Average Surface Coverage Research Articles

Effect of recycled powder on the yield stress of cement paste with varied superplasticizers

The influence of superplasticizer on the yield stress of cement pastes with recycled powder (RP) was examined in the study. Four superplasticizers were used to obtain the similar fluidity by adjusting the dosage. The results show that the 10% RP decreases the yield stress of paste compared to the reference paste at the same fluidity, but 20% and 30% RP increases the yield stress, ranging from 11 to 599%. The superplasticizer with adsorptive group of phosphate-type minimizes the yield stress of paste than that of polycarboxylate -type, but it made a significant increment in yield stress as the incorporating of RP increased. Besides, the polycarboxylate superplasticizer with the higher molecular weight of side chain and charge density led to lower yield stress. Based on the Yodel model, the yield stress of paste with RP was analyzed by the polymer adsorption and particle packing density of particles to reveal the influence of RP with different superplasticizers on the colloidal interaction and contact network among the particles. The packing density of particles with recycled powder was a little higher than the reference paste, but the higher fraction of fine particles made a stronger PSD effect, which improved the particle contact interaction. On the other hand, due to the higher polymer adsorption of recycled powder than cement, especially for superplasticizer with phosphate group, the average surface coverage was increased, which extended the separation distance, so that colloidal interaction among particles was weaken.

Prediction of surface excess adsorption and retention factors in reversed-phase liquid chromatography from molecular dynamics simulations

An alternative method to the classical fit of semi-empirical, statistical, or artificial intelligence-based models to retention data is proposed to predict surface excess adsorption and retention factors in liquid chromatography. The approach is based on a fundamental, microscopic description of the liquid-to-solid adsorption of analytes taking place at the interface between a bulk liquid phase and a solid surface. Molecular dynamics (MD) simulations are performed at T=300 K in a 100 Å wide slit-pore model (β-cristobalite-C18 surface in contact with an acetonitrile/water mobile phase) to quantify a priori the retention factors of small molecules expected in reversed phase liquid chromatography (RPLC). Uracil is chosen as the reference “non-retained” marker, whereas benzyl alcohol, acetophenone, benzene, and ethylbenzene are four selected retained, neutral compounds. The MD simulations allow to determine the pore-level density profiles of these five compounds, i.e., the variation of the analyte concentration as a function of distance from the silica surface. The retention factors of the retained analytes are expressed using their respective calculated surface excess adsorption relative to uracil. By definition, the retention factors are proportional to the surface excess adsorbed and the proportionality constant is directly scaled to the retention time of the “non-retained” marker. Experimentally, a 4.6 mm × 150 mm RPLC-C18 column packed with 5 μm 100 Å High Strength Silica (HSS)-C18 particles is used and the retention times of these five compounds are measured. The volume fraction of acetonitrile in water increases from 20 to 90% generating a wide range of retention factors from 0.15 to 183 at T=300 K. The results demonstrate very good agreement between the MD-predicted surface excess adsorption data and measured retention factors (R2> 0.985). A systematic error is observed as the proportionality constant is not exactly scaled to the retention time of uracil. This is most likely caused by the differences between the chemical and morphological features of the slit-pore model adopted in the MD simulations and those of the actual HSS-C18 particles: the average surface coverage with C18 chains, the geometry of the mesopores, and the pore size distribution. Specifically, the impact on RPLC retention of slight, local variations in surface chemistry (e.g., functional group density and uniformity) and how this aspect is affected by the pore space morphology (e.g., pore curvature and size) is worth investigating by future MD simulations.

Mechanisms for undesired nucleation on H-terminated Si and dimethylamino-trimethylsilane passivated SiO2 during TiO2 area-selective atomic layer deposition

