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A newborn is often covered in a creamy white, cheesy biofilm called vernix caseosa. During the last trimester of gestation, this biofilm covers the skin of the fetus and after delivery, it dries. The boy pictured is Tristan Le Dévédec, son of Robert Rissmann, PhD, on whose thesis this review article is partly based. Reproduced with the kind permission of the father.
a) Lipid analyses of a standard solution (STD), two vernix caseosa (VC) samples and one stratum corneum (SC) sample by HPTLC; b) quantitative analysis of the free lipid extracts for all vernix caseosa compounds; c) quantitative analysis of ceramides only. Results are shown as weight percentage ± standard deviation. SQ = squalane; SE = sterol esters; WE = wax esters; DIOL = dihydroxy WE; TG = triglycerides; CHOL = cholesterol; FFA = free fatty acid; Cer = ceramides (EOS-1, NS-2, NP-3, EOH-4, AS-5, AP-6, AH-7, NH-8, EOP-9); CSO4 = CHOL sulfate; reproduced with permission from Reference 15.
Water loss profiles of vernix caseosa, w/o emulsiona and o/w emulsionb films (applied at a rate of 3 mg/cm2) for 3 hr; note that the three films have different initial water contents (82.1%, 37.4% and 70.0%, respectively); reproduced with permission from Reference 25; later re-published in Reference 26.
Water loss profiles of vernix caseosa films applied at a rate of 2.5mg/cm2 as a function of relative humidity; reproduced with permission from Reference 25.
Equilibrium water sorption-desorption curves of a) native vernix caseosa (n = 4) and b) vernix corneocytes (n = 6), expressed as % w/w water in the tissue (mean ± SD) versus water activity; reproduced with permission from Reference 27.
Percent barrier recovery after tape stripping versus film permeability; reproduced with permission from Reference 33; later re-published in Reference 25.
Moisture accumulation was assessed under probe occlusion of the skin surface at a) 8 min, b) 60 min, and c) 120 min after topical application of barrier creams. At 1 hr after application, control and vernix-treated sites had significantly lower water accumulation; at 2 hr, petrolatum and petrolatum- and mineral oil-based ointment had a significantly higher rate of moisture accumulation relative to the control site. All results are presented as mean capacitance reactance units per second ± SEM, *p < 0.05; reproduced with permission from Reference 23.
Water release profile of vernix caseosa, typical emulsions and selected w/o high internal phase emulsion (HIPE) based on 100% initial water content; reproduced with permission from Reference 26.
a) Hyperbranched polyglycerol methacrylate microgels labeled with FITC-dextran and b) the coating lipids, labeled with Texas Red, surrounding the microgels as visualized by confocal laser scanning microscopy. Confocal laser scanning microscopy was performed with 488 nm and 543 nm excitation wavelengths for a) and b), respectively. Scale bar represents 25 μm; reproduced with permission from Reference 28.
Water release profiles of native VC and various biofilms obtained by monitoring the weight loss of the specimen in a desiccator over P2O5 at room temperature. Various parameters were changed in the formulations: the initial water content of the particles was either 50% or 80%. The particles were coated with lipids (dashed lines) or were kept uncoated (solid lines) prior to embedding in the synthetic biofilm lipid matrix. The particle/lipid ratio was either 2:1 or 5:1. Data is presented as mean (w/w) – S.D. (n = 3); reproduced with permission from Reference 28.