Equilibrium Water Sorption in Human Stratum Corneum

Kasting, Gerald B.; Barai, Namrata D.

doi:10.1002/jps.10420

Cited by 71 publications

(100 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The isotherm shapes illustrated in figure 4 correspond well with others found in earlier sorption studies [2,17,18] . From the figure we noted that our measurements showed very small, if any at all, amounts of hysteresis, being of a size comparable to the uncertainties between the different samples, and may therefore be due to the relatively large inter-individual spread with respect to skin sorption properties.…”

Section: Discussionsupporting

confidence: 77%

“…This corresponds to our findings of the time constants for absorption in figures 5 and 6 combined with the mass gains in figure 4 . The strongly bound water, potentially bound to polar functional groups of lipid bilayers until monolayer coverage was reached [17,23] , entered the SC very rapidly at low RH, and the increase in time constants with RH could be induced by less available sites to attach. Thereafter, as a new type of water was bound in the SC, the time constant de-creased, which is an expected behaviour since the diffusion coefficient of water in SC, inversely related to the absorption time constant, usually increases with concentration [15,16] .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Sorption Properties of the Human Stratum Corneum

Johnsen

Norlén²,

Martinsen³

et al. 2011

Skin Pharmacol Physiol

View full text Add to dashboard Cite

Water sorption is important for the overall structure and function of keratinized tissues such as the human epidermal stratum corneum (SC). In this study we report on a gravimetric method for studying sorption properties of human SC, both from heel and female breast skin. Changes in mass were measured as the relative humidity was altered in steps under controlled environmental conditions. The possibility of hysteresis is also discussed. Furthermore, we have found that the sorption time constants show triphasic behaviour during absorption, but not during desorption. This behaviour is connected to the 3 different types of water present in the SC. Water also enters the SC much more rapidly compared to its exit at relative humidities <50%. Finally, the amount of time between sample preparation and onset of measurement seems to have an effect on the absorption rate, but less on the total amount of water absorbed.

show abstract

Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Sorption Properties of the Human Stratum Corneum

Johnsen

Norlén²,

Martinsen³

et al. 2011

Skin Pharmacol Physiol

View full text Add to dashboard Cite

show abstract

“…According to the BET model, the monolayer is formed by the same mechanisms as the Langmuir type adsorption, the subsequent layers are condensation of the adsorbate molecules, and the layers beyond the first are assumed to have equal energies of adsorption, which is characteristic for a uniform surface [42]. In addition, the BET model considers only short-range interactions between adsorbate and adsorbent [43]. The adsorption phenomena presented here did not fit the model because the idealized nature of the BET model, significant adsorbate-adsorbate interactions and the nonuniform surface interactions are not expected.…”

Section: Discussionmentioning

confidence: 99%

Understanding the adsorption mechanism of chitosan onto poly(lactide-co-glycolide) particles

Guo

Gemeinhart

2008

European Journal of Pharmaceutics and Biopharmaceutics

112

View full text Add to dashboard Cite

Polyelectrolyte-coated nanoparticles or microparticles interact with bioactive molecules (peptides, proteins or nucleic acids) and have been proposed as delivery systems for these molecules. However, the mechanism of adsorption of polyelectrolyte onto particles remains unsolved. In this study, cationic poly(lactide-co-glycolide) (PLGA) nanoparticles were fabricated by adsorption of various concentrations of a biodegradable polysaccharide, chitosan (0-2.4 g/L), using oil-in-water emulsion and solvent evaporation techniques. The particle diameter, zeta-potential, and chitosan adsorption of chitosan coated PLGA nanoparticles confirmed the increase of polyelectrolyte adsorption. Five adsorption isotherm models (Langmuir, Freundlich, Halsey, Henderson and Smith) were applied to the experimental data in order to better understand the mechanism of adsorption. Both particle diameter and chitosan adsorption increased with chitosan concentration during adsorption. A good correlation was obtained between PLGA-chitosan nanoparticle size and adsorbed chitosan on the surface, suggesting the increased particle size was primarily due to the increased chitosan adsorption. The zeta-potential of chitosan-coated PLGA nanoparticles was positive and increased with chitosan adsorbed until a maximum value (+55 mV) was reached at approximately 0.4-0.6 g/L; PLGA nanoparticles had a negative zeta-potential (−20 mV) prior to chitosan adsorption. Chitosan adsorption on PLGA nanoparticles followed a multilayer adsorption behavior, although the Langmuir monolayer equation held at low concentrations of chitosan. The underlying reasons for adsorption of chitosan on PLGA nanoparticles were thought to be the cationic nature of chitosan, high surface energy and microporous non-uniform surface of PLGA nanoparticles.

show abstract

“…This can be explained from the known characteristics of adsorption isotherms for stratum corneum [16]. The moisture content of stratum corneum is a supra-linear function of ambient relative humidity.…”

Section: Resultsmentioning

confidence: 99%

Effect of Ambient Humidity on the Transmission of UV/Visible Light through Model Human Epidermis

Farley¹,

Kassu²,

Sadate³

et al. 2016

OJAppS

View full text Add to dashboard Cite

Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements through the samples at a UVA wavelength of 365 nm, and visible wavelengths of 460 nm, 500 nm, and 595 nm. Ambient air-humidity is varied between 20% and 100%. Results show that for high ambient humidity, near 100%, transmission of light through the epidermis is higher than at low ambient humidity, 60% or lower. These results are explained with a simple model of epidermis as a turbid medium and the effect of adsorbed water in reducing light-scattering by refractive-index-matching. Biological implications of increased light-transmission through epidermis at high ambient humidity are discussed. KeywordsModel Human Epidermis, Model Skin, Effect of Humidity, Transmission of Light, Optical Properties of Epidermis

show abstract

Equilibrium Water Sorption in Human Stratum Corneum

Cited by 71 publications

References 28 publications

Sorption Properties of the Human Stratum Corneum

Sorption Properties of the Human Stratum Corneum

Understanding the adsorption mechanism of chitosan onto poly(lactide-co-glycolide) particles

Effect of Ambient Humidity on the Transmission of UV/Visible Light through Model Human Epidermis

Contact Info

Product

Resources

About