During TiO2 atomic layer deposition (ALD) using TiCl4 and H2O at ∼150 °C, nucleation proceeds rapidly on hydroxylated SiO2 but is inherently delayed on passivated surfaces such as H-terminated silicon (Si-H) and trimethylsilyl-passivated SiO2 (SiO2-TMS) formed using dimethylamino-trimethylsilane (DMA-TMS) as a small molecule inhibitor. In this work, we explore details of TiO2 nucleation on both Si-H and SiO2-TMS and show that the mechanisms leading to unwanted nuclei depend strongly on the passivation mechanism. Initial growth is observed as a function of ALD cycles using scanning electron microscopy to obtain average particle size, density, and overall surface coverage fraction. Also, average film thickness vs cycle is estimated using ellipsometry or Rutherford backscattering spectrometry. Data are compared to an analytical model that considers that either nucleation sites are present on the starting non-growth surface or sites are generated during the ALD process. On the Si-H surface, data and modeling indicate that nucleation occurs predominantly from a fixed number of nucleation sites present on the starting growth surface that start to immediately grow. However, on TMS-passivated SiO2, nucleation sites are predominantly generated during the growth process so that the density of nucleation sites increases as growth proceeds. Results indicate that nucleation sites are created when adsorbed ALD reactants become kinetically trapped on the SiO2-TMS surface. This demonstrates that mechanisms associated with unwanted nucleation during area-selective deposition (ASD) can depend on details of the surface passivation scheme, thereby providing insight to help to improve ASD strategies for advanced applications.

Quantitative assessment of coagulation of atmospheric particles onto airborne birch pollen grains

The coagulation of airborne particles on the surface of allergenic pollen grains is poorly described in the literature. However, particles deposited on the surface of pollen grains could have an effect on allergy and its symptoms. Observations of pollen surface alterations reported in the literature are either qualitative or are tainted by sampling artifacts that overestimate surface particulate pollution. Birch pollen grains (BPGs) were sampled in the atmosphere during pollination to quantitatively assess the extent of particulate deposition on allergenic pollen surfaces. Airborne PGs were collected with a cascade impactor ensuring no sampling artifact unlike pollen samplers usually used in this type of study. Counting, sizing and elemental analysis of particles adhering on pollen surfaces were performed by SEM/EDX. 68% of PGs did not carry any particle on their visible surface while the remaining 32% had between 1 and 16 particles on their surface. On average, polluted BPGs carried 2 ± 1 particles, representing an average surface coverage of 0.95%. We hypothesized that the main coagulation process was particle deposition by gravitational settling. Collision velocity calculations indicate that coagulation due to gravitational settling is prevalent under typical pollination atmospheric conditions. However, the effects of electric charges carried by pollen are largely unknown and may significantly alter coagulation rates. The presence of particle-polluted allergenic pollens appears to be common in the urban atmosphere, even under low air pollution conditions. The impact of chemical pollution of BPGs due to the presence of particulate matter (including soot particles) remains relatively unknown, both on the allergy and on the reproductive capacity of the trees.

Effect of microfines from manufactured sand on yield stress of cement paste

With the depletion of natural sand, the manufactured sand is frequently used in cement-based materials, which inevitably affects the flowability. It is mainly due to that the yield stress is affected by the microfines (≤75 μm) in manufactured sand. However, the mechanism is still not fully understood. This paper investigated the effects of the microfines of limestone, granite, and two tuffs on the yield stress of cement pastes with superplasticizer. The average surface coverage, packing density, and particle size distribution (PSD) of the suspending particles were measured to reveal the affecting mechanism of microfines on the internal particle network of the pastes. Results show that the incorporation of the microfines increases the yield stress of cement pastes. Limestone with the highest specific surface area (SSA) and granite with the lowest SSA caused the largest and smallest increases of the yield stress, respectively. Two different tuffs with similar SSA led to equivalent increases of yield stress. It is ascribed to the reduction of the average surface coverage, which reduces the average surface-to-surface separation distance and enhances the colloidal interactions with the incorporation of microfines. Due to the high fraction of fine particles in microfines, although the packing density increases slightly, the PSD effect of the suspending particles is significantly enhanced, which increases the number and effective volume fraction of the contacting particles and therefore the particle contact interactions. The internal particle network of the cement pastes is jointly affected by colloidal interactions and particle contact interactions, which thereby leads to the different influences of the microfines on the yield stress.

Quantification of surface composition and surface structure of inhalation powders using TOF-SIMS

A multivariate TOF-SIMS methodology has been developed and applied to quantify surface composition and chemical distribution for dry powder blends. Surface properties are often critical to the behavior of powder formulations, especially in the case of dry powders for inhalation, as surface properties directly affect inter-particulate forces and, hence, the dispersibility of the formulation. The mass spectrum at each pixel was fit to a linear combination of reference spectra obtained by non-negatively constrained alternating least squares. From the pixel compositions, average surface coverage and a range of other image features were calculated. Two kinds of systems have been examined: 1) binary blends of lactose particles and coating agents, and 2) blends of different inhalation drugs with carrier lactose. For both kinds of systems, detailed insight into the surface composition and structure could be derived. For the former study, TOF-SIMS results were compared with a complementary surface analysis technique, XPS.

