A CuO/TiO_(2)Heterojunction Based CO Sensor with High Response and Selectivity

The use of heterojunctions is a promising solution to the problem of cross-sensitivity in gas sensors.In this work,a carbon monoxide sensor based on the CuO/TiO_(2)heterojunction was designed and fabricated.Due to the good adsorption properties of CuO materials to CO,and the heterojunction interface charge transfer,the CuO/TiO_(2)thin film sensor exhibits high sensitivity to CO at room temperature.The response is as high as 10.8–200 ppm CO,about 10 times its response to H_(2).Interference from H_(2)is greatly reduced by optimizing the structure of the CuO/TiO_(2)heterojunction.This reliable detection of carbon monoxide with excellent discrimination against H_(2)is of great significance for the development of CO gas sensors.

两步蒸镀法制备高质量(CH3NH3)3Bi2I9钙钛矿薄膜

(CH3NH3)3Bi2I9 (MBI)钙钛矿属于六方晶系,在薄膜制备时,晶体颗粒具有c轴优先生长的特性,因而很难获得平整均一的高质量薄膜。在前期研究的基础上,我们通过两步蒸镀法得到了致密无针孔的薄膜。该薄膜的可重复性不够理想,有时仍有一定量的六方片状晶粒出现,显著降低了薄膜的质量。在此基础上,我们通过引入氯元素,从根本上抑制了MBI薄膜的c轴优先生长,制备出具有良好重复性、光滑平整且晶粒尺寸较大的高质量MBI薄膜。

Fabrication of microwave-sensitized nanospheres of covalent organic framework with apatinib for tumor therapy

A new nanocomposite of hollow covalent organic framework(COF)conjugated with the apatinib(AP)and loading microwave-sensitizer(ionic liquid,IL)was prepared by layer by layer(LBL)method and hyaluronic acid(HA)coating,named as COF-AP-IL@HA.AP loading rate in COF hollow-spheres(~30 nm shell thickness)was~40.3%,due to the interactions of hydrogen andπ-πbonds between AP and COF shell,and acidic environment destroyed COF structure,promoting AP release.Microwave sensitization of loaded IL in COF hollow-spheres could enhance the microwave heat-effect,and combined AP therapeutic ability,leading to their higher inhibitation on tumor,due to targeting ability of HA and the local release of apatinib.88.9%of inhibition rate of COF-AP-IL@HA under microwave on the in vivo tumor was significantly higher than those without microwave(12.3%)and COF-IL@HA with microwave(37.5%),indicating a synergism of sensitized microwave hyperthermia and AP therapy on the reduced expression of VEGF via the downregulation pathway of hypoxia inducible factor.These results indicated that COF-AP-IL@HA was potential to the application in the combination therapy of tumor of the sensitized microwave hyperthermia and apatinib.

Preparation,properties and biomedical applications progress of 1D magnetic nanomaterials with iron

1D magnetic nanomaterials with iron,with the special physical properties and biological behaviour,have been found to possess the great promising applications in many fields.In this review,the components,structure,physicochemical properties,biocompatibility and in vitro and in vivo biomedical functions of magnetic nanowires(MNWs),nanorods(MNRs)with iron are summarised,especially their anisotropy shape and magnetism result in their many applications in biodetections and medical treatment fields.The potential future functions of these 1D magnetic nanomaterials compared to magnetic nanoparticles also is discussed by highlighting the possibility of integration with other metal-compositions or bio-compositions and with existing biotechnology as well as by point-ing out their specific properties.Current limitations in the property improvement and issues related with the outcome of the MNRs in the body are also summarised in order to address the remaining challenge for the extended biomedical functions of MNRs in the clinical application field.

A novel akermanite/poly (lactic-co-glycolic acid) porous composite scaffold fabricated via a solvent casting-particulate leaching method improved by solvent self-proliferating process

Desirable scaffolds for tissue engineering should be biodegradable carriers to supply suitablemicroenvironments mimicked the extracellular matrices for desired cellular interactions and to providesupports for the formation of new tissues. In this work, a kind of slightly soluble bioactiveceramic akermanite (AKT) powders were aboratively selected and introduced in the PLGA matrix,a novel L-lactide modified AKT/poly (lactic-co-glycolic acid) (m-AKT/PLGA) composite scaffold wasfabricated via a solvent casting-particulate leaching method improved by solvent self-proliferatingprocess. The effects of m-AKT contents on properties of composite scaffolds and on MC3T3-E1 cellularbehaviors in vitro have been primarily investigated. The fabricated scaffolds exhibited threedimensionalporous networks, in which homogenously distributed cavities in size of 300–400 lmwere interconnected by some smaller holes in a size of 100–200 lm. Meanwhile, the mechanicalstructure of scaffolds was reinforced by the introduction of m-AKT. Moreover, alkaline ionic productsreleased by m-AKT could neutralize the acidic degradation products of PLGA, and the apatitemineralizationability of scaffolds could be largely improved. More valuably, significant promotionson adhesion, proliferation, and differentiation of MC3T3-E1 have been observed, which implied thecalcium, magnesium and especially silidous ions released sustainably from composite scaffoldscould regulate the behaviors of osteogenesis-related cells.

