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An inorganic caesium cation was incorporated into perovskite to improve the performance and stability of solar cells with a hole-transport-material free structure in ambient air. A triple cation device with a champion power conversion efficiency of over 15% was achieved, exhibiting superior thermal, long-term and operational stabilities.

Hole transport material free (HTM-free) perovskite solar cells (PSCs) with carbon counter electrode have the advantages of low-cost, good efficiency and high stability. Here in this work, we demonstrate that incorporating Au@SiO2 core-shell NPs into TiO2 scaffold layer increases the power conversion efficiencies (PCEs) of PSCs by improving the light absorption and facilitating carrier transfer or separation through SPR effect. With the optimal concentration of 0.3 wt % Au@SiO2 incorporation, the average PCE of PSCs enhances to 13.85 ± 0.45% from the reference samples of 12.01 ± 0.44%, which is mainly caused by the improved short circuit current density.

Effective capture and release of circulating tumor cells (CTCs) with high viability is still a challenge in medical research. We design a novel approach with efficient yield and high cell activity for the capture and release of CTCs. Our platform is based on TiO2 nanorod arrays coated with transparent MnO2 nanoparticles. We use hydrothermal synthesis to prepare TiO2 nanorod arrays, the MnO2 nanoparticles are fabricated through in situ self-assembly on the substrate to form a monolayer and etched by oxalic acid with low concentration at room temperature. Up to 92.9% of target cells are isolated from the samples using our capture system and the captured cells can be released from the platform, the saturated release efficiency is 89.9%. Employing lower than 2 × 10-3 M concentration of oxalic acid to dissolve MnO2, the viability of MCF-7 cancer cells exceed 90%. Such a combination of the two-dimensional and three-dimensional platforms provides a new approach isolate CTCs from patient blood samples.

Anatase TiO2 ultra-thin nanosheets (TiO2-NS) are synthesized by a facile hydrothermal method. Several merits are realized when employing the prepared TiO2-NS as lithium ion battery anode material, compared to TiO2 nanoparticles. Firstly, the as-prepared TiO2-NS has high charge capacities and a specific surface area up to 98.8 m2g−1, which is beneficial for the insertion of lithium ion. Secondly, the large specific surface area is helpful in enlarging the electrode/electrolyte interfacial area. Finally, the EIS result verifies short electron transfer paths. More importantly, the stability of the nanosheet structure is indirectly confirmed by the excellent cycling performance of charge capacity and the curve of charge capacities versus cycle number at different current densities. After galvanostatic charge/discharge of the batteries for 1000 cycles, the HRTEM images of post-mortem batteries directly reveal a good reversibility of the lithium ion insertion/extraction process aided by TiO2-NS. Thus, all these advantages and the special structure facilitate an excellent cycling performance: the charge capacity with the maximum value of 250 mAh g−1 keeps half after 2000 cycles at a current density of 840 mA g−1 (5 C).

The recovery of rare single circulating tumor cells (CTCs) from patients has great potential to facilitate the study of cell heterogeneity and cancer metastasis, which may promote the development of individualized cancer immunotherapy. Herein, a versatile single-cell recovery approach that utilizes an acoustic droplet-induced enzyme responsive platform for the capture and on-demand release of single CTCs is proposed. The platform combines a multifunctional enzyme-responsive gelatin nanoparticle (GNP)-decorated substrate (GNP-chip) for specific capture with an acoustic droplet positioning technique to realize on-demand release of single CTCs. The acoustic droplet dispenser is employed to generate oxidized alginate microdroplets containing the MMP-9 enzyme (OA-MMP-9) with controllable size and precise positioning upon the cell-attached GNP-chip, allowing controlled cell-surface biodegradation under enzymatic reactions followed by calcium chloride (CaCl2) solution treatment to form single-cell encapsulated calcium alginate hydrogels. Benefitting from the existence of hydrogels, the released cells could be efficiently recovered by microcapillary. Results demonstrate that the encapsulated cells maintain good cell morphology in the hydrogels, which allow further single-cell nucleic acid analysis. As a proof-of-concept platform, this approach enables reliable and efficient retrieval of single CTCs and holds the potential for versatility in single-cell analysis systems.

The development of tin-based perovskite solar cells (PSCs) is a promising approach to meet the demand of eco-friendly, lead-free perovskite photovoltaics. Limited to the poor chemical stability of tin perovskites, tin-based PSCs usually have to be fabricated with an inverted device structure and both the device efficiency and stability are highly dependent on the selection of hole transport materials (HTMs). Here, we report the synthesis of inorganic nickel oxide (NiO x ) nanoparticles (NPs) via a soft base precipitation method, which enables us to obtain highly dispersed NiO x NPs over a wide pH window. The as-prepared NiO x NPs are employed as the HTM for formamidinium tin iodide (FASnI3) PSCs, resulting in excellent device efficiency (∼8%) and stability (1200 h). Our study offers a facile strategy for mass production of NiO x NPs and easy access to efficient and robust inorganic HTMs that could further boost the development of high performance tin-based PSCs.