Determination of rainfall effects on kaolin clay coverage rates used in prevention plant from sunburn

Sunburn, which is an important problem in agricultural products grown in arid and semi-arid regions, causes economic losses of up to 40-60% in some years. Sunburn occurs as a result of overheating of the surfaces of fruits exposed to high air temperature and solar radiation from the sun. Increase in the temperature stress for plants is observed during months of high temperature, this is one of the main reasons for many negative conditions (changes in fruit colour, cell death in plants, etc.) in fruits and leaves. While the shelf life of damaged agricultural products is shortened, deterioration is observed even in the storage stage. Today, different applications are made to reduce the sunburn in many kinds of fruits and sunburn damage can be significantly reduced as a result of these applications. For this purpose, it was aimed to reduce the temperature on the leaf surface by the application of kaolin clay (Trade name; Güneş Stop) applied to the plant surface at the beginning of the season. In the study; eight different concentrations of kaolin clay with tree application volume were applied and after the application, leaf samples of the citrus trees were taken from the predetermined regions, and the coverage rate was measured in an image processing program. From 8 different regions, 15 pieces of leaf were randomly taken from each region. The same process was carried out again by collecting leaf samples from the same regions after the rain; thus, the performance analysis of kaolin clay was determined after the rainfall. As a result of kaolin clay application; according to the results of image analysis of average leaf surface coverage rates obtained by regions and after the rainfall, the results obtained from the same regions showed that kaolin clay was washed at a rate of 39.64% with precipitation.

Wastewater biofilm formation on self-assembled monolayer surfaces using elastomeric flow cells

In anaerobic wastewater treatment, microbial biofilm is beneficial for efficient substrate utilization and for preventing the wash-out of key microorganisms. By providing solid supports, biofilm formation can be accelerated due to the early initial adhesion of residing microbes. Alteration in surface properties is therefore one such approach that helps us understand microbial interfacial interaction. Here, self-assembled monolayers of alkanethiols with carboxyl (-COOH), hydroxyl (-OH), and amine (-NH2) terminal moieties on gold (Au) substrates were employed to study the initial adhesion of wastewater microbes. An elastomeric flow cell was also utilized to simulate the environment of wastewater bioreactor. Results from fluorescence in situ hybridization (FISH) portrayed more enhanced microbial adhesion after 2 h on -NH2 functional group with the calculated surface coverage of 12.8 ± 2.4% as compared to 7.7 ± 1.6% on -COOH, 11.0 ± 2.0% on -OH, and 1.2% on unmodified Au surfaces. This might be because of concomitant electrostatic attraction between negatively-charged bacteria and positively-charged (-NH3+) functional groups. Nevertheless, the average surface coverage by individual biofilm clusters was 28.0 ± 5.0 μm2 and 32.0 ± 9.0 μm2 on -NH2 and -OH surfaces, respectively, while -COOH surfaces resulted in higher value (60.0 ± 5.0 μm2) and no significant cluster formation was observed on Au surfaces. Accordingly, the average inter-cluster distance observed on -NH2 surfaces was relatively smaller (3.0 ± 0.6 μm) as compared to that on other surfaces. Overall, these data suggest favorable initial biofilm growth on more hydrophilic and positively-charged surfaces. Furthermore, the analysis of the mean fluorescence intensity revealed preferred initial adhesion of key microbes (archaea) on -OH and -NH2 surfaces. Indeed, results obtained from this study would be beneficial in designing selective biointerfaces for certain biofilm carriers in a typical wastewater bioreactor. Importantly, our elastomeric flow cell integrated with SAM-modified surfaces demonstrated an ideal platform for high-throughput investigation of wastewater biofilm under controlled environments.

Chelating Surfaces for Oriented Human Serum Albumin Molecules.