Fabrication of extracellular matrix-coated conductive polypyrrolepoly(L-lactide)fiber-films and their synergistic effect with(nerve growth factor)/(epidermal growth factor) on neurites growth

Non-nerve cell-derived extracellular matrix(ECM)wa s coated on the aligned porous polypyrrole-poly(Llactide)(PPy-PLLA)fiber-films with the conductivity of^12 mS/m via L929 cells culture and lysing,resulting in^10%increase of PC12 cells attachment and^26μm increase of neurites length.The neurite length of^149μm in EGF/NGF group(optimal concentration radio of 12.5/50(ng/mL))on aligned and ECM-conjugated fiber-films was significantly larger than^94μm in only NGF group(50 ng/mL),confirming the synergy of EGF,NGF and aligned ECM-conjuaged PPy-PLLA fibers.When differentiated PC12 cells were exerted electrical stimulation(ES)of 100 mV/cm for 4 h/day in 2 day through ECM-PPyPLLA fiber-films,their neurite length reached to^251μm,significantly larger than^149μm of group without ES,due to the higer expression of related neural proteins in ES group.A simple mechanism was proposed to analyze synergistical effect of ECM,EGF,NGF on axons adhesion and elongation along the aligned ECM-coated fibers under ES condition.

MBG/PGA-PCL composite scaffolds provide highly tunable degradation and osteogenic features

It remains a challenge to achieve satisfactory balance between biodegradability and osteogenic capacity in biosynthetic bone grafts.In this study,we aimed to address this challenge by incorporating mesoporous bioactive glass(MBG)into poly(caprolactone-co-glycolide)(PGA-PCL)at gradient ratios.MBG/PGA-PCL(PGC/M)scaffolds with MBG incorporation ratio at 0,10%,25%and 40%(PGC/M0-40)were synthesized using a modified solvent casting-particulate leaching method,and their physiochemical and biological properties were comprehensively evaluated.PGC/M scaffolds exhibited highly perforated porous structure with a large-pore size of 300-450μm,with ordered MBGs of around 6.0 nm mesopores size uniformly dispersed.The increase in MBG incorporation ratio significantly improved the scaffold surface hydrophilicity,apatite-formation ability and pH stability,increased the weight loss rate while insignificantly influenced the molecular chains degradation of PGA-PCL component,and facilitated the attachment,spreading,viability and proliferation of rat bone marrow stromal cells(rBMSCs)on scaffolds.Moreover,rBMSCs cultured on PGC/M10-40 scaffolds demonstrated enhanced ALP activity and osteogenesis-related gene expression in a MBG dose-dependent manner as compared with those cultured on PGC/M0 scaffolds.When implanted to the rat cranial bone defect,PGC/M25 and PGC/M40 scaffolds induced significantly better bone repair as compared to PGC/M0 and PGC/M10 scaffolds.Besides,the biodegradability of PGC/M scaffolds correlated with the MBG incorporation ratio.These data suggested this novel PGC/M scaffolds as promising bone repair biomaterial with highly tunable hydrophilicity,bioactivity,cytocompatibility,osteogenic activity as well as biodegradability.

Fabrication of carboxylic graphene oxide-composited polypyrrole film for neurite growth under electrical stimulation

An aligned composite film was fabricated via the deposition of carboxylic graphe ne oxide(C-GO)and polypyrrole(PPy)nano particles on alig ned poly(L-lactic acid)(PLLA)fiber-films(named as C-GO/PPy/PLLA),which has the core(PLLA)-sheath(C-GO/PPy)structure,and the composition of C-GO(~4.8 wt.%of PPy sheath)significantly enhanced the tensile strength and the conductivity of the PPy/PLLA film?Especially,after 4 weeks of immersion in the PBS solution,the conductivity and the tensile strength of CGO/PPy/PLLA films still remained-6.10 S/cm and 28.9 MPa,respectively,which could meet the need of the sustained electrical stimulation(ES)therapy for nerve repair.Moreover,the neurite length and the neurite alignment were significantly in creased through exerting ES on C-GO/PPy/PLLA films due to their sustained conductivity in the fluid of cell culture.These results indicated that C-GO/PPy/PLLA with sustained conductivity and mechanical property possessed great potential of nerve repair by exerting lasting-ES.

