Zeta-potential measurement

Bauerle and Seelig [395] studied the structural aspects of amlodipine (weak base, primary amine pKa 9.26 [162]) and nimodipine (nonionizable) binding to phospholipid bilayers, using NMR, microcalorimetry, and zeta-potential measurements. They were able to see evidence of interactions of amlodipine with the cis double bond in the acyl chains. They saw no clear evidence for (=P—O- 1 H N—) electrostatic interactions. 

Warwick, P., Hall, A., Pashley, V. and Bryan, N. (2001). Investigation of the permeability of humic molecules using zeta potential measurements, Chemo-sphere, 45, 303-307. 

The obtained STPP liposomes were characterized by size distribution analysis, P NMR spectroscopy (Fig. 3), and by zeta potential measurements (Fig. 4). The size of liposomes with 20 mol% incorporated STPP was determined to be 132 zb 59 nm, which did not change significantly upon storage at 4°C over several days. The P NMR spectrum of STPP liposomes shows two chemical shifts correlating to the phosphorus in the lipid s phosphate groups and to the positively charged phosphorus of STPP. No differences in both chemical shifts between the free compounds (i.e., free STPP and free... 

Kuzniatsova, T., Kim, Y., Shqau, K., Dutta, P.K., and Verweij, H. (2007) Zeta potential measurements of zeolite Y application in homogeneous deposition of particle coatings micropor. Mesopor. Mater., 103,102-107. 

Fig. 32 Schematic representation of the correlation of surface charge and growth of the aggregates for the various regions of the adsorption isotherm of SDS on alumina based on fluorescence data and zeta potential measurement...

Experiment 6.1 Zeta potential measurements at the silica/water interface... 

Ciani, L., Ristori, S., Salvati, A., Calamai, L., Martini, G. (2004) DOTAP/DOPE and DC-Chol/DOPE lipoplexes for gene delivery zeta potential measurements and electron spin resonance spectra. Biochim. Biophys. Acta., 1664(1), 70-79. 

One of the applications of zeta potential measurements is in the determination of surface charges of colloids such as proteins. We look into this briefly in Section 12.10 and derive the equation connecting the surface charge to the zeta potential under some simplifying assumptions. 

Surface polarity can also be independently evaluated by physical means. deMayo and coworkers have assigned surface polarity of silica gel particles by observing shifts in the absorption spectra of absorbed spiropyrans which are sensitive to solvent polarity . Darwent and coworkers have shown that kinetic salt effects follow surface charge on colloidal titanium dioxide and, with zeta potential measurements, that surface area and charge could be separately evaluated... 

Relation to Other Studies. Interaction of Ca++ with phosphatidyl choline (PC) mono- and bimolecular membranes has been investigated carefully by Hauser and Phillips (15) and McLaughlin (17). Using a variety of approaches such as AV, surface radioactivity, zeta potential measurements, and NMR studies, both groups of investigators concluded that Ca++ interacts with the phosphate residues of lecithin the extent of the interaction, however, is very small since it involves less than 5% of the phosphate residues (17). 

R.H. Yoon and J.L. Yorden, Zeta-potential measurements on microbubbles generated using various surfactants, J. Colloid Interface Sci. 113 (1986) 430-438. 

Lopes, M. A., Monteiro, E J., Santos, J. D., Serro, A. P, and Saramago, B., Hydrophobic-ity, surface tension, and zeta potential measurements of glass-reinforced hydroxyapatite composites. /. Biomed. Mater. Res. 45 (4), 370-375 (1999). 

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