Sodium Salt Of Ethylenediaminetetraacetic Acid Research Articles

In situ Ion Pumping Anodization to Confine Single‐Atom Fe onto TiO2 Nanotubes for Enhanced Noble‐Metal‐Free Photocatalytic Hydrogen Generation

AbstractAchieving a high dispersity of deposited transition metal is crucial in the anodization preparation of noble‐metal‐free composites for photocatalytic hydrogen generation. Herein, for the first time, an in situ ion pumping anodization method is proposed to confine single‐atom Fe within the spatially ordered structure of anodized TiO2 nanotubes (TNT), assisted by ferric sodium salt of ethylenediaminetetraacetic acid (EDTA) as an “ion pump” to deliver Fe3+ toward anodes. Both experimental and theoretical calculations confirm that highly dispersed single‐atom Fe can interact with single‐electron‐trapped oxygen vacancies (SETOV), effectively reducing the oxygen vacancy concentration in TiO2 nanotubes. This reduction promotes efficient charge carrier separation through the Fe(III)/Fe(II) pathway and enhances hydrogen desorption, ultimately boosting the photocatalytic hydrogen evolution performance.

Boosting Mg-Air Primary Battery Performance Via Addition of Complexing Agents in the Electrolyte: A Mechanistic View on the Effect of EDTA

Diverse novel energy conversion and storage systems have developed rapidly in the last few decades to address the growing demand for sustainable and environmentally friendly energy sources. In this respect, aqueous Mg-air batteries have drawn much attention for their high energy density, cost-effectiveness, and environmental friendliness.A primary Mg-air battery can theoretically provide a relatively high voltage and specific energy density of 3.1 V and 6.8 kW.h.kg-1, respectively [1]. However, the high wasteful self-corrosion rate of Mg alloys during discharge in aqueous electrolytes and fouling of the anode surface with corrosion products significantly reduce the delivered voltage and the specific energy of the Mg-air battery. These drawbacks are exacerbated by the anodic polarization due to the well-known phenomenon called Negative Difference Effect (NDE). Recently, pioneered by Höche et al. [2], the use of Mg complexing agents in the battery electrolyte has revolutionized the performance of Mg-air batteries by mitigating the mentioned shortcomings. However, the understanding of the enhancement mechanism, which may differ for different complexing agents, is at its nascent stage.In this work, sodium salt of ethylendiaminetetraacetic acid (EDTA) is used as the additive for the electrolyte of a primary Mg-air battery with a commercially pure Mg anode [3]. The electrolyte pH was taken as the main parameter to explore the effect of EDTA on the discharge performance of the Mg anode.The battery voltage was improved at all tested electrolyte pH values, which ranged from 7.0 to 11.0. The utilization efficiency (UE) of the discharged Mg anode is also enhanced by the presence of EDTA in the electrolyte at pH of 11, resulting in a 10-fold increase in the full-cell battery discharge time as compared to the reference battery in NaCl electrolyte without EDTA.Different methods, including EIS, local pH and dissolved O2 measurements, and H2 evolution tests were employed to study the interaction of EDTA with the Mg anode surface during discharge. Several mechanisms of enhancement in the UE have been concluded, including suppressing the chunk effect, weakening the detrimental NDE, and promoting the formation of a more protective layer on the Mg anode surface.The findings of this study provides an improved understanding of the interaction of the complexing agents with the Mg anode in Mg-air batteries, which further helps finding the tuning parameters to optimize its performance.[1] T. Zhang, Z. Tao, J. Chen, Magnesium-air batteries: From principle to application, Materials Horizons, 1 (2014) 196-206.[2] D. Höche, S.V. Lamaka, B. Vaghefinazari, T. Braun, R.P. Petrauskas, M. Fichtner, M.L. Zheludkevich, Performance boost for primary magnesium cells using iron complexing agents as electrolyte additives, Sci Rep, 8 (2018) 7578.[3] B. Vaghefinazari, D. Snihirova, C. Wang, L. Wang, M. Deng, D. Höche, S.V. Lamaka, M.L. Zheludkevich, Exploring the effect of sodium salt of Ethylenediaminetetraacetic acid as an electrolyte additive on electrochemical behavior of a commercially pure Mg in primary Mg-air batteries, Journal of Power Sources, 527 (2022) 231176.

