Electrophoresis Measurements Research Articles

Six coordination compounds: mode of cytotoxic action and biological evaluation

This study describes the biological and anticancer properties of followed coordination compounds. IR spectra, magnetic properties, thermal analyses and crystal structures of six cyanido-complexes derivatives with [M II (CN) 4 ] 2- (M II = Ni and Pd) and [Co(CN) 6 ] 3- anions and N - bishydeten ( N,N -bis(2-hydroxyethyl)ethylenediamine) as a capping ligand have been previously reported. Here, we investigated these complexes denoted as[Ni( N-bishydeten )Ni(CN) 4 ] ( C1 ), [Zn 2 ( N-bishydeten ) 2 Ni(CN) 4 ] ( C2 ), [Ni( N-bishydeten )Pd(CN) 4 ] ( C3 ), [Cd( N-bishydeten ) 2 ][Pd(CN) 4 ] ( C4 ), [Ni 2 ( N-bishydeten ) 2 Co(CN) 6 ].3H 2 O ( C5 ) and K[Cd( N-bishydeten )Co(CN) 6 ].1.5H 2 O ( C6 ), which were tested for their anti-proliferative activity against human cervical cancer (HeLa), human colon cancer (HT29), rat glioma (C6) and African green monkey kidney (Vero) cell lines. The DNA/BSA binding affinities of these compounds were also elucidated by spectroscopic titrations, displacement experiments and electrophoresis measurements. Studies on cancerous cells revealed that C1 , C2 , C4 and C6 exhibited significant antitumor activity and inhibited tumor progression in testing cell lines and showed high solubility in the solvent. Absorbance and emission spectra data results revealed that the complexes interact with the DNA via groove binding mode of interaction. Overall, these compounds have been found to demonstrate effective anti-proliferative activity against the cancer cell lines, indicating that they are a potent candidate for preclinical or clinical study.

The Influence of Carbonate Ions on the Structure of the Electrical Double Layer at the Interface of Hydroxyapatite/Electrolyte Solution

The aim of the work was to investigate the changes in the double electrical layer at the hydroxyapatite containing different amount of carbonate ions/electrolyte solution. Besides, the main properties of the edl (electrical double layer), i.e. surface charge density and zeta potential were determined by electrophoresis measurements and potentiometer titration, respectively. The synthesized adsorbents were characterized by the following methods: X-ray diffraction, FTIR (Fourier Transform Infrared Spectroscopy), adsorption and desorption of nitrogen and scanning electron microscopy. The analyzed samples had different structures and particle sizes. It was proved that increase in the carbonate groups content is connected with the decrease of apatite grain sizes and crystallinity reduction. The characteristic parameters of the electric double layer were also different: pHpzc (point zero of charge) of hydroxyapatite was 6.5 whereas for carbonate apatite was higher – pHpzc = 8. In both cases determination of precise pHIEP (isoelectric point) was not possible but it is known that its value is lower than 4.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7817

Development and evaluation of a spray drying microencapsulation process for water-insoluble milk protein capsules

A spray drying process for water-insoluble milk protein capsules was developed, based on the classical rennet gelation mechanism. The process consisted of an initial gelation during drying and a final gelation under controlled rehydration conditions. A rheological characterisation of the feed solution with different total solid (TS) contents was carried out to determine the process limiting concentration. The maximal TS content was 35% to prevent premature gelation. Additionally, the rehydration temperature-dependent capsule-forming behaviour was characterised by sodium dodecylsulphate polyacrylamide gel electrophoresis and particle size measurements. In addition to the rehydration temperature, the product and process parameters during spray drying, such as initial TS content, feed rate and drying temperature, showed a great impact on the final capsule formation behaviour. A degree of aggregation (DA) of 80% was achieved using a combination of low TS and high feed rate, which shows that complete capsule formation after rehydration is possible.