Upconversion nanoparticles (UCNPs), with fascinating optical and chemical features, are a promising new generation of fluorescent probes. Although UCNPs have been widely used in diagnosis and therapy, there is an unmet need for a simple and effective surface engineering method that can produce cancer-targeting UCNPs. Here, we show that by coating particles with macrophage membranes, it becomes possible to utilize the adhesion between macrophages and cancer cells for effective cancer targeting. Natural macrophage membranes along with their associated membrane proteins were reconstructed into vesicles and then coated onto synthetic UCNPs. The resulting macrophage membrane-camouflaged particles (MM-UCNPs) exhibited effective cancer targeting capability inherited from the source cells and were further used for enhanced in vivo cancer imaging. Finally, the blood biochemistry, hematology testing and histology analysis results suggested a good in vivo biocompatibility of MM-UCNPs. The combination of synthetic nanoparticles with biomimetic cell membranes embodies a novel design strategy toward developing biocompatible nanoprobes for potential clinical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 521-530, 2017.

The two-step spin coating process produces rough perovskite surfaces in ambient condition with high humidity, which are unfavorable for the contact between the perovskite film and the low temperature carbon electrode. To tackle this problem, multi-walled carbon nanotubes (MWCNTs) are embedded into the perovskite layer. The MWCNTs can act as charge transport high way between individual perovskite nanoparticles and facilitate the collection of the photo-generated holes by the carbon electrode. Longer carrier lifetime is confirmed in the perovskite solar cells with addition of MWCNTs using open circuit voltage decay measurement. Under optimized concentration of MWCNT, average power conversion efficiency of 11.6% is obtained in hole transport material free perovskite solar cells, which is boosted by ∼15% compared to solar cells without MWCNT.

In this paper, autofluorescent gelatin nanoparticles were synthesized as matrix metalloproteinase (MMP) responsive probes for cancer cell imaging. A modified two-step desolvation method was employed to generate these nanoparticles whose size was controllable and had stable autofluorescence. As glutaraldehyde was introduced as the crosslinking agent, the generation of Schiff base (CN) and double carbon bond (CC) between glutaraldehyde and gelatin endowed these gelatin nanoparticles distinct autofluorescence. Considering MMPs were usually overexpressed on the surface of cancer cells and they had degradation ability toward gelatin, we utilized these nanoparticles as imaging probes to responsively monitor the MMP metabolism of cancer cells according to the luminance change. As fluorescent probes, these nanoparticles had facile synthesis procedure and good biocompatibility, and provided a smart strategy to monitor cancer cell behaviors. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2854-2860, 2016.

A mesoporous SiO2 layer is successfully introduced into the hole transport material free perovskite solar cells by spin-coating a SiO2 paste onto the TiO2 scaffold layer. This SiO2 layer can act as an insulating layer and effectively inhibit the charge recombination between the TiO2 layer and carbon electrode. The variation of power conversion efficiencies with the thickness of SiO2 layer is studied here. Under optimized SiO2 thickness, perovskite solar cell fabricated on the TiO2/SiO2 film shows a superior power conversion efficiency of ∼12% and exhibits excellent long time stability for 30 days.

An optimized two-step sequential deposition method to fabricate hole-transport-layer-free carbon-based methyl ammonium lead bromide (MAPbBr3) perovskite solar cells is reported. Small amounts of MABr are introduced into the PbBr2 precursor solution during the first step to prepare MAPbBr3 perovskite films (labeled as MAPB-xMABr), which promotes the conversion of PbBr2 into perovskite phase and results in denser perovskite films with increased crystallinity, lower trap density, and longer carrier lifetime. After optimization, a maximum power conversion efficiency (PCE) of 7.64% (VOC = 1.36 V) is obtained for MAPB-0.2MABr based solar cells. Significantly, the non-encapsulated devices exhibit excellent long-term stability in ambient air (25–30 °C and 20–30% relative humidity), showing no degradation after a year’s exposure. While, it also shows superior thermal stability with PCE retaining 95% of the initial efficiency after 120 h under thermal stress of 80 °C and 40–70% relative humidity.

Two dimensional materials have promising benefits in photoelectronic devices, including facilitating charge transport and reducing defects in perovskite solar cells (PSCs) and photodetectors (PDs) through interface engineering. Herein, a two dimension polymeric material of graphitic carbon nitride quantum dots (g-CNQDs) interlayer is used to modify the SnO2/perovskite interface in both ambient PSCs and PDs to improve the overall performance. The introduction of g-CNQD layer improves the crystalline quality of sequential perovskite absorber with high phase purity, less grain boundaries, low trap states and suppressed carrier recombination due to the intrinsic cross-linkable feature and relatively smooth surface of g-CNQD. As a result, with optimal modification, fully air-processed PSC reached a champion power conversion efficiency of 21.23% with negligible hysteresis, and the PDs had remarkable performance enhancement. Moreover, our PSCs have good stability in ambient air, keeping over 90% of the initial efficiency after 30 days’ exposure.

Stable hosts containing pre-stored metallic lithium (Li) are typically used to tackle irregular dendrite formation and infinite relative volume changes of lithium metal anodes. In this sense, oversimplified molten Li infusion strategies have been widely proposed to build lithiophilic architectures with uncontrollable amount and configuration of metallic Li in obtained hosts. In this work, tin oxide (SnO2) deposited Ni foam (SNF) with superior molten Li wettability is employed to construct two distinct lithiophilic architectures namely, Li coated SNF skeletons and Li infiltrated SNF frameworks. The cycling stability and dendritic behavior of these lithiophilic architectures are systematically compared. Both of these lithiophilic architectures significantly outperformed bare Li foils in terms of cycling performance and electrode dimension stability. The fully covered lithiophilic host with Li infiltrated SNF frameworks shows much better cycling stability and lower hysteresis than the porous lithiophilic host with Li coated skeletons, especially at high current densities and large stripping/plating capacities. In full-cell configurations, the batteries based on Li infiltrated SNF frameworks also show significantly higher rate capabilities than Li coated SNF skeletons counterpart. Our results provide a better understanding to design stable lithiophilic hosts for high-rate and high-capacity lithium metal anodes.