Exploring the effect of sodium salt of Ethylenediaminetetraacetic acid as an electrolyte additive on electrochemical behavior of a commercially pure Mg in primary Mg-air batteries

In this study, sodium salt of Ethylendiaminetetraacetic acid (EDTA), a strong and widely-used complexing agent, was utilized as an additive for a primary Mg-air battery electrolyte with a commercially pure magnesium anode. The electrolyte pH (ranged 7.0 to 11.0) was taken as the main parameter to explore the effect of EDTA on the discharge performance of the Mg anode. The results show that the most negative half-cell discharge potential of the Mg anode is achieved in the slightly alkaline pH around 9, at which the EDTA has the strongest ability to prevent the formation of fouling Mg(OH)2 and improve the anode activity. The utilization efficiency of the discharged Mg anode is enhanced with the increase in pH of the electrolyte due to several mechanisms, including suppressing the chunk effect, weakening the detrimental Negative Difference Effect (NDE), and promoting the formation of a more protective layer on the Mg anode surface.

Mucoadhesive Buccal Films Based on Chitosan and Carboxymethylated Feronia Limonia Fruit Pulp Mucilage Interpolymer Complex for delivery of Opioid Analgesics

Aim: To develop and evaluate interpolymer complex (IPC) based buccal mucoadhesive films for delivery of opioid analgesics. The IPC was prepared using Chitosan and carboxymethylated Feronia limonia fruit pulp mucilage. Materials and Methods: In this study, the IPC is formed between mucoadhesive polymer chitosan and carboxymethylated F. limonia fruit pulp mucilage. The resulted IPC is used to prepare buccal mucoadhesive films of a model opioid analgesic. Other excipients include glycerin as plasticizer, a combination of sodium dihydrocholate and ethylenediaminetetraacetic acid sodium salt as permeation enhancers and a backing layer of 1% ethyl cellulose is placed on each film to ensure unidirectional drug release to systemic circulation. The solvent casting method is used to prepare buccal films and evaluated for bioadhesion strength, tensile strength, swelling index, ex vivo diffusion, and in vitro dissolution. Results and Discussion: Formulations are prepared and optimized by 32 factorial design. Formulation F7 was found to be optimized formulation which contained 50 mg drug, 100 mg IPC, and 2% glycerin as plasticizer. Thus, this study suggests that IPC between chitosan and carboxymethylated F. limonia fruit pulp mucilage can act as a potential mucoadhesive polymer system for buccal delivery of opioid analgesic drugs. Conclusion: In this study novel, buccoadhesive film was developed using IPC between chitosan and carboxymethylated F. limonia fruit pulp mucilage. The film was releasing drug over a period of 8-h directly to systemic circulation through buccal mucosa. The extensive first pass metabolism of a drug was prevented to a great extent.

Mesoporous films prepared from synthesized TiO2 nanoparticles and their application in dye-sensitized solar cells (DSSCs)

In this paper, we propose a novel method for preparation of high surface area titania nanoparticles, and investigate their photovoltaic performance in dye sensitized solar cells (DSSCs). The precursor compound titanium(IV)-isopropoxide is hydrolyzed in the presence of nonionic surfactant (Triton X100) and ethylenediaminetetraacetic acid sodium salt (EDTA-Na2) and thermally transformed into gel. The gel is autoclaved, resulting in submicronic micelles which are further processed into mesoporous films. The films are deposited from paste, composed of ultrasonically broken micelles and the organic ingredients. The crack-free film structures, composed of sub–25nm pure anatase particles are observed using the appropriate instrumental techniques: scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), UV-VIS-NIR spectroscopy. The large surface area of 158m2g−1 and mesoporosity are confirmed using the data obtained from the nitrogen adsorption-desorption isotherm. The photovoltaic performance of the operating N719-sensitized solar devices are tested using electrochemical impedance spectroscopy (EIS), open-circuit voltage decay (OCVD) and by recording current density-voltage (J-V) curves. The cell exhibits promising photocurrent density up to 11.7mAcm−2, and the photo-to-electric power efficiency of 5.22%, for cell area of 0.24cm2, under 100mWcm−2 halogen light source.

