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Deng Y.,Guangdong University of Technology | Deng Y.,Ecole Polytechnique Federale de Lausanne | Deng Y.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Renaud P.,Ecole Polytechnique Federale de Lausanne | And 3 more authors.
Journal of Biological Engineering | Year: 2017

Background: A viable single cell is crucial for studies of single cell biology. In this paper, laser-induced forward transfer (LIFT) was used to isolate individual cell with a closed chamber designed to avoid contamination and maintain humidity. Hela cells were used to study the impact of laser pulse energy, laser spot size, sacrificed layer thickness and working distance. The size distribution, number and proliferation ratio of separated cells were statistically evaluated. Glycerol was used to increase the viscosity of the medium and alginate were introduced to soften the landing process. Results: The role of laser pulse energy, the spot size and the thickness of titanium in energy absorption in LIFT process was theoretically analyzed with Lambert-Beer and a thermal conductive model. After comprehensive analysis, mechanical damage was found to be the dominant factor affecting the size and proliferation ratio of the isolated cells. An orthogonal experiment was conducted, and the optimal conditions were determined as: laser pulse energy, 9 μJ; spot size, 60 μm; thickness of titanium, 12 nm; working distance, 700 μm;, glycerol, 2% and alginate depth, greater than 1 μm. With these conditions, along with continuous incubation, a single cell could be transferred by the LIFT with one shot, with limited effect on cell size and viability. Conclusion: LIFT conducted in a closed chamber under optimized condition is a promising method for reliably isolating single cells. © 2017 The Author(s).


Tan J.,Guangdong University of Technology | Tan J.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Huang C.,Guangdong University of Technology | Liu D.,Guangdong University of Technology | And 4 more authors.
ACS Macro Letters | Year: 2016

We report a fast alcoholic photoinitiated polymerization-induced self-assembly (photo-PISA) formulation via photoinitiated RAFT dispersion polymerization of isobornyl acrylate (IBOA) in an ethanol/water mixture at 40 °C using a monomethoxy poly(ethylene glycol) (mPEG) based chain transfer agent. Polymerization proceeded rapidly via the exposure to visible light irradiation (405 nm, 0.5 mW/cm2), and high monomer conversion (>95%) was achieved within 30 min. Kinetic studies confirmed that good control was maintained during the photo-PISA process, and the polymerization can be activated or deactivated by light. Finally, we demonstrated that a diverse set of complex morphologies (spheres, worms, or vesicles) could be achieved by varying reaction parameters, and a phase diagram was constructed. © 2016 American Chemical Society.


Li J.,Guangdong University of Technology | Zhang H.,Guangdong University of Technology | Zhang H.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Wang W.,Guangdong University of Technology | And 3 more authors.
Physica B: Condensed Matter | Year: 2016

The dye-sensitized solar cell (DSSC) based on TiO2 photoanode with FTO glass and TiO2 film co-treated by TiCl4 were fabricated. The effects of TiCl4 treatment on the photovoltaic performance of the DSSCs were investigated. TiCl4 treatment of the FTO glass resulted in the formation of a compact TiO2 thin layer on its surface, which could increase the electron collection efficiency. Meanwhile, TiCl4 treatment of the TiO2 film could fill gaps between nanoparticles in the TiO2 film, leading to better electron transfer. These advantages make the DSSC exhibit a highest conversion efficiency of 3.34% under a simulated solar irradiation with an intensity of 100 mW/cm2 (1 sun), increased by 38% compared with that of the untreated DSSC. © 2016 Elsevier B.V.


Tan J.,Guangdong University of Technology | Tan J.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Bai Y.,Guangdong University of Technology | Zhang X.,Guangdong University of Technology | And 2 more authors.
Polymer Chemistry | Year: 2016

The photoinitiated polymerization-induced self-assembly (photo-PISA) of 2-hydroxypropyl methacrylate (HPMA) is conducted in water by using poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) based macro-RAFT agents. Polymerizations were carried out at room temperature via exposure to visible light irradiation, and quantitative monomer conversions (>99%) were achieved within 30 min of visible light irradiation. A remarkably diverse set of complex morphologies (spheres, worms, and vesicles) have been prepared by aqueous photo-PISA under mild conditions (water medium, room temperature, and visible light). The morphology of nano-objects can be tuned by changing the reaction parameters (e.g. degree of polymerization, solids concentration), and two detailed phase diagrams were constructed. The polymerization can be activated or deactivated by a simple "ON/OFF" switch of the light source. A thermo-responsive behavior of PPEGMA14-PHPMA200 nanoparticles prepared at 15% w/w was investigated by changing the temperature from 25°C to 4°C. © The Royal Society of Chemistry 2016.


