Influence of surface charge of gold nanorods on skin penetration.

BACKGROUND/PURPOSE: The skin plays an important role as a protective barrier against toxic environments and also is a route of drug administration. In spite of evidence for and interest in the skin penetration of nanoparticles, no study has examined the effect of nanoparticle surface charge on percutaneous absorption. In this study, we investigated the effect of surface charges of gold nanorods (GNs) on skin penetration. METHODS: Using transmission electron microscopy (TEM) and image analysis, we quantitatively measured the ability of GNs to penetrate the skin. RESULTS: Our results showed that the area density of the electron-dense dots of GNs, which penetrated into the stratum corneum, significantly increased for negatively charged GNs compared to those with a positive charge (P < 0.01). To investigate the percutanoues absorption of charged GNs, in vitro skin permeation studies were carried out using a Franz-type diffusion cell (FDC). The penetration of GNs through the skin was quantified by inductively coupled plasma mass spectrometry. Consistent with TEM observations, our penetration study using an FDC also revealed that negative particles were frequently detected in samples of receptor fluid at 48 h after exposure (P < 0.01). CONCLUSION: Together our results showed that anionic GNs penetrate skin better than cationic GNs.

Laboratory tests and compliance of dermatologic outpatients.

Laboratory tests, including blood tests and urine analysis, are frequently performed in the dermatology outpatient clinic, but doctors often do not consider the cognitive or psychological effect of the examinations. Based on terror management theory, we hypothesized that performing laboratory tests increases the patient's fear of mortality, and therefore has a positive effect on the patient's attitude toward the doctor's recommendations and willingness to accept them. The study employed a single factor between-subjects design, using a questionnaire completed by the patients. One group consisted of patients who had undergone laboratory tests 1 week before the survey, and the other group consisted of patients who had not undergone a laboratory test. Although the differences between two groups were not statistically significant, the patients who had laboratory tests had tendency to show even lower positive attitude toward the doctor's recommendations and less intention to follow the recommendations. In contrast to our hypothesis, performing laboratory tests does not subliminally increase patients' fears or anxieties about their disease or their compliance with doctors' recommendations.