Determining the critical micelle concentration of a novel lipid-lowering agent, disodium ascorbyl phytostanyl phosphate (FM-VP4), using a fluorescence depolarization procedure

The objective of this study was to determine the critical micelle concentration (CMC) of a novel water-soluble plant sterol derivative (FM-VP4) using a fluorescence depolarization method. The CMC was determined by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence depolarization. Test solutions of various concentrations of sodium dodecylsulphate (SDS) as a positive control or FM-VP4 in water were spiked with 2 µL of 4 mM DPH in tetrahydrofuran (THF) and left overnight to equilibrate in a dark chamber. Fluorescence of each solution was measured at room temperature using a Perseptive Biosystems Cytofluor Series 4000 multi-well plate reader. Fluorescence intensity increases as DPH is incorporated into the hydrophobic core of micelles. Thus, the CMC is the value at which an abrupt increase in intensity is observed. These points were observed at 8 mM and 0.014 mM for SDS and FM-VP4, respectively. Sodium dodecylsulphate was used as a positive control and supports the validity of our results, as the literature values of SDS are reported to be between 8-8.3 mM. The CMC of FM-VP4 is reported to be 0.014 mM.     

Laser-induced fluorescence ratios of Cajanus cajan L. under the stress of cadmium and its correlation with pigment content and pigment ratios

Laser-induced fluorescence spectra were used to characterize the effect of cadmium on the pigment status of the leaves of Cajanus cajan L. Laser-induced fluorescence spectra of untreated as well as cadmium treated (0.01 mM, 0.10 mM, and 1.00 mM) Cajanus cajan L. were recorded using the 355 nm line of a Nd:YAG laser as the excitation source and a monochromator with an intensified charge-coupled device as a detector in the region 400-800 nm. The fluorescence intensity ratios (FIR) of control as well as treated Cajanus cajan L. have been calculated by evaluating curve fitted parameters using a Gaussian spectral function. In addition, some growth parameters, such as photosynthetic pigment content, were also measured. The 355 nm line of the laser-light-excited leaves not only showed a fluorescence emission in the red spectral region (650-800 nm), but also in the blue-green region (400-570 nm). The chlorophyll FIR F690/F740 strongly correlated with the photosynthetic pigment content (total chlorophyll and carotenoids) and its ratio. Consequently, a correlation was also seen between the ratio of the blue-green fluorescence F470/F540 and the photosynthetic pigment content. The results indicated that the plants treated with 0.01 mM of cadmium exhibited better growth, while higher concentrations of cadmium were hazardous for Cajanus cajan L.     

Thin-film glucose biosensor based on plasma-polymerized film: simple design for mass production

We propose a simple thin-film glucose biosensor based on a plasma-polymerized film. The film is deposited directly onto the substrate under dry conditions. The resulting films are extreme thin, adhere well onto the substrate (electrode), and have a highly cross-linked network structure and functional groups, such as amino groups, which enable a large amount of enzyme to be immobilized. Since this design allows fabrication through a dry process, with the exception of the enzyme immobilization, which is the last stage of the process, the chip fabrication can be designed as a full-wafer process to achieve mass production compatibility. The resulting sensors produced using this film are more reproducible, exhibit lower noise, and reduce the effect of interference to a greater degree than sensors made using conventional immobilization methods, e.g., via 3-(aminopropyl)triethoxysilane. The obtained film is a good interfacial design between enzyme and electrode; enzyme two-dimensionally locates very close to the electrode in a manner that is quite reproducible. Therefore, a wide dynamic range (up to 60 mM) and rapid response time (11.5+/-0.8 s) were obtained. Because of its highly cross-linking network structure, the amperometric response due to interferences such as ascorbic acid and acetaminophen was reduced by size discrimination of plasma-polymerized films.     

