A nano-based thermotherapy for cancer stem cell-targeted therapy.

Cancer stem cells (CSCs) exhibit high resistance to conventional therapy and are responsible for cancer metastasis and tumor relapse. Therefore, it is of significance to develop effective novel strategies to target CSCs for cancer therapies. The challenges associated with developing novel strategies include specific CSC targeting and overcoming their therapeutic resistance. In the present review, we summarize the various strategies for CSC-targeted cancer thermotherapy and combinational therapy, and the potential challenges and prospects for future work in this emerging field.

Boronic acid-modified polyhedral oligomeric silsesquioxanes on polydopamine-coated magnetized graphene oxide for selective and high-capacity extraction of the catecholamines epinephrine, dopamine and isoprenaline.

Amino-functionalized polyhedral oligomeric silsesquioxanes (POSS-8NH2) were covalently bound to the surface of polydopamine-coated magnetized graphene oxide. It was then reacted with 4-formylphenylboronic acid to prepare a "cubic boronic acid"-bonded magnetic graphene oxide adsorbent. The new adsorbent exhibits better selectivity and much higher adsorption capacity for ortho-phenols over adsorbents where small boronic ligands are directly bound to the surface of the material. It is shown to enable selective and faster enrichment of the catecholamines epinephrine (EP), dopamine (DA) and isoprenaline (IP) with high selectivity over many potential interferents that can occur in urine. The analytes were then quantified by HPLC with fluorometric detection. Under optimal conditions, response is linear (R2 ≥ 0.9907), limits of detection are low (0.54-2.3 ng·mL-1), and reproducibility is acceptable (inter- and intra-day assay RSDs of≤10.9%). The method was successfully applied to the determination of endogenous EP and DA and exogenous IP in urine samples. Graphical abstractSchematic of boronic acid (BA)-modified polyhedral oligomeric silsesquioxanes (POSS) on polydopamine-coated magnetized graphene oxide (magGO). The material (magGO@POSS-BA) has good selectivity and higher adsorption capacity to ortho-phenols and can be applied to enrich the catecholamines in urine.

Green fluorescent carbon quantum dots functionalized with polyethyleneimine, and their application to aptamer-based determination of thrombin and ATP.

Brightly fluorescent carbon quantum dots coated with polyethylenimine (PEI-CDs) were prepared using malic acid and PEI as the precursors. The PEI-CDs have a high quantum yield (41%) and green emission (peaking at 502 nm under 430 nm excitation), both of which are not affected by high ionic strength. The PEI-CDs have a positive charge at physiological pH values and can electrostatically bind aptamers with their negative charge. This is shown for aptamers binding thrombin or ATP. Binding of aptamers results in quenching of fluorescence. If thrombin or ATP are introduced, the respective aptamer will bind them, and the complex is then released from the PEI-CDs. Fluorescence increases in proportion to the analyte concentration. Under optimized conditions, thrombin and ATP can be sensitively and selectively detected by fluorometry with lower detection limits of 1.2 and 13 nM, respectively. The assay was successfully applied to the determination of thrombin and of ATP in spiked serum samples. Graphical abstract Green fluorescent carbon quantum dots were functionalized with polyethyleneimine. They were applied to aptamer-based determination of thrombin and ATP. The PEI-functionalized carbon quantum dots (PEI-CDs) have bright green fluorescence are were synthesized by one-step hydrothermal treatment of malic acid and PEI. Employing the PEI-CDs, a fluorometric aptamer-based assay was developed for the determination of thrombin and ATP.

Recent advances in aflatoxin B1 detection based on nanotechnology and nanomaterials-A review.

Aflatoxin B1(AFB1) is one of the most toxic mycotoxins produced by fungi and results in inevitable contamination of food and feed at very low concentrations. Therefore, there is an urgent need to implement selective, sensitive and highly convenient methods for the determination of aflatoxin B1. Among these methods, the progress of nanomaterials, owing to their high performances and versatile properties, offers great prospects for realizing highly sensitive, selective and simple detection of AFB1, overcoming the restrictions of traditional methods such as process-complicated, time-consuming, labor-intensive and instruments-expensive. Many nanomaterials have been used for the immobilization of biomolecules as signal generators or fluorescent quenchers or for signal amplification in AFB1 detection. This review highlights recent progress that has been made in the development of nanoparticle-based assays and focuses on the analytical potential of nanomaterials, such as Au/Ag nanoparticles (Au/Ag NPs), carbon-based nanoparticles (CBNs), magnetic nanoparticles (MNPs), Quantum dots (QDs) and novel nanomaterials, including up-conversion nanoparticles (UCNPs), metal-organic frameworks (MOFs) and nanomaterial-functional DNA intelligent hydrogels, as well as hybrid nanostructures. The determination of AFB1 is divided into three aspects: sample pretreatment prior to AFB1 detection, immunoassays and biosensors. The details of the detection methods and their application principles are described, and the challenges and opportunities in the field of food analysis are described.

