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Carbon nanotube (CNT) arrays show great promise in developing anisotropic thermal conductive composites for efficiently dissipating heat from high-power devices along thickness direction. However, CNT arrays are always grown on some substrates and liable to be deformed and broken into pieces during transfer and solution treatment. In the present study, we intentionally synthesized well-crystallized and large-diameter (~80 nm) multiwalled CNT (MWCNT) arrays by floating catalyst chemical vapor deposition (FCCVD) method. Such arrays provided high packing density and robust structure from collapse and crack formation during post solution treatment and therefore favored to maintain original thermal and electrical conductive paths. Under optimized condition, the CNT arrays can be transferred into flexible composite films. Furthermore, the composite film also exhibited excellent thermal conductivity at 8.2 W/(m·K) along thickness direction. Such robust, flexible, and highly thermal conductive composite film may enable some prospective applications in advanced thermal management.

Supercapacitors are important energy storage technologies in fields such as fuel-efficient transport and renewable energy. State-of-the-art supercapacitors are capable of supplanting conventional batteries in real applications, and supercapacitors with novel features and functionalities have been sought for years. Herein, we report the realization of a new concept, a smart supercapacitor, which functions as a normal supercapacitor in energy storage and also communicates the level of stored energy through multiple-stage pattern indications integrated into the device. The metal-oxide W18O49 and polyaniline constitute the pattern and background, respectively. Both materials possess excellent electrochemical and electrochromic behaviors and operate in different potential windows, -0.5-0 V (W18O49) and 0-0.8 V (polyaniline). The intricate cooperation of the two materials enables the supercapacitor to work in a widened, 1.3 V window while displaying variations in color schemes depending on the level of energy storage. We believe that our success in integrating this new functionality into a supercapacitor may open the door to significant opportunities in the development of future supercapacitors with imaginative and humanization features.

Heat shock protein 90 (Hsp90) serves as an ATP-dependent molecular chaperone for numerous cell signaling proteins, including many oncogenes and clinically validated cancer targets that are involved in cell proliferation and survival. Recent studies have shown that the Hsp90 inhibitor, SNX-2112, effectively inhibits tumor cell growth and angiogenesis in hematological and solid tumors. However, little is known about the effects of SNX-2112 on leukemias that are resistant to chemotherapy, which is emerging as a major clinical problem. In this study, the effects of SNX-2112 on the multidrug-resistant human chronic myeloid leukemia (CML) K562/ADR cell line were investigated. We observed that SNX-2112 exhibited dose- and time-dependent inhibitory activities against K562/ADR cells. These effects included the induction of apoptosis and secondary necrosis in addition to cell cycle arrest at the G1 and G2 phases. Furthermore, SNX-2112-induced apoptosis was predominantly mediated by the mitochondrial pathway, initiated by the release of cytochrome c and the participation of Bcl-2 family proteins. SNX-2112 also induced the activation of the caspase-3, -8 and -9 cascade and the subsequent cleavage of PARP in K562/ADR cells. Moreover, the inactivation of the Akt and NF-κB signaling pathways may be involved in SNX-2112-induced apoptosis. The expression levels of P-glycoprotein (P-gp) and several chaperons related to drug resistance and apoptosis were also shown to be inhibited, including the Grp78 and Hsp90 isoforms, Grp94 and Trap1. Taken together, these results provide a possible molecular mechanism for the anti-cancer effect of SNX-2112 on K562/ADR cells and provide new insights into the future application of SNX-2112 as a therapeutic agent for anti-multidrug-resistant leukemias., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

The liver transplant (LT) situation represents an attractive model for studying hepatocellular carcinoma (HCC) metastasis. Based on microarray data, we previously found that miR-126 expression was lower in tumor tissues of patients with post-LT HCC recurrence compared with non-recurrence. In this study, we examined the expression of miR-126 in HCC samples from 68 patients who had undergone LT using quantitative real-time PCR and analyzed its correlation with clinicopathological features and prognosis of patients. Furthermore, we performed experimental analyses to explore the involvement of miR-126 in HCC metastasis. We found that miR-126 levels were lower in tumor tissues of patients with post-LT HCC recurrence in comparison to patients with no-recurrence (p = 0.009). Lower expression of miR-126 in HCC was associated significantly with tumor recurrence (p = 0.011) and poor survival (p = 0.009) of patients. Functional studies indicated that ectopic expression of miR-126 significantly inhibits HCC cells migration, invasion, proliferation and colony formation in vitro, and suppresses experimental lung colonization in vivo. Our study revealed that down-regulation of miR-126 plays an important role in HCC metastasis, and suggest a potential application of miR-126 in prognosis prediction and HCC treatment.

