title: Exploitation of sub-micron cavitation nuclei to enhance ultrasound-mediated transdermal transport and penetration of vaccines.
abstract: Inertial cavitation mediated by ultrasound has been previously shown to enable skin permeabilisation for transdermal drug and vaccine delivery, by sequentially applying the ultrasound then the therapeutic in liquid form on the skin surface. Using a novel hydrogel dosage form, we demonstrate that the use of sub-micron gas-stabilising polymeric nanoparticles (nanocups) to sustain and promote cavitation activity during simultaneous application of both drug and vaccine results in a significant enhancement of both the dose and penetration of a model vaccine, Ovalbumin (OVA), to depths of 500μm into porcine skin. The nanocups themselves exceeded the penetration depth of the vaccine (up to 700μm) due to their small size and capacity to 'self-propel'. In vivo murine studies indicated that nanocup-assisted ultrasound transdermal vaccination achieved significantly (p<0.05) higher delivery doses without visible skin damage compared to the use of a chemical penetration enhancer. Transdermal OVA doses of up to 1μg were achieved in a single 90-second treatment, which was sufficient to trigger an antigen-specific immune response. Furthermore, ultrasound-assisted vaccine delivery in the presence of nanocups demonstrated substantially higher specific anti-OVA IgG antibody levels compared to other transdermal methods. Further optimisation can lead to a viable, safe and non-invasive delivery platform for vaccines with potential use in a primary care setting or personalized self-vaccination at home.
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Oxford, OX3 7DQ, UK. Electronic address: sunali.bhatnagar@eng.ox.ac.uk.
authors.forename: Sunali
authors.initials: S
authors.lastname: Bhatnagar
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Oxford, OX3 7DQ, UK.
authors.forename: James J
authors.initials: JJ
authors.lastname: Kwan
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Oxford, OX3 7DQ, UK; Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK.
authors.forename: Apurva R
authors.initials: AR
authors.lastname: Shah
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Oxford, OX3 7DQ, UK.
authors.forename: Constantin-C
authors.initials: CC
authors.lastname: Coussios
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Oxford, OX3 7DQ, UK.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Carlisle
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D000917:Antibody Formation; D005260:Female; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000008:administration & dosage* / Q000276:immunology / Q000493:pharmacokinetics; D012867:Skin / Q000378:metabolism; D012869:Skin Absorption; D013552:Swine; D014465:Ultrasonics / Q000379:methods*; D014611:Vaccination / Q000379:methods*; D014612:Vaccines / Q000008:administration & dosage* / Q000276:immunology / Q000493:pharmacokinetics
chemical_list: D014612:Vaccines; D010047:Ovalbumin
keywords: Immunisation; Ovalbumin; Transdermal delivery; Ultrasound