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Unlabelled: Hearing loss is a very significant health problem. The methods currently available for inner ear drug delivery are limited and a noninvasive cell-specific drug delivery strategy needs to be found., Aim: In this study we investigated the ability of polymersomes, lipid core nanocapsules and hyperbranched poly-L-lysine to cross the round window membrane., Materials & Methods: Nanoparticles (NPs) used in this study have different size and chemical compositions. Freshly frozen human temporal bones were used for this investigation. Intact human round window membrane within the freshly frozen human temporal bone served as an excellent model to test the membrane permeation and distribution within the tissues., Results: In this investigation we were able to visualize the NPs across the round window membrane. The NPs were subsequently found to be distributed in the sensory hair cells, nerve fibers and to other cells of the cochlea., Conclusion: This finding raises hope in terms of future multifunctional NP-based drug delivery strategy to the human inner ear.

In the field of nanometre-sized drug-delivery systems, a wide range of colloidal systems have been created in recent decades. All of the systems have a similar global structure, that is, an inner part and an external surface/interface. In several applications, the external interface is the support for desired properties and the basis of future developments. The engineering of the particle's surface is an emerging step in the design of systems at the nanometre scale. This review presents and summarises the available techniques with a particular attention to recent advances. It is also a base for future works in this expanding area of research., (Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Hearing loss is a major public health problem, and its treatment with traditional therapy strategies is often unsuccessful due to limited drug access deep in the temporal bone. Multifunctional nanoparticles that are targeted to specified cell populations, biodegradable, traceable in vivo, and equipped with controlled drug/gene release may resolve this problem. We developed lipid core nanocapsules (LNCs) with sizes below 50 nm. The aim of the present study is to evaluate the ability of the LNCs to pass through the round window membrane and reach inner ear targets. FITC was incorporated as a tag for the LNCs and Nile Red was encapsulated inside the oily core to assess the integrity of the LNCs. The capability of LNCs to pass through the round window membrane and the distribution of the LNCs inside the inner ear were evaluated in rats via confocal microscopy in combination with image analysis using ImageJ. After round window membrane administration, LNCs reached the spiral ganglion cells, nerve fibers, and spiral ligament fibrocytes within 30 min. The paracellular pathway was the main approach for LNC penetration of the round window membrane. LNCs can also reach the vestibule, middle ear mucosa, and the adjacent artery. Nuclear localization was detected in the spiral ganglion, though infrequently. These results suggest that LNCs are potential vectors for drug delivery into the spiral ganglion cells, nerve fibers, hair cells, and spiral ligament. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008 [ABSTRACT FROM AUTHOR]

In this study, we evaluated the potential of lipid nanocapsules (LNC) of 120 nm as drug nanocarriers to treat skin diseases. As a model molecule, we encapsulated the fluorescent dye curcumin, which also is an antioxidant. Curcumin-loaded LNC showed interesting antioxidant properties and a low toxicity on human skin cells. The penetration of curcumin in the skin was determined by 2 complementary methods: high performance liquid chromatography was used to measure total curcumin accumulation in the skin, whereas fluorescence confocal spectral imaging of skin sections showed that curcumin preferentially accumulates in the stratum corneum and the viable epidermis. These results confirm that LNC of a size above 100 nm can vectorize hydrophobic compounds to the keratinocytes without transdermal delivery. They also demonstrate the interest of combining 2 analytical methods when studying the skin penetration of nanovectorized molecules. [ABSTRACT FROM AUTHOR]

Abstract: Nanoparticle-mediated drug delivery represents the future in terms of treating inner ear diseases. Lipid core nanocapsules (LNCs), 50nm in size, were shown to pass though the round window membrane (RWM) and reached the spiral ganglion cells and nerve fibers, among other cell types in the inner ear. The present study aimed to evaluate the toxicity of the LNCs in vitro and in vivo, utilizing intact round window membrane delivery in rats. The primary cochlear cells and mouse fibroblast cells treated with LNCs displayed dosage dependant toxicity. In vivo study showed that administration of LNCs did not cause hearing loss, nanoparticle application-related cell death, or morphological changes in the inner ear, at up to 28 days of observation. The cochlear neural elements, such as synaptophysin, ribbon synapses, and S-100, were not affected by the administration of LNCs. However, expression of neurofilament-200 decreased in SGCs and in cochlear nerve in osseous spiral lamina canal after LNC delivery, a phenomenon that requires further investigation. LNCs are potential vectors for the delivery of drugs to the inner ear. [ABSTRACT FROM AUTHOR]