Selective catalytic oxidation of DMF over Cu-Ce/H-MOR by modulating the surface active sites.

Selective catalytic oxidation of the hazardous DMF exhaust gas presents a significant challenge in balancing oxidation activity and products selectivity (CO, NOx, N2, etc.). It is found that Cu/H-MOR demonstrates superior performance for DMF oxidation compared to CuO on other supports (γ-Al2O3, HY, ZSM-5) in terms of product selectivity and stability. The geometric and electronic structures of CuO active sites in Cu/H-MOR have been regulated by CeO2 promoter, leading to an increase in the ratio of active CuO (highly dispersed CuO and Cu+ specie). As a result, the oxidation activity and stability of the Cu/H-MOR catalyst were enhanced for DMF selective catalytic oxidation. However, excessive CuO or CeO2 content led to decreased N2 selectivity due to over-high oxidation activity. It is also revealed that Ce3+ species, active CuO species, and surface acid sites play a critical role in internal selective catalytic reduction reaction during DMF oxidation. The 10Cu-Ce/H-MOR (1/4) catalyst exhibited both high oxidation activity and internal selective catalytic reduction activity due to its abundance of active CuO specie as well as Ce3+ species and surface acid sites. Consequently, the 10Cu-Ce/H-MOR (1/4) catalyst demonstrated the widest temperature window for DMF oxidation with high N2 selectivity. These findings emphasize the importance of surface active sites modification for DMF selective catalytic oxidation.

PFKFB3 regulates breast cancer tumorigenesis and Fulvestrant sensitivity by affecting ERα stability.

Estrogen receptor alpha (ERα) is expressed in approximately 70% of breast cancer cases and determines the sensitivity and effectiveness of endocrine therapy. 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase3 (PFKFB3) is a glycolytic enzyme that is highly expressed in a great many human tumors, and recent studies have shown that it plays a significant role in improving drug sensitivity. However, the role of PFKFB3 in regulating ERα expression and the underlying mechanism remains unclear. Here, we find by using immunohistochemistry (IHC) that PFKFB3 is elevated in ER-positive breast cancer and high expression of PFKFB3 resulted in a worse prognosis. In vitro and in vivo experiments verify that PFKFB3 promotes ER-positive breast cancer cell proliferation. The overexpression of PFKFB3 promotes the estrogen-independent ER-positive breast cancer growth. In an estrogen-free condition, RNA-sequencing data from MCF7 cells treated with siPFKFB3 showed enrichment of the estrogen signaling pathway, and a luciferase assay demonstrated that knockdown of PFKFB3 inhibited the ERα transcriptional activity. Mechanistically, down-regulation of PFKFB3 promotes STUB1 binding to ERα, which accelerates ERα degradation by K48-based ubiquitin linkage. Finally, growth of ER-positive breast cancer cells in vivo was more potently inhibited by fulvestrant combined with the PFKFB3 inhibitor PFK158 than for each drug alone. In conclusion, these data suggest that PFKFB3 is identified as an adverse prognosis factor for ER-positive breast cancer and plays a previously unrecognized role in the regulation of ERα stability and activity. Our results further explores an effective approach to improve fulvestrant sensitivity through the early combination with a PFKFB3 inhibitor.

V-doped porous CoP nanoarrays grown on carbon cloth with optimized electronic structure for the hydrogen evolution reaction.

As an efficient, renewable and clean energy, hydrogen is expected to replace traditional fossil fuel energy in the future. Currently, platinum-based materials (Pt) are excellent electrocatalysts for hydrogen evolution reaction (HER), but their high cost and low natural abundance limit their widespread application. Therefore, it is urgent to develop low-cost, highly efficient and earth-abundant electrocatalysts to replace the precious platinum-based materials. In this study, a Co-based organic framework (ZIF-67) was grown on a flexible substrate carbon cloth (CC), and a V-doped CoP nanoarray (V-CoP/CC) was prepared using a simple in situ ion exchange/phosphating method. Due to its unique porous structure, effective doping of V atoms and the in situ electrode construction, the V-CoP/CC exhibited high electrolytic hydrogen evolution reaction (HER) performance, with an overpotential of 98 mV at a current density of 10 mA cm-2. This work has important theoretical and practical significance for in situ construction of heteroatom-doped CoP electrodes.

High-efficiency hydrocracking of phenanthrene into BTX aromatics over a Ni-modified lamellar-crystal HY zeolite.

