A novel transdermal protein delivