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BMC Oral Health Nov 2019The aim of this study was to compare free fluoride concentration and total fluoride concentration in mouthwashes. (Comparative Study)
Comparative Study
BACKGROUND
The aim of this study was to compare free fluoride concentration and total fluoride concentration in mouthwashes.
METHODS
Fluorine-containing mouthwashes from various companies and manufacturers (Colgate Total Plax Classic Mint®, Colgate-Palmolive, New York, USA; Colgate Total Plax Gentle Mint®, Colgate-Palmolive, New York, USA; Colgate Total Plax Fresh Mint®, Colgate-Palmolive, New York, USA; Oral B Advantage®, Procter&Gamble, Cincinnati, USA; Reach Fresh Mint®, Johnson&Johnson, New Brunswick, USA; Foramen®, Laboratorios Foramen, Guarnizo, Spain; Lacalut Sensitive®, Dr. THEISS, Homburg, Germany; Sensodyne®, GlaxoSmithKline, London, UK; Vesna F®, Vita, Saint Petersburg, Russia; Lacalut Fresh®, Dr. THEISS, Homburg, Germany) were selected as study objects. Fluoride measurements were carried out using the fluoride selective electrode.
RESULTS
Free fluoride:total fluoride ratio was more than 80% for six samples (Colgate Total Plax Gentle Mint® - 88%, Colgate Total Plax Fresh Mint® - 99%, Oral B Advantage® - 92%, Reach Fresh Mint® - 92 and 89% for the mouthwash of another batch, Lacalut Sensitive® - 94%) and less than 63% for three samples (Colgate Total Plax Classic Mint® - 56%, Foramen® - 62%, Vesna F® - 61%). Two samples had more than 70% and less than 80% of unbound fluoride, respectively (Sensodyne® - 77%, another batch of Oral B Advantage® mouthwash - 74%). Rinse containing sodium monofluorophosphate (NaPOF) (Vesna F®) had more than 50% of free fluoride, while the rinse containing amine fluoride (AmF) (Lacalut Sensitive®) had 94%. The difference in the free fluoride:total fluoride ratio can be explained by binding of fluoride ions by components contained in mouthwashes, such as coloring agents and polymeric compounds. The lowest concentration of free fluoride ions (0.000093 mol/L) was observed for aluminum fluoride (AlF) rinse (Lacalut Fresh®), while the total fluoride amount was not determined due to possible generation of strong fluoride complexes. This implies that fluoride ions will not be uptaken by tooth tissue and may even be washed away from it, compromising the efficacy of mouthwashes.
CONCLUSIONS
The differences in free fluoride: total fluoride ratio between analyzed mouthwashes reveal a need to develop a method for evaluation of free fluorides in mouthwashes for proper updating of national and international guidelines.
Topics: Fluorides; Humans; Ion-Selective Electrodes; Mouthwashes; Potentiometry
PubMed: 31747894
DOI: 10.1186/s12903-019-0908-0 -
Sensors (Basel, Switzerland) Nov 2021Potentiometric pH measurements have long been used for the bioanalysis of biofluids, tissues, and cells. A glass pH electrode and ion-sensitive field-effect transistor... (Review)
Review
Potentiometric pH measurements have long been used for the bioanalysis of biofluids, tissues, and cells. A glass pH electrode and ion-sensitive field-effect transistor (ISFET) can measure the time course of pH changes in a microenvironment as a result of physiological and biological activities. However, the signal interpretation of passive pH sensing is difficult because many biological activities influence the spatiotemporal distribution of pH in the microenvironment. Moreover, time course measurement suffers from stability because of gradual drifts in signaling. To address these issues, an active method of pH sensing was developed for the analysis of the cell barrier in vitro. The microenvironmental pH is temporarily perturbed by introducing a low concentration of weak acid (NH) or base (CHCOO) to cells cultured on the gate insulator of ISFET using a superfusion system. Considering the pH perturbation originates from the semi-permeability of lipid bilayer plasma membranes, induced proton dynamics are used for analyzing the biomembrane barriers against ions and hydrated species following interaction with exogenous reagents. The unique feature of the method is the sensitivity to the formation of transmembrane pores as small as a proton (H), enabling the analysis of cell-nanomaterial interactions at the molecular level. The new modality of cell analysis using ISFET is expected to be applied to nanomedicine, drug screening, and tissue engineering.
