Dissolving microneedles are a subgroup of microneedle types that completely dissolve within the skin. During this dissolving process the vaccine, stored in the needle matrix, is released into the... Show moreDissolving microneedles are a subgroup of microneedle types that completely dissolve within the skin. During this dissolving process the vaccine, stored in the needle matrix, is released into the skin. Dissolving microneedles are made of a water-soluble, inert and safe material, such as hyaluronic acid. The microneedles have been used to vaccinate via the skin, which is a very immune competent organ that holds great potential for vaccine delivery. The minimally invasive and easy nature of the injections can reduce the risk of infections and alleviate the need for trained personnel. Furthermore, they eliminate all sharp waste as the needles dissolve during drug delivery.The goals of this project has been to improve the immunogenicity of vaccines through skin delivery, allowing for increased understanding of skin immunology and the development of pain free and safe vaccine delivery systems. Show less
Leone, M.; Romeijn, S.; Slütter, B.; O'Mahony, C.; Kersten, G.; Bouwstra, J.A. 2020
Biomaterials used as matrix for dissolving micro needles (dMNs) may affect the manufacturing process as well as the potency of the active pharmaceutical ingredient, e.g. the immunogenicity of... Show moreBiomaterials used as matrix for dissolving micro needles (dMNs) may affect the manufacturing process as well as the potency of the active pharmaceutical ingredient, e.g. the immunogenicity of incorporated vaccine antigens. The aim of this study was to investigate the effect of the molecular weight of hyaluronan, a polymer widely used in the fabrication of dMNs, ranging in molecular weight from 4.8 kDa to 1.8 MDa, on the dissolution of microneedles in the skin in time as well as the antibody response in mice and T-cell activation in vitro. Hyaluronan molecular weight (HA-MWs) did not affect antibody responses (when lower than 150 kDa) nor CD4 + T-cell responses against model antigen ovalbumin. However, the HA-MWs had an effect on the fabrication of dMNs. The 1.8 MDa HA was not suitable for the fabrication of dMNs. Similarly, the 4.8 kDa HA generated dMN arrays less robust compared to the other HA-MWs requiring optimization of the drying conditions. Finally, higher HAMWs led to longer application time of dMN arrays for a complete dissolution of microneedles into the skin. Specifically, we identified 20 kDa HA as the optimal HA-MW for the fabrication of dMNs as with this MW the dMNs are robust and dissolve fast in the skin without affecting immunogenicity. Show less
