Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK.
Int J Cosmet Sci. 2012 Jun;34(3):257-62. doi: 10.1111/j.1468-2494.2012.00711.x. Epub 2012 Mar 14.
The surface energy of the human nail plate is expected to influence the adhesion of microorganisms (and subsequent colonization and infections) as well as that of medicines (and subsequent drug permeation) and of cosmetics. The aim of the study was therefore to measure the surface energy of nail plates in vivo. The surface energy of healthy human fingernails (untreated, hydrated and abraded) and of hoof membranes (often used as a model for the nail plate) was estimated from contact angle measurements of liquids (water, formamide, diiodomethane and glycerol) on the nail plate and subsequent computation using the Lifshitz-van der Waals/acid-base (LW-AB) approach. The surface energy of untreated fingernail plates was found to be 34 mJ m(-2) . Most of this total energy was from the apolar Lifshitz-van der Waals component. When the polar component of the surface energy was analysed, the electron donor component was considerably larger than the electron acceptor one. Hydrating the nail plate had no significant influence on the surface energy. In contrast, abrasion caused a small, but statistically significant increase in the apolar surface energy component. The surface energy of bovine hoof membrane was similar to that of the fingernail plate. We conclude that the human fingernail plate is a low-energy surface and that bovine hoof membranes may be used as a substitute for the nail plate in certain experiments.
人体指甲板的表面能预计会影响微生物的附着（以及随后的定植和感染）以及药物（以及随后的药物渗透）和化妆品的附着。因此，本研究旨在测量体内指甲板的表面能。通过测量液体（水、甲酰胺、二碘甲烷和甘油）在指甲板上的接触角，并使用 Lifshitz-van der Waals/酸碱（LW-AB）方法进行后续计算，估算了健康人手指甲（未经处理、水合和磨损）和蹄膜（常被用作指甲板模型）的表面能。未经处理的指甲板的表面能为 34 mJ m(-2)。该总能量的大部分来自非极性的 Lifshitz-van der Waals 分量。当分析表面能的极性分量时，电子供体分量明显大于电子受体分量。水合作用对表面能没有显著影响。相比之下，磨损会导致非极性表面能分量略有但统计学上显著增加。牛蹄膜的表面能与指甲板相似。我们得出结论，人手指甲板是一种低能量表面，并且在某些实验中，牛蹄膜可以替代指甲板。