A new Ni-HY zeolite with lamellar-crystals was prepared as a catalyst for phenanthrene hydrocracking. It showed significantly improved reactivity and BTX (benzene, toluene and xylene) selectivity (up to 99.1% and 75.6%, respectively), depending on a reasonable synergistic effect between its excellent internal-diffusion and the high-efficiency concerted catalysis of surface metal-Ni active sites and acid sites. In particular, compared with a conventional Ni-HY with diamond-shaped crystals, its significantly shortened diffusion-reaction path of the micropore system in the lamellar crystals greatly enhanced the diffusion-reaction efficiency of large-molecule phenanthrene and polycyclic intermediates and remarkably improved the utilization of both pores and internal reactive sites, powerfully promoting phenanthrene into benzene series conversion. The much decreased diffusion-residence time of benzene-series products in shortened channels also effectively weakened the further cracking loss of the benzene-ring, leading to enhanced BTX selectivity. Moreover, this shorter-channel Ni-HY catalyst with a higher external surface area and mesoporous volume also exhibited greatly improved catalytic stability attributed to its stronger capabilities of accommodating coke and resisting coke-deposition. The phenanthrene conversion of >76.3% and the BTX yield of >46.3% were obtained during a 60 h on-stream reaction.

RNA-binding protein p54nrb/NONO potentiates nuclear EGFR-mediated tumorigenesis of triple-negative breast cancer.

Nuclear-localized epidermal growth factor receptor (EGFR) highly correlates with the malignant progression and may be a promising therapeutic target for breast cancer. However, molecular mechanisms of nuclear EGFR in triple-negative breast cancer (TNBC) have not been fully elucidated. Here, we performed gene-annotation enrichment analysis for the interactors of nuclear EGFR and found that RNA-binding proteins (RBPs) were closely associated with nuclear EGFR. We further demonstrated p54nrb/NONO, one of the RBPs, significantly interacted with nuclear EGFR. NONO was upregulated in 80 paired TNBC tissues and indicated a poor prognosis. Furthermore, NONO knockout significantly inhibited TNBC proliferation in vitro and in vivo. Mechanistically, NONO increased the stability of nuclear EGFR and recruited CREB binding protein (CBP) and its accompanying E1A binding protein p300, thereby enhancing the transcriptional activity of EGFR. In turn, EGFR positively regulated the affinity of NONO to mRNAs of nuclear EGFR downstream genes. Furthermore, the results indicated that the nuclear EGFR/NONO complex played a critical role in tumorigenesis and chemotherapy resistance. Taken together, our findings indicate that NONO enhances nuclear EGFR-mediated tumorigenesis and may be a potential therapeutic target for TNBC patients with nuclear EGFR expression.

Prognostic values of ALDOB expression and 18F-FDG PET/CT in hepatocellular carcinoma.

Purpose: The glycolytic enzyme fructose 1,6-bisphosphate aldolase B (ALDOB) is aberrantly expressed and impacts the prognosis in hepatocellular carcinoma (HCC). Hepatic ALDOB loss leads to paradoxical upregulation of glucose metabolism, favoring hepatocellular carcinogenesis. Nevertheless, the relationship between ALDOB expression and 18F-fluorodeoxyglucose (18F-FDG) uptake, and their effects on HCC prognosis remain unclear. We evaluated whether ALDOB expression is associated with 18F-FDG uptake and their impacts on HCC prognosis prediction. Methods: Changes in ALDOB expression levels and the prognostic values in HCC were analyzed using data from The Cancer Genome Atlas (TCGA) database. Ultimately, 34 patients with HCC who underwent 18F-FDG positron emission tomography/computed tomography (PET/CT) preoperatively were enrolled in this retrospective study. ALDOB expression was determined using immunohistochemistry (IHC) staining, and the maximum standardized uptake value (SUVmax) of HCC was calculated from the 18F-FDG PET/CT scans. The relationship between ALDOB expression and SUVmax was examined, and their impacts on overall survival were evaluated using Cox proportional hazards models and Kaplan-Meier survival analysis. ALDOB overexpression in HUH7 and 7721 cells was used to analyze its role in tumor metabolism. Results: According to TCGA database, the ALDOB mRNA level was downregulated in HCC compared to normal tissue, and significantly shortened overall survival in HCC patients. ALDOB protein expression was similarly decreased in IHC findings in HCC than that in adjacent normal tissues (P<0.05) and was significantly associated with tumor size (P<0.001), high tumor-node-metastasis stage (P=0.022), and elevated SUVmax (P=0.009). ALDOB expression in HCC was inversely correlated with SUVmax (r=-0.454; P=0.012), and the optimal SUVmax cutoff value for predicting its expression was 4.15. Prognostically, low ALDOB expression or SUVmax ≥3.9 indicated shorter overall survival time in HCC. Moreover, COX regression analysis suggested high SUVmax as an independent prognostic risk factor for HCC (P=0.036). HCC patients with negative ALDOB expression and positive SUVmax (≥3.9) were correlated with worse prognosis. ALDOB overexpression in HCC cells significantly decreases 18F-FDG uptake and lactate production. Conclusion: SUVmax in HCC patients is inversely correlated with ALDOB expression, and 18F-FDG PET/CT may be useful for ALDOB status prediction. The combined use of ALDOB expression and 18F-FDG PET/CT data can provide additional information on disease prognosis in HCC patients.