Effect of ethylenediaminetetraacetic acid (di sodium salt) and aquasoft 330 on crystal growth and morphology of calcium oxalate

Calcium oxalate was synthesized from calcium chloride solution using oxalic acid in the presence of di sodium salt of ethylenediaminetetraacetic acid (EDTA) and commercially available1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aquasoft having chelating value 330 (AQ 330). The experiments were carried out at three different temperatures 60, 80 and 100°C. The samples were characterized using scanning electron microscope (SEM), powder X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. The morphological studies reveal that the tendency for agglomeration increases with increase in temperature. Interpretation of XRD pattern confirmed that whewellite with monoclinic structured is the most favored structure in the presence of EDTA where calcium oxalate hydrate having orthorhombic structure is most favored structure in the presence of AQ 330.

Determination of macrolide and lincosamide antibiotics by pressurised liquid extraction and liquid chromatography-tandem mass spectrometry in meat and milk

A total of 155 samples, including meat and milk, were analyzed using a method developed for determining five macrolide antibiotics: tilmicosin (TILM), tylosin (TS), spiramycin (SPM), erythromycin (ERY), and tulathromycin (TULA) and two lincosamide antibiotics: pirlimycin (PIRL) and lincomycin (LM). The method was performed by pressurised liquid extraction (PLE) coupled to LC–MS/MS using electrospray ionization in positive ion mode. 2.5 mL of milk or 2.5 g of meat were dispersed in ethylenediaminetetraacetic acid sodium salt 2-hydrate (EDTA) and sea sand. The PLE conditions as: solvent, temperature, pressure, static time, and cell size were optimized. The following analytical parameters were validated according to the guidelines laid down by European Commission Decision 2002/657/EC linearity, specificity, decision limit (CCα), detection capability (CCβ), repeatability, reproducibility, recovery and ruggedness. The frequency of analyzed antibiotics in milk and meat was 48 and 15%, respectively. Four of positives samples (two of meat and two of milk) were higher than the maximum residues levels (MRLs) established by European Union legislation. The found levels were lower than 78.3 μg/kg in milk and 156 μg/kg in meat. Calculation of the estimated daily intakes (EDIs) from these data showed that contribution of meat and milk to dietary intakes were lower than acceptable daily intakes (ADIs) proposed by JECFA.

Characterization of polyphenol oxidase from broccoli ( Brassica oleracea var. botrytis italica) florets

Polyphenol oxidase (PPO) from broccoli florets was extracted and purified through (NH 4) 2SO 4 precipitation, ion-exchange and gel filtration chromatography. The molecular weight was estimated to lie between 51.3 and 57 kDa by sodium dodecyl sulphate-polyacrylamide gel electophoresis (SDS-PAGE) and gel filtration. The effects of substrate specificity, pH, and sensitivity to various inhibitors: citric acid, ascorbic acid, sodium sulphate and EDTA (sodium salt of ethylenediaminetetraacetic acid) of partially purified PPO were investigated. Polyphenol oxidase showed the best activity toward catechol ( K M = 12.34 ± 0.057 mM, V max = 2000 ± 8736 U/ml/min) and 4-methyl catechol ( K M = 21 ± 0.087 mM, V max = 28.20 ± 0.525 U/ml/min). The optimum pH for broccoli PPO was 5.7 with catechol and 4-methylcatechol as substrates. The most effective inhibitor was sodium sulphate.

Characterization of proteolytic bacteria from the Aleutian deep-sea and their proteases

Six deep-sea proteolytic bacteria taken from Aleutian margin sediments were screened; one of them produced a cold-adapted neutral halophilic protease. These bacteria belong to Pseudoalteromonas spp., which were identified by the 16S rDNA sequence. Of the six proteases produced, two were neutral cold-adapted proteases that showed their optimal activity at pH 7-8 and at temperature close to 35 degrees C, and the other four were alkaline proteases that showed their optimal activity at pH 9 and at temperature of 40-45 degrees C. The neutral cold-adapted protease E1 showed its optimal activity at a sodium chloride concentration of 2 M, whereas the activity of the other five proteases decreased at elevated sodium chloride concentrations. Protease E1 was purified to electrophoretic homogeneity and its molecular mass was 34 kDa, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of protease E1 was determined to be 32,411 Da by mass spectrometric analysis. Phenylmethyl sulfonylfluoride (PMSF) did not inhibit the activity of this protease, whereas it was partially inhibited by ethylenediaminetetra-acetic acid sodium salt (EDTA-Na). De novo amino acid sequencing proved protease E1 to be a novel protein.