Recently, red blood cell (RBC) membrane-coated nanoparticles have attracted much attention because of their excellent immune escapability; meanwhile, gold nanocages (AuNs) have been extensively used for cancer therapy due to their photothermal effect and drug delivery capability. The combination of the RBC membrane coating and AuNs may provide an effective approach for targeted cancer therapy. However, few reports have shown the utilization of combining these two technologies. Here, we design erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy. First, anti-EpCam antibodies were used to modify the RBC membranes to target 4T1 cancer cells. Second, the antitumor drug paclitaxel (PTX) was encapsulated into AuNs. Then, the AuNs were coated with the modified RBC membranes. These new nanoparticles were termed EpCam-RPAuNs. We characterized the capability of the EpCam-RPAuNs for selective tumor targeting via exposure to near-infrared irradiation. The experimental results demonstrate that EpCam-RPAuNs can effectively generate hyperthermia and precisely deliver the antitumor drug PTX to targeted cells. We also validated the biocompatibility of the EpCam-RAuNs in vitro. By combining the molecularly modified targeting RBC membrane and AuNs, our approach provides a new way to design biomimetic nanoparticles to enhance the surface functionality of nanoparticles. We believe that EpCam-RPAuNs can be potentially applied for cancer diagnoses and therapies.

Nanotechnology possesses the potential to revolutionize the diagnosis and treatment of tumors. The ideal nanoparticles used for in vivo cancer therapy should have long blood circulation times and active cancer targeting. Additionally, they should be harmless and invisible to the immune system. Here, we developed a biomimetic nanoplatform with the above properties for cancer therapy. Macrophage membranes were reconstructed into vesicles and then coated onto magnetic iron oxide nanoparticles (Fe3O4 NPs). Inherited from the Fe3O4 core and the macrophage membrane shell, the resulting Fe3O4@MM NPs exhibited good biocompatibility, immune evasion, cancer targeting and light-to-heat conversion capabilities. Due to the favorable in vitro and in vivo properties, biomimetic Fe3O4@MM NPs were further used for highly effective photothermal therapy of breast cancer in nude mice. Surface modification of synthetic nanomaterials with biomimetic cell membranes exemplifies a novel strategy for designing an ideal nanoplatform for translational medicine.

As "liquid biopsies", circulating tumor cells (CTCs) have been thought to hold significant insights for cancer diagnosis and treatment. Despite the advances of microfluidic techniques that improve the capture of CTCs to a certain extent, recovering the captured CTCs with enhanced purity at the same time remains a challenge. Here, by combining on-chip purification and off-chip enzymatic treatment, we demonstrate a two-stage strategy to enhance the purity of captured cancer cells from blood samples. The on-chip purification introduces a stirring flow to increase the capture sensitivity and decrease nonspecifically bounded cells. The off-chip enzymatic treatment enables the cancer cells to be released from the attached magnetic beads, further improving the purity and enabling next reculture. For the proof-of-concept study, spiked cancer cells are successfully obtained from unprocessed whole blood with high recovery rate (∼68%) and purity (∼61%), facilitating subsequent RNA expression analysis.

Upconversion nanoparticles (UCNPs) with superior optical and chemical features have been broadly employed for in vivo cancer imaging. Generally, UCNPs are surface modified with ligands for cancer active targeting. However, nanoparticles in biological fluids are known to form a long-lived "protein corona", which covers the targeting ligands on nanoparticle surface and dramatically reduces the nanoparticle targeting capabilities. Here, for the first time, we demonstrated that by coating UCNPs with red blood cell (RBC) membranes, the resulting cell membrane-capped nanoparticles (RBC-UCNPs) adsorbed virtually no proteins when exposed to human plasma. We further observed in various scenarios that the cancer targeting ability of folic acid (FA)-functionalized nanoparticles (FA-RBC-UCNPs) was rescued by the cell membrane coating. Next, the FA-RBC-UCNPs were successfully utilized for enhanced in vivo tumor imaging. Finally, blood parameters and histology analysis suggested that no significant systematic toxicity was induced by the injection of biomimetic nanoparticles. Our method provides a new angle on the design of targeted nanoparticles for biomedical applications.

Thin titanium dioxide (TiO2) semiconductor layer with different scattering layers are investigated in dye-sensitized solar cells (DSSCs). Usually, the scattering layer is placed after the photoanode films in order to harvest more incidents light. The scattering layer based on rutile phase TiO2 is prepared, and placed in the different position of the photoanode films (on the surface of the FTO glass, between the two layers of transparent TiO2 film and after the transparent TiO2 film). We use STT, TST and TTS as marks (T and S represent the transparent TiO2 layer and the scattering layer respectively). The result of this study indicates that STT which has the lowest incident light harvesting efficiency demonstrates the highest electron collection efficiency, while TTS which has the highest incident light harvesting efficiency sacrifices the electron collection efficiency greatly. It is discovered that TST, of which the incident light harvesting efficiency basically remains unchanged compared to TTS, reveals higher electron collection efficiency and achieves the maximum photovoltaic conversion efficiency (7.0%). By applying UV-Visible and diffuse reflectance spectroscopy, electrochemical impedance spectroscopy (EIS), the effects of the incident light harvesting and electron collection efficiencies on different cells are analyzed. It makes the best use of this scattering layer and has a reference for the application of other scattering layer types.