Factors affecting the behavior and effectiveness of phospholipid bilayer coatings for capillary electrophoretic separations of basic proteins

Phospholipid bilayer coatings can prevent adsorption of cationic proteins on the surface of fused silica capillaries used in capillary electrophoresis. However, the performance of such bilayer coatings is strongly dependent on solution conditions. The factors affecting the rate of formation of phospholipid bilayer coatings were investigated using the double-chained zwitterionic 1,2-dimyristoyl-sn-glycero-phosphocholine (DMPC, C(14)) as a model phospholipid. The effectiveness of these coatings for CE separations of model cationic lysozyme, cytochrome c, ribonuclease A, and alpha-chymotrypsinogen A was also assessed. Increasing the ionic strength of a 0.1 mM DMPC solution reduced capillary coat times from >2 hours in 2.5 mM Tris (pH 7.4) buffer to 3.4 min in 40 mM Tris and dramatically improved separation performance such that > or =1.4 x 10(5) plates/m were observed in capillaries coated for 5 min with 0.1 mM DMPC in 20 mM Tris-HCl (pH 7.4). The presence of Ca(2+) in the coating solution also increases the rate of formation of the phospholipid bilayer coating. The type of vesicle strongly affects its adsorption rate onto the silica surface. The time required to coat the capillary was 7.2 min for small unilamellar vesicles (SUVs) and 22.5 min for large unilamellar vesicles and excessively long for multilamellar vesicles. Highest efficiency protein separations were achieved with bilayer coatings prepared from SUVs. The coating rate was enhanced by using greater DMPC concentrations and unaffected by pH. The type of buffer present in the DMPC coating solution affects the coating behavior, with HEPES buffer yielding a faster coat time than either Tris or phosphate buffers. Histone H1 was separated on a 0.1 mM DMPC-coated capillary.     

Dynamic cross-linking effect of Mg2+ to enhance sieving properties of low-viscosity poly(vinylpyrrolidone) solutions for microchip electrophoresis of proteins

We report a dynamic cross-linking effect of Mg2+ that enhances the sieving properties of low-viscosity poly(vinylpyrrolidone) (PVP) solutions. A low-viscosity PVP solution was applied to nondenaturing microchip electrophoresis of protein samples using microchips made of poly(methyl methacrylate). The separation resolution of nondenatured protein markers in 1.8% PVP solution was improved by adding 1-20 mM MgCl2. We studied the effect of the ratio of cross-linking agent on mobility of protein samples and showed that protein retardation (ln micro/micro0) is correlated with the ratio of cross-linking agent to PVP ([cMg2+/cPVP]) as ln micro/micro0=A'[cMg2+/cPVP]b'. A' was related to the protein radius (R), and b' was found to be 0.72 for proteins with R=2.4 nm and 0.82 for proteins with R=1.85 nm. A structural study of PVP in semidilute solutions using dynamic light scattering showed that incremental increases of Mg2+ ion concentration from 5 to 20 mM in 1.8% PVP solution increased the hydrodynamic radius of PVP polymers by 20%.     

Chemical reduction method for preparation of silver nanoparticles on a silver chloride substrate for application in surface-enhanced infrared optical sensors

A new method for the preparation of silver nanoparticles (AgNPs) on silver chloride discs was developed to integrate the unique properties of plasmonic nanoparticles into infrared optical sensing technologies. AgNP layers exhibiting strong infrared surface enhancement were prepared by reacting silver chloride discs in a solution containing hydrazine, which acts as a reducing agent. The silver ions in the outer layer of the disc could be reduced under proper conditions and the reduced silver coagulated to form suitable AgNPs for surface-enhanced infrared absorption (SEIRA) measurements. To examine the influences of the reaction solution composition and also to optimize preparation of SEIRA substrates, factors such as pH value, reaction time, and concentration of reducing agent were examined. Results indicated that both the concentrations of hydrazine and hydroxide strongly influenced the SEIRA signals. The strongest signals were observed when AgNPs on a AgCl substrate were prepared by using a reducing solution of 20 mM NaOH with 0.75 mM hydrazine. Using the optimized substrates, intense SEIRA spectra were observed with an enhancement factor around two orders of magnitude compared to measurements made using conventional sampling techniques.     

Pseudo first-order adsorption kinetics of N719 dye on TiO2 surface

We have investigated the adsorption kinetics of Ru-based N719 dye on TiO(2) surface in dye-sensitized solar cell using 0.5 mM and 5 mM dye solutions. The amount of adsorbed dye on TiO(2) surface of ca. 5 μm-thick film was measured as a function of immersion (adsorption) time. The amount of adsorbed dye increases with increasing the adsorption time and keeps constant after saturation. Completion of dye adsorption is found to be more than 5 times faster in 5 mM than in 0.5 mM. Since the change of dye concentration is negligible compared to that of number of TiO(2) adsorption site, reaction order and rate constant can be estimated from a pseudo reaction. Among the zeroth-, first-, and second-order simulation, the observed data follow first order reaction for both 0.5 mM and 5 mM cases. The rate constant is estimated to be 0.504 min(-1) for 5 mM and 0.094 min(-1) for 0.5 mM, which indicates that completion of dye adsorption is about 5 times shorter in 5 mM than in 0.5 mM. This is consistent with the observed adsorption time difference. Except for the difference in adsorption kinetics, best cell efficiency is similar regardless of dye solution concentration.     

