Size-dependent passage of liposome nanocarriers with preserved posttransport integrity across the middle-inner ear barriers in rats.
Otol Neurotol 2012;
33:666-73. [PMID:
22569149 DOI:
10.1097/mao.0b013e318254590e]
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Abstract
OBJECTIVE
The goal of this study was to evaluate the impact of liposome nanocarrier size on the efficacy of its transport across the middle-inner ear barriers.
MATERIALS AND METHODS
The dynamic distribution of liposome nanocarriers encapsulating gadolinium-tetra-azacyclo-dodecane-tetra-acetic acid (LPS+Gd-DOTA) of sizes 95, 130, and 240 nm were observed with a 4.7 T magnetic resonance machine after transtympanic injection in Wistar rats. Histology was performed with confocal microscopy using TRITC conjugated LPS+Gd-DOTA. The integrity of the LPS+Gd-DOTA after transportation was evaluated using cryo-transmission electron microscopy (Cryo-TEM).
RESULTS
Size-dependent transport of the LPS+Gd-DOTA across the middle-inner ear barriers was shown using magnetic resonance imaging, which indicated that the 95-nm nanocarrier showed the significantly highest transport percentage, that the 130-nm nanocarrier showed moderate transport, and that the 240 nm nanocarrier showed the lowest transport. Histologic examinations showed that the LPS+Gd-DOTA were distributed in the epithelial cells of the utricle, capillaries of the spiral ligament, and the spiral ganglion cells. LPS+Gd-DOTA remained intact in the perilymph after transportation.
CONCLUSION
The nanocarrier delivery strategy used in this work could be effective in the development of novel inner ear treatments.
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