Nuclear scaffold protein p54nrb/NONO facilitates the hypoxia-enhanced progression of hepatocellular carcinoma.

Hypoxia and related oxidative stress are closely related to the development and treatment of hepatocellular carcinoma (HCC). However, the mechanism mediated by hypoxia in HCC has not yet been elucidated. Here, we found multifunction scaffold protein p54nrb/NONO exerted pleiotropic effects to regulate hypoxia transcription signals, thereby enhancing the progression of liver cancer. Extensive analysis of clinical data demonstrated that NONO was significantly upregulated and represented as a poor prognostic indicator of HCC. The crucial role of NONO in driving angiogenesis and glycolysis, two well-known cancer phenotypes mediated by hypoxia, was examined in vitro an in vivo. Mechanistically, NONO interacted with and stabilized both HIF-1 and HIF-2 complexes thus activating the transcription of hypoxia-induced genes. Besides, NONO bound pre-mRNA and subsequent mRNA of these genes to facilitate them splicing and mRNA stability, respectively. Thus, NONO knockout seriously disrupted the expression of a cluster of HIF-1/2 targets and impeded hypoxia-enhanced progression in HCC. In conclusion, NONO functioned as a multipurpose scaffold that interacted with HIF-1/2 complex and their downstream transcripts to facilitate the expression of hypoxia-induced genes, allowing malignant proliferation, indicating that NONO might be a potential therapeutic target for HCC.

SIRT5-mediated deacetylation of LDHB promotes autophagy and tumorigenesis in colorectal cancer.

Lactate dehydrogenase B (LDHB) is a glycolytic enzyme that catalyses the conversion of lactate and NAD+ to pyruvate, NADH and H+ . Protons (H+ ) generated by LDHB promote lysosomal acidification and autophagy in cancer, but how this role is regulated has not been defined. In this study, we identified an important post-translational mechanism by which LDHB is regulated during autophagy in cancer cells. Mass spectrometry revealed that protein sirtuin 5 (SIRT5) is a binding partner of LDHB that deacetylated LDHB at lysine-329, thereby promoting its enzymatic activity. Deacetylated LDHB increased autophagy and accelerated the growth of colorectal cancer (CRC) cells. Notably, SIRT5 knockout or inhibition by GW5074 increased LDHB acetylation at K329 and inhibited LDHB activity, which downregulated autophagy and CRC cell growth in vitro and in vivo. Clinically, the LDHB-Ac-K329 staining score in CRC tissues was lower than that in corresponding peritumour tissues. Low LDHB-Ac-K329 status was associated with malignant progression of human CRC and served as a potential prognostic indicator for patients with CRC. Altogether, we conclude that SIRT5-induced deacetylation of LDHB triggers hyperactivation of autophagy, a key event in tumorigenesis. Thus, the SIRT5/LDHB pathway may represent a novel target for treating CRC.

Non-canonical roles of PFKFB3 in regulation of cell cycle through binding to CDK4.