Co-metabolism of 2,4-dichlorophenol and 4-Cl-m-cresol in the presence of glucose as an easily assimilated carbon source by Staphylococcus xylosus

Comparison of the ability of Staphylococcus xylosus to degrade 2,4-dichlorophenol and 4-Cl-m-cresol in separate cultures is reported. Bacterial adaptation and the continuous presence of glucose, as a conventional carbon source, were found to stimulate the degrading efficiency of S. xylosus. 4-Cl-m-cresol exhibited higher substrate-induced toxicity with K(ig) value at 0.25 mM, comparing to 2,4-dichlorophenol (K(ig) value at 0.90 mM) at initial concentration ranging from 0.1 to 0.5 mM. Degradation rate of 4-Cl-m-cresol was found to decrease only, revealing lower value of inhibition degradation constant (K(i) at 0.019 mM) comparing to that of 2,4-dichlorophenol (K(i) at 0.41 mM). Both glucose and each one of the chloro-aromatic compounds tested were simultaneously consumed and an increase of chloride ions in the medium appeared, during the exponential phase of growth. The chloride ions increase was nearly stoichiometric in the presence of 2,4-dichlorophenol and one of its several intermediate products identified was 2-Cl-maleylacetic acid. In the case of 4-Cl-m-cresol, only one metabolic product was found and identified as 3-methyl-4-oxo-pentanoic acid.     

Polyaniline-carboxymethyl cellulose nanocomposite for cholesterol detection

Cholesterol oxidase (ChOx) has been covalently immobilized onto polyaniline-carboxymethyl cellulose (PANI-CMC) nanocomposite film deposited onto indium-tin-oxide (ITO) coated glass plate using glutaraldehyde as a cross-linker. Fourier transform infrared (FTIR) spectroscopic and electrochemical studies have been used to characterize the PANI-CMC/ITO nanocomposite electrode and ChOx/PANI-CMC/ITO bioelectrode. Scanning electron microscopy (SEM) studies reveal the formation of PANI-CMC nanocomposite fibers of size approximately 150 nm in diameter. The ChOx/PANI-CMC/ITO bioelectrode exhibits linearity as 0.5-22 mM, detection limit as 1.31 mM, sensitivity as 0.14 mA/mM cm2, response time as 10 s and shelf-life of about 10 weeks when bioelectrode is stored at 4 degrees C. The low value of Michaelis-Menten constant (K(m)) obtained as 2.71 mM reveals high affinity of immobilized ChOx for PANI-CMC/ITO nanocomposite electrode.     

In vitro studies toward noninvasive glucose monitoring with optical coherence tomography

We use optical coherence tomography (OCT) to measure glucose-induced changes in Intralipid and in mouse skin samples in vitro. Mouse skin samples are cultured in a CO2 incubator before measurements are made with different amounts of added glucose concentrations. The results show that the glucose-induced changes in the OCT slope value vary between 20% and 52%/30 mM glucose in different mouse skin samples. This change is much larger than the change in 2% Intralipid (2.1%/30 mM) and in 5% Intralipid (0.86%/30 mM). Hence the results show that OCT has potential to monitor glucose-induced changes in tissues in vitro.     