Zirconium metal-organic framework nanocrystal as microwave sensitizer for enhancement of tumor therapy

Although surgical resection and chemotherapy were widely applied in tumor therapy, the dysfunction of normal cells resulted in the side effects (such as anorexia, nausea). MW thermal therapy is a non-invasive anticancer strategy under the help of MW sensitizer, with the safety and higher efficacy. Zirconium metal-organic framework nanocubes (ZrMOF NCs) modified with polyethylene glycol, were prepared via one pot method and carbodiimide technique, resulting in their large specific surface area and porosity.Our results showed that non-ion-loaded ZrMOF NCs in 0.9% NaCl solution exhibited better heating effect,higher than that in pure water, due to the robust collision among the ions under MW irradiation. The in vivo experiments confirmed that ZrMOF-PEG NCs + MW group exhibited the higher temperature in the tumor region than that of only MW treatment, suggesting a better MW thermal therapeutic anticancer efficacy. This work provides a new preparation strategy of biosafety nanomaterial as MW sensitizer for enhancing MW thermal anticancer therapy.

Electroactive chitosan-aniline pentamer hydrogel for peripheral nerve regeneration

Electroactive hydrogels could guide the regeneration of nerves and promote their functional recovery.An aniline pentamer-crosslinked chitosan(CS-AP)hydrogel with better electroactivity and degradation was fabricated by the carbodiimide method,and then injected into the repair site of sciatic nerve damage,with its gelation time,tensile strength,and conductivity reaching 35 min,5.02-6.69 MPa,and from 2.97×10^(-4) to 3.25×10^(-4) S-cm^(-1),respectively,due to the cross-linkage and well-distribution of AP.There was better cytocompativility of CS-AP hydrogel on nerve cells.The results of the in vivo repair indicated that CS-AP10 hydrogel induced the capillaries formation and the repair of sciatic nerve defect,and re-innervated gastrocnemius muscle in the CS-AP10 group were obviously better than other experimental groups,due to the electroactivity of CS-AP and its degradation into fragments.These results indicated the potential application of CS-AP hydrogel in the regeneration and function recovery of peripheral nerve injury.

Fabrication of doxorubicin and chlorotoxin-linked Eu-Gd2O3 nanorods with dual-model imaging and targeted therapy of brain tumor

It is urgent to find a technology accurately to better diagnose and treat to brain tumor.Eu-doped Gd2 O3 nanorods(Eu-Gd2 O3 NRs)with paramagnetic and fluorescent properties were conjugated with doxorubicin(Dox)and chlorotoxin(CTX)via PEGylation,hydrazone bond and sulfur bond(named as CTXNRs-Dox),and these NRs could release more Dox in lower pH environment.The results of cell experiments indicated that CTX-NRs-Dox had obvious targeting and toxic effects on U251 cells,as well as good fluorescence imaging behavior.The orthotopic glioma-transplanted mice models were constructed via the intracranial injection of glioma cells(U87 MG).The result of experiments after the tail-vein injection of the prepared NRs suggested that CTX-NRs-Dox could target to brain tumors via the long-time blood circulation,leading to their obvious contrast enhancement of MR imaging of the intracranial tumor and their significant inhibitory effect on the growth and metastasis of brain tumors.A mechanism of synergistic effect of CTX-NRs-Dox on targeting and inhabiting the brain tumor was proposed.Our research suggested that CTX-NRs-Dox had potential application prospect in the detection and treatment of glioma.

Preparation and enhanced properties of ZrMOF@CdTe nanoparticles with high-density quantum dots

ZrMOF@CdTe nanoparticles(NPs)with high fluorescence were synthe-sized by hydrothermal method.The morphology,particle size distribution,compositions,fluorescence properties and stability of the synthesized ZrMOF@CdTe were analyzed via the characterization by TEM,ICP-AES and fluorescence spectrophotometry,and the effects of the reaction time and pH value on the fluorescent property of ZrMOF@CdTe NPs were discussed.The results show that ZrMOFs could maintain its morphology and structure well during the process of loading CdTe quantum dots.With the increase of the loading reaction time,the red-shifted emission peaks of ZrMOF@CdTe NPs appear,and their fluorescence gradually changes from green to red color.With the increase of the pH value and temperature of the hydrothermal reaction,the fluorescence of ZrMOF@CdTe NPs was also consistent with the red-shifted change.The fluorescent property of ZrMOF@CdTe NPs could be remained for more than 3 months.Therefore,ZrMOF@CdTe NPs synthesized by the hydrothermal method have the characteristics of simple operation,adjustable fluorescent color and high stability,and the potential application in the fields of biological detection and sensing is expected.

Preparation and properties of covalent organic framework nanoparticles with high drug loading

With the rapid development of nanotechnology,nano-drug carrier systems in biomedicine have received extensive attention from researchers.By adsorbing or coating the drug in/on a nano-sized carrier,this system improves the drug’s stability and selectivity in the body,reducing the toxicity and side effects of the drug.Thus these carrier systems have broad application prospects in the field of biomedicine.A common nano-drug carrier system includes inorganic nano-carriers,organic nano-carriers,and metal nano-carriers.Inorganic nano-carriers have the advantages of good stability,controllable size,larger specific surface area,and unique photothermal electromagnetic properties.