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Electrode design for skin electroporation with minimal nerve stimulation
Author(s) -
Pliquett U.
Publication year - 2004
Publication title -
experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 96
eISSN - 1600-0625
pISSN - 0906-6705
DOI - 10.1111/j.0906-6705.2004.0212ck.x
Subject(s) - stratum corneum , electroporation , electrode , electric field , dielectric , transdermal , materials science , penetration (warfare) , biophysics , optoelectronics , biomedical engineering , chemistry , composite material , medicine , biochemistry , physics , pathology , quantum mechanics , operations research , biology , engineering , pharmacology , gene
Electroporation is an efficient tool for transdermal delivery of water‐soluble molecules sizing up to several kDa. The main barrier to these agents is the stratum corneum, a 15 mm thin layer of dead keratinized cells. Once this layer is charged (approximately 50 V) by an outer electric field, structural rearrangements of the lipids create aqueous pathways (electroporation). Due to the high electric field within the stratum corneum, (E = 50 V/15 µm = 33 kV/cm) electrophoresis can drive charged molecules into the deeper skin layers. A major concern is the high electric field required, because nerve stimulation is inconvenient for the patient. Taking advantage of the fact that up to a depth of 50 µm no nervous receptors appear, a confinement of the field within the upper 15 µm would circumvent sensation. Field confinement within the stratum corneum is arranged by a special electrode geometry, an array of 300 µm holes within a 0.5 mm thick dielectric. The bottom, facing the stratum corneum, is metalized with a gap to the holes. The size of this gap (3–10 µm) is critical for the penetration depth of the electric field between the metalized bottom and a distant electrode at the other side of the holes. A drug reservoir is implemented below the distant electrode and the dielectric.