Monitoring of chloride and activity of glycine receptor channels using genetically encoded fluorescent sensors

Genetically encoded probes have become powerful tools for non-invasive monitoring of ions, distributions of proteins and the migration and formation of cellular components. We describe the functional expression of two molecular probes for non-invasive fluorescent monitoring of intracellular Cl ([Cl]i) and the functioning of glycine receptor (GlyR) channels. The first probe is a recently developed cyan fluorescent protein-yellow fluorescent protein-based construct, termed Cl-Sensor, with relatively high sensitivity to Cl (Kapp approximately 30mM). In this study, we describe its expression in retina cells using in vivo electroporation and analyse changes in [Cl]i at depolarization and during the first three weeks of post-natal development. An application of 40mM K+ causes an elevation in [Cl]i of approximately 40mM. In photoreceptors from retina slices of a 6-day-old rat (P6 rat), the mean [Cl]i is approximately 50mM, and for P16 and P21 rats it is approximately 30-35mM. The second construct, termed BioSensor-GlyR, is a GlyR channel with Cl-Sensor incorporated into the cytoplasmic domain. This is the first molecular probe for spectroscopic monitoring of the functioning of receptor-operated channels. These types of probes offer a means of screening pharmacological agents and monitoring Cl under different physiological and pathological conditions and permit spectroscopic monitoring of the activity of GlyRs expressed in heterologous systems and neurons.     

Separation and determination of polycyclic aromatic hydrocarbons by solid phase microextraction/cyclodextrin-modified capillary electrophoresis

A sensitive method for the determination of polycyclic aromatic hydrocarbons (PAHs) by solid phase microextraction coupled with cyclodextrin (CD)-modified capillary electrophoresis (CE) using UV detection has been developed. A glass fiber was prepared and used for absorbing 16 EPA priority PAHs from diluted samples until equilibrium was reached. After the glass fiber was connected to a separation capillary via an adapter, the absorbed analytes were directly released into the CE buffer stream, and electrophoretic separation was effected using a 50 mM borate, pH 9.2, buffer containing 35 mM sulfobutyloxy-β-CD, 10 mM methyl-β-CD, and 4 mM α-CD. Separation was effected since neutral PAHs differentially partitioned between the neutral and charged CD phases. Under 30 kV applied potential, separation was achieved in less than 15 min with high resolution and number of theoretical plates. Pyrene as low as 8 ppb was detected, while the highest limit of detection was 75 ppb for acenaphthene. Very satisfactory reproducibility with respect to migration time and peak area was obtained for repetitions using the same separation capillary and adapter, where only the extraction fiber was discarded after each analysis.     

Structure of kaolinite flocs formed in an aqueous medium

The structure evolution of kaolinite flocs during their formation in aqueous medium was studied under a scanning electron microscope by hypercritical drying with liquid CO₂, as a function of Fe electrolyte content. Without any Fe electrolyte, a sediment with uniform porosity formed by accumulation of particles under gravity. Fresh Fe electrolytes made it possible to aggregate the kaolinite particles to flocs with an architecture consistent with diffusion limited aggregation (DLA). With 0.67 mM Fe, a single shrinking DLA flocs layer formed. With 3.33 mM Fe, extensive face to face aggregation of the clay particles occurred and a sediment with preferred horizontal orientation accumulated. With 0.17 mM Fe a shrinking DLA floc layer and a uniformly porous accumulated sediment formed concurrently, while with 1.67 mM Fe a shrinking DLA floes layer and an accumulated sediment with preferred orientation formed concurrently.     

Metal-binding particles alleviate lead and zinc toxicity during seed germination of metallophyte grass Astrebla lappacea

Combining metal-binding particles and metal-tolerant plants (metallophytes) offers a promising new approach for rehabilitation of heavy metal contaminated sites. Three types of hydrogel metal-binding polymer particles were synthesized and their effects on metal concentrations tested in vitro using metal ion solutions. The most effective of the tested polymers was a micron-sized thiol functional cross-linked acrylamide polymer which reduced the available solution concentrations of Pb(2+) (9.65 mM), Cu(2+) (4mM) and Zn(2+) (10mM) by 86.5%, 75.5% and 63.8%, respectively, and was able to store water up to 608% of its dry mass. This polymer was not toxic to seed germination. In deionised water, it enhanced seed germination, and at otherwise phytotoxic Pb(2+) (9.65 mM) and Zn(2+) (10mM) concentrations, it allowed normal germination and root elongation of the metallophyte grass Astrebla lappacea. We conclude that the polymer has the potential to facilitate restoration of heavy metal contaminated lands by reducing the concentration of metal cations in the soil solution and improving germination rates through reduced toxicity and enhanced plant water relations.     