Facile preparation of partially reduced graphite oxide nanosheets as a binder-free electrode for supercapacitors.

Preparation of graphene (GR) based electrode materials with excellent capacitive properties is of great importance to supercapacitors. Herein, we report a facile approach to prepare partially reduced graphite oxide (PRG) nanosheets by reducing graphite oxide (GO) using commercial Cu2O powder as a reduction agent, moreover, we demonstrate that the PRG nanosheets can act as building blocks for assembling hydrogels (PRGH) and flexible film (PRGF). The obtained PRGH and PRGF can be directly used as binder-free electrodes for supercapacitors and give high specific capacitance (292 and 273 F g-1 at a current density of 0.5 A g-1 in a three-electrode system, respectively) due to the existence of oxygen-containing functional groups in PRG nanosheets. PRG also gives excellent rate ability and cycle stability. This study suggests a facile pathway to produce GR-based materials with excellent capacitive properties and is meaningful for flexible supercapacitors.

Arsenic removal from aqueous solutions by diethylenetriamine-functionalized resin: isotherm, kinetics, selectivity and mechanism.

The surface-initiated atom transfer radical polymerization method was used to graft glycidyl methacrylate (GMA) on chloromethylated cross-linked styrene-divinylbenzene resin, and then the novel diethylenetriamine-functionalized resin was prepared through the amination reaction between amino group of diethylenetriamine and epoxy group in GMA. The adsorption properties were evaluated with As(V). The adsorption of As(V) was mainly regarded as the electrostatic interaction between the adsorbent and the adsorbate by analysing the relationship between adsorption capacity with the solution pH, adsorption isotherm and adsorption kinetics. The maximum sorption capacity of As(V) was 5.25 mmol g-1. The adsorption isotherms of As(V) were best described by the Langmuir model, and its adsorption kinetics followed the pseudo-second-order kinetic equation. The adsorption of As(V) ions was hardly affected by common coexisting ions such as Na(I), K(I), Ca(II) and Mg(II), whereas it was slightly decreased when Fe(II) and Zn(II) coexisted in the solution, which illustrates the selective adsorption of As(V) from wastewater. Ten adsorption-desorption cycles demonstrated that the resin possessed high recycling efficiency and stability and was suitable for efficient removal of metal ions from aqueous solution.

Biocompatibility evaluation of dicalcium phosphate/calcium sulfate/poly (amino acid) composite for orthopedic tissue engineering in vitro and in vivo.

In vitro cytocompatibility of ternary biocomposite of dicalcium phosphate (DCP) and calcium sulfate (CS) containing 40 wt% poly (amino acid) (PAA) was evaluated using L929 fibroblasts and MG-63 osteoblast-like cells. Thereafter, the biocompatibility of biocomposite in vivo was investigated using an implantation in muscle and bone model. In vitro L929 and MG-63 cell culture experiments showed that the composite and PAA polymer were noncytotoxic and allowed cells to adhere and proliferate. The scanning electron microscope (SEM) confirmed that two kinds of cells maintained their phenotype on all of samples surfaces. Moreover, the DCP/CS/PAA composite showed higher cellular viability than that of PAA; meanwhile, the cell proliferation and ALP activity were much higher when DCP/CS had added into PAA. After implanted in muscle of rabbits for 12 weeks, the histological evaluation indicated that the composite exhibited excellent biocompatibility and no inflammatory responses were found. When implanted into bone defects of femoral condyle of rabbits, the composite was combined directly with the host bone tissue without fibrous capsule tissue, which shown good biocompatibility and osteoconductivity. Thus, this novel composite may have potential application in the clinical setting.

[Role of oxygen therapy in prevention of chronic mountain sickness].