Effect of protein structure and/or conformation on the dityrosine cross-linking induced by haem-hydrogen peroxide

BackgroundHaem, an essential cofactor in aerobic organisms, can cause oxidative stress and impose toxic effects on tissues and organs. It can induce aggregation of proteins via dityrosine cross-linking and cause neurodegenerative diseases. Although dityrosine cross-linking in many proteins induced by haem has been reported, not all the proteins have the same effect or the efficiency of cross-linking varies, while the reason has not been clarified. MethodsThe correlation of protein structure/conformation with its aggregation tendency via dityrosine induced by hematin (oxidized form of haem) in the presence of hydrogen peroxide (H2O2) was studied through reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fluorescence and circular dichroism (CD) measurements, and the mechanism was investigated by performing UV–Vis absorbance, Raman spectroscopy and low-temperature electron spin resonance (ESR) experiments. ResultsIt was found that proteins in unstructured state are more readily to be cross-linked via dityrosine formation by hematin-H2O2. The unstructured protein without steric effect can coordinate with hematin to form six-coordinated protein-hematin complex, in which the produced tyrosyl radicals by H2O2 are with high tendency to dimerize to form dityrosine. ConclusionsOur results demonstrate that protein structure/conformation can affect its coordination state with haem, and the tendency of reaction of two tyrosyl radicals, further influencing the yield and efficiency of dityrosine cross-linking in the presence of H2O2. General significanceThis research can help to deepen our understanding of the protein aggregation and inactivation mechanisms in varied sophisticated conditions, and especially give us the new insight into the toxic effects under haem stress.

Guía práctica para el examen del paciente adulto con hipertransaminasemia asintomática

The causes of sustained elevation of serum transaminases in asymptomatic adults, both hepatic and extrahepatic, are varied. In order to reach an aetiological diagnosis, a standardized protocol should be applied, aimed firstly at ruling out the most common causes, such as chronic hepatitis (viral or autoimmune), metabolic diseases, and toxic liver diseases. Several biochemical patterns, which take into account transaminase, cholestatic enzyme, muscle enzyme, ferritin and ceruloplasmin levels, as well protein electrophoresis and autoantibody measurement, will identify most causes. In cases in which a diagnosis cannot be reached with the use of these non-invasive methods, a needle liver biopsy will be justified.

Electrophoresis-enhanced localized surface plasmon resonance sensing based on nanocup array for thrombin detection

Based on the special electrical and optical properties resulted from periodic nanostructure, localized surface plasmon resonance (LSPR) sensors have been widely used for various chemical and biological detections. Utilizing uniform alignment nanocups, an electrophoresis-enhanced LSPR sensor was designed for sensitive thrombin detection. The nanocup array was composed of nano-scaled funnel shaped cups with nanoparticles along the side walls. Through self-assembly, polyethylene glycol, thrombin-specific peptide, and bovine serum albumin were successively immobilized on the nanocup array. The results demonstrated that the synchronous implementation of electrophoresis and LSPR measurement could lead to obvious peak shifts in optical transmission spectra for detecting thrombin. The detection limit was as low as 10−11M. With the high sensitivity and well linearity, the electrophoresis-enhanced LSPR sensing offered a novel design perspective for chemical and biological sensors with specific modifications on the nanosensor surfaces.

Influence of protein bulk properties on membrane surface coverage during immobilization

Biomolecules immobilization is a key factor for many biotechnological applications. For this purpose, the covalent immobilization of bovine serum albumin (BSA), lipase from Candida rugosa and protein G on differently functionalized regenerated cellulose membranes was investigated.Dynamic light scattering and electrophoresis measurements carried out on biomolecules in solution indicated the presence of monomers, dimers and trimers for both BSA and protein G, while large aggregates were observed for lipase.The immobilization rate and the surface coverage on functionalized regenerated cellulose membranes were studied as a function of biomolecule concentration. Results indicated that the saturation coverage of BSA and protein G was concentration independent (immobilized protein amount of 2.40±0.03mg/g and 2.65±0.07mg/g, respectively). Otherwise, a different immobilization kinetics trend was obtained for lipase, for which the immobilized amount increases as a function of time without reaching a saturation value.Atomic force microscopy (AFM) micrographs showed the formation of monolayers for both BSA and protein G on the membrane surface, while a multilayer structure is found for lipase, in agreement with the trends observed in the related immobilization kinetics. As a result, the morphology of the proteins layer on the membrane surface seems to be strictly dependent on the proteins behavior in solution.Besides, the surface coverage has been described for BSA and protein G by the pseudo second order models, the results indicating the surface reaction as the controlling step of immobilization kinetics. Finally, enzyme activity and binding capacity studies indicated the preservation of the biomolecule functional properties.