Topics: Biosensing Techniques; Electrodes; Hydrogen-Ion Concentration; Ions; Potentiometry; Transistors, Electronic
PubMed: 34770587
DOI: 10.3390/s21217277 -
Frontiers in Chemistry 2022In the present study, the acid-base behavior of compounds constituting the headgroups of biomembranes, O-phosphorylethanolamine (), and O-phosphorylcholine () was...
In the present study, the acid-base behavior of compounds constituting the headgroups of biomembranes, O-phosphorylethanolamine (), and O-phosphorylcholine () was investigated by potentiometric titrations in NaCl aqueous solutions at different temperatures (15 ≤ /°C ≤ 37) and ionic strength (0.15 ≤ /mol L ≤ 1) values. The complexation properties and the speciation of these ligands with Mg were defined under different temperatures (15 ≤ /°C ≤ 37) and = 0.15 mol L. The results evidenced the formation of three species for , namely, MLH, MLH, and ML and two species for , namely, MLH and ML. H-NMR titrations were performed on solutions containing ligand and metal-ligand solutions at = 25°C and = 0.15 mol L. The estimated values of ligand protonation and complex formation constants and the speciation model are in accordance with the potentiometric data. The enthalpy changes were also determined at = 25°C and = 0.15 mol L by the dependence of formation constants on the temperature, confirming the electrostatic nature of the interactions. Matrix-assisted laser desorption mass spectrometry (MALDI-MS) was applied for the characterization of Mg-L systems (L = or ). MS/MS spectra of free ligands and of Mg-L species were obtained. The observed fragmentation patterns of both Mg-L systems allowed elucidating the interaction mechanism that occurs the phosphate group generating a four-membered cycle.
PubMed: 35419347
DOI: 10.3389/fchem.2022.864648 -
Journal of Biological Inorganic... Sep 2023A series of novel Ga(III)-pyridine carboxylates ([Ga(Pic)]·HO (GaPic; HPic = picolinic acid), HO[Ga(Dpic)]·HO (GaDpic; HDpic = dipicolinic acid),...
A series of novel Ga(III)-pyridine carboxylates ([Ga(Pic)]·HO (GaPic; HPic = picolinic acid), HO[Ga(Dpic)]·HO (GaDpic; HDpic = dipicolinic acid), [Ga(Chel)(HO)(OH)]·4HO (GaChel; HChel = chelidamic acid) and [Ga(Cldpic)(HO)(OH)] (GaCldpic; HCldpic = 4-chlorodipicolinic acid)) have been synthesized by simple one-step procedure. Vibrational spectroscopy (mid-IR), elemental analysis, thermogravimetric analysis and X-ray diffraction confirmed complexes molecular structure, inter and intramolecular interactions and their influence to spectral and thermal properties. Moreover, complex species speciation was described in Ga(III)-HPic and Ga(III)-HDpic systems by potentiometry and H NMR spectroscopy and mononuclear complex species were determined; [Ga(Pic)] (logβ = 16.23(6)), [Ga(Pic)] (logβ = 20.86(2)), [Ga(Dpic)] (logβ = 15.42(9)) and [Ga(Dpic)(OH)] (logβ = 11.08(4)). To confirm the complexes stability in 1% DMSO (primary solvent for biological testing), timescale H NMR spectra were measured (immediately after dissolution up to 96 h). Antimicrobial activity evaluated by IC (0.05 mM) is significant for GaDpic and GaCldpic against difficult to treat and multi-resistant P. aeruginosa. On the other hand, the GaPic complex is most effective against Jurkat, MDA-MB-231 and A2058 cancer cell lines and significantly also decreases the HepG2 cancer cells viability at 75 and 100 μM concentrations in a relatively short time (up to 48 h). In addition, fluorescence measurements have been used to elucidate bovine serum albumin binding activity between ligands, Ga(III) complexes and bovine serum albumin.
Topics: Humans; Serum Albumin, Bovine; Pyridines; Neoplasms; Molecular Structure; Cell Line; Coordination Complexes; Ligands
PubMed: 37498326
DOI: 10.1007/s00775-023-02012-2 -
Membranes Nov 2023Recently, there has been rapid development of electrochemical sensors, and there have been numerous reports in the literature that describe new constructions with... (Review)
Review
Recently, there has been rapid development of electrochemical sensors, and there have been numerous reports in the literature that describe new constructions with improved performance parameters. Undoubtedly, this is due to the fact that those sensors are characterized by very good analytical parameters, and at the same time, they are cheap and easy to use, which distinguishes them from other analytical tools. One of the trends observed in their development is the search for new functional materials. This review focuses on potentiometric sensors designed with the use of various metal oxides. Metal oxides, because of their remarkable properties including high electrical capacity and mixed ion-electron conductivity, have found applications as both sensing layers (e.g., of screen-printing pH sensors) or solid-contact layers and paste components in solid-contact and paste-ion-selective electrodes. All the mentioned applications of metal oxides are described in the scope of the paper. This paper presents a survey on the use of metal oxides in the field of the potentiometry method as both single-component layers and as a component of hybrid materials. Metal oxides are allowed to obtain potentiometric sensors of all-solid-state construction characterized by remarkable analytical parameters. These new types of sensors exhibit properties that are competitive with those of the commonly used conventional electrodes. Different construction solutions and various metal oxides were compared in the scope of this review based on their analytical parameters.
