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Microconduits in Stratum Corneum
 
 
Microconduit in SC created by treatment with a keratolytic agent. Top left
shows the microconduit (outlined by the white circle). Top right shows
the fluorescent micrograph of the skin with the dye concentrated in the
microconduit. The bottom row shows the concentration of charged fluorescent
beads in the microconduit
Controlled transport of molecules across the skin's main barrier, the
stratum corneum (SC), is a long standing goal of transdermal drug delivery.
Traditional, needle-based injection provides delivery of almost any water
soluble compound, by creating a single large aqueous pathway in the form
of the hollow core of a needle, through which drug is delivered by
pressure-driven flow. We have extended our previous work to show that
SC-spanning microconduits (here diameters of about 170 um)
can be created by skin electroporation and low toxicity, keratin disrupting
molecules (here sodium thiosulfate and urea). A single microconduit in
isolated SC can support volumetric flow of order 0.01 ml/s by a pressure
difference of only 0.01 atm, demonstrating that the SC barrier has been
completely removed within this microscopic area. |
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