Simultaneous measurement of dopamine and ascorbate at their physiological levels using voltammetric microprobe based on overoxidized poly(1,2-phenylenediamine)-coated carbon fiber

Overoxidized poly-(1,2-phenylenediamine) (OPPD)-coated carbon fiber microelectrodes (CFMEs) exhibit, in combination with square-wave voltammetry (SWV) detection mode, the attractive ability to simultaneously measure low nM dopamine (DA) and mM ascorbate (AA) in a pH 7.4 medium. The PPD polymer film is electrodeposited onto a carbon fiber at a constant potential of 0.8 V versus Ag/AgCl using a solution containing sodium dodecylsulfate as the dopant. After overoxidation using cyclic voltammetry (CV) in the potential range from 0 to 2.2 V at a scan rate of 10 V/s, the resulting OPPD-CFME displays a high SWV current response to cationic DA at approximately 0.2 V and has a favorably low response to anionic AA at approximately 0.0 V vs Ag/AgCl. The preparation of the new OPPD-sensing film has been carefully studied and optimized. The OPPD properties and behavior were characterized using CV and SWV under various conditions and are discussed with respect to DA and AA detection. The linear calibration range for DA in the presence of 0.3 mM AA is 50 nM to 10 microM, with a correlation coefficient of 0.998 and a detection limit of 10 nM using 45-s accumulation. The detection limit for DA in the absence of AA was estimated to be 2 nM (S/N = 3). The linear range for AA in the presence of 100 nM DA is 0.2-2 mM, with a correlation coefficient of 0.999 and a detection limit of 80 microM. The reproducibilities of SWV measurements at OPPD-CFCMEs are 1.6% and 2.5% for 100 nM DA and 0.3 mM AA, respectively. Potential interfering agents, such as 3,4-dihydroxyphenylacetic acid, uric acid, oxalate, human serum proteins, and glucose, at their physiologically relevant or higher concentrations did not have any effect. These favorable features offer great promise for in vitro and in vivo application of the proposed OPPD-coated microprobe.     

Steel dust catalysis for Fenton-like oxidation of polychlorinated dibenzo-p-dioxins

An advanced oxidation process (AOP) for degrading toxic contaminants, specifically polychlorinated dibenzo-p-dioxins (PCDDs), was developed to utilize steel dust, a steel industry by-product, as the heterogenous catalyst for a Fenton-like oxidation. The steel dust was treated using a chemical acid etchant (HCl) and ultrasound to remove surface anchored groups, reduce aggregation, and thereby increase the specific surface areas, resulting in increased access to catalytic sites. The removal of PCDD was optimized through various reaction conditions. The removal percentage of 1,2,3,4-tetrachlorintated dibenzo-p-dioxins (1,2,3,4-TCDD, 3.1 microM) after 3 h of Fenton-like oxidation under the conditions of 3 g/L (88 mM) H(2)O(2) and pH 3 was approximately 97% with 10 g/L of steel dust, compared to approximately 99% when 5 g/L metallic iron was used as a control. When a PCDD mixture (0.5-0.7 nM) was treated, 10 g/L (92 mM) steel dust achieved approximately 88% removal, comparable to the removal with 5 g/L (89 mM) Fisher iron with 3 g/L (88 mM) H(2)O(2.) These results indicate that the steel dust is a potentially viable catalyst for removing PCDDs from contaminated water.     

Focusing and Mobilization of Bacteria in Capillary Electrophoresis

An isotachophoretic method has been developed for mobilizing and focusing bacteria. This allows quantification and detection of bacteria in a narrow zone. Very good linearity was obtained for Micrococcus lysodeikticus (also called Micrococcus luteus, studied as a model of Gram+ bacteria) in the range of 0.4 × 10(8) cells/mL to 2.9 × 10(8) cells/mL, with correlation coefficients for peak height and peak area as a function of cell concentration of 0.999 and 0.998, respectively. This method is usable on both bare and hydroxypropyl cellulose-coated fused silica capillaries. The best results were obtained using 13.6 mM Tris, 150 mM boric acid as terminating electrolyte, and 4.5 mM Tris, 50 mM boric acid, and 3.31 mM HCl as leading electrolyte. With a 33.5 cm ×100 μm i.d. capillary, short migration times were obtained while maintaining very low electrical current in order to minimize any Joule heating and lysis of the bacteria. A UV area imaging detector (ActiPix D100, Paraytec) was used with a 109 cm × 100 μm i.d. capillary having three loops and four detection windows to monitor the migration behavior of M. luteus and to show the stability of the zone of the focused bacteria along the capillary. Similar results were obtained for Erwinia carotovora (a model of Gram- bacteria), and for Enterobacter cloacae and Vibrio splendidus.     