MnO2 has been widely studied as the pseudo-capactive electrode material of high-performance supercapacitors for its large operating voltage, low cost, and environmental friendliness. However, it suffers from low conductivity and being hardly handle as the electrodes of supercapacitors especially with flexibility, which largely limit its electrochemical performance and application. Herein, we report a novel ternary composite paper composed of reduced graphene sheet (GR)-patched carbon nanotube (CNT)/MnO2, which has controllable structures and prominent electrochemical properties for a flexible electrode of the supercapacitor. The composite paper was prepared by electrochemical deposition of MnO2 on a flexible CNT paper and further adsorption of GR on its surface to enhance the surface conductivity of the electrode and prohibit MnO2 nanospheres from detaching with the electrode. The presence of GR was found remarkably effective in enhancing the initial electrochemical capacitance of the composite paper from 280 F/g to 486.6 F/g. Furthermore, it ensures the stability of the capacitance after a long period of charge/discharge cycles. A flexible CNT/polyaniline/CNT/MnO2/GR asymmetric supercapacitor was assembled with this composite paper as an electrode and aqueous electrolyte gel as the separator. Its operating voltage reached 1.6 V, with an energy density at 24.8 Wh/kg. Such a composite structure derived from a multiscale assembly can offer not only a robust scaffold loading MnO2 nanospheres but also a conductive network for efficient ionic and electronic transport; thus, it is potentially promising as a novel electrode architecture for high-performance flexible energy storage devices.

A luminol electrochemiluminescence assay was reported to analyze active cholesterol at the plasma membrane in single mammalian cells. The cellular membrane cholesterol was activated by the exposure of the cells to low ionic strength buffer or the inhibition of intracellular acyl-coA/cholesterol acyltransferase (ACAT). The active membrane cholesterol was reacted with cholesterol oxidase in the solution to generate a peak concentration of hydrogen peroxide on the electrode surface, which induced a measurable luminol electrochemiluminescence. Further treatment of the active cells with mevastatin decreased the active membrane cholesterol resulting in a drop in luminance. No change in the intracellular calcium was observed in the presence of luminol and voltage, which indicated that our analysis process might not interrupt the intracellular cholesterol trafficking. Single cell analysis was performed by placing a pinhole below the electrode so that only one cell was exposed to the photomultiplier tube (PMT). Twelve single cells were analyzed individually, and a large deviation on luminance ratio observed exhibited the cell heterogeneity on the active membrane cholesterol. The smaller deviation on ACAT/HMGCoA inhibited cells than ACAT inhibited cells suggested different inhibition efficiency for sandoz 58035 and mevastatin. The new information obtained from single cell analysis might provide a new insight on the study of intracellular cholesterol trafficking.

In this study, BODIPY-appended calix[4]arene was chosen as a fluorescent probe for intracellular pH. The compound with cell permeability can monitor the minor pH change near neutrality inside the cell and is the first BODIPY-derived probe reported for cytosolic pH. Owing to a high level of cell retention and minor cytotoxicity of the probe, stable fluorescence is provided in the cells for 24h, facilitating the precise observation of intracellular pH. A model of cell apoptosis was designed by exposure of the cells to a low concentration of hydrogen peroxide. An increase in the fluorescence of the cells confirmed that BODIPY-appended calix[4]arene sensed the fluctuation of the cellular pH during early cell apoptosis. The developed fluorescent pH probe will be useful for the study of cell apoptosis., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Two new series of 15-membered macrocyclic peptidomimetics, in which the P1 and P3 residues of the peptide backbone are linked by a bridge containing a 1,4-disubstituted 1H-imidazole, are reported. The structure with an aldehyde at the C-terminus and the imidazole at P3, i.e., 4c, shows significant inhibitory activity against calpain 2, with an IC(50) value of 238 nM. The macrocyclic aldehyde with the imidazole at the alternative P1 position, i.e., 5c, is significantly less active. The relative activities are linked to the ability of the component macrocycles to mimic a β-strand geometry that is known to favor active-site binding. This ability is defined by conformational searches and docking studies with calpain., (Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.)