The novel concept of introducing intermediate band into the mesoporous TiO2 backbone of dye-sensitized solar cells (DSSCs) is proposed to take full advantage of the sunlight and enhance the power conversion efficiency. Nominal trace amount W-doped TiO2 nanocrystralline films were prepared with the purpose of forming intermediate band in the bandgap of TiO2. A notable improvement of the device performance was obtained when N-type W-doped TiO2 films were applied as the photoanode of DSSCs. The short-circuit current density (Jsc) increased from 12.40 mA cm–2 to 15.10 mA cm–2, and the conversion efficiency increased from 6.64 to 7.42% when nominal 50 ppm (ppm) W-doped TiO2 was adopted.

A novel approach has been developed to fabricate an oriented flat porous carbon (OFPC) by combining the polymerizationinduced phase separation and pyrolysis (PIPSP) and the directional compressive deformation (DCD). At first, an elastic body in the shape of cylinder is obtained by controlling the polymerization degree of resin, and then the application of symmetrical axial pressures results in the directional deformation of two interconnected phases (of a polymerized resin phase and a poreforming agent phase) in the elastic body. Then the elastic deformed body is transformed to the rigid deformed body by precuring and further to the cured body by curing. At last, the cured body is pyrolyzed to form an OFPC. The pressures are removed after precuring. The pores in the OFPC are survived as the discs in the radial direction. Both flat pores and carbon skeletons in the OFPC are oriented toward a radial direction. The OFPC has comparable pore volume with a normal porous carbon, which is fabricated by the PIPSP with same process except for the application of the DCD.

Three-dimensional branched TiO2 architectures (3D BTA) with controllable morphologies were synthesized via a facile template-free one-pot solvothermal route. The volume ratio of deionized water (DI water) and diethylene glycol in solvothermal process is key to the formation of 3D BTA assembled by nanowire-coated TiO2 dendrites, which combines the advantages of 3D hierarchical structure and 1D nanoscale building blocks. Benefiting from such unique structural features, the BTA in full bloom achieved significantly increased specific surface areas and shortened Li(+) ion/electrons diffusion pathway. The lithium-ion batteries based on BTA in full bloom exhibited remarkably enhanced reversible specific capacity and rate performance, attributing to the high contact area with the electrolyte and the short solid state diffusion pathway for Li(+) ion/electrons promoting lithium insertion and extraction.

Biomimetic cell-membrane-camouflaged particles with desirable features have been widely used for various biomedical applications. However, there are few reports on employing these particles for cancer drug delivery due to the failure of the membrane coatings to be efficiently degraded in the tumor microenvironment which hampers the drug release. In this work, core-shell SiO2 @TiO2 nanoparticles with enhanced photocatalytic activity are used for controlled degradation of surface erythrocyte membrane coatings. The antitumor drug docetaxel is encapsulated into nanocarriers to demonstrate the controlled drug release under ultraviolet irradiation, and the drug-loaded nanoparticles are further used for enhanced cancer cell therapy. Here, a simple but practical method for degradation of cell membrane coatings is presented, and a good feasibility of using cell membrane-coated nanocarriers for controlled drug delivery is demonstrated.

In this work, we developed a shape-controllable nozzle inside a multilayer PDMS microchip. The nozzle was able to control the shape of the fluid channel in three dimensions. All the four walls of the fluid channel were comprised of pneumatic PDMS membrane valves, and their deformation was controlled by air pressure. As both the limitation of the fluid flux and the shape of the fluid channel were adjustable spatially in three dimensions, this valve-based nozzle generated droplets with less response time and in a more effectively controlled manner comparing to conventional droplet devices. It could also function as a microinjector to modulate the compositions of droplets precisely and continuously. In addition, the nozzle was able to form a specific shape to generate core–shell particles.

We report on the feasible fabrication of microfluidic devices for ferroelectric polymers' synthesis in a rapid and stable fashion. Utilizing micro-mixing and flow-focusing in microchannels, poly(vinylidene fluoride-trifluoroethylene) and copper phthalocyanine are uniformly dispersed in one hydrogel particle, which are then demonstrated to immediate and complete on-chip steady polymerization by moderate ultraviolet treatment. The advantage of our droplet-based microfluidic devices is generating versatile particles from simple spheres to disks or rods, and the lengths of particles can be precisely tuned from 30 to 400 μm through adjusting the flow rates of both disperse and oil phases. In addition, this mixed technique allows for the continuous production of dielectric microparticles with controlled dielectric properties between 10 and 160. Such a microfluidic device offers a flexible platform for multiferroic applications.