Removal of Heavy Metals from Sewage Sludge Used as Soil Fertilizer

This work has examined sewage sludge of the following heavy metal concentrations (mg/kg): Cd-3.43; Co-5.25; Cu-131; Fe-51300; Mn-177; Ni-37.5; Pb-104; Zn-3300. Metals speciation by sequential extraction according to Tessier et al. (1979), and Rudd et al. (1988), and a procedure recommended by European Community Bureau of Reference (BCR) (Ure et al., 1993; Quevauiller et al., 1996; Davidson et al., 1999), as well as analysis of chemical forms of metals, have been carried out. It has been found that only Zn concentration is higher than the value permissible for agricultural sewage sludge application (2500 mg/kg). The results obtained by Tessier et al. (1979), and BCR procedures (Ure et al., 1993; Quevauiller et al., 1996; Davidson et al., 1999) appeared to be consistent. A comparison of the sequential analysis and the analysis of chemical forms of metals indicates that the sum of metal concentrations for the exchangeable, carbonate and bound to Fe/Mn oxyhydroxides forms (found by Tessier et al., 1979, and BCR analyses (Ure et al., 1993; Quevauiller et al., 1996; Davidson, et al., 1999)) corresponds to the sum of sulfate, oxide, metallic and siliceous forms. The concentrations of the forms bound to organic matter or sulfides correspond to the sulfide form while the residue corresponds to the ferrate form. Preparative extraction of metals from the sewage sludge using sodium salt of ethylenediaminetetraacetic acid (EDTA-Na), sodium pyrophosphate (V) and ammonia water has also been investigated. As far as the examined leaching agents are concerned, EDTA-Na appeared to be the best. Single leaching with this agent results in the following metal concentrations remaining in the sludge (mg/kg): Cd-1.1; Co-2.1; Cu-105; Fe-17700; Mn-28.3; Ni-12.8; Pb-44; Zn-1200. They meet the requirements of Polish regulations concerning the use of sewage sludge as a soil fertilizer.

Development of Cultured Rabbit Corneal Epithelium for Drug Permeation Studies: A Comparison with Excised Rabbit Cornea

The aim of this study was to prepare and test an artificial corneal epithelium (reconstituted rabbit corneal epithelium, RRCE) exhibiting barrier characteristics and paracellular permeability similar to those of native rabbit cornea. The RRCE was obtained from a rabbit corneal epithelium (RCE) cell line grown for 8 days in submerged culture, then for 7 days in air-interface conditions on Snapwell polyester membranes. Permeation studies on the RRCE were carried out in comparison with rabbit excised corneas in vitro, using timolol maleate (TM) as the test drug, alone and in association with the following ocular permeation enhancers: benzalkonium chloride, ethylene-diaminetetraacetic acid sodium salt, polyethoxylated castor oil, polyoxyethylene stearyl ether, sodium deoxycholate, and escin. The integrity of the RRCE was assessed by measuring the transepithelial electrical resistance (TEER) during culture time and after every permeation experiment. When TM was tested alone, the permeation parameters (apparent permeability coefficient, lag time) obtained with the RRCE were similar to those of excised rabbit corneas. The artificial epithelium, however, was less sensitive than native cornea to the effect of permeation enhancers.

Acidic property of modified ultra stable Y zeolite: increase in catalytic activity for alkane cracking by treatment with ethylenediaminetetraacetic acid salt

Temperature-programmed desorption (TPD) of ammonia with improved techniques was applied to quantitative determination of the strength and number of acid sites of a series of modified Y zeolites. A weak acid site was generated by the isomorphous substitution of aluminum for silicon, and the strength was independent of the aluminum concentration. This type of acid site showed almost no activity for cracking of octane at 573 K. Multiple types of extra-framework aluminum were formed on the ultra stable Y (USY) zeolite by steaming to create the cracking activity. Strong Brønsted acid sites were increased by the treatment of USY with a sodium salt of ethylenediaminetetraacetic acid (EDTA). The catalytic activity for alkane cracking showed a positive relationship with the number of this type of acid site, suggesting that the active site of USY for the catalytic cracking is this strong Brønsted acid site.