OBJECTIVE: To explore the effect of prophylaxis on youth's chronic mountain sickness(CMS) who moved to an altitude of above 5 000 meters by long-term oxygen therapy (LTOT). METHODS: Ninety-six male youth stationed at 5 070 m, 5 200 m and 5 380 m took oxygen continuously by nasal cannula (LTOT group) every body per day. One year later, epidemiological survey were carried out according to the international CMS diagnostic criteria consist of examining right ventricle end-diastolic dimension (RVED), right ventricular anterior wall (RVAW), right ventricular outflow tract (RVOT), main pulmonary artery (MPA), left ventricular end systolic diameter (LVSD) by ultrasonic diagnostic apparatus, and blood test of alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (gamma-GT), creatine kinase (CK), lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), nitric-oxide synthase (NOS) blood oxygen saturation (SaQ2). Then, they were compared with 91 males in the same group stationed at the same altitude (without any interventions, control group). RESULTS: (1) The epidemiological survey showed that, SaO2 were increased significantly (P < 0.05) and the prevalence rate of CMS were decreased compared with that of control group (P < 0.05). (2) Echocardiography showed that SOD, NO, NOS were increased (P < 0.05 or 0.01) and LVSD, MPA had no significant difference compared with that of control group (P > 0.05). (3) Biochemical index showed that, SOD, NO, NOS were increased (P < 0.05 or 0.01), MDA, ALT, AST, LDH were decreased (P < 0.05 or 0.01) and gamma-GT, CK had no significant difference compared with that of the control group. CONCLUSION: At high altitude, LTOT can reduce lipid peroxidation, improve the important organ injuries caused by hypoxia and protect the mitochondria respiratory function and play an important role on the prevention of chronic mountain sickness.

An ultrasensitive post chemiluminescence reaction of ammonium in NBS-dichlorofluorescein system and its application.

A strong post chemiluminescence (PCL) phenomenon was observed when ammonium was injected into the reaction mixture after the finish of CL reaction of N-bromosuccinimide (NBS) and dichlorofluorescein. Based on this, a sensitive flow injection PCL method was established for the determination of ammonium. The possible CL mechanism of the reaction was proposed based on a series of experiments. The PCL intensity responded linearly to the concentration of ammonium in the range 3.0 × 10(-11) -1.0 × 10(-7) g mL(-1) with a detection limit of 1 × 10(-11) g mL(-1). The relative standard deviation (R.S.D.) was 1.4% for 1.0 × 10(-9) g mL(-1) ammonium (n=11). This method had been applied to the determination of ammonium in samples of mineral water, tap water and river water.

An ionic liquid supported CeO2 nanoparticles-carbon nanotubes composite-enhanced electrochemical DNA-based sensor for the detection of Pb2.

An electrochemical sensor incorporating a signal enhancement for the determination of lead (II) ions (Pb2+) was designed on the basis of the thrombin-binding aptamer (TBA) as a molecular recognition element and ionic liquid supported cerium oxide (CeO2) nanoparticles-carbon nanotubes composite modification. The composite comprises nanoparticles CeO2, multi-wall carbon nanotubes (MWNTs) and hydrophobic room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4). The electrochemical sensors were fabricated by immersing the CeO2-MWNTs-EMIMBF4 modified glassy carbon electrode (GCE) into the solution of TBA probe. In the presence of Pb2+, the TBA probe could form stable G-quartet structure by the specific binding interactions between Pb2+ and TBA. The TBA-bound Pb2+ can be electrochemically reduced, which provides a readout signal for quantitative detection of Pb2+. The reduction peak current is linearly related to the concentration of Pb2+ from 1.0×10-8 M to 1.0×10-5 M with a detection limit of 5×10-9 M. This work demonstrates that the CeO2-MWNTs-EMIMBF4 nanocomposite modified GCE provides a promising platform for immobilizing the TBA probe and enhancing the sensitivity of the DNA-based sensors.

[Determination of binding domains of paeonol on immobilized human serum albumin by high-performance affinity chromatography].

High-performance affinity chromatography was used to investigate the binding of paeonol (PAE) to immobilized human serum albumin (HSA) under the condition of pH 7.4 and temperature of 37 degrees C. Self-competition zonal elution indicated that there was only one major binding site on HSA for PAE. The association constant of PAE with HSA was 4.84 x 10(3) L/mol. Competition studies based on zonal elution were carried out between PAE and various probes which have been known to interact with several major and minor sites on HSA. PAE was found to have direct competition with L-tryptophan. The results indicated that PAE interacted with Sudlow site II on HSA. The thermodynamic analysis indicated that the main force between the paeonol and HSA was hydrogen bond or van der Waals force.