Solution-gated graphene field effect transistors (SGGT) were integrated in microfluidic systems. The transfer characteristics of a SGGT with an Ag/AgCl gate electrode shifted horizontally with the change of the ionic concentration of KCl solution in the microchannel and the relationship can be fitted with the Nernst equation, which was attributed to the change of the potential drop at the Ag/AgCl electrode. Therefore the gate electrode is one important factor for the ion sensitive property of the SGGT. Then SGGTs were used as flow velocity sensors, which were based on measuring the streaming potentials in microfluidic channels. A linear relationship between the shift of the transfer curve of the SGGT and the flow velocity was obtained, indicating that the SGGT is a promising transducer for measuring flow velocity in a microchip. Since the streaming potential is influenced by the three physical quantities, including the flow velocity, the ionic strength of the fluid and the zeta potential of the substrate, the device can be used for sensing any one of the three quantities when the other two were known. It is noteworthy that SGGTs have been used for various types of chemical and biological sensors. Array of the devices integrated in multichannel microchips are expected to find many important applications in the lab-on-a-chip systems in the future.

Cancer cell membrane-coated upconversion nanoprobes (CC-UCNPs) with immune escape and homologous targeting capabilities are used for highly specific tumor imaging. The combination of UCNPs with biomimetic cancer cell membranes embodies a novel materials design strategy and presents a compelling class of advanced materials.

Fe-doped Pb0.3Sr0.7TiO3 (PST) thin films have been fabricated on Pt/Ti/SiO2/Si substrates with sol–gel method. The structure and surface morphology of Fe-doped PST thin films were investigated as a function of Fe concentration by x-ray diffraction (XRD) and atomic force microscopy (AFM). The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1M Hz at room temperature. It’s found that the dielectric constant, dielectric loss and tunability of Fe-doped PST films decreased with the increase of Fe content. The effects of Fe doping on the microstructure, dielectric and tunable properties of thin films were analyzed. Though the undoped PST thin film exhibited the highest dielectric constant of 2011 and the largest tunability of 76%, the 6 mol% Fe doped PST thin films had the highest figure of merit (FOM) of 17.9 for its lowest dielectric loss.

Fe doped up-graded and down-graded PST thin films were prepared on Pt/Ti/SiO2/Si with sol–gel method. Crystal structure and surface morphology of graded PST thin films were characterized by X-ray diffraction (XRD) and atom force microscope (AFM). The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1M Hz and at room temperature. It was found that the up-graded PST thin film had a larger dielectric constant and lower figure of merit (FOM) than the down-graded film. At 1M Hz, the tunability of up-graded PST thin film was about 65.48%, which was higher than that (about 41.84%) of down-graded PST thin film. The FOM of up-graded and down-graded PST thin films were 16.3 and 9.2, respectively. Our results showed that the dielectric tunable properties of the Fe doped graded PST films depended strongly on the direction of the composition gradient of the graded PST films.

Pb0.3Sr0.7TiO3 (PST) and 4.5 mol% Mn doped Pb0.3Sr0.7TiO3 (PSTMn) thin films as well as PST/PSTMn/PST/PSTMn/PST (ML-a) and PSTMn/PST/PSTMn/PST/PSTMn (ML-b) multilayered thin films have been fabricated on Pt/Ti/SiO2/Si substrate with sol–gel method. The structure and surface morphology of PST, PSTMn, ML-a and ML-b thin films were investigated by x-ray diffraction (XRD) and atom force microscopy (AFM). The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1M Hz and at room temperature. It was found that the surface microstructure of multilayered thin films is influenced by deposition sequence and the dielectric constant and tunability of two multilayered thin films lie between that of PST and PSTMn thin films. However, two multilayered thin films have higher the figure of merit (FOM) for lower dielectric loss. The FOM of PST and PSTMn single-component films as well as ML-a and Ml-b multilayered films are 14.2, 14.6, 16.3 and 20.2, respectively. Our results showed that multilayer structure can improve the comprehensive dielectric tunable performance of PST film.

In this work, one-dimensional (1D) multiferroic BiFeO3 (BFO) and poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] composite nanofibers are fabricated by using a two-step sol–gel based electrospinning method. X-ray diffraction (XRD) study reveals that crystalline phases corresponding to both BiFeO3 and P(VDF-TrFE) are found. Microstructure measurement shows that the nanofibers are alignment and BFO nanorods are well-dispersed in the P(VDF-TrFE) fiber matrix. The coexistence of electric and magnetic hysteresis for the composite materials also has been observed successfully at room temperature. It indicates that such nanofibers would perform a wide range of potential applications in flexibility information storage, magnetic recording media, spintronics devices and sensors.

Non-invasive prenatal diagnostics (NIPD) has been an emerging field for prenatal diagnosis research. Carrying the whole genome coding of the fetus, fetal nucleated red blood cells (FNRBCs) have been pursued as a surrogate biomarker traveling around in maternal blood. Here, by combining a unique microbead-based centrifugal separation and enzymatic release, we demonstrated a novel method for FNRBC isolation from the blood samples. First, the gelatin-coated silica microbeads were modified with FNRBC-specific antibody (anti-CD147) to capture the target cells in the blood samples. Then, the density difference between microbead-bound FNRBCs and normal blood cells enables the purification of FNRBCs via an improved high-density percoll-based separation. The non-invasive release of FNRBCs can then be achieved by enzymatically degrading the gelatin film on the surface of the microbeads, allowing a gentle release of the captured target cells with as high as 84% efficiency and ∼80% purity. We further applied it to isolate fetal cells from maternal peripheral blood. The released cells were analyzed by real-time polymerase chain reaction to verify their fetal origin and fluorescent in situ hybridization to detect fetal chromosome disorders. This straightforward and reliable alternative platform for FNRBC detection may have the potential for realizing facile NIPD.