There is growing interest in studying the molecular mechanisms of crosstalk between cancer metabolism and the cell cycle. 6-phosphate fructose-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) is a well-known glycolytic activator that plays an important role in tumorigenesis. We investigated whether PFKFB3 was directly involved in oncogenic signaling networks. Mass Spectrometry showed that PFKFB3 interacts with cyclin-dependent kinase (CDK) 4, which controls the transition from G1 phase to S phase of the cell cycle. Further analysis indicated that lysine 147 was a key site for the binding of PFKBFB3 to CDK4. PFKFB3 binding resulted in the accumulation of CDK4 protein by inhibiting ubiquitin proteasome degradation mediated by the heat shock protein 90-Cdc37-CDK4 complex. The proteasome-dependent degradation of CDK4 was accelerated by disrupting the interaction of PFKFB3 with CDK4 by mutating lysine (147) to alanine. Blocking PFKFB3-CDK4 interaction improved the therapeutic effect of FDA-approved CDK4 inhibitor palbociclib on breast cancer. These findings suggest that PFKFB3 is a hub for coordinating cell cycle and glucose metabolism. Combined targeting of PFKFB3 and CDK4 may be new strategy for breast cancer treatment.

PRMT5 competitively binds to CDK4 to promote G1-S transition upon glucose induction in hepatocellular carcinoma.

Although cancer cells are known to be "addicted" to glucose, the effect of glucose in proliferation of these cells remains elusive. Here, we report that upon glucose induction, protein arginine methyltransferase 5 (PRMT5) exerts a profound effect on the G1-S cell cycle progression via directly interacting with cyclin dependent kinase 4 (CDK4) in hepatocellular carcinoma (HCC). Upregulation of both PRMT5 and CDK4 predicts more malignant characteristics in human HCC tissues. Mechanistically, glucose promotes the interaction between PRMT5 and CDK4, which leads to activation of CDK4-RB-E2F-mediated transcription via releasing CDKN2A from CDK4. Moreover, the PRMT5 competitive inhibition of the interaction between CDK4 and CDKN2A is important for glucose-induced growth of HCC cells. Furthermore, the CDK4 mutant R24A weakly binds to PRMT5, inhibiting HCC cell cycle progression and tumor growth. Thus, our findings uncover a critical function for PRMT5 and CDK4 and provide an improved therapeutic strategy against HCC.

Inhibition of SREBP increases gefitinib sensitivity in non-small cell lung cancer cells.

The clinical success of EGFR inhibitors in patients with lung cancer is limited by the inevitable development of treatment resistance. Here, we show that inhibition of SREBP increase gefitinib sensitivity in vitro and in vivo. Interference of SREBP1 binding partner MARVELD1 potentiate the therapeutic effect of gefitinib as well. Mechanistically, SREBP inhibition decreases the cell membrane fluidity, results in a decreased tyrosine phosphorylation of EGFR. Therefore, targeting lipid metabolism combined with EGFR-TKIs is potentially a novel therapeutic strategies for cancer treatment.

Additive anticancer effects of chrysin and low dose cisplatin in human malignant glioma cell (U87) proliferation and evaluation of the mechanistic pathway.

PURPOSE: To evaluate the anticancer effect of chrysin and its additive combination with low-dose cisplatin in human glioma (U87) cancer cells and to study its underlying mechanism. METHODS: Inverted phase and fluorescence microscopic studies were done to demonstrate the effect of chrysin and its combination with cisplatin on cellular morphology and apoptosis. Annexin V-FITC assay was used to quantify the extent of apoptosis in chrysin and chrysin+cisplatin treated cells. Flow cytometry using propidium iodide (PI) as a staining agent was used to study the effect of chrysin and its combination with cisplatin on cell cycle phase distribution. RESULTS: The results showed chrysin brought about a potent and dose-dependent antiproliferative effect in human glioma cancer cells. However, the combination of chrysin with low dose cisplatin led to a much higher growth inhibitory effects indicating an additive effect between the two compounds. The combined effect of chrysin and cisplatin also gave rise to a greater apoptosis induction as well as cell cycle arrest in comparison to the treatment by chrysin or cisplatin alone. Fluorescence microscopy as well as inverted phase contrast microscopy also revealed that the combination of chrysin plus cisplatin resulted in greater apoptosis induction as well as cell morphology alterations. Combination treatment of chrysin and cisplatin resulted in greater percentage of cells in early as well as in late apoptotic stages. The combination effect was also seen in mitochondrial membrane potential loss. CONCLUSION: Chrysin additively potentiates the antiproliferative, cell cycle arrest and apoptotic activity of cisplatin in human glioma cancer (U87) cells.

Exploration of two-enzyme coupled catalysis system using scanning electrochemical microscopy.