Modifying effect of XmnI, BCL11A, and HBS1L-MYB on clinical appearances: A study on β-thalassemia and hemoglobin E/β-thalassemia patients in Indonesia

Objective/backgroundThalassemia is a monogenic hematologic disease that has the highest prevalence globally. In addition, there is complexity of the genetic background associated with a variety of phenotypes presented among patients. Genetic heterogeneity related to fetal hemoglobin (HbF) production has been reported as an influencing phenotypic factor of β-thalassemia (β-thal). Therefore, this study aimed to find the effect of these genetic modifiers, especially in the XmnI locus, rs11886868, rs766432 (BCL11A), and rs9399137 (HBS1L-MYB), among β-thal and HbE/β-thal patients in Indonesia, according to laboratory and clinical outcomes, including HbF levels and clinical scores. This study was also designed to compare these modifying effects among β-thal and HbE/β-thal patients in Indonesia. MethodsA total of 189 patients with genotyping of β-thal and HbE/β-thal were included in this study. The erythrocytes index and Hb electrophoresis measurements were calculated using appropriate methods. The severity of β-thal and HbE/β-thal was classified based on the Mahidol score. Polymorphism of the XmnI locus, rs11886868, rs766432 (BCL11A), and rs9399137 (HBS1L-MYB) was determined using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and amplification refractory mutation system (ARMS) methods. ResultsThe distributions of minor allele in the XmnI locus, rs11886868, rs766432, and rs9399137 were 14%, 22%, 19% and 18% respectively. The variation allele in the XmnI locus, rs11886868, and rs766432 showed a significant value for modifying HbF and clinical score in HbE/β-thal patients, but rs9399137 did not demonstrate such features. In β-thal patients, however, no correlation was found for any single-nucleotide polymorphisms and clinical appearance. ConclusionThe XmnI locus, rs11886868, and rs766432 have a modifying effect on HbF and clinical score in HbE/β-thal patients in Indonesia, but not in β-thal patients.

Mechanism and In Vivo Evaluation: Photodynamic Antibacterial Chemotherapy of Lysine-Porphyrin Conjugate.

Lysine-porphyrin conjugate 4i has potent photosensitive antibacterial effect on clinical isolated bacterial strains such as Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa. The mechanism of photodynamic antibacterial chemotherapy of 4i (4i-PACT) in vitro and the treatment effect in vivo was investigated in this paper. Atomic force microscopy (AFM) revealed that 4i-PACT can effectively destroy membrane and wall of bacteria, resulting in leakage of its content. This was confirmed by dual fluorescent staining with acridine orange/ethidium bromide and measuring materials absorption at 260 nm. Agarose gel electrophoresis measurement showed that 4i-PACT can damage genomic DNA. Healing of wound in rat infected by mixed bacteria showed that the efficiency of 4i-PACT is dependent on the dose of light. These results showed that 4i-PACT has promising bactericidal effect both in vitro and in vivo.

Introduction of new formulas and evaluation of the previous red blood cell indices and formulas in the differentiation between beta thalassemia trait and iron deficiency anemia in the Makkah region

Background: Many formulas from red blood cell (RCB) indices are instructed to differentiate between iron deficiency anemia (IDA) and beta thalassemia trait. None had 100% Youden index.Aim of the work: To introduce two new formulas and evaluate them in the differentiation between IDA and beta thalassemia trait in adults Saudi (male and female; male; female) in the Makkah region. Furthermore, to evaluate the previous formulas in our population.Methods: A total of 249 participants, 91 with IDA, 123 with beta thalassemia trait, and 35 healthy persons. All subjected to complete blood count, measurement of iron profile, hemoglobin electrophoresis and hemoglobin A2 by column chromatography. The first new formula equal hemoglobin (Hb) + hematocrit (Hct) + RBC and second equals Hb + Hct + RBC-red cell distribution (RDW). The previous formula used is England and Fraser, Mentzer, Strivastava, Ehsani, Green and King, red cell distribution index, Ricerca, and Shine and LalResults: In both men and women, the England and Fraser was the best with a Youden's index of 70.4%, followed by Green and King 67.4%. In men, the England and Fraser and our new formula 1 had the highest Youden’ index 84.7% and 84.1%, respectively. In women, the England and Fraser and RDW index had the highest Youden’ index 74% and 69.2%, respectively.Conclusion: The England and Fraser and our new formula 1 are the best formulas in men. The England and Fraser and RDW index are the best formulas in women.