ZnO thin films were deposited on glass substrates at room temperature (RT) similar to 500 degrees C by pulsed laser deposition (PLD) technique and then were annealed at 150-450 degrees C in air. The effects of annealing temperature on the microstructure and optical properties of the thin films deposited at each substrate temperature were investigated by XRD, SEM, transmittance spectra, and photoluminescence (PL). The results showed that the c-axis orientation of ZnO thin films was not destroyed by annealing treatments: the grain size increased and stress relaxed for the films deposited at 200-500 degrees C, and thin films densified for the films deposited at RT with increasing annealing temperature. The transmittance spectra indicated that E-g of thin films showed a decreased trend with annealing temperature. From the PL measurements, there was a general trend, that is UV emission enhanced with lower annealing temperature and disappeared at higher annealing temperature for the films deposited at 200-500 degrees C; no UV emission was observed for the films deposited at RT regardless of annealing treatment. Improvement of grain size and stoichiometric ratio with annealing temperature can be attributed to the enhancement of UV emission, but the adsorbed oxygen species on the surface and grain boundary of films are thought to contribute the annihilation of UV emission. It seems that annealing at lower temperature in air is an effective method to improve the UV emission for thin films deposited on glass substrate at substrate temperature above RT.

A piezoelectric nanogenerator based on poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] nanofibers with an Au interdigital electrode (IDT)/P(VDF-TrFE) nanofiber film/well-ordered cylindrical cavity structure was prepared by combining Au IDTs with a rotary collector to obtain highly aligned P(VDF-TrFE) nanofiber arrays. The Au IDTs work not only as parallel electrodes to collect P(VDF-TrFE) nanofibers during electrospinning but also as charge-collecting electrodes in the nanogenerator. The well-ordered cylindrical cavities improve output performance by enhancing the deformation of P(VDF-TrFE) nanofiber films when subjected to external force. The nanogenerator performs well; as an example of application, we demonstrate energy harvesting from human walking, with a peak output voltage of 5 V and a peak short-circuit current of 1.2 μA. Such a device could have practical applications in wearable, self-powered devices.

ZnO films are prepared on glass substrates by pulsed laser deposition (PLD) at different oxygen pressures, and the effects of oxygen pressure on the structure and optoelectrical properties of as-grown ZnO films are investigated. The results show that the crystallite size and surface roughness of the films increase, but the carrier concentration and optical energy gap E-g decrease with increasing oxygen pressure. Only UV emission is found in the photoluminescence (PL) spectra of all the samples, and its intensity increases with oxygen pressure. Furthermore, there are marked differences in structure and properties between the films grown at low oxygen pressures (0.003 and 0.2 Pa) and the films grown at high oxygen pressures (24 and 150 Pa), which is confirmed by the fact that the crystallite size and UV emission intensity markedly increase, but the carrier concentration markedly decreases as oxygen pressure increases from 0.2 to 24 Pa. These results show that the crystal quality, including the microstructural quality and stoichiometry proportion, of the prepared ZnO films improves as oxygen pressure increases, particularly from 0.2 to 24 Pa.

C-axis-orientated ZnO thin films were prepared on glass substrates by pulsed-laser deposition (PLD) technique in an oxygen-reactive atmosphere, using a metallic Zn target. The effects of growth condition such as laser energy and substrate temperature on the structural and optical properties of ZnO films had been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission spectra and room-temperature (RT) photoluminescence (PL) measurements. The results showed that the thickness, crystallite size, and compactness of ZnO films increased with the laser energy and substrate temperature. Both the absorption edges and the UV emission peaks of the films exhibited redshift, and UV emission intensity gradually increased as the laser energy and substrate temperature increased. From these results, it was concluded that crystalline quality of ZnO films was improved with increasing laser energy and substrate temperature.

Effects of calcining and sintering temperatures on the microstructure and the microwave dielectric properties of Ba6-3x(Sm0.2Nd0.8)8+2xTi18O54(x=2/3) ceramics were studied. When the calcining temperature was lower (1373K), the dielectric constant ε and the Qf factor initially increased with increasing sintering temperature, but decreased when sintering temperature was higher than 1603K. As a whole, the temperature coefficients of the resonant frequency τf tended to increase with increasing sintering temperature. The microstructure of the sintered ceramic consisted mainly of columnar and block-shape grains. The grain size increased with increasing sintering temperature. When the calcining temperature was higher (1473K), εr and τf were nearly independent of sintering temperature. The excellent microwave dielectric properties were achieved in the Ba6-3x(Sm0.2Nd0.8)8+2xTi18O54 (x=2/3) ceramic calcined at 1373K and sintered at 1603K for 3 h: ε = 80.8, Qf = 8114 (GHz) and τf = 5.6.