In biological metabolism, a given metabolic process usually occurs via a group of enzymes working together in sequential pathways. To explore the metabolism mechanism requires the understanding of the multienzyme coupled catalysis systems. In this paper, an approach has been proposed to study the kinetics of a two-enzyme coupled reaction using SECM combining numerical simulations. Acetylcholine esterase and choline oxidase are immobilized on cysteamine self-assembled monolayers on tip and substrate gold electrodes of SECM via electrostatic interactions, respectively. The reaction kinetics of this two-enzyme coupled system upon various separation distance precisely regulated by SECM are measured. An overall apparent Michaelis-Menten constant of this enzyme cascade is thus measured as 2.97 mM at an optimal tip-substrate gap distance of 18 µm. Then, a kinetic model of this enzyme cascade is established for evaluating the kinetic parameters of individual enzyme by using the finite element method. The simulated results demonstrate the choline oxidase catalytic reaction is the rate determining step of this enzyme cascade. The Michaelis-Menten constant of acetylcholine esterase is evaluated as 1.8 mM. This study offers a promising approach to exploring mechanism of other two-enzyme coupled reactions in biological system and would promote the development of biosensors and enzyme-based logic systems.

Retinoic acid and dexamethasone induce differentiation and maturation of somatotroph cells at different stages in vitro.

The purpose of this study was to investigate the role of retinoic acid (RA) and/or dexamethasone and growth hormone releasing hormone (GHRH) in the induction of somatotroph cell differentiation. Immunohistochemistry, radioimmunoassay, 3-(4,5-dimethylthiazol -1,2-y1)-2,5-diphenyltetrazolium bromide assay, and immune electron microscopy were employed to determine the effect of incubation with these constituents on the differentiation into somatotrophs of cells isolated from the rat embryonic pituitary gland. RA administration increased the proportion of growth hormone (GH) positive somatotroph cells and GH secretion in embryonic pituitary cells (P<0.01). After 4 days of incubation with RA, additional administration of dexamethasone further increased the proportion of somatotroph cells and GH secretion (P<0.01), and increased the number of secretory granules in the somatotroph cells. Addition of GHRH alone had no such effect (P>0.05). However, addition of GHRH to treatment with RA plus dexamethasone significantly increased both the proportion of somatotroph cells and the secretion of GH compared to treatment with RA or dexamethasone alone or RA plus dexamethasone (P<0.01). RA promoted the early differentiation of somatotroph cells, dexamethasone promoted the differentiation and maturation of somatotroph cells and in addition, RA, dexamethasone and GHRH together exerted synergistic effects that markedly promoted somatotroph cell differentiation, maturation and GH secretion.

Towards a high potential biocathode based on direct bioelectrochemistry between horseradish peroxidase and hierarchically structured carbon nanotubes.

Adsorption of horseradish peroxidase (HRP) on graphite rod electrodes sequentially modified with carbon microfibers (CMF) carrying carbon nanotubes in a hierarchically structured arrangement and finally pyrene hexanoic acid (PHA) for improving hydrophilicity of the electrode surface is the basis for the direct bioelectrocatalytic reduction of H(2)O(2) at potentials as high as about +600 mV. The high-potential direct bioelectrocatalytic reduction of H(2)O(2) is implying a direct bioelectrochemical communication between the Fe(IV)=O,P(+*) redox state known as compound I. The HRP loading was optimized leading to a current of 800 microA at a potential of 300 mV.

Simple approach for efficient encapsulation of enzyme in silica matrix with retained bioactivity.

We developed an alcohol-free sol-gel approach to encapsulate biomolecules such as horseradish peroxidase (HRP) in an electrochemically induced three-dimensional porous silica matrix by a one-step process. In this sol-gel process, the electrochemically generated hydroxyl ions at the electrode surface by applying cathodic current promote the hydrolysis of ammonium fluorosilicate to produce silica, and simultaneously the generated hydrogen bubbles play an important role in forming porous silica matrix. If HRP is mixed with ammonium fluorosilicate solution, it can be encapsulated in the forming silica matrix. Since there is no ethanol involved in the entire procedure, bioactivities of the encapsulated HRP can be effectively retained. As revealed by scanning electron microscopy (SEM) characterization, the resultant silica matrix has interconnected and network-like porous structures. Macroporous holes induced by hydrogen bubbles scattering on the relatively flat areas of porous structure can be observed. Such structure free from cracks provides effective mass transport and long-term stability. Scanning electrochemical microscope (SECM) characterization shows that the immobilized HRP molecules uniformly distribute in the silica matrix. The present HRP electrochemical biosensor exhibits a quick response (within 5 s) to H(2)O(2) in the concentration range from 0.02 to 0.20 mM (correlation coefficient of 0.9934) with a detection limit of 3 microM. The apparent Michaelis-Menten constant is 0.88 mM. The present alcohol-free sol-gel approach is effective for biomolecule encapsulation and is promising for the construction of biosensors, bioelectronics, and biofuel cells.