Protein immobilization in a specific conformation or orientation at an interface is influenced by specific interactions with the outer layer of the surface. A strategy to build-up a complex construct which is able to orient protein molecules, based on metal-cation chelation processes, is reported. The proposed methodology implies the formation of a mercaptoundecanoic acid monolayer on a gold surface that is activated to attach covalently the tripeptide glycyl-l-histidyl-l-lysine (GHK) on the surface, whose sites are then employed to chelate copper ions, providing a selective platform for the orientation of human serum albumin (HSA) molecules. The protein adsorption process on GHK and GHK-Cu(II)-complex surfaces was monitored by the in situ quartz crystal microbalance with dissipation monitoring (QCM-D) and force spectroscopy technique. The changes in frequency and dissipation factor as well as the D- f plots from QCM-D measurements help to characterize the changes in the protein conformation and are confirmed by force curve spectroscopy results. An improved kinetic model, based on random sequential adsorption with variable protein footprints, has been developed to predict and simulate the experimentally found HSA average surface coverage onto the GHK and GHK-Cu(II)-complex surfaces.

Computational discovery of chemically patterned surfaces that effect unique hydration water dynamics

The interactions of water with solid surfaces govern their apparent hydrophobicity/hydrophilicity, influenced at the molecular scale by surface coverage of chemical groups of varied nonpolar/polar character. Recently, it has become clear that the precise patterning of surface groups, and not simply average surface coverage, has a significant impact on the structure and thermodynamics of hydration layer water, and, in turn, on macroscopic interfacial properties. Here we show that patterning also controls the dynamics of hydration water, a behavior frequently thought to be leveraged by biomolecules to influence functional dynamics, but yet to be generalized. To uncover the role of surface heterogeneities, we couple a genetic algorithm to iterative molecular dynamics simulations to design the patterning of surface functional groups, at fixed coverage, to either minimize or maximize proximal water diffusivity. Optimized surface configurations reveal that clustering of hydrophilic groups increases hydration water mobility, while dispersing them decreases it, but only if hydrophilic moieties interact with water through directional, hydrogen-bonding interactions. Remarkably, we find that, across different surfaces, coverages, and patterns, both the chemical potential for inserting a methane-sized hydrophobe near the interface and, in particular, the hydration water orientational entropy serve as strong predictors for hydration water diffusivity, suggesting that these simple thermodynamic quantities encode the way surfaces control water dynamics. These results suggest a deep and intriguing connection between hydration water thermodynamics and dynamics, demonstrating that subnanometer chemical surface patterning is an important design parameter for engineering solid-water interfaces with applications spanning separations to catalysis.

Fabrication and characterization of cytochrome c-immobilized polyaniline/multi-walled carbon nanotube composite thin film layers for biosensor applications

ABSTRACT Cytochrome c (Cyt c)-immobilized thin films of electropolymerized polyaniline (PANI)/carboxylated multi-walled carbon nanotube (cMWCNT) composite on a glassy carbon (GC) electrode were prepared and applied for trace level detection of hydrogen peroxide. The chemical structure, elemental analysis and surface morphology of the prepared thin films were respectively examined by Fourier-transform infrared spectroscopy, energy dispersive X-ray spectroscopy and scanning electron microscopy. Their electrochemical properties were characterized using, electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry techniques. The formal potential, average surface coverage, electron transfer rate constant, and charge transfer coefficient of the prepared electrodes were calculated to be −0.35 V, 3.1 × 10−9 mol cm−2, 3.01 s−1, and 0.37, respectively. The modified electrode was highly sensitive for hydrogen peroxide detection with a sensitivity of 97.6 nA μM−1 and a detection limit of 0.2 μmol L−1 in a linear response range of 2–600 μmol L−1. According to the obtained results, the proposed PANI/cMWCNT composite thin film could facilitate direct electron-transfer between the GC electrode surface and the redox center of Cyt c, indicating a promising application in next-generation biosensors.

Surface functionalisation significantly changes the physical and electronic properties of carbon nano-dots.

Biomolecule functionalisation of carbon nano-dots (CDs) greatly enhances their biocompatibility and applicability, however, little is known about their molecular structure. Using an arsenal of spectroscopic and analytical techniques, we provide new insights into the physical and electronic structure of uncoated and glycan-functionalised CDs. Our studies reveal that surface functionalisation does not always result in a homogenous corona surrounding the core, and the choice of carbohydrate significantly affects the electronic structure of the surface CD states. Further, the average surface coverage of an ensemble of CDs can be probed via transient absorption spectroscopy. These findings have implications for CDs targeted at interactions with biological systems or local sensors.

