Food allergen immunotherapy via electrospray coated microneedles - a potential transdermal therapy

Microneedle (MN) technologies offer a minimally invasive platform for allergen delivery; however, controlled transdermal administration of complex allergenic proteins remains a challenge. This communication reports the fabrication and evaluation of peanut (PN), and pistachio (PS) loaded polylactic-co-glycolic acid (PLGA) coatings onto stainless-steel MNs via electrohydrodynamic atomisation (EHDA). Electrosprayed coatings exhibited uniform morphology and comparable hydrophilicity across formulations. In-vitro release study revealed an early burst (20% release within 24 h) followed by sustained delivery. The kinetic modelling indicated near-zero-order release governed by Fickian or quasi-Fickian diffusion. Ex-vivo insertion studies confirmed consistent membrane penetration with minimal invasiveness. Permeation study demonstrated efficient allergen transport (80-90%) across rat skin from coated MNs. In rats, a significant (p < 0.05) elevation in IgE (immunoglobulin E) titres following MN mediated delivery of PN (1.78-fold) and PS (1.39-fold) loaded PLGA matrices was recorded by day 50. These findings established EHDA-processed nut-PLGA coated MNs as a potentially promising platform for transdermal food allergen immunotherapy, enabling controlled release, effective skin permeation and preserved immunogenicity. The ability to coat allergen-formulations in minute and scalable quantities provides an opportunity to personalise specific food therapies using transdermal MNs.