For decades, poly(ethylene glycol) (PEG) has been widely incorporated into nanoparticles for evading immune clearance and improving the systematic circulation time. However, recent studies have reported a phenomenon known as "accelerated blood clearance (ABC)" where a second dose of PEGylated nanomaterials is rapidly cleared when given several days after the first dose. Herein, we demonstrate that natural red blood cell (RBC) membrane is a superior alternative to PEG. Biomimetic RBC membrane-coated Fe(3)O(4) nanoparticles (Fe(3)O(4) @RBC NPs) rely on CD47, which is a "don't eat me" marker on the RBC surface, to escape immune clearance through interactions with the signal regulatory protein-alpha (SIRP-α) receptor. Fe(3)O(4) @RBC NPs exhibit extended circulation time and show little change between the first and second doses, with no ABC suffered. In addition, the administration of Fe(3)O(4) @RBC NPs does not elicit immune responses on neither the cellular level (myeloid-derived suppressor cells (MDSCs)) nor the humoral level (immunoglobulin M and G (IgM and IgG)). Finally, the in vivo toxicity of these cell membrane-camouflaged nanoparticles is systematically investigated by blood biochemistry, hematology testing, and histology analysis. These findings are significant advancements toward solving the long-existing clinical challenges of developing biomaterials that are able to resist both immune response and rapid clearance.

Control over one-dimensional growth of spinel-type LiMn2O4 nanowires is challenging in the area of materials science due to their cubic crystal structure. The current strategy is to use a self-support template to fabricate LiMn2O4 nanowires, which is time-consuming and limits their large-scale commercial production. In this paper, we propose a general strategy to construct well-defined LiMn2O4 nanowires terminated with amorphous carbon at the edges by an ingenious method without using any template. Benefited from its unique carbon-coated nanowire structure, the electrode exhibits a capacitor-like rate performance and battery-like high capacity for long-time cycling. Even after 1500 cycles at an extremely high current density of 30 C, approximately 82% of its initial capacity can still be retained. Significantly, the strategy reported here will be beneficial and revelatory to manufacture other extensive one-dimensional robust carbon-decorated nanowires, paving new ways for future developments of ultrafast rechargeable lithium-ion batteries.

Hydrogen-induced degradation in CaCu 3 Ti 4 O 12 (CCTO) ceramics was studied using an electrochemical hydrogen charging method, in which the silver electrodes of CCTO ceramic pellets were made a cathode in 0.01 M NaOH solution to deposit hydrogen through the electrolysis of water. The dielectric loss was greatly increased and the insulation resistance was greatly decreased after the treatment. X-ray diffraction analysis showed that no new phases were formed. It is proposed that atomic hydrogen is diffused into CCTO lattice and free electrons are formed through the ionization of hydrogen atoms, which lead to the observed degradation. Hydrogen-induced degradation occurs very quickly in CCTO ceramics and it is important to prevent hydrogen-induced degradation in CCTO ceramics.

Nanoparticles possess the potential to revolutionize cancer diagnosis and therapy. The ideal theranostic nanoplatform should own long system circulation and active cancer targeting. Additionally, it should be nontoxic and invisible to the immune system. Here, the authors fabricate an all-in-one nanoplatform possessed with these properties for personalized cancer theranostics. Platelet-derived vesicles (PLT-vesicles) along with their membrane proteins are collected from mice blood and then coated onto Fe3O4 magnetic nanoparticles (MNs). The resulting core–shell PLT-MNs, which inherit the long circulation and cancer targeting capabilities from the PLT membrane shell and the magnetic and optical absorption properties from the MN core, are finally injected back into the donor mice for enhanced tumor magnetic resonance imaging (MRI) and photothermal therapy (PTT). Meanwhile, it is found that the PTT treatment impels PLT-MNs targeting to the PTT sites (i.e., tumor sites), and exactly, in turn, the enhanced targeting of PLT-MNs to tumor sites can improve the PTT effects. In addition, since the PLT membrane coating is obtained from the mice and finally injected into the same mice, PLT-MNs exhibit stellar immune compatibility. The work presented here provides a new angle on the design of biomimetic nanoparticles for personalized diagnosis and therapy of various diseases.

We demonstrated an enhanced particle focusing in microfluidic channels by using standing surface acoustic waves (SAWs) generated on a piezoelectric substrate. Interdigitized microelectrode arrays patterned by standard photolithography and lift-off techniques are used for both excitation and detection of SAWs. Bragg reflectors (BR) are also integrated to enhance the standing SAW formation. Furthermore, air cavities are introduced in both sides of microfluidic channels made of polydimethylsiloxane (PDMS). Whereas the system without PDMS cover layer showed a loss less than 2db, the absorption loss after adding PDMS structures was also limited to a few db. Consequently, enhanced particle focusing could be easily observed, showing clear advantages of the use of BR and minimized PDMS wall thicknesses.

A CTCs detection assay using transparent MnO2 nanospheres thin films to capture and release of CTCs is reported. The enhanced local topography interaction between extracellular matrix scaffolds and the antibody-coated substrate leads to improved capture efficiency. CTCs captured from artificial blood sample can be cultured and released, represent a new functional material capable of CTCs isolation and culture for subsequent studies.

The influence of electron dosage on the field induced strain, dielectric constant, and polarization response has been investigated in electron irradiated poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) 50/50 copolymer. It was found that under suitable electron dosage an ultrahigh electrostrictive strain can be achieved. Interestingly, material after irradiation exhibits many features resembling those of relaxor ferroelectrics, suggesting that the electron irradiation breaks up the coherent polarization domain in normal ferroelectric P(VDF-TrFE) copolymer into nano-polar regions that transform the material into a relaxor ferroelectric. In addition, many of the material properties including the field induced polarization, the electrostrictive strain, and elastic modulus exhibit irregular change (non-monotonical) with electron dosage, indicating a complex relation among the crosslinking density, crystallinity, crystallite size, and molecular conformation in determining the material responses.