An Integrated Microsystem for Real-Time Detection and Threshold-Activated Treatment of Bacterial Biofilms.

Bacterial biofilms are the primary cause of infections in medical implants and catheters. Delayed detection of biofilm infections contributes to the widespread use of high doses of antibiotics, leading to the emergence of antibiotic-resistant bacterial strains. Accordingly, there is an urgent need for systems that can rapidly detect and treat biofilm infections in situ. As a step toward this goal, in this work we have developed for the first time a threshold-activated feedback-based impedance sensor-treatment system for combined real-time detection and treatment of biofilms. Specifically, we demonstrate the use of impedimetric sensing to accurately monitor the growth of Escherichia coli biofilms in microfluidic flow cells by measuring the fractional relative change (FRC) in absolute impedance. Furthermore, we demonstrate the use of growth measurements as a threshold-activated trigger mechanism to initiate successful treatment of biofilms using bioelectric effect (BE), applied through the same sensing electrode array. This was made possible through a custom program that (a) monitored the growth and removal of biofilms within the microfluidic channels in real-time and (b) enabled the threshold-based activation of BE treatment. Such BE treatment resulted in a ∼74.8 % reduction in average biofilm surface coverage as compared to the untreated negative control. We believe that this smart microsystem for integrated biofilm sensing and treatment will enable future development of autonomous biosensors optimized for accurate real-time detection of the onset of biofilms and their in situ treatment, directly on the surfaces of medical implants.

Rhenium filament oxidation: Effect on TIMS performance and the roles of carburization and humidity

This communication presents findings on the effect of rhenium filament oxidation on thermal ionization mass spectrometry (TIMS) analyses of plutonium. Additionally, the roles of atmospheric humidity and carburization on the oxidation characteristics (i.e. aging) of rhenium filaments were studied. Degassed and carburized filaments were aged for up to 79 days under dry and humid conditions, and the growth of oxo-rhenium crystallites was investigated intermittently by scanning electron microscopy (SEM) to construct growth profiles. SEM images were analyzed to determine average crystallite size, number density, and percent surface coverage. Crystallite growth was found to be suppressed by both filament carburization and dry storage conditions (~13% relative humidity). Under humid conditions (75% relative humidity), crystallite growth progressed steadily over the investigatory period, reaching >2.3% surface coverage within 79 days of aging. Atomic ion production of Pu (Pu+) was suppressed by approximately 20% and the standard deviation of isotope ratio measurements was increased by 170% when filaments with 1% oxide surface coverage were used in sample loading. Measurement sensitivity and reproducibility are imperative for applications involving ultra-trace analysis of plutonium by TIMS. These findings offer validation for observations regarding the detrimental effect of excessive filament aging post-degassing, improve the understanding of conditions that impel the oxidation of rhenium filaments, and provide practical means to suppress the growth of oxides.

Microstructural, optical and electrical properties of Cl-doped CdTe single crystals

AbstractMicrostructural, optical and electrical properties of Cl-doped CdTe crystals grown by the low pressure Bridgman (LPB) method were investigated for four different doping concentrations (unintentionally doped, 4.97 × 1019 cm−3, 9.94 × 1019 cm−3 and 1.99 × 1020 cm−3) and three different locations within the ingots (namely, samples from top, middle and bottom positions in the order of the distance from the tip of the ingot). It was shown that Cl dopant suppressed the unwanted secondary (5 1 1) crystalline orientation. Also, the average size and surface coverage of Te inclusions decreased with an increase in Cl doping concentration. Spectroscopic ellipsometry measurements showed that the optical quality of the Cl-doped CdTe single crystals was enhanced. The resistivity of the CdTe sample doped with Cl at the 1.99 × 1020 cm−3 was above 1010 Ω.cm.

The Average Coverage of Sprayed Objects Depending on the Coefficient of Spray Surface for the Selected Nozzles

Abstract The primary objective of the experiment was to determine the average coverage of the sprayed liquid on the plant surface according to the adopted coefficient of the spray surface of plants (Wpo). Examinations were performed under laboratory conditions, using a sprayer, which was moving with a constant operating speed, at various operating pressures. During the study four types of nozzles were used: standard and ejector. They sprayed objects, which were artificial plants, equipped with probes in the form of water-sensitive papers. Probes were placed on the horizontal and vertical surfaces of the plants. The degree of coverage was determined by computer image analysis. The analysis of obtained results showed that the coefficient of the surface spray has a significant impact on the size of the average surface coverage of sprayed objects. It was found that in case where the Wpo <1, standard nozzles are better for spraying, and when Wpo > 1, ejector nozzles and standard double may be used more successfully.