Recovery of EDTA and metal precipitation from soil flushing solutions

This work studies the effectiveness of a process proposed for the recovery of ethylenediaminetetraacetic acid (EDTA) and metal precipitation from soil flushing solutions. Two series of experimental tests were carried out on two samples of a soil artificially contaminated with copper or lead. The metals were extracted from the soil by flushing with a 0.05 M aqueous solution of EDTA sodium salt (E-Na 2). Cu or Pb extraction efficiencies of about 95 and 98% were observed, respectively. The two extracted solutions were then treated to obtain EDTA recovery and metal precipitation from the aqueous solution. EDTA recovery was achieved in two steps. An initial evaporation treatment lead to reduce the solution volume by about 75%. This was followed by the acidification of the residue solution, which precipitated more than 93% of the used EDTA. The precipitated EDTA was removed by filtration, and was suitable for reuse after adding an alkaline agent. Metal precipitation from the filtered solution was performed using two different methods: an almost total (99.5%) Pb precipitation in alkaline conditions was achieved after complex destabilization through the sequential addition of ferric ions and sodium phosphate, while 93.6% copper precipitation was achieved with ferrous sulfate as a destabilization agent.

The Use of Eucalyptus Barks for the Adsorption of Heavy Metal Ions and Dyes

Eucalyptus barks harvested in Lebanon were used for the adsorption of pollutants such as heavy metal ions and dyes. Washing with water or pretreatment with formaldehyde was performed on the bark powder. The adsorption capacity of this material towards CuII, CrIII, CdIIand NiIIwas evaluated in a batch process for various parameters. The results obtained showed that the retention capacity increased with contact time, pH and initial metal ion concentration but decreased with temperature. The adsorption capacities were 2.61, 0.71, 2.24 and 0.75 mmol/g adsorbent for CuII, CrIII, CdIIand NiII, respectively.Eucalyptus barks are also very efficient for the adsorption of dyes (Acid Blue 25, Erichrome Blue Black B and Calmagite) because of interaction between the hydroxy and amino groups of the dyes and the phenolic moities of bark. This adsorption was modified when metal ions had already been adsorbed on to the barks as a result of the formation of a 1:1 complex between the dye and the metal ion. Desorption was achieved by treating with the sodium salt of ethylenediamine-tetraacetic acid (EDTA) for metal ions and by heating at 75°C in aqueous medium for dyes. After desorption, the recycling of the support was tested for potential use as a means of concentrating pollutants.

SEQUENTIAL EXTRACTION AND DETERMINATION OF CHEMICAL FORMS OF ZINC IN SULFATE SLUDGE

Total content of zinc and other metals has been assayed in thesludge that remained after leaching zinc-bearing smelting losswith sulfuric acid. The paper also presents zinc speciationcarried out by means of the sequential extraction by Rudd and an analysis of chemical forms of zinc. It has been found thatzinc occurs mainly in the mobile, bioavailable, soluble form and in the moderately mobile, carbonate form. The speciationcarried out showed that zinc occurred in the sludge in the following forms (mg kg-1): sulfate 143 000, oxide 79 000,metallic 68 200, siliceous 35 500, sulfide 20 800 and ferrate18 500. Preparatory extraction of zinc from the sludge usingwater, sodium salt of ethylenediaminetetraacetic acid (EDTA)and acetic acid has also been conducted.

Utilization of fluorescein sodium salt in laser-induced indirect fluorimetric detection of ions separated by capillary zone electrophoresis

Indirect detection, the principles of which were demonstrated some years ago, has attracted renewed interest in both UV-visible and fluorimetric detection. This paper reports the implementation of laser-induced indirect fluorimetric detection using a commercially available detector and its association with high-performance capillary electrophoresis for the determination of inorganic ions. In order to optimize the response sensitivity, the fluorescent agent being fluorescein sodium salt, the influence of the fluorescein sodium salt concentration, the ionic strength, the electrolyte pH and the gain on the signal-to-noise ratio were studied successively, the injection mode being either electrokinetic or hydrodynamic. In the case of a 75 μm I.D. fused-silica capillary, detection limits were in the ppb range or about 10 ppb for alkali metal cations using injection in the electrokinetic or in the hydrodynamic mode, respectively. As the detection system used had its maximum sensitivity at basic pH, the use of a complexing agent was required in order to perform the determination of alkaline earth metal cations, because they precipitate or are adsorbed at basic pH. Therefore, using ethylenediaminetetraacetic acid sodium salt (EDTA), it is possible to analyse at pH 7.5, in less than 5 min, a mixture containing three alkaline earth metal cations (Ba 2+, Ca 2+ and Mg 2+) and three transition metal cations (Fe 3+, Zn 2+ and Cu 2+) in addition to the previously mentioned alkali metal cations (Li + and K +).