Carbon nanotube-enhanced electrochemical aptasensor for the detection of thrombin.

A novel electrochemical aptasensor for the detection of thrombin was developed on basis of the thrombin-binding aptamer (TBA) as a molecular recognition element and multi-walled carbon nanotubes (MWCNTs) as a carrier of the electrochemical capture probe. Amine-modified capture probe (12-mer) was covalently conjugated to the MWCNTs modified glassy carbon electrode (GCE). The target aptamer probe (21-mer) contains TBA (15-mer) labeled with ferrocene (Fc), which is designed to hybridize with capture probe and specifically recognize thrombin, is immobilized on the electrode surface by hybridization reaction. Introduction of the analyte thrombin triggered the dissociation of the aptamer probe labeled with Fc from the biosensors, led to a significant decrease in peak current intensity. Differential pulse voltammetry (DPV) was employed to detect the target analyte with different concentrations. The decreased peak current was in proportion to the concentration of thrombin in a range from 1.0x10(-12) to 5.0x10(-10)M with a detection limit of 5x10(-13)M. The present work demonstrates that using MWCNTs as a carrier for electrochemical capture probe is a promising way to amplify the electrochemical signal and to improve the sensitivity of the electrochemical aptasensor.

Diaqua-(5-methyl-pyrazine-2-carboxyl-ato-κN,O)iron(II).

In the neutral title complex, [Fe(C(6)H(5)N(2)O(2))(2)(H(2)O)(2)], the coordination geometry aound the Fe(II) atom, which lies on an inversion centre, is distorted octa-hedral comprising two N atoms and two O atoms from two 5-methyl-pyrazine-2-carboxyl-ate ligands, and two water mol-ecules. The crystal structure is stabilized by a network of O-H⋯O hydrogen bonds, resulting in a two-dimensional supra-molecular structure.

Flow-injection biamperometry of pyrogallol compounds.

A biamperometric method for the direct determination of pyrogallol compounds has been designed for flow-injection analysis. The method is based on the electrocatalytic oxidation of pyrogallol compounds at one pretreated platinum electrode and the reduction of platinum oxide at the other pretreated platinum electrode to form a biamperometric detection system with the applied potential difference of 10 mV. Three important compounds, pyrogallol, gallic acid and tannic acid, have been detected by the method. The linear relationships between currents and the concentrations of pyrogallol, gallic acid and tannic acid are obtained over the range 1.0x10(-6)-1.0x10(-4), 1.0x10(-6)-1.0x10(-4) and 1.0x10(-6)-2.0x10(-4) mol l(-1) with the detection limit of 6.0x10(-7), 6.0x10(-7) and 8.0x10(-7) mol l(-1) (S/N=2), respectively. The R.S.D. observed for 30 successive determinations of 5.0x10(-5) mol l(-1) pyrogallol, gallic acid and tannic acid are 1.9, 2.5 and 2.0%, respectively. Most ions and organic compounds tested are found not to cause significant interference in the determinations. The method is simple, selective and efficient (180 h(-1)), performing well as a routine assay, and has been validated by the determination of pyrogallol compounds in tea and Chinese gall.

Determination of total phenols in environmental wastewater by flow-injection analysis with a biamperometric detector.

A flow injection (FI) method with a biamperometric detector, based on the biamperometry for an irreversible redox couple, is described for the determination of phenols in environmental wastewater. The method relies on coupling of the oxidation of phenols at one platinum-wire electrode with the reduction of MnO4- at another platinum wire electrode to enable biamperometric detection with an applied potential difference of 0 V. The linear dynamic range for the dependence of current on phenol concentration was from 1.0 x 10(-6) to 1.0 x 10(-4) mol L(-1), with a detection limit of 4.0 x 10(-7) mol L(-1) (signal-to-noise ratio, S/N=3). In comparison with the 4-aminoantipyrine (4-AAP) standard method and the 3-methyl-2-benzothiazoline hydrazone (MBTH) method the proposed method can be used to detect many para-substituted phenols that do not react with 4-AAP and MBTH, and response factors are higher for most of the phenols tested. The method, which is simple, economic, and rapid (180 samples h(-1)), has been applied to the analysis of four wastewater samples. The results obtained were compared with those from 4-AAP method. The recoveries obtained by adding phenol standards to samples ranged from 94.3 to 105.2% with a standard deviation of 3.6%.