PubMed: 37999362
DOI: 10.3390/membranes13110876 -
Molecules (Basel, Switzerland) Jan 2023Sweat contains a broad range of important biomarkers, which may be beneficial for acquiring non-invasive biochemical information on human health status. Therefore,... (Review)
Review
Sweat contains a broad range of important biomarkers, which may be beneficial for acquiring non-invasive biochemical information on human health status. Therefore, highly selective and sensitive electrochemical nanosensors for the non-invasive detection of sweat metabolites have turned into a flourishing contender in the frontier of disease diagnosis. A large surface area, excellent electrocatalytic behavior and conductive properties make nanomaterials promising sensor materials for target-specific detection. Carbon-based nanomaterials (e.g., CNT, carbon quantum dots, and graphene), noble metals (e.g., Au and Pt), and metal oxide nanomaterials (e.g., ZnO, MnO, and NiO) are widely used for modifying the working electrodes of electrochemical sensors, which may then be further functionalized with requisite enzymes for targeted detection. In the present review, recent developments (2018-2022) of electrochemical nanosensors by both enzymatic as well as non-enzymatic sensors for the effectual detection of sweat metabolites (e.g., glucose, ascorbic acid, lactate, urea/uric acid, ethanol and drug metabolites) have been comprehensively reviewed. Along with this, electrochemical sensing principles, including potentiometry, amperometry, CV, DPV, SWV and EIS have been briefly presented in the present review for a conceptual understanding of the sensing mechanisms. The detection thresholds (in the range of mM-nM), sensitivities, linear dynamic ranges and sensing modalities have also been properly addressed for a systematic understanding of the judicious design of more effective sensors. One step ahead, in the present review, current trends of flexible wearable electrochemical sensors in the form of eyeglasses, tattoos, gloves, patches, headbands, wrist bands, etc., have also been briefly summarized, which are beneficial for on-body in situ measurement of the targeted sweat metabolites. On-body monitoring of sweat metabolites via wireless data transmission has also been addressed. Finally, the gaps in the ongoing research endeavors, unmet challenges, outlooks and future prospects have also been discussed for the development of advanced non-invasive self-health-care-monitoring devices in the near future.
Topics: Humans; Wearable Electronic Devices; Biosensing Techniques; Sweat; Manganese Compounds; Oxides; Graphite
PubMed: 36770925
DOI: 10.3390/molecules28031259 -
Sensors and Actuators. B, Chemical Feb 2023Biofilms are complex three-dimensional microbial communities that adhere to a variety of surfaces and interact with their surroundings. Because of the dynamic nature of...
Biofilms are complex three-dimensional microbial communities that adhere to a variety of surfaces and interact with their surroundings. Because of the dynamic nature of biofilm formation, establishing a uniform technique for quantifying and monitoring biofilm volume, shape, and features in real-time is challenging. Herein, we describe a noninvasive electrochemical impedance approach for real-time monitoring of dental plaque-derived multispecies biofilm growth on a range of substrates. A working equation relating electrochemical impedance to live biofilm volume has been developed that is applicable to all three surfaces examined, including glass, dental filling resin, and Ca-releasing resin composites. Impedance changes of 2.5, 35, 50, and 65% correlated to biofilm volumes of 0.10 ± 0.01, 16.9 ± 2.2, 29.7 ± 2.3, and 38.6 ± 2.8 μm/μm, respectively. We discovered that glass, dental filling resin, and Ca-releasing dental composites required approximately 3.5, 4.5, and 6 days, respectively, to achieve a 50% change in impedance. The local pH change at the biofilm-substrate interfaces also monitored with potentiometry pH microsensor, and pH change varied according to biofilm volume. This impedance-based technique can be a useful analytical method for monitoring the growth of biofilms on a variety of substrates in real-time. Therefore, this technique may be beneficial for examining antibacterial properties of novel biomaterials.
