Zeta Potentials of Human Enamel and Hydroxyapatite as Measured by the Coulter® DELSA 440

1997 ◽  
Vol 11 (4) ◽  
pp. 560-565 ◽  
Author(s):  
A. Young ◽  
G. Smistad ◽  
J. Karlsen ◽  
G. Rölla ◽  
M. Rykke
Keyword(s):  
Zeta Potential ◽  
Electric Field ◽  
Doppler Shift ◽  
Parotid Saliva ◽  
Physiological Importance ◽  
Zeta Potentials ◽  
Human Enamel ◽  
Whole Saliva ◽  
Buffer Content ◽  
Study Support

The zeta potential of human enamel is of physiological importance for interactions between enamel surfaces and the surrounding aqueous medium of saliva. The zeta potentials of both enamel and hydroxyapatite (HA) have been examined previously by various techniques. In this study, we examined the zeta potential of human enamel and HA using the Coulter® DELSA 440, which, by a laser, makes independent Doppler shift measurements of moving particles in an electric field at 4 different angles, providing advantages over previous techniques. The enamel and HA particles were suspended directly in different phosphate buffers, or first incubated for 2 hrs in parotid (PS) or whole saliva (HWS) and then suspended in the same buffers. The enamel and HA particles exhibited an overall net surface potential of -15 to -30 mV, depending on the buffer content. Incubation in PS and HWS gave less negative potentials of -8 to -14 mV. In our previous studies, the salivary micelle-like structures (SMSs), seen in TEM of parotid saliva, were observed to have a zeta potential of -9 mV (Rykke et al., 1996). The zeta potential determinations in this study support the concept of an adsorption of mostly SMSs to the enamel surfaces, with a change of the zeta potential of the enamel and HA toward that of the SMSs.

scholarly journals Liquid Mixing Based on Electrokinetic Vortices Generated in a T-Type Microchannel

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 130
Author(s):  
Chengfa Wang
Keyword(s):  
Zeta Potential ◽  
Electric Field ◽  
Microfluidic Devices ◽  
Outlet Channel ◽  
Mixing Performance ◽  
Zeta Potentials ◽  
Potential Applications ◽  
Dc Electric Field ◽  
Good Potential ◽  
Downstream Section

This article proposes a micromixer based on the vortices generated in a T-type microchannel with nonuniform but same polarity zeta potentials under a direct current (DC) electric field. The downstream section (modified section) of the outlet channel was designed with a smaller zeta potential than others (unmodified section). When a DC electric field is applied in the microchannel, the electrokinetic vortices will form under certain conditions and hence mix the solution. The numerical results show that the mixing performance is better when the channel width and the zeta potential ratio of the modified section to the unmodified section are smaller. Besides, the electrokinetic vortices formed in the microchannel are stronger under a larger length ratio of the modified section to the unmodified section of the outlet channel, and correspondingly, the mixing performance is better. The micromixer presented in the paper is quite simple in structure and has good potential applications in microfluidic devices.

scholarly journals Towards bio-inspired artificial muscle: a mechanism based on electro-osmotic flow simulated using dissipative particle dynamics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramin Zakeri
Keyword(s):  
Zeta Potential ◽  
Electric Field ◽  
Dissipative Particle Dynamics ◽  
Artificial Muscle ◽  
Particle Dynamics ◽  
Polymer Membrane ◽  
Channel Width ◽  
Micro Channel ◽  
Osmotic Flow ◽  
Electro Osmotic Flow

AbstractOne of the unresolved issues in physiology is how exactly myosin moves in a filament as the smallest responsible organ for contracting of a natural muscle. In this research, inspired by nature, a model is presented consisting of DPD (dissipative particle dynamics) particles driven by electro-osmotic flow (EOF) in micro channel that a thin movable impermeable polymer membrane has been attached across channel width, thus momentum of fluid can directly transfer to myosin stem. At the first, by validation of electro-osmotic flow in micro channel in different conditions with accuracy of less than 10 percentage error compared to analytical results, the DPD results have been developed to displacement of an impermeable polymer membrane in EOF. It has been shown that by the presence of electric field of 250 V/m and Zeta potential − 25 mV and the dimensionless ratio of the channel width to the thickness of the electric double layer or kH = 8, about 15% displacement in 8 s time will be obtained compared to channel width. The influential parameters on the displacement of the polymer membrane from DPD particles in EOF such as changes in electric field, ion concentration, zeta potential effect, polymer material and the amount of membrane elasticity have been investigated which in each cases, the radius of gyration and auto correlation velocity of different polymer membrane cases have been compared together. This simulation method in addition of probably helping understand natural myosin displacement mechanism, can be extended to design the contraction of an artificial muscle tissue close to nature.

scholarly journals Manipulation of surface charges of oil droplets and carbonate rocks to improve oil recovery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Hou ◽  
Ming Han ◽  
Jinxun Wang
Keyword(s):  
Zeta Potential ◽  
Oil Recovery ◽  
Carbonate Rocks ◽  
Zwitterionic Surfactant ◽  
Surface Charges ◽  
Oil Droplets ◽  
Zeta Potentials ◽  
Potential Value ◽  
Oil Water ◽  
Incremental Oil Recovery

AbstractThis work investigates the effect of the surface charges of oil droplets and carbonate rocks in brine and in surfactant solutions on oil production. The influences of the cations in brine and the surfactant types on the zeta-potentials of both oil droplets and carbonate rock particles are studied. It is found that the addition of anionic and cationic surfactants in brine result in both negative or positive zeta-potentials of rock particles and oil droplets respectively, while the zwitterionic surfactant induces a positive charge on rock particles and a negative charge on oil droplets. Micromodels with a CaCO3 nanocrystal layer coated on the flow channels were used in the oil displacement tests. The results show that when the oil-water interfacial tension (IFT) was at 10−1 mN/m, the injection of an anionic surfactant (SDS-R1) solution achieved 21.0% incremental oil recovery, higher than the 12.6% increment by the injection of a zwitterionic surfactant (SB-A2) solution. When the IFT was lowered to 10−3 mM/m, the injection of anionic/non-ionic surfactant SMAN-l1 solution with higher absolute zeta potential value (ζoil + ζrock) of 34 mV has achieved higher incremental oil recovery (39.4%) than the application of an anionic/cationic surfactant SMAC-l1 solution with a lower absolute zeta-potential value of 22 mV (30.6%). This indicates that the same charge of rocks and oil droplets improves the transportation of charged oil/water emulsion in the porous media. This work reveals that the surface charge in surfactant flooding plays an important role in addition to the oil/water interfacial tension reduction and the rock wettability alteration.

Formation of Hydroxycarbonate Apatite Layer on Poly(Lactic Acid) Composites in Simulated Body Fluid

2005 ◽  
Vol 284-286 ◽  
pp. 489-492 ◽  
Author(s):  
Hirotaka Maeda ◽  
Toshihiro Kasuga ◽  
Masayuki Nogami
Keyword(s):  
Lactic Acid ◽  
Simulated Body Fluid ◽  
Zeta Potential ◽  
Calcium Chloride ◽  
Composite Membrane ◽  
Body Fluid ◽  
Poly Lactic Acid ◽  
Zeta Potentials ◽  
Carbonate Ion ◽  
Ft Ir

Hydroxycarbonate apatite (HCA), which formed on a poly(lactic acid) (PLA) composite membrane containing vaterite or calcium chloride after soaking in simulated body fluid, was examined to clarify the importance of the ceramic phases in the composites. FT-IR spectra showed that the ratio of CO3/PO4 in the infrared adsorption bands of HCA formed on the PLA composite containing vaterite was much larger than that of HCA formed on the PLA composite containing calcium chloride. Substitution of carbonate ion in hydroxyapatite is believed to be strongly influenced by ceramic phases in the composites. The zeta potentials of HCA formed on the PLA composite containing vaterite or calcium chloride was -6 mV or -17 mV, respectively. The zeta potential may be influenced by the amount of carbonate ion in hydroxyapatite.

Dispersion of Barium Ferrite Particles for Slip Casting in Magnetic Field

2006 ◽  
Vol 317-318 ◽  
pp. 143-146 ◽  
Author(s):  
Jing Long Li ◽  
Saburo Sano ◽  
Akihiro Tsuzuki ◽  
Akihiro Gotou ◽  
Yasuo Shibasaki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Polyethylene Glycol ◽  
Zeta Potential ◽  
Barium Ferrite ◽  
Slip Casting ◽  
Steric Repulsion ◽  
Ph Titration ◽  
Zeta Potentials ◽  
Water Based ◽  
Slip Cast

Water-based slurries containing barium ferrite particles have been prepared and slip cast in magnetic field. This paper presents the characteristics of the suspensions in terms of Iso-Electric Points (IEP) and zeta potential that were evaluated through pH titration and polymer adsorption. Both enlarging the specific surface area of particles by planetary milling and adjusting the pH to low value apparently increase the zeta potentials. Stable slurry was obtained by adding polyethylene glycol (PEG) into the suspension at pH = 2 ~ 3.5. The steric repulsion plays key role in dispersion and PEG films served as insulative layers and mechanically kept particles from contact each other. The barium ferrite particles formed many stacks of plates during slip casting, which either aligned randomly without magnetic field applied or regularly aligned to form textured structure when magnetic field was applied.

scholarly journals A Surface Complexation Model of Alkaline-SmartWater Electrokinetic Interactions in Carbonates

2020 ◽  
Vol 146 ◽  
pp. 02003
Author(s):  
Moataz Abu-Al-Saud ◽  
Amani Al-Ghamdi ◽  
Subhash Ayirala ◽  
Mohammed Al-Otaibi
Keyword(s):  
Experimental Data ◽  
Zeta Potential ◽  
Crude Oil ◽  
Oil Recovery ◽  
Surface Complexation ◽  
Surface Complexation Model ◽  
Zeta Potentials ◽  
Smart Water ◽  
Injection Water ◽  
Carbonate Formations

Understanding the effect of injection water chemistry is becoming crucial, as it has been recently shown to have a major impact on oil recovery processes in carbonate formations. Various studies have concluded that surface charge alteration is the primary mechanism behind the observed change of wettability towards water-wet due to SmartWater injection in carbonates. Therefore, understanding the surface charges at brine/calcite and brine/crude oil interfaces becomes essential to optimize the injection water compositions for enhanced oil recovery (EOR) in carbonate formations. In this work, the physicochemical interactions of different brine recipes with and without alkali in carbonates are evaluated using Surface Complexation Model (SCM). First, the zeta-potential of brine/calcite and brine/crude oil interfaces are determined for Smart Water, NaCl, and Na2SO4 brines at fixed salinity. The high salinity seawater is also included to provide the baseline for comparison. Then, two types of Alkali (NaOH and Na2CO3) are added at 0.1 wt% concentration to the different brine recipes to verify their effects on the computed zeta-potential values in the SCM framework. The SCM results are compared with experimental data of zeta-potentials obtained with calcite in brine and crude oil in brine suspensions using the same brines and the two alkali concentrations. The SCM results follow the same trends observed in experimental data to reasonably match the zeta-potential values at the calcite/brine interface. Generally, the addition of alkaline drives the zeta-potentials towards more negative values. This trend towards negative zeta-potential is confirmed for the Smart Water recipe with the impact being more pronounced for Na2CO3 due to the presence of divalent anion carbonate (CO3)-2. Some discrepancy in the zeta-potential magnitude between the SCM results and experiments is observed at the brine/crude oil interface with the addition of alkali. This discrepancy can be attributed to neglecting the reaction of carboxylic acid groups in the crude oil with strong alkali as NaOH and Na2CO3. The novelty of this work is that it clearly validates the SCM results with experimental zeta-potential data to determine the physicochemical interaction of alkaline chemicals with SmartWater in carbonates. These modeling results provide new insights on defining optimal SmartWater compositions to synergize with alkaline chemicals to further improve oil recovery in carbonate reservoirs.

Apparatus for determination of zeta potentials from streaming potentials

1963 ◽  
Vol 18 (6) ◽  
pp. 1263-1264 ◽  
Author(s):  
R. E. Beck ◽  
V. Mirkovitch ◽  
P. G. Andrus ◽  
R. I. Leininger
Keyword(s):  
Zeta Potential ◽  
Streaming Potential ◽  
Salt Solutions ◽  
Streaming Potentials ◽  
Zeta Potentials ◽  
Quartz Capillary ◽  
Flow Through

A system was developed to measure the streaming potential generated between the ends of a capillary by the flow of a fluid through the capillary. Zeta potential can be calculated from the streaming potential. Adequate sensitivity and reproducibility were achieved by making special electrodes: silver wires plated in KCl solution and embedded in agar, careful electrical shielding, and provision for reversal of flow through the capillary to minimize electrode errors. The apparatus was developed to measure streaming potentials generated by either RingerS's solution or blood in contact with capillaries made of different materials such as quartz, polyethylene, etc. An example of a determination using a quartz capillary is presented. interfaces; blood; salt solutions; glass; quartz Submitted on February 25, 1963

Chaotic Electroosmotic Flow

2002 ◽  
Author(s):  
Shizhi Qian ◽  
Haim H. Bau
Keyword(s):  
Zeta Potential ◽  
Electroosmotic Flow ◽  
Analytic Solution ◽  
Microfluidic Devices ◽  
Chaotic Advection ◽  
Uniform Electric Field ◽  
Periodic Modulation ◽  
Chaotic Flows ◽  
Zeta Potentials ◽  
Series Convergence

Two dimensional, time-independent and time-dependent electroosmotic flows driven by a uniform electric field in rectangular cavities with uniform and non-uniform zeta potential distributions along the cavities’ walls are investigated theoretically. The time-independent flow fields are computed with the aid of Fourier series. The series’ convergence is accelerated so that highly accurate solutions are obtained with just a few (<10) terms in the series. The analytic solution is used to compute flow patterns for various distributions of the zeta potential along the cavities’ boundaries. It is demonstrated that by time-wise periodic modulation of the zeta potentials, one can induce chaotic advection in the cavities. Such chaotic flows may be used to stir and mix fluids in microfluidic devices.

Direct Ink Printing of Cavities in DPC Ceramic Substrates With Kaolin Pastes for Hermetic Packaging

2019 ◽  
Author(s):  
Qinglei Sun ◽  
Yang Peng ◽  
Hao Cheng ◽  
Yun Mou ◽  
Mingxiang Chen
Keyword(s):  
Zeta Potential ◽  
Viscoelastic Properties ◽  
Three Dimensional ◽  
Kaolin Clay ◽  
Ceramic Substrates ◽  
Light Emitting ◽  
Zeta Potentials ◽  
Hermetic Packaging ◽  
Content Variation ◽  
Ultraviolet Light Emitting Diodes

Abstract Fabrication of three-dimensional cavities containing kaolin pastes to be used as direct plated copper (3DPC) substrates ceramics is a very important advancement for electronic packaging of hermetic and ultraviolet light emitting diodes. This work demonstrates usage of pastes consisting of 32–40 wt% of kaolin clay and polyacrylic acid for direct ink printing (DIP) of 3DPC. Rheological and zeta potential tests were performed to determine printability and stability, respectively, of these kaolin pastes. Kaolin content variation had minimum effect on absolute values of the zeta potentials. All pastes had enough stability with the absolute values larger than 30 mV. 40 wt% kaolin solids mass paste was the optimal for DIP due to its excellent shear thinning and viscoelastic properties. Cured 40 wt% kaolin solids mass paste had superior compressive, flexural and bonding strengths. DIP using pastes containing 40 wt% of kaolin is promising for electronic chip integrated hermetic packaging.

scholarly journals PHYSICOCHEMICAL CHARACTERIZATION OF PROPRANOLOL-LOADED CHITOSAN NANOPARTICLES FOR A BUCCAL DRUG DELIVERY SYSTEM

2020 ◽  
pp. 243-247
Author(s):  
SIRIPORN KITTIWISUT ◽  
PAKORN KRAISIT
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Zeta Potential ◽  
Drug Delivery System ◽  
Delivery System ◽  
Chitosan Nanoparticles ◽  
Particle Sizes ◽  
Zeta Potentials ◽  
Ph Values ◽  
Buccal Drug Delivery

Objective: This study aimed to characterize the physicochemical properties, including pH, zeta potential, and particle size of propranolol-loaded nanoparticles that were incorporated into a buccal transmucosal drug-delivery system. Methods: An ionotropic gelation technique was used to formulate propranolol-loaded chitosan nanoparticles. Chitosan used as the nanoparticle base, using tripolyphosphate (TPP) as a cross-linking agent. The effects on nanoparticle physical properties, including pH, zeta potential, and particle size were examined when various chitosan [0.150-0.300 % (w/v)] and propranolol contents (0-40 mg) were used during the preparation. The effects of using chitosan solutions with different pH values on nanoparticle properties were also determined. Results: The pH values of all nanoparticles ranged between 4.14–4.55. The zeta potentials of the prepared nanoparticles ranged between 22.6–52.6 mV, with positive charges. The nanoparticle sizes ranged from 107–140 nm, which are within the range of suitable particle sizes for transmucosal preparations. Conclusion: The pH values, zeta potentials, and particle sizes of the nanoparticle formulations were influenced by the concentrations of chitosan and propranolol and by the pH of the initial chitosan solution. The relationships between nanoparticle properties and all factors primarily depended on the ionic charges of the components, especially chitosan. Our study provides beneficial physicochemical knowledge for the further development of chitosan-based nanoparticles containing propranolol for buccal drug delivery systems.

Sign in / Sign up

Export Citation Format

Share Document