Zhao Y.,Guangdong University of Technology | Zhao Y.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Wei A.-X.,Guangdong University of Technology | Wei A.-X.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | And 2 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2015

Junction temperature, as one of the most important properties of light-emitting diodes (LEDs), has great impact on LEDs' power efficiency, luminosity, reliability, life-time, and so on. Precise measurement of junction temperature for LED device is quite important in the research of chip's fabrication, device packaging and related applications. In this paper, we propose a new approach to measure the junction temperature of LEDs by using temperature-dependent capacitance. The capacitance of white LEDs at room temperature is measured and found to be decreased first and then increased with an increasing reverse bias. Equivalent model using vertical and horizontal capacitances connected in parallel is proposed to qualitatively explain the variation of capacitance under different reverse bias. Result obtained from the model fitting agrees well with the experimental result. The capacitance-temperature (C-T) curve of white LEDs under different reverse bias is measured and analysed. Results show that the capacitance of LEDs is sensitive to temperature at all biases. Under a reverse voltage of 0.5 V, the capacitance has the maximal response of 1.971 pF/℃ and a good linear temperature-dependent property. The C-T curve is used as the calibration for the measurement of junction temperature. By monitoring the change of capacitance of the working LEDs and comparing it with the C-T curve, the junction temperature of the LED device is successfully measured. The junction temperature of a white LED obtained by the proposed C-T method is compared with that by tranditional forward voltage method, and they are in good agreement. The C-T method is also used to measure the real-time junction temperatures of white LEDs under a constant current of 350 mA and a constant voltage of 3.2 V, respectively. In both conditions, the junction temperature of an LED needs approximately 110 sec to rise from room temperature to a steady value, and subsequently needs approximately 500 sec to fall back to room temperature after the LED is turned off. Compared with traditional methods, C-T method only needs to measure one calibration and this calibration can be applied to LEDs working at any current and voltage. Therefore, C-T method is a simple and flexible alternative to the existing technique of temperature measurement in electronic device. ©, 2015, Chinese Physical Society. All right reserved.


Liu L.,Guangdong University of Technology | Liu L.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Qiu Y.,Guangdong University of Technology | Qiu Y.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | And 6 more authors.
Journal of Power Sources | Year: 2015

A series of neodymium doped Li3V2-xNdx(PO4)3/C cathode materials have been successfully synthesized by a citric acid assisted sol-gel method. Nd doped samples (x < 0.10) have well developed monoclinic structure of Li;3V;2(PO;4)3 with enlarged unit cell volume. All samples present typical characteristics of paramagnetism in 4 < T < 300 K, but the magnetic susceptibilities of Nd doped samples increase with Nd content (except for x = 0.15). Nd doped composites show better electrochemical property than that of the undoped one. Among them, the Li3V1.95Nd0.05(PO4)3/C displays the highest capacity and best cycle stability. The Li3V1.95Nd0.05(PO4)3/C presents the first discharge capacity of 129.2 mAh g-1 at 1 C rate in the voltage range of 3.0-4.3 V, 21.7% higher than that of Li3V2(PO4)3/C. And no capacity loss occurs after 100 cycles. The high structural stability, low charge-transfer resistance and rapid Li+ diffusion due to the presence of Nd3+ are mainly responsible for the superior electrochemical performance of Nd doped Li3V2(PO4)3/C cathode materials. © 2015 Elsevier B.V. All rights reserved.


Xu R.,Guangdong University of Technology | Lei C.,Guangdong University of Technology | Lei C.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Cai Q.,Guangdong University of Technology | And 2 more authors.
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2015

Polypropylene thermal conductive composites with different hybrid fillers were prepared, and the thermal conductivity, electrical conductivity and rheological properties were tested. The results show that the thermal conductivity is improved by adding hybrid parts. By adding 10% of carbon black and carbon nanotube simple mixture and chemical bonded filler to PP/Al2O3 composite, the thermal conductivity is improved to 0.60 W/mk and 0.63 W/mk, respectively. Using pure carbon black and pure carbon nanotubes as hybrid parts, the thermal conductivity is only 0.36 W/mk and 0.45 W/mk. The volume resistance declines 106 order of magnitude for the composite using carbon nanotube and the simple mixture, whereas the composite filled with pure carbon black or chemical bonded fillers show insulation behavior. An obvious shear thinning phenomenon appears in η* vs. ω curves after adding hybrid parts. A second plateau at low frequency region is observed, but it is very weak for the chemical bonded filler modified composites. For this composite, the microstructure shows that the filler distributes well in the matrix and connecting bridges are formed between the fillers. The results show that the thermal conductivity cannot be improved pronouncedly by pure carbon black or pure carbon nanotube. The simple mixture of carbon black and carbon nanotube can induce better thermal conductivity, but it will also lead to some electrical conductivity. The application of chemical bonded carbon black and carbon nanotube can meet the demand of thermally conductive and insulated composites. ©, 2015, Chengdu University of Science and Technology. All right reserved.