Aiming to highly efficient capture and analysis of circulating tumor cells, a micropillar device decorated with graphite oxide-coated magnetic nanoparticles is developed for magneto-controllable capture and release of cancer cells. Graphite oxide-coated, Fe3 O4 magnetic nanoparticles (MNPs) are synthesized by solution mixing and functionalized with a specific antibody, following by the immobilization of such modified MNPs on our designed micropillar device. For the proof-of-concept study, a HCT116 colorectal cancer cell line is employed to exam the capture efficiency. Under magnetic field manipulation, the high density packing of antibody-modified MNPs on the micropillars increases the local concentration of antibody, as well as the topographic interactions between cancer cells and micropillar surfaces. The flow rate and the micropillar geometry are optimized by studying their effects on capture efficiency. Then, a different number of HCT116 cells spiked in two kinds of cell suspension are investigated, yielding capture efficiency >70% in culture medium and >40% in blood sample, respectively. Moreover, the captured HCT116 cells are able to be released from the micropillars with a saturated efficiency of 92.9% upon the removal of applied magnetic field and it is found that 78% of the released cancer cells are viable, making them suitable for subsequent biological analysis.

We designed a highly uniform core double-shell (CDS) structure consisting of -NaYF4:Er3+,Yb3+ crystal as core (~400 nm in diameter and ~470 nm in height), amorphous SiO2 as inner shell (~10 nm in thickness), and interconnected anatase TiO2 grains as outer shell (~30 nm in thickness). For device application, various amount of these hexagonal submicroprisms (HSMs) were introduced into TiO2nanoparticles (20-40 nm in diameter) to form a bifunctional nano-submicron composite (NSMC) layer upon a prior prepared transparent TiO2 layer. By utilization of these efficient -NaYF4:Er3+,Yb3+ upconversion cores, near-infrared irradiation can be absorbed and harvested indirectly by dye molecules to broaden the absorption region and produce more electrons. Owing to the excellent insulating properties, SiO2 shell creates a perfect electrical isolation for the UCP cores. Through this method, the problem of electron trapping and capture caused by ligands and defects on the surface of NaYF4:Er3+, Yb3+ crystals can be thoroughly overcome. However, employment of this submicron sized composites can seriously reduce the internal surface area, leading to a less amount of dye loading. By coating of the outer TiO2 shell, the disadvantage of SiO2 shell can be avoided to the utmost extent. Computer simulation results have shown that scattering of 10-25 nm TiO2particles is negligible and effective Mie scatterers are those particles whose dimensions are comparable to the wavelength of light. With the increasing of mixing amount of these submicron sized HSMs, these bifunctional layers become white gradually, indicating their significant scattering effect of incident light. It is experimentally damostrated that performance of DSCs can be effectively enhanced by employing these bifunctional highly uniform core/double-shell(CDS) structure in the photoelectrodes, an efficiency of 8.65% was obtained, which is 120% higher than the device based on bare NaYF4:Er3+,Yb3+ employed photoelectrode.

Aiming to synthesize multiferroic materials in microscale, a microfluidic device capable of generating multiferroic Janus microparticles is demonstrated. Through bonding two polydimethylsiloxane (PDMS) layers “face to face,” laminar flow containing an upper layer and a lower layer can be realized. Accordingly, poly(vinylidene fluoride-trifluoroethylene) ferroelectric polymers and Fe3O4 ferromagnetic particles are separately encapsulated in the two layers of a single droplet. Numerical simulation enables the analysis of cross-mixing between the two counterparts and helps to find an optimized location for adding subsequent ultraviolet treatment, which will polymerize the droplets into Janus particles without any side effect. By modulation of the flow rate, the size of the Janus particles can be precisely tuned. Finally, the ferroelectricity and magnetism of the Janus particles are verified by the magnetization and polarization measurements, indicating the multiferroic nature.

Suppression of the reticuloendothelial system (RES) uptake is one of the most challenging tasks in nanomedicine. Coating stratagems using polymers, such as poly(ethylene glycol) (PEG), have led to great success in this respect. Nevertheless, recent observations of immunological response toward these synthetic polymers have triggered a search for better alternatives. In this work, natural red blood cell (RBC) membranes are camouflaged on the surface of Fe3O4 nanoparticles for reducing the RES uptake. In vitro macrophage uptake, in vivo biodistribution and pharmacokinetic studies demonstrate that the RBC membrane is a superior alternative to the current gold standard PEG for nanoparticle 'stealth'. Furthermore, we systematically investigate the in vivo potential toxicity of RBC membrane-coated nanoparticles by blood biochemistry, whole blood panel examination and histology analysis based on animal models. The combination of synthetic nanoparticles and natural cell membranes embodies a novel and biomimetic nanomaterial design strategy and presents a compelling property of functional materials for a broad range of biomedical applications.

A microfluidic flow sensor based on aligned piezoelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] nanofibers has been developed. The flow sensor is able to linearly measure low flow rates ranging from 13 μl/h to 301 μl/h with a sensitivity of 0.36 mV per 1 μl/h, and the highest voltage difference of 120 mV at a flow rate of 451 μl/h. Moreover, the viscosity of the ethylene glycol aqueous solution ranging from 1 mPa·s to 16.1 mPa·s at 25 °C can be detected in dynamic flow with a stable output. These findings highlight the potential of piezoelectric P(VDF-TrFE) nanofibers in multiferroic applications.