 μm emission is also obtained upon excitation of 1550 nm due to the efficient energy transfer from Er 3+ to Ho 3+ . Meanwhile, the calculated maximum gain is 2.13 cm −1 at 2024 nm. These results suggest that Er 3+ /Ho 3+ co-doped barium gallo-germanate glasses is a potential material for 2.0 μm fiber laser.

Elemental bismuth (Bi) exhibits a high magnetoresistance as a typical example of semimetal, which has significant application in information technologies. Silicate glass-clad Bi core fibers were fabricated by a molten core method and maintained core diameter of 100–150 µm and overall diameter of 300–450 µm. X-ray diffraction (XRD) and micro-Raman spectra showed the core to be highly crystalline with no observed secondary phases. Electro-probe micro-analyzer (EPMA) measurements confirmed a very well-defined core-clad interface. Demonstration of fibers with high magnetoresistance core materials and the potential integration with current state of the art technologies represents the first step in providing the building blocks for all-fiber sensors.

In this work, we successfully synthesized heterostructured ZnO-SnO2 composite nanotubes for high performance glycol gas sensor combined with certain calcination treatment. The as-prepared sample was characterized by various technologies. The sensor based on this hybrid nanotube displayed high response (47.71) toward 150 ppm glycol at 210 °C with response/recovery time of approximately 55 and 13 s respectively, even to 5 ppm glycol with a response of about 2.16. It also showed excellent repeatability and long-term stability. These good sensing properties are mainly attributed to the ZnO-SnO2 hollow heterostructure which possesses a large surface area and porosity. Besides, the sensing mechanism was elaborated at length.

In this study, perovskite samarium ferrite (SmFeO3) nanofibers have been successfully fabricated by electrospinning route and calcination process. The as-prepared sample was characterized by various technologies. The results show that the surfaces of SmFeO3 nanofibers are of extreme depression and roughness, which increases contact area between gases and material surface, contributing to enhancing gas sensing properties. The sensor based on as-prepared SmFeO3 nanofibers owns good response and distinct selectivity to ethylene glycol, and response value reaches 18.19 to 100 ppm ethylene glycol at 240 °C, even to 5 ppm ethylene glycol with high response value of 2.18. In addition, the gas sensing mechanism based on hole accumulation layer model was explained in detail.

In this work, we studied Pr doped BiFeO3 hollow nanofibers as a potential functional material, assembled from nanoparticles through electrospinning technique and calcination route, which were decorated by Pr ions and ameliorated by hollow nanofiber structure. The Pr doped BiFeO3 hollow nanofibers, improved by the uniform and tubular structure with a larger specific surface area (63.53 m2/g), higher pore size (38.17 nm) and smaller grain size, revealed better response to formaldehyde (50 ppm, 190 °C, Rgas/Rair = 17.6) along with long-term stability. Moreover, the influence of the relative humidity in atmosphere on the gas performance of the as-prepared sensors was also investigated.

Bi2Te3-based materials have been reported to be one of the best room-temperature thermoelectric materials, and it is a challenge to substantially improve their thermoelectric properties. Here novel Bi2Te3 core fibers with borosilicate glass cladding were fabricated utilizing a modified molten core drawing method. The Bi2Te3 core of the fiber was found to consist of hexagonal polycrystalline nanosheets, and polycrystalline nanosheets had a preferential orientation; in other words, the hexagonal Bi2Te3 lamellar cleavage more tended to be parallel to the symmetry axis of the fibers. Compared with a homemade 3-mm-diameter Bi2Te3 rod, the polycrystalline nanosheets’ preferential orientation in the 89-μm-diameter Bi2Te3 core increased its electrical conductivity, but deduced its Seebeck coefficient. The Bi2Te3 core exhibits an ultrahigh ZT of 0.73 at 300 K, which is 232% higher than that of the Bi2Te3 rod. The demonstration of fibers with oriented nano-polycrystalline core and the integration with an efficient fabrication technique will pave the way for the fabrication of high-performance thermoelectric fibers.

A method of fabricating selenium (Se) microwire is demonstrated. A multimaterial fiber with amorphous selenium (a-Se) core and multicomponent phosphate glass cladding is drawn by using a conventional optical fiber drawing technique. Then the a-Se core of the fiber is crystallized by a post thermal process at 150 °C. After the multicomponent phosphate glass cladding is stripped from the multimaterial fiber by marinating the fiber in HF acid solution, a crystalline selenium (c-Se) microwire with high uniformity and smooth surface is obtained. Based on microstructure measurements, the c-Se microwire is identified to consist of most hexagonal state particles and very few trigonal state whiskers. The good photoconduction property of c-Se microwire with high quality and longer continuous length makes it possible to apply to functional devices and arrays.

Tm3+ doped lead silicate glasses with good thermal stability were prepared by the melt-quenching method. Based on the absorption and emission spectra, Judd-Ofelt intensity parameters, absorption and emission cross sections, gain spectra, and σe × FWHM were calculated and analyzed. These results suggest that Tm3+ doped lead silicate glasses are promising as mid-infrared laser materials. Tm3+ doped lead silicate glass single mode (SM) fibers with cladding diameter of 125 μm and core diameter of 8.5 μm were then fabricated by the rod-in-tube technique. The Tm3+ doping concentration reached as high as 4.545 × 1020 ions/cm3. ~2.0 μm amplified spontaneous emission (ASE) was realized in a 3.5-cm-long as-drawn SM fiber when pumped by a homemade single mode 1560 nm fiber laser. The results indicate that these Tm3+ doped lead silicate glass single mode fibers are promising fiber material for 2.0 μm fiber laser applications.