Exploring the photochemosensitivity by novel cysteine-based mixed ligand complexes

A new series of cysteine-based metal(II) complexes with 2,2′-bipyridine or 1,10-phenanthroline as co-ligand have been prepared and characterized. Their DNA binding and cleavage properties have been studied. The analytical and spectroscopic data of complexes 1–18 reveal that the complexes adopt an octahedral geometry around the central metal ion in which the cysteine is coordinated through NS and NN atoms, respectively. Spectroscopic titration and viscosity measurements reveal that the complexes bind to DNA through an intercalative mode. Electrophoresis measurements exhibit that they cleave pBR322 DNA efficiently in the presence of 3-mercaptopropionic acid (MPA), probably via hydrolytic mechanism with the involvement of •OH. The in vitro anticancer activities indicate that the Cu(II) complexes are active against four selected human tumor cell lines. Furthermore, it is remarkable that all the complexes exhibit significant photocytotoxicity against human breast cancer cell lines (MCF-7) with a potency more than the widely used drugs photofrin and cisplatin indicating that they have the potential to act as effective anticancer drugs in a dose-dependent manner.

Aggregation-free DNA nanocage/Quantum Dot complexes based on electrostatic adsorption

Fabrication of DNA/Quantum Dot (QD) complexes making use of electrostatic adsorption forces has advantages of the cost-efficiency and simplicity. To obtain aggregation-free complexes, high molecular weight polymers or the purposefully designed ligands are commonly employed as a bridge between DNA and QDs, which limits their applications in practice. In this work, DNA/QDs complexes were obtained using electrostatic adsorption between cysteamine stabilized CdTe QDs and self-assembled DNA nanocages. Zeta potential, dynamic light scattering and gel electrophoresis measurements demonstrated their aggregation-free state, different from the cases where single-stranded and double-stranded DNAs were used. The appearance of aggregation-free complexes in the case of DNA nanocages was ascribed to their 3D rigid structure. Forster resonance energy transfer (FRET) was demonstrated for the complexes of Cy3 labeled DNA nanocages and QDs, pointing out on the close proximity of these building blocks.

Analytical approaches for clarification of DNA-double decker phthalocyanine binding mechanism: As an alternative anticancer chemotherapeutic

In the present study a novel water soluble double-decker phthalocyanine was synthesized and calf thymus DNA interaction of the synthesized double-decker phthalocyanine was investigated. 5-(3-pyridyl)-1,3,4-oxadiazole substituted phthalonitrile 1 was prepared by a nucleophilic displacement reaction of 4-nitrophthalonitrile with 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol. Lutetium(III) double-decker phthalocyanine 2 was prepared by cyclotetramerization of compound 1. Water soluble lutetium(III) double-decker phthalocyanine 3 was prepared with quaternarization of compound 2. The synthesized double-decker phthalocyanine and calf thymus DNA interaction was investigated with UV–vis titrimetric methods, gel electrophoresis, and viscosity measurements. The fluorometric ethidium bromide replacement assay was conducted to clarify the binding mode of water soluble double-decker phthalocyanine. The thermodynamic parameters for interaction, K, ΔG0, ΔH0 and ΔS0 were calculated between the temperature ranges of 25°C–75°C. To the best of our knowledge, this is the first study about a double-decker phthalocyanine and DNA interaction.

Ready-to-use colloidal adjuvant systems for intranasal immunization

Adjuvant systems based on oil-in-water (o/w) microemulsions (MEs) for vaccination via intranasal administration were prepared and evaluated. A ready-to-use blank ME system composed of mineral oil (oil), Labrasol (surfactant), Tween 80 (cosurfactant), and water was prepared and blended with antigen (Ag) solution prior to use. The o/w ME system developed exhibited nano-size droplets within the tested range of Ag concentrations and dilution factors. The maintenance of primary, secondary, and tertiary structural stability of ovalbumin (OVA) in ME, compared with OVA in solution, was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism (CD), and fluorescence intensity measurements, respectively. The uptake efficiency in RAW 264.7 cells, evaluated by flow cytometry, of OVA in the ME group was significantly higher than that of the OVA solution group (p<0.05). In an intranasal immunization study with OVA ME in mice, elevated adjuvant effects in terms of mucosal immunization and Th1-dominant cell-mediated immune responses were identified. Given the convenience of use (simply mixing with Ag solution prior to use) and the adjuvant effects after intranasal immunization, the new o/w ME may be a practical and efficient adjuvant system for intranasal vaccination.