High-resolution computer simulations of stacking of weak bases using a transient pH boundary in capillary electrophoresis. 1. Concept and impact of sample ionic strength

The dynamics of focusing weak bases using a transient pH boundary was examined via high-resolution computer simulation software. Emphasis was placed on the mechanism and impact that the presence of salt, namely, NaCl, has on the ability to focus weak bases. A series of weak bases with mobilities ranging from 5 x 10(-9) to 30 x 10(-9) m2/V x s and pKa values between 3.0 and 7.5 were examined using a combination of 65.6 mM formic acid, pH 2.85, for the separation electrolyte, and 65.6 mM formic acid, pH 8.60, for the sample matrix. Simulation data show that it is possible to focus weak bases with a pKa value similar to that of the separation electrolyte, but it is restricted to weak bases having an electrophoretic mobility of 20 x 10(-9) m2/V x s or quicker. This mobility range can be extended by the addition of NaCl, with 50 mM NaCl allowing stacking of weak bases down to a mobility of 15 x 10(-9) m2/V x s and 100 mM extending the range to 10 x 10(-9) m2/V x s. The addition of NaCl does not adversely influence focusing of more mobile bases, but does prolong the existence of the transient pH boundary. This allows analytes to migrate extensively through the capillary as a single focused band around the transient pH boundary until the boundary is dissipated. This reduces the length of capillary that is available for separation and, in extreme cases, causes multiple analytes to be detected as a single highly efficient peak.     

A weak-base fibrous anion exchanger effective for rapid phosphate removal from water

This work investigated that weak-base anion exchange fibers named FVA-c and FVA-f were selectively and rapidly taken up phosphate from water. The chemical structure of both FVA-c and FVA-f was the same; i.e., poly(vinylamine) chains grafted onto polyethylene coated polypropylene fibers. Batch study using FVA-c clarified that this preferred phosphate to chloride, nitrate and sulfate in neutral pH region and an equilibrium capacity of FVA-c for phosphate was from 2.45 to 6.87 mmol/g. Column study using FVA-f made it clear that breakthrough capacities of FVA-f were not strongly affected by flow rates from 150 to 2000 h(-1) as well as phosphate feed concentration from 0.072 to 1.6mM. Under these conditions, breakthrough capacities were from 0.84 to 1.43 mmol/g indicating high kinetic performances. Trace concentration of phosphate was also removed from feeds containing 0.021 and 0.035 mM of phosphate at high feed flow rate of 2500 h(-1), breakthrough capacities were 0.676 and 0.741 mmol/g, respectively. The column study also clarified that chloride and sulfate did not strongly interfere with phosphate uptake even in their presence of equimolar and fivefold molar levels. Adsorbed phosphate on FVA-f was quantitatively eluted with 1M HCl acid and regenerated into hydrochloride form simultaneously for next phosphate adsorption operation. Therefore, FVA-f is able to use long time even under rigorous chemical treatment of multiple regeneration/reuse cycles without any noticeable deterioration.     

Superstable advanced hydrogen peroxide transducer based on transition metal hexacyanoferrates

We report on a superstable hydrogen peroxide (H(2)O(2)) transducer made by sequential deposition of the iron- and nickel-hexacyanoferrate (NiHCF) layers. Both chemical and mechanical stability of the latter, as well as similarity of its structure to Prussian Blue (PB) provide a substantial stabilization of the most advantageous H(2)O(2) transducer. The electrochemically deposited five bilayers of PB-NiHCF exhibit a complete stability under the continuous wall-jet flow of 1 mM of H(2)O(2) during more than 2 h, maintaining current at a level of 0.2 mA cm(-2), whereas common Prussian Blue loses half of its response within the first 20-25 min. Even being deposited in the open circuit regime on screen-printed electrodes, PB-NiHCF bilayers dramatically improve tolerance of the resulting transducer to alkaline solutions and iron ligands. Despite their 2-2.5 times decreased sensitivity (compared to common Prussian Blue), the sequentially deposited bilayers of PB-NiHCF provide a similar dynamic range of the transducer due to the decreased noise level.