Noninvasive Transdermal Vaccination Using Hyaluronan Nanocarriers and Laser Adjuvant

Vaccines are commonly administered by injection using needles. Although transdermal microneedles are less invasive promising alternatives, needle-free topical vaccination without involving physical damage to the natural skin barrier is still sought after as it can further reduce needle-induced anxiety and is simple to administer. However, this long-standing goal has been elusive since the intact skin is impermeable to most macromolecules. Here, we show an efficient, noninvasive transdermal vaccination by employing two key innovations: the use of hyaluronan (HA) as vaccine carriers and non-ablative laser adjuvants. Conjugates of a model vaccine ovalbumin (OVA) and HAHA-OVA conjugates-induced more effective maturation of dendritic cells in vitro, compared to OVA. Following topical administration in the skin, HA-OVA conjugates penetrated into the epidermis and dermis in murine and porcine skins, as revealed by intravital microscopy and fluorescence assay. Topical administration of HA-OVA conjugates significantly elevated both humoral and mucosal antibodies, with peak levels at four weeks. An OVA challenge at week eight elicited strong immune-recall responses. With pretreatment of the skin using non-ablative fractional laser beams as adjuvant, strong immunization was achieved with much reduced doses of HA-OVA (1 mg kg(-1) OVA). Our results demonstrate the potential of the noninvasive patch-type transdermal vaccination platform.