Preparation of strong, flexible, and multifunctional carbon-based films has attracted considerable interest not only in fundamental research areas but also for industrial applications. We report a binder-free, ultrastrong, and foldable carbon nanotube (CNT) film using aligned few-walled nanotube sheets drawn from spinnable nanotube arrays. The film exhibits tensile strengths up to ∼2 GPa and a Young's modulus up to ∼90 GPa, which is markedly superior to other types of carbon-based films reported, including commercial graphite foils, buckypapers, and graphene-related papers. The film can bear severe bending (even being folded) and shows good structure integrity and negligible change in electric conductivity. The unique structure of the CNT film (good nanotube alignment, high packing density) provides the film with direct and efficient transport paths for electricity. As a flexible charge collector, it favors a magnesium oxide coating to exhibit high charge/discharge rate stability and an excellent electrochemical capacitance close to its theoretical value.

Genetic variations in the gene XPC may be associated with increased risk for gallbladder cancer (GBC). In this study, we detected two non-synonymous polymorphisms in XPC (Ala499Val and Lys939Gln) in 334 cases of GBC and 329 subjects of hospital-based age- and sex frequency-matched controls in China using a polymerase chain reaction-restriction fragment length polymorphism assay. Allelic association analysis for the two single-nucleotide polymorphisms (SNPs) showed that the risk allele T of Ala499Val was significantly associated with GBC [odds ratio (OR)=1.40, 95% confidence interval (CI): 1.11-1.76, P=0.005), with a population attributive risk of 5.3%. Logistic regression analysis revealed that Ala499Val CT heterozygote (OR=1.56, 95% CI: 1.13-2.14, P=0.002) and TT homozygote (OR=1.93, 95% CI: 1.04-3.55, P=0.048) had a significantly increased risk compared with CC homozygotes. Genetic analysis suggested that either the SNPs directly exert an effect or the linked functional gene impact of the disease trait likely follows an additive or dominant model. Gene interaction analysis demonstrated that the effects of XPC diplotypes (defined as the number of risk genotypes at the two SNP loci) were highly dependent on gallstone. The data from this case-control study indicated that XPC exonic variants contributed to the risk of GBC in this Chinese population.

A composite film with switchable transparency is fabricated by sandwiching a carbon nanotube (CNT) sheet within polyurethane (PU) films. The introduction of CNTs not only makes the composite film electrically conductive but also induces a rapid crystal melting of soft segments in the PU. As a result, the film can be switched from opaque to transparent in just several seconds after turning on voltage, and reversed back to opaque after turning off voltage. The film also possesses several other attractive properties, including excellent flexibility, low energy consumption, switching speed insensitivity to ambient temperature, and easy coloration, which make the film promising for a wide variety of practical applications.

Based on the invasive plasmid antigen H gene (ipaH) of S. dysenteriae, one pair of specific primers was designed for PCR assays in this study. The concentrations of dNTP, Mg2+ and primer, dosage of Taq DNA polymerase, annealing temperature and circulating parameter in the PCR amplification system were optimized. In this way, a rapid and stable method of PCR assay for the detection of S. dysenteriae was established. The specificity and sensitivity of PCR were also analyzed. The detection limits of pure culture and genomic DNA in the PCR assay were 1.06 x 10(2) cfu/ml and 106.34 pg/PCR system, respectively. The detection limit for S. dysenteriae in artificially contaminated food samples was 3.21 x 10(4) cfu/ml. These results indicated that the PCR method for S. dysenteriae detection was simple, rapid, high in specificity and sensitivity and suitable for the detection of pathogens in foods caused by Shigella dysenteriae.

A rapid method for the analysis of the main components of the total glycosides of Ranunculus japonicus (TGOR) was developed using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). The separation analysis was performed on a Waters Acquity UPLC system and the accurate mass of molecules and their fragment ions were determined by Q-TOF MS. Twenty compounds, including lactone glycosides, flavonoid glycosides and flavonoid aglycones, were identified and tentatively deduced on the basis of their elemental compositions, MS/MS data and relevant literature. The results demonstrated that lactone glycosides and flavonoids were the main constituents of TGOR. Furthermore, an effective and rapid pattern was established allowing for the comprehensive and systematic characterization of the complex samples.