Effects of a calcium binder on the solubility of bile acids and fatty acids in the large intestine of the rat

Kidney stone patients with hypercalciuria type I are treated with an oral calcium binder. Lower intakes of calcium (Ca) in the range of 0–1500 mg/day have been associated with an increased incidence of colorectal cancer. The aim of this study is to analyze the effects of feeding ethylene diamine tetraacetic acid sodium salt (EDTA), a strong, non-absorbable binder of Ca, on the solubility of bile acids (BA) and long chain fatty acids (LCFA) in the large intestine of the rat. We have shown that the concentrations of soluble BA and LCFA in the large intestine contents remained constant while the concentration of total BA and LCFA decreased. Therefore, lowering the amount of Ca available for binding BA or LCFA is unlikely to increase the risk of colorectal cancer by that method.

Chromium Speciation Using Ion Chromatography-Atomic Absorption System with On-Line Preconcentration

Abstract A method using ion chromatography-atomic absorption system (IC-AA) with on-line preconcentration unit is developed for the speciation of chromium in aqueous samples. Both Cr(III) and Cr(VI) species are pre-treated with sodium salt of ethylenediaminetetraacetic acid (EDTA) in consecutive steps. The treated samples can then be injected into an on-line preconcentration unit followed by ion chromatographic separation with UV or selective flame AA detection. Both chromium species can be separated within 10 minutes, and the method is applicable for aqueous samples with ppm levels of chromium.

Hyperpolarization/Depolarization on Human Spermatozoa

The accumulation of the lipophilic cation radiolabeled triphenylmethylphosphonium (TPMP+) was utilized to determine the resting membrane potential across the plasma membrane (psi) of human sperm. Washed sperm were suspended and incubated in low-K+ and high-K+ medium and allowed to take up the cation to a steady state (20 min at 37 degrees C). By using this differential, the value obtained was inserted in the Nernst equation and the value yielded a psi of -69 +/- 2 mV. When the Na+ or K+ concentration is high in the medium, the accumulation of TPMP+ in the membrane sperm cells was increased or decreased, respectively, inducing hyperpolarization and depolarization of the membrane 20% and 85%, respectively. The presence of divalent cations Zn++ and Mg++ in the incubation medium both induced a hyperpolarization of 10% and 8.6%, respectively. The addition of specific reagents such as p-chloromercuribenzenosulfonate and ethylenediaminetetraacetic acid sodium salt both decreased the psi 35% and 58%, respectively. The agents acting on the sperm cell membrane, such as dithiothreitol and progesterone, both induced hyperpolarization and depolarization of the membrane 16% and 40%, respectively. The presence of propranolol and L-alpha-lysophosphatidylcholine, which affect the ionic gradients present across the plasma membrane, both induced a depolarization from 43% and 92%, respectively. Finally the psi was glucose-dependent. The result of these studies was that, by the use of agents causing hyperpolarization or depolarization, we obtained changes in the psi of -83.4 +/- 2.2 mV, until -6 +/- 0.6 mV changes of -76.8 +/- 2 mV translated across the sperm cell membrane.

Control of release of encapsulated molecules from polymerized mixed liposomes induced by physical or chemical stimuli

Small unilamellar mixed liposomes composed of polymerizable and non-polymerizable lipids are polymerized to prepare stimuli-responsive polymerized liposomes. Encapsulated 5(6)-carboxyfluorescein (CF) is released from non-polymerizable regions by physical and/or chemical stimuli. As the liposome structure is maintained by polymerized lipid frames, the release is stopped by removing the stimuli. This process can be repeated several times. CF is released rapidly at the phase transition temperature of the non-polymerizable lipids, e.g., at 37 and 19°C for dipalmitoylphosphatidylcholine and dimyristoylphosphatidykholine, respectively. The temperature dependence is further affected by the size of the phase-separated domains. Polymerized mixed liposomes having larger phase-separated domains show a sharper response to the phase transition. In case of polymerized mixed liposomes containing phosphatidylethanolamine, CF is released as a function of pH. The release rate is very small at pH 11, but it increases with pH decreasing to 7.5, which is attributed to the structural change of the bilayer induced by the change in dissociation of the head groups. On the other hand, in case of polymerized mixed liposomes containing phosphatidylserine, release of CF is accelerated by the addition of Ca 2+ ions and is restored to the initial rate by eliminating Ca 2+ ions with ethylenediamine tetraacetic acid sodium salt (EDTA). The CF release response is obtained repeatedly by the alternating addition of Ca 2+ ion and EDTA.