Early tissue formation on whole‐area osteochondral defect of rabbit patella by covering with fibroin sponge

Large osteochondral defects have been difficult to repair via tissue engineering treatments due to the lack of a sufficient number of source cells for repairing the defect and to the severe mechanical stresses affecting the replacement tissue. In the present study, whole-area osteochondral defects of rabbit patella were covered and wrapped with a fibroin sponge containing chondrocytes, with or without Green Fluorescent Protein (GFP) transgenic marking, on the surface facing the osteochondral defect. Five of eight osteochondral defects that were covered with the chondrocyte-seeded fibroin sponges showed hyaline cartilage-like repair containing no fibroin fragments at 6 weeks after surgery. The repaired tissue showed a layer formation, which showed intensive safranin-O and toluidine blue staining, and which showed positive type II collagen immunostaining. The average surface coverage of the repaired cartilage was 53%. On average, 48% of the cells in the repaired tissue were derived from GFP transgenic chondrocytes, which had been seeded in the fibroin sponge. The fibroin-sponge covering had the potential to allow the early repair of large osteochondral defects. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1474-1482, 2016.

Micromechanical Behavior of Polycrystalline Metal–Organic Framework Thin Films Synthesized by Electrochemical Reaction

We have studied the mechanical properties of an archetypical metal–organic framework (MOF) polycrystalline thin-film material, termed HKUST-1 or Cu3(BTC)2, which was synthesized by means of electrochemistry. We demonstrate that the average crystal size and surface coverage of electrochemically grown thin films, with associated coating thickness and surface roughness, can be controlled by adjusting not only the reaction time but also the anodic substrate surface characteristics. The polycrystalline films were characterized via scanning electron microscopy, optical three-dimensional profilometry, atomic force microscopy, and X-ray diffraction. Using an instrumented nanoindenter, we performed fine-scale nanoscratch experiments under two distinct test modes: (i) ramp-load and (ii) pass-and-return (cyclic wear), to establish the underpinning failure mechanisms of MOF coatings with varied average thicknesses (∼ 2–10 μm). Our results reveal that the ramp-load approach is ideal to pinpoint the critical force requ...

Micro-Macro Transition of Population Balances in Fluidized Bed Granulation

The objective of this study is to introduce a generalized population balance model for simulating spray fluidized bed agglomeration of non-porous particles by extending the recent works of Hussain et al. [9,10]. In this context, the focus of this work is to model the average wet surface coverage fraction per wet particle and average success fraction concerning the dissipation of kinetic energy on a macroscopic scale. Average wet surface coverage fraction per wet particle is modeled by assuming the steric hindrance to be constant and discretizing the surface area of primary particles into smaller areas. Moreover, an algorithm is presented which takes into account Stokes criterion to predict an average success fraction concerning the dissipation of kinetic energy on a macroscopic scale.The proposed model with these variables is capable of predicting the particle size distribution, the total number of agglomerates, the total number of droplets and the total number of wet particles present in the system. The population balance model is validated by comparing its results with the experimental data. All comparisons show, at least qualitatively, good agreement, and the ability and generality of the proposed model to predict system dynamics with adequate accuracy.

Achieving direct electrochemistry of glucose oxidase by one step electrochemical reduction of graphene oxide and its use in glucose sensing

In this paper, the direct electrochemistry of glucose oxidase (GOD) was accomplished at a glassy carbon electrode modified with electrochemically reduced graphene oxide/sodium dodecyl sulfate (GCE/ERGO/SDS). A pair of reversible peaks is exhibited on GCE/ERGO/SDS/GOD by cyclic voltammetry. The peak-to-peak potential separation of immobilized GOD is 28mV in 0.1M phosphate buffer solution (pH7.0) with a scan rate of 50mV/s. The average surface coverage is 2.62×10−10molcm−2. The resulting biosensor exhibited a good response to glucose with linear range from 1 to 8mM (R2=0.9878), good reproducibility and detection limit of 40.8μM. The results from the biosensor were similar (±5%) to those obtained from the clinical analyzer.