Article ID Journal Published Year Pages File Type
1425515 Journal of Controlled Release 2010 7 Pages PDF
Abstract

Microneedles can enhance the penetration of vaccines into the skin for transcutaneous vaccination. In this study for the first time the influence of microneedle geometry on the transport through the formed conduits was visualised in human volunteers by confocal laser scanning microscopy. Three differently shaped 300 μm long microneedle arrays were selected and fluorescein was applied either before or after piercing. Based on the intensity a distinction was made between regions with high and low intensity fluorescence (HIF and LIF). The areas of both intensities were quantified over time. In most cases HIF areas were only present in the stratum corneum, while LIF areas were also present in the viable epidermis. The areas were larger if fluorescein was applied after piercing compared to before piercing. After 15 min almost no HIF was present anymore at the skin surface. The microneedle geometry, but not the manner of application affected the shape and depth of the conduits. In conclusion we showed that the different microneedle arrays are able to form conduits in the skin, but the geometry of the microneedles influences the penetration of the fluorescent dye. This is the first step towards a more rational design of microneedle arrays for transcutaneous vaccination.

Graphical abstractLSM images at different depths of the conduits formed by the three different microneedle arrays 5 min after application of the fluorescent dye. Dimensions of the images are 235 by 235 µm2Figure optionsDownload full-size imageDownload as PowerPoint slide

Related Topics
Physical Sciences and Engineering Materials Science Biomaterials
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