Lei X.,Guangdong University of Technology | Zhang H.,Guangdong University of Technology | Zhang H.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Chen Y.,Guangdong University of Technology | And 8 more authors.
Journal of Alloys and Compounds | Year: 2015

A three-dimensional lithium iron phosphate (LiFePO4)/carbon nanotubes (CNTs)/graphene composite was successfully synthesized via solid-state reaction. The LiFePO4/carbon nanotubes/graphene (LFP-CNT-G) composite used as Li-ions battery cathode material exhibits superior high-rate capability and favorable charge-discharge cycle performance under relative high current density compared with that of LiFePO4/carbon nanotubes (LFP-CNT) composite and LiFePO4/graphene (LFP-G) composite. Graphene nanosheets and CNTs construct 3D conducting networks are favor for faster electron transfer, higher Li-ions diffusion coefficient and lower resistance during the Li-ions reversible reaction. The synergistic effect of graphene nanosheets and CNTs improves the rate capability and cycling stability of LiFePO4-based cathodes. The LFP-CNT-G electrode shows reversible capacity of 168.9 mA h g-1 at 0.2 C and 115.8 mA h g-1 at 20 C. The electrochemical impedance spectroscopy demonstrate that the LFP-CNT-G electrode has the smallest charge-transfer resistance, indicating that the fast electron transfer from the electrolyte to the LFP-CNT-G active materials in the Li-ions intercalation/deintercalation reactions owing to the three-dimensional networks of graphene and carbon nanotubes. © 2014 Elsevier B.V. All rights reserved.


Tan J.,Guangdong University of Technology | Tan J.,Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter | Bai Y.,Guangdong University of Technology | Zhang X.,Guangdong University of Technology | And 4 more authors.
Macromolecular Rapid Communications | Year: 2016

Photoinitiated reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of 2-hydroxypropyl methacrylate is conducted in water at low temperature using thermoresponsive copolymers of 2-(2-methoxyethoxy) ethyl methacrylate and oligo(ethylene glycol) methacrylate (Mn = 475 g mol−1) as the macro-RAFT agent. Kinetic studies confirm that quantitative monomer conversion is achieved within 15 min of visible-light irradiation (405 nm, 0.5 mW cm−2), and good control is maintained during the polymerization. The polymerization can be temporally controlled by a simple “ON/OFF” switch of the light source. Finally, thermoresponsive diblock copolymer nano-objects with a diverse set of complex morphologies (spheres, worms, and vesicles) are prepared using this particular formulation. (Figure presented.). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


PubMed | Ecole Polytechnique Federale de Lausanne, Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter and Guangdong University of Technology
Type: | Journal: Journal of biological engineering | Year: 2017

A viable single cell is crucial for studies of single cell biology. In this paper, laser-induced forward transfer (LIFT) was used to isolate individual cell with a closed chamberdesigned to avoid contamination and maintain humidity. Hela cells were used to study the impact of laser pulse energy, laser spot size, sacrificed layer thickness and working distance. The size distribution, number and proliferation ratio of separated cells were statistically evaluated. Glycerol was used to increase the viscosity of the medium and alginate were introduced to soften the landing process.The role of laser pulse energy, the spot size and the thickness of titanium in energy absorption in LIFT process was theoretically analyzed with Lambert-Beer and a thermal conductive model. After comprehensive analysis, mechanical damage was found to be the dominant factor affecting the size and proliferation ratio of the isolated cells. An orthogonal experiment was conducted, and the optimal conditions were determined as: laser pulse energy, 9J; spot size, 60m; thickness of titanium, 12nm; working distance, 700m;, glycerol, 2% and alginate depth, greater than 1m. With these conditions, along with continuous incubation, a single cell could be transferred by the LIFT with one shot, with limited effect on cell size and viability.LIFT conducted in a closed chamber under optimized condition is a promising method for reliably isolating single cells.

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