Electric-field distribution at the end of a charged capillary - a coupling imaging study.

The electric-field distribution at the end of a charged capillary system is detected using a scanning electrochemical microscopy (SECM) coupling imaging mode. A theoretical model based on the resistance of solution at the capillary end describes the three-dimensional distribution of the electric field. The effect of the detection electrode position and separation high voltage on solution potential is observed and analyzed. Results demonstrate that the electric field at the end-channel shows an isopotential contour changing from a disk shape into a hemispherical shape when leaving the capillary opening. The solution potential decreases along the central axis of the capillary to the detection reservoir. In the same scanning plane, the solution potential decreases along the radial direction. Increase of the separation high voltage results in the increase of the absolute solution potential but does not change the relative spatial electric-field distribution.

Highly selective amperometric glucose microdevice derived from diffusion layer gap electrode.

Although most of enzyme catalytic reactions are specific, the amperometric detection of the enzymatic reaction products is largely nonselective. How to improve the detection selectivity of the enzyme-based electrochemical biosensors has to be considered in the sensor fabrication procedures. Herein, a highly selective amperometric glucose biosensor based on the concept of diffusion layer gap electrode pair which we previously proposed was designed. In this biosensor, a gold tube coated with a conductive layer of glucose oxidase/Nafion/graphite was used to create an interference-free region in its diffusion layer by electrochemically oxidizing the interfering electroactive species at proper potentials. A Pt probe electrode was located in this diffusion layer of the tube electrode to selectively detect hydrogen peroxide generated from the enzyme catalytic oxidation of glucose in the presence of oxygen in the solution. In practical performance of the microdevice, parameters influencing the interference-removing efficiency, including the tip-tube opening distance, the tube electrode potential and the electrolyzing time had been investigated systematically. Results showed that glucose detection free from interferents could be achieved at the electrolyzing time of 30s, the tip-tube opening distance of 3mm and the tube electrode potential of 0.4V. The electrochemical response showed linear dependence on the concentration of glucose in the range of 1 x 10(-5) to 4 x 10(-3) M (the correlation coefficient: 0.9936, without interferents; 0.9995, with interferents). In addition, the effectiveness of this device was confirmed by numerical simulation using a model system of a solution containing interferents. The simulated results showed good agreement with the experimental data.

One-step immobilization of glucose oxidase in a silica matrix on a Pt electrode by an electrochemically induced sol-gel process.

We demonstrate here that the electrochemical generation of hydroxyl ions and hydrogen bubbles can be used to induce the synthesis of enzyme- or protein-encapsulated 3D porous silica structure on the surface of noble metal electrodes. In the present work, the one-step synthesis of a glucose oxidase (GOD)-encapsulated silica matrix on a platinum electrode is presented. In this process, glucose oxidase was mixed with ethanol and TEOS to form a doped precursory sol solution. The electrochemically generated hydrogen bubbles at negative potentials assisted the formation of the porous structure of a GOD-encapsulated silica gel, and then the one-step immobilization of enzyme into the silica matrix was achieved. Scanning electron microscopy (SEM) and scanning electrochemical microscopy (SECM) characterizations showed that the GOD-encapsulated silica matrix adhered to the electrode surface effectively and had an interconnected porous structure. Because the pores started at the electrode surface, their sizes increased gradually along the distance away from the electrode and reached maximum at the solution side, and effective mass transport to the electrode surface could be achieved. The entrapped enzyme in the silica matrix retained its activity. The present glucose biosensor had a short response time of 2 s and showed a linear response to glucose from 0 to 10 mM with a correlation coefficient of 0.9932. The detection limit was estimated to be 0.01 mM at a signal-to-noise ratio of 3. The apparent Michaelis-Menten constant (K m app) and the maximum current density were determined to be 20.3 mM and 112.4 microA cm-2, respectively. The present method offers a facile way to fabricate biosensors and bioelectronic devices in situ.