Nanopatch™ Technology Overview
The Nanopatch™ approach consists of an array of thousands of vaccine-coated microprojections that perforate into the outer layers of the skin when applied with an applicator device. The tips of Nanopatch's microprojections are coated with a vaccine material and release this material directly to the large numbers of key immune cells immediately below the skin surface.
The central element of this technology is the Nanopatch™ array itself which consists of a 1 cm2 square of silicon with ~20,000 microprojections on its surface - invisible to the naked eye. The Nanopatch™ array penetrates through the protective outer skin layer (stratum corneum) and targets immune-activating material to the immune-cell rich layers just beneath the outermost skin layer utilising the microprojections with optimised spacing and length. The result, demonstrated in a mouse model, is an effective increase in immunogenicity, which can be leveraged for two different purposes: either reducing the dose required to achieve efficacy (100-fold reduction has been achieved in the mouse model when delivering Fluvax®), and for amplifying the vaccine efficacy. Pre-clinical experiments have also shown the ability of the Nanopatch™ to remove or significantly reduce the amount of adjuvant required for effective vaccination.
Traditionally, microneedle delivery systems have been held back from commercialisation due in part to challenges in manufacture scaling. Even in early research programs within Professor Kendall's laboratory, this consideration was always at the forefront of new process developments. At Vaxxas today personnel in both our technical and commercial camps - and those spanning both - are confident that we have a technology which is inherently simple and feasible for high throughput, cost effective manufacture.
Formulation and coating
To ensure that the Nanopatch™ device delivers an effective volume of vaccine to the desired targets, it is essential that microprojection arrays are not only fabricated to the correct geometry, but also coated uniformly and consistently. The manufactured patches are coated with a formulation containing the vaccine. Coating methods have been optimised to be scalable and efficiently apply coating formulations rapidly with minimal wastage. The coatings are stable at ambient temperature (avoiding refrigeration requirements) and strong so they remain intact when inserted through the outer skin layer, but release quickly (often seconds) once in contact with moisture within the skin.
The outer layer of the skin varies its properties considerably depending on age, gender, health and even environmental humidity. This introduces variability which must be overcome to achieve consistent and repeatable vaccine delivery. The Nanopatch™ approach achieves this by combining the coated Nanopatch™ arrays with a carefully considered applicator. The applicator addresses variations in the skin by exploiting our knowledge of the skin's mechanical properties to achieve uniform penetration and delivery across the natural variation in a patient population. The applicator design overcomes the inconsistency that plagues other transdermal vaccine delivery approaches.