Biorelevant reactions of the potential anti-tumor agent vanadocene dichloride.

The interaction of the potential anti-tumor agent vanadocene dichloride ([Cp2VCl2] or VDC) with some relevant bioligands of the cytosol such as proteins (Hb), amino acids (glycine and histidine), NADH derivatives (NADH, NADPH, NAD(+) and NADP(+)), reductants (GSH and ascorbic acid), phosphates (HPO4(2-), P2O7(4-), cAMP, AMP, ADP and ATP) and carboxylate derivatives (lactate) and its uptake by red blood cells were studied. The results indicated that [Cp2VCl2] transforms at physiological pH into [Cp2V(OH)2] and that only HPO4(2-), P2O7(4-), lactate, ATP and ADP form mixed species with the [Cp2V](2+) moiety replacing the two hydroxide ions. EPR and electronic absorption spectroscopy, agarose gel electrophoresis and spin trapping measurements allow excluding any direct interaction and/or intercalation with DNA and the formation of reactive oxygen species (ROS) in Fenton-like reactions. Uptake experiments by erythrocytes suggested that VDC crosses the membrane and enters inside the cells, whereas 'bare' V(IV) transforms into V(IV)O species with loss of the two cyclopentadienyl rings. This transformation in the cellular environment could be related to the mechanism of action of VDC.

Challenges of measuring monoclonal proteins in serum.

The measurement of monoclonal protein (M-protein) is vital for stratifying risk and following individuals with a variety of monoclonal gammopathies. Direct measurement of the M-protein spike by electrophoresis and immunochemical measurements of specific isotypes or free light chains pairs has provided useful information about the quantity of M-protein. Nonetheless, both traditional electrophoresis and immunochemical methods give poor quantification with M-proteins smaller than 10 g/L (1 g/dL) when in the presence of polyclonal immunoglobulins that co-migrate with the M-protein. In addition, measurements by electrophoresis of M-proteins migrating in the β- and α-regions are contaminated by normal serum proteins in those regions. The most precise electrophoretic method to date for quantification involves exclusion of the polyclonal immunoglobulins by using the tangent skimming method on electropherograms, which provides a 10-fold improvement in precision. So far, however, tangent measurements are limited to γ migrating M-proteins. Another way to improve M-protein measurements is the use of capillary electrophoresis (CE). With CE, one can employ immunosubtraction to select a region of interest in the β region thereby excluding much of the normal proteins from the M-protein measurement. Recent development of an immunochemical method distinguishing heavy/light chain pairs (separately measuring IgGK and IgGL, IgAK and IgAL, and IgMK and IgML) provides measurements that could exclude polyclonal contaminants of the same heavy chain with the uninvolved light chain type. Yet, even heavy/light results contain an immeasurable quantity of polyclonal heavy/light chains of the involved isotype. Finally, use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) looms on the horizon as a means to provide more consistent and sensitive measurements of M-proteins.

Injectable gellan gum-based nanoparticles-loaded system for the local delivery of vancomycin in osteomyelitis treatment.

Infection spreading in the skeletal system leading to osteomyelitis can be prevented by the prolonged administration of antibiotics in high doses. However systemic antibiotherapy, besides its inconvenience and often low efficacy, provokes numerous side effects. Thus, we formulated a new injectable nanoparticle-loaded system for the local delivery of vancomycin (Vanc) applied in a minimally-invasive way. Vanc was encapsulated in poly(l-lactide-co-glycolide) nanoparticles (NPs) by double-emulsification. The size (258 ± 11 nm), polydispersity index (0.240 ± 0.003) and surface potential (−25.9 ± 0.2 mV) of NPs were determined by dynamic light scattering and capillary electrophoresis measurements. They have a spherical morphology and a smooth topography as observed using atomic force microscopy. Vanc loading and encapsulation efficiencies were 8.8 ± 0.1 and 55.2 ± 0.5 %, respectively, based on fluorescence spectroscopy assays. In order to ensure injectability, NPs were suspended in gellan gum and cross-linked with Ca2+; also a portion of dissolved antibiotic was added to the system. The resulting system was found to be injectable (extrusion force 11.3 ± 1.1 N), reassembled its structure after breaking as shown by rheology tests and ensured required burst release followed by sustained Vanc delivery. The system was cytocompatible with osteoblast-like MG-63 cells (no significant impact on cells’ viability was detected). Growth of Staphylococcus spp. reference strains and also those isolated from osteomyelitic joints was inhibited in contact with the injectable system. As a result we obtained a biocompatible system displaying ease of application (low extrusion force), self-healing ability after disruption, adjustable drug release and antimicrobial properties.