PubMed: 36688105
DOI: 10.1016/j.snb.2022.133034 -
Sensors (Basel, Switzerland) Nov 2021The next future strategies for improved occupational safety and health management could largely benefit from wearable and Internet of Things technologies, enabling the...
The next future strategies for improved occupational safety and health management could largely benefit from wearable and Internet of Things technologies, enabling the real-time monitoring of health-related and environmental information to the wearer, to emergency responders, and to inspectors. The aim of this study is the development of a wearable gas sensor for the detection of NH at room temperature based on the organic semiconductor poly(3,4-ethylenedioxythiophene) (PEDOT), electrochemically deposited iridium oxide particles, and a hydrogel film. The hydrogel composition was finely optimised to obtain self-healing properties, as well as the desired porosity, adhesion to the substrate, and stability in humidity variations. Its chemical structure and morphology were characterised by infrared spectroscopy and scanning electron microscopy, respectively, and were found to play a key role in the transduction process and in the achievement of a reversible and selective response. The sensing properties rely on a potentiometric-like mechanism that significantly differs from most of the state-of-the-art NH gas sensors and provides superior robustness to the final device. Thanks to the reliability of the analytical response, the simple two-terminal configuration and the low power consumption, the PEDOT:PSS/IrOx Ps/hydrogel sensor was realised on a flexible plastic foil and successfully tested in a wearable configuration with wireless connectivity to a smartphone. The wearable sensor showed stability to mechanical deformations and good analytical performances, with a sensitivity of 60 ± 8 μA decade in a wide concentration range (17-7899 ppm), which includes the safety limits set by law for NH exposure.
Topics: Ammonia; Porosity; Potentiometry; Reproducibility of Results; Wearable Electronic Devices
PubMed: 34883908
DOI: 10.3390/s21237905 -
Sensors (Basel, Switzerland) Jun 2022A light-addressable potentiometric sensor (LAPS) is a chemical sensor that is based on the field effect in an electrolyte-insulator-semiconductor structure. It requires...
A light-addressable potentiometric sensor (LAPS) is a chemical sensor that is based on the field effect in an electrolyte-insulator-semiconductor structure. It requires modulated illumination for generating an AC photocurrent signal that responds to the activity of target ions on the sensor surface. Although high-power illumination generates a large signal, which is advantageous in terms of the signal-to-noise ratio, excess light power can also be harmful to the sample and the measurement. In this study, we tested different waveforms of modulated illuminations to find an efficient illumination for a LAPS that can enlarge the signal as much as possible for the same input light power. The results showed that a square wave with a low duty ratio was more efficient than a sine wave by a factor of about two.
Topics: Biosensing Techniques; Light; Lighting; Potentiometry; Semiconductors
PubMed: 35746324
DOI: 10.3390/s22124541 -
International Journal of Molecular... Sep 2021The angiogenin protein (ANG) is one of the most potent endogenous angiogenic factors. In this work we characterized by means of potentiometric, spectroscopic and...
The angiogenin protein (ANG) is one of the most potent endogenous angiogenic factors. In this work we characterized by means of potentiometric, spectroscopic and voltammetric techniques, the copper complex species formed with peptide fragments derived from the N-terminal domain of the protein, encompassing the sequence 1-17 and having free amino, Ang1-17, or acetylated N-terminus group, AcAng1-17, so to explore the role of amino group in metal binding and cellular copper uptake. The obtained data show that amino group is the main copper anchoring site for Ang1-17. The affinity constant values, metal coordination geometry and complexes redox-potentials strongly depend, for both peptides, on the number of copper equivalents added. Confocal laser scanning microscope analysis on neuroblastoma cells showed that in the presence of one equivalent of copper ion, the free amino Ang1-17 increases cellular copper uptake while the acetylated AcAng1-17 strongly decreases the intracellular metal level. The activity of peptides was also compared to that of the protein normally present in the plasma (wtANG) as well as to the recombinant form (rANG) most commonly used in literature experiments. The two protein isoforms bind copper ions but with a different coordination environment. Confocal laser scanning microscope data showed that the wtANG induces a strong increase in intracellular copper compared to control while the rANG decreases the copper signal inside cells. These data demonstrate the relevance of copper complexes' geometry to modulate peptides' activity and show that wtANG, normally present in the plasma, can affect cellular copper uptake.
Topics: Cell Line, Tumor; Copper; Electron Spin Resonance Spectroscopy; Escherichia coli; Humans; Ribonuclease, Pancreatic
PubMed: 34502439
DOI: 10.3390/ijms22179530