To study the anticancer activities of curcumin on human hepatocarcinoma cell line Sk-hep-1 and its related molecular mechanism which has not been elucidated. In the present study,we showed that curcumin inhibited proliferation of Sk-hep-1 cells in a dose-dependent manner through MTF assay. The effect of curcumin on apoptosis in Sk-hep-1 cells was investigated by DAPI staining and the various apoptosis was observed in hepatocarcinoma cell lines Sk-hep-1, HepG2 and Hep3B, but not in normal liver cell line Chang's liver with curcumin treatment. Cell cycle analysis results showed that curcumin treatment resulted in dramatic accumulation of Sk-hep-1 cells at the G0/G1 or G2/M phase. The effect of curcumin on the expression of anti-apoptosis genes (Survivin and BCl-xL) and drug resistance genes (DRG2 and MDR1) was studied by reverse transcription-polymerase chain reaction (RT-PCR). The expression of MDR1 mRNA was significantly decreased in Sk-hep-1 cells treated with curcumin, while no alterations in the amount of DRG2 and anti-apoptosis genes' mRNA levels were found. These results indicate that curcumin is able to inhibit proliferation and induce apoptosis in Sk-hep-1 cells and it may cause by down-regulating the expression of MDR1 mRNA.

We report the synthesis of macrocycles 1-6 via ring closing metathesis of dienes 7-12. Addition of chlorodicyclohexylborane to thermal and microwave assisted RCM of dienes 8 and 9 markedly improves the yield. The geometric isomers of macrocycles 1-3 and 5 have been assigned using X-ray crystallography and NMR.

In the current paper, enzyme enhanced simultaneous quantitative determination of multiple DNA targets based on capillary electrophoresis (CE) was described. We used three biotin-modified DNA probes, which reacted with avidin-conjugated horseradish peroxidase (avidin-HRP) conjugate to obtain the HRP labeled probes, to hybridize with three corresponding targets. The resulting mixture containing double-strand DNA (dsDNA)-HRP, excess single-strand DNA (ssDNA)-HRP and remaining avidin-HRP was separated by capillary electrophoresis, and then the system of HRP catalyzing H(2)O(2)/o-aminophenol (OAP) reaction was adopted. The catalytic product was detected with electrochemical detection. With this protocol, the limits of quantification for the hybridization assay of 21-, 39- and 80-mer DNA fragments were of 1.2 x 10(-11), 2.4 x 10(-11) and 3.0 x 10(-11)M, respectively. The multiplex assay also provided good specificity without any cross-reaction.

To investigate the impact of phenotypic knockout of CXCR4 on Molt-4 cells via intrakine technology,the C-terminal alpha-helix gene SDF-1alpha/54/KDEL of human stromal cell-derived Faceor-1 deletion is fused to a retention signal 4-peptide -KDEL that retains the newly synthesized receptor within the Molt-4 cells endoplasimc reticulum. Subsequently, PCR is used to amplify the target gene SDF-1alpha/54/ KDEL from the constructed plasmid SDF-WT-Gly x 4-Dec/PET-30a(+) at its C-terminal and subclone it into eukaryotic expression vectors pEGFP-C3 for generating recombinant vector cells by lipEGFP-C3/SDF-1alpha/54/KDEL, and then have it sequenced. After the transfection of recombinant plasmids into COS-7 posome, SDF-1alpha/54/KDEL protein is confirmed with Western blot. The recombinant plasmids pEGFP-C3/SDF-1alpha/54/KDEL are isolated and transiently transfected in Molt-4 cells by electroporation. Flow cytometric analysis shows a dramatic reduction of CXCR4 expression on Molt-4 cells. The conclusion is that SDF-1alpha/54/KDEL could assume a role in the phenotypic knockout of CXCR4, and the findings suggest that the inhibiting effect of SDF-1alpha/54 against CXCR4 is not influenced by the deletion of SDF-1alpha helix at the C terminal.

Several studies have shown that the interaction of CXC chemokine receptor 4 (CXCR4) with its ligand, stromal cell-derived factor-1alpha (SDF-1alpha) is closely involved in the directional migration of some tumors toward specific organs, which provides a new pathway against cancer metastasis. We previously developed an alpha-helix-defective mutant of SDF-1alpha, SDF-1/54 that displays obvious antagonistic activity to CXCR4. But it is necessary to ensure the targeting of SDF-1/54 to tumors in vivo since many normal tissues also express CXCR4. It is known that most tumor cells highly express epidermal growth factor receptor (EGFR). Meanwhile, decorin (DCN), a specific antagonist of EGFR, can target the tumor cells enriched in EGFR and cause a significant downregulation of EGFR. Hereby, we further generated a fusion construct of SDF-1/54 and DCN to expect to enhance the targeting of SDF-1/54 to tumors by dual blocking effects on CXCR4 and EGFR. This study focused on expression of recombinant chimera SDF-1/54-DCN in Escherichia coli, purification and bioactivity to inhibit the physiological functions mediated by CXCR4 and EGFR respectively in various tumor cell lines in vitro. Results indicated that SDF-1/54-DCN could inhibit both chemotaxis and proliferation of the tumor cells we used, which may be attributed to its blocking to CXCR4 and EGFR. These findings suggest that this strategy to link SDF-1/54 with DCN may be a promising approach to increase the targeting of SDF-1/54 to the tumors coexpressing CXCR4 and EGFR.

Human immunoglobulin E (hIgE) is such an important protein, because of its involvement in allergic disease, that it is of significance to study the interactions between it and its recognizing elements. In this report an analytical strategy based on surface plasmon resonance (SPR) was developed to probe the pattern of interaction between hIgE and its recognizing molecules, including aptamers and antibodies. The affinity constants of hIgE for the antibody and the aptamer were compared first; the aptamer has more affinity than the antibody for human IgE. To study their pattern of interaction, three different binding approaches, including adding the antibody and the streptavidin-coupled aptamer to the sensing surface, were designed. The results showed that hIgE captured on the sensing surface could form a multivalent complex with the aptamer. An ELISA-like assay using the aptamer as both capture and detection probes was then developed. This work highlights an SPR method for characterizing the interaction between the protein and aptamers that is useful for study of biomolecular interaction patterns and binding properties.

CXC chemokine receptor 4 (CXCR4) is a cell surface receptor that has been reported to mediate the metastasis of many solid tumors including ovarian, breast, lung and prostate. The over-expression of the epidermal growth factor receptor (EGFR) is associated with the majority of ovarian cancer and has been implicated in the process of malignant transformation by promoting cell proliferation, survival, and motility. In this research, the result first showed that epidermis growth factor (EGF) enhanced the expression of CXCR4 and the migration of ovarian cancer cells, moreover, both stromal cell derived factor-1alpha (SDF-1alpha) and EGF-induced high matrix metallopeptidase 9 (MMP9) expressions. Molecular analysis indicated that augmented CXCR4 and MMP9 expression was regulated by phosphatidylinositol-3-kinase(PI3K)/Akt signal transduction pathway. These results suggested a possible important "cross-talk" between CXCR4 and EGFR intracellular pathways that might link signals of tumor deteriorated and provided a plausible explanation for the poor overall survival rate of patients whose co-expression of CXCR4 and EGFR was detected in their tissue sections. It enlightened that, compared to the respective inhibition of the EGFR or CXCR4 signaling, the simultaneous inhibition of them might be a more useful therapeutic strategy of cancer.

The chemokine SDF-1 (CXCL12) and its receptor, CXCR4, have been implicated in organ-specific metastases of several malignancies. CXCR4 expression has recently been characterized in many cancer cell types and is thought to play a pivotal role in directing the migration of metastasizing tumor cells to SDF-1-rich tissues. SDF-1, which is highly expressed in the organs where breast cancers preferentially metastasize, has been shown to promote cancer cell migration. The tumor cells use chemotaxis which occurred between CXCR4 and its ligand SDF-1 to direct migration from their primary sites via the circulation to the preferential sites of metastases, and further studies on the mechanism involved in a variety of cellular signaling pathways are beneficial to tumor therapy.

Decorin (DCN) is a member of the small leucine-rich proteoglycan gene family. Many studies indicated that DCN inhibited fibrosis and scar-formation by neutralization of TGF-P and interfering the binding of TGF-beta with its receptor, which induced ectopic deposition of extracellular matrix. Additionally, DCN can prevent the proliferation and metastasis of tumor cells by activating EGFR/MAPK/p21 signal pathway and inhibiting the cell proliferation pathway mediated by EGF-EGFR. It is suggested that the recombinant DCN had potential pharmaceutical potency in treatment of chronic fibrosis and neoplasm for its critical biological activities and low immunogenicity.

Objective: A novel C-terminal alpha-helix-defective mutant of human stromal cell-derived factor-1 (SDF-1), hSDF-154, was designed and produced in order to develop an optimal CXC chemokine receptor 4 (CXCR4) antagonist., Materials and Methods: Human native SDF-1 and alpha-helix defective SDF-1 (hSDF-154) were cloned from human bone marrow stromal cells by reverse transcription polymerase chain reaction, inserted into vector pET-30a(+), and transformed into Escherichia coli strain BL21(DE3). The recombinant hSDF-154 was purified and refolded under optimized conditions and its functional characteristics were compared with the native form of SDF-1. Functional evaluation includes migration of Jurkat and MOLT4 cells assessed by chemotaxis assay, intracellular calcium influx in these cells measured by flow cytometry, extracellular signal-regulated kinase (ERK) phosphorylation analyzed by Western blot assay, receptor binding affinity examined by sequential concentrations of unlabeled SDF-1alpha, hSDF-154 competition with (125)I- SDF-1alpha, and internalization of CXCR4 on the cell surface detected by flow cytometry., Results: hSDF-154 had significantly decreased chemotaxic ability, such as cell migration, as compared to the native hSDF-1. hSDF-154 failed to trigger CXCR4 to induce transient calcium influx and ERK phosphorylation. However, both hSDF-154 and the native hSDF-1 have similar binding affinity to CXCR4 and a similar ability to induce CXCR4 internalization., Conclusion: These results indicate that hSDF-154, which has a defective C-terminal alpha-helix, a normal N-terminus, and a normal central beta-strand scaffold structure, retains normal binding affinity to CXCR4 and normal induction of CXCR4 internalization, but fails to activate CXCR4-mediated cellular signaling and chemotaxis. Therefore, the C-terminal alpha-helix of hSDF-1 plays a critical role for CXCR4 stimulation. The hSDF-154, which efficiently binds to and induces internalization of CXCR4 without activating CXCR4-related intracellular signaling and cell migration, may serve as an optimal CXCR4 antagonist.

A strategy to detect P-glycoprotein (P-gp) on cell membrane and quantify the cell number using electrochemical immunoassay was developed by effective surface immunoreactions and immobilization of cells on a highly hydrophilic interface, which was constructed by adsorption of colloidal gold nanoparticles on a methoxysilyl-terminated (Mos) butyrylchitosan modified glassy carbon electrode (Au-CS/GCE). Atomic force microscopy studies proved that the nanoparticles adsorbed on Mos-butyrylchitosan were efficient in preventing the cell leakage and retaining the activity of immobilized living K562/ADM leukemic cells. The incubation with P-gp monoclonal antibody and then the secondary alkaline phosphatase (AP) conjugated antibody introduced AP onto the K562/ADM cell immobilized on Au-CS/GCE. The bound AP led to an amperometric response of 1-naphthyl phosphate. Under optimal conditions the response was proportional to the logarithm of cell concentration in the range from 5.0 x 10(4) to 1.0 x 10(7) cells mL(-)(1) with a detection limit of 1.0 x 10(4) cells mL(-)(1). The results were comparable to flow cytometric analysis of P-gp expression. This proposed method was practical, convenient, and significant in the clinic and cytobiology.

A new zwitterionic monolayer film of sulfobetaine was constructed by grafting novelly designed N,N-dimethyl (beta-hydroxyethyloxyethyl) ammonium propanesulfonate (DHAPS) to hydroxyl groups of glass in the presence of hexamethylene diisocyanate (HDI) as a coupling agent and dibutyltin dilaurate (DBTDL) as a catalyst. Experiments of blood adhesion proved that the zwitterionic film possessed excellent hydrophilicity and very good biocompatibility and provided an appropriate biomimetic interface for adhesion and proliferation of cells. Thus, the monitoring of the cell proliferation and apoptotic processes on the zwitterionic surface during an incubation process was achieved, using different techniques, such as electrochemical impedance spectroscopy, scanning electron microscopy, flow cytometric assay, and Trypan blue staining. K562 leukemia cells, as a model, cultured in vitro on the zwitterionic surface kept their viability for 5 days and remained healthy and undifferentiated, indicating that the zwitterionic surface did not have a deleterious effect on cell growth in normal conditions. Thus, this man-made interface would be applicable to the growth of cells and the study of biomaterial-cell interaction and has potential applications in medicine and cytobiology.

Single and multijunction nanowires with diameters of 10-40 nm were synthesized by an electrically assisted sonochemical method in aqueous solution at room temperature. By properly controlling the reaction conditions and reactants, this method opens a new strategy towards the fabrication of one-dimensional superlattices in nanowires under ambient conditions. Such a chemical approach provides a promising and simple way to synthesize high-performance building blocks for device applications.

A reliable method is presented for the chiral separation of three basic drugs (mexiletine, chlorpheniramine and propranolol) with serum albumins (human and porcine, HSA and PSA) as chiral selectors by capillary electrophoresis in combination with the partial filling technique. Based on the systematic optimization of operation variables, the chiral separation of mexiletine, chlorpheniramine and propranolol was achieved in the pH 7.4 phosphate buffer by using HSA, PSA and PSA as selectors, respectively. The chiral recognition ability of HSA and PSA was compared. HSA and PSA show a different chiral recognition ability for each of the three drugs. In addition, the association constants between enantiomeric drugs and proteins were determined to be 2.00 and 3.80 x 10(2) M(-1) for mexiletine and HSA, 0.59 and 1.12 x 10(3) M(-1) for chlorpheniramine and PSA, and 0.87 and 1.42 x 10(3) M(-1) for propranolol and PSA. The method for the chiral separation and determination of association constants possesses the advantages of simple performance, effective avoiding of the interference of the UV detection from protein, and lowering of the reagent consumption.

Direct electrochemistry and thermal stability of hemoglobin (Hb) immobilized on a nanometer-sized zirconium dioxide (ZrO2) modified pyrolytic graphite (PG) electrode were studied. The immobilized Hb displayed a couple of stable and well-defined redox peaks with an electron transfer rate constant of (7.90 +/- 0.93)s(-1) and a formal potential of -0.361 V (-0.12 V versus NHE) in 0.1M pH 7.0 PBS. Both nanometer-sized ZrO2 and dimethyl sulfoxide (DMSO) could accelerate the electron transfer between Hb and the electrode. Spectroscopy analysis of the Hb/ZrO2/DMSO film showed that the immobilized Hb could retain its natural structure. This modified electrode showed a high thermal stability up to 74 degrees C and an electrocatalytic activity to the reduction of hydrogen peroxide (H2O2) without the aid of an electron mediator. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging from 1.5 to 30.2 microM with a detection limit of 0.14 microM at 3sigma. The apparent Michaelis-Menten constant KMapp for H2O2 sensor was estimated to be (0.31 +/- 0.02) mM, showing a high affinity.

The direct electrochemistry of hemoglobin (Hb) immobilized on a hexagonal mesoporous silica (HMS)-modified glassy carbon electrode was described. The interaction between Hb and the HMS was investigated using UV-Vis spectroscopy, FT-IR, and electrochemical methods. The direct electron transfer of the immobilized Hb exhibited two couples of redox peaks with the formal potentials of -0.037 and -0.232 V in 0.1 M (pH 7.0) PBS, respectively, which corresponded to its two immobilized states. The electrode reactions showed a surface-controlled process with a single proton transfer at the scan rate range from 20 to 200 mV/s. The immobilized Hb retained its biological activity well and displayed an excellent response to the reduction of both hydrogen peroxide (H2O2) and nitrate (NO2-). Its apparent Michaelis-Menten constants for H2O2 and NO2- were 12.3 and 49.3 microM, respectively, showing a good affinity. Based on the immobilization of Hb on the HMS and its direct electrochemistry, two novel biosensors for H2O2 and NO2- were presented. Under optimal conditions, the sensors could be used for the determination of H2O2 ranging from 0.4 to 6.0 microM and NO2- ranging from 0.2 to 3.8 microM. The detection limits were 1.86 x 10(-9) M and 6.11 x 10(-7) M at 3sigma, respectively. HMS provided a good matrix for protein immobilization and biosensor preparation.