Binding-regulated click ligation for selective detection of proteins

Herein, a binding-regulated click ligation (BRCL) strategy for endowing selective detection of proteins is developed with the incorporation of small-molecule ligand and clickable DNA probes. The fundamental principle underlying the strategy is the regulating capability of specific protein-ligand binding against the ligation between clickable DNA probes, which could efficiently combine the detection of particular protein with enormous DNA-based sensing technologies. In this work, the feasibly of the BRCL strategy is first verified through agarose gel electrophoresis and electrochemical impedance spectroscopy measurements, and then confirmed by transferring it to a nanomaterial-assisted fluorescence assay. Significantly, the BRCL strategy-based assay is able to respond to target protein with desirable selectivity, attributing to the specific recognition between small-molecule ligand and its target. Further experiments validate the general applicability of the sensing method by tailoring the ligand toward different proteins (i.e., avidin and folate receptor), and demonstrate its usability in complex biological samples. To our knowledge, this work pioneers the practice of click chemistry in probing specific small-molecule ligand-protein binding, and therefore may pave a new way for selective detection of proteins.

A highly effective and versatile technology for the isolation of RNAs from grapevines and other woody perennials for use in virus diagnostics.

BackgroundIsolation of pure RNA from woody perennials, especially fruit crops such as grapevine rich in complex secondary metabolites, has remained very challenging. Lack of effective RNA isolation technology has resulted in difficulties in viral diagnosis and discovery as well as studies on many biological processes of these highly important woody plants. It is imperative to develop and refine methodologies with which large amounts of pure nucleic acids can be readily isolated from woody perennials.MethodsWe compared five commonly used RNA isolation kits in isolating total RNA from twelve species of woody perennials. We made modifications to select RNA isolation systems to simplify and improve their efficiency in RNA isolation. The yield and quality of isolated RNAs were assessed via gel electrophoresis and spectrophotometric measurement. We also performed RT-PCR and RT-qPCR to detect several major viruses from grapevines.ResultsTwo of the kits were shown to be the best in both the yield and quality of the isolated RNA from all twelve woody species. Using disposable extraction bags for tissue homogenization not only improved the yield without affecting quality, but also made the RNA isolation technology simpler, less costly, and suitable for adoption by many potential users with facility limitations. This system was successfully applied to a wide range of woody plants, including fruit crops, ornamentals and timber trees. Inclusion of polyvinylpyrrolidone in the extraction buffer drastically improved the performance of the system in isolating total RNA from old grapevine leaves collected later in the season. This modification made our system highly effective in isolating quality RNA from grapevine leaves throughout the entire growing season. We further demonstrated that the resulting nucleic acid preparations are suitable for detection of several major grapevine viruses with RNA or DNA genomes using PCR, RT-PCR and qPCR as well as for assays on plant microRNAs.ConclusionsThis improved RNA isolation system would have wide applications in viral diagnostics and discovery, studies on gene expression and regulation, transcriptomics, and small RNA biology in grapevines. We believe this system will also be useful in diverse applications pertaining to research on many other woody perennials and recalcitrant plant species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12985-015-0376-3) contains supplementary material, which is available to authorized users.

Adsorption of Cd(II) ions at the hydroxyapatite/electrolyte solution interface

The study of the Cd(II) ions adsorption at the hydroxyapatite/electrolyte solution interface and the changes of the electrical double layer (EDL) structure in this system are presented. The adsorption of Cd(II) ions was calculated from the loss of their concentration from the solution using the radioisotope method. The adsorption was studied in the range of the initial concentration from 0.000001 to 0.001mol/dm3 and as the function of pH. The results of measurements of Cd(II) ions adsorption kinetics on hydroxyapatite were fitted using the pseudo-first, pseudo-second, and multiexponential modes to check which model describes this process in the best way. In addition, the main properties of the EDL, i.e., surface charge density and zeta potential were determined by the potentiometeric titration and electrophoresis measurements, respectively. The adsorption of Cd(II) ions at hydroxyapatite contributed to the increase of the zeta potential and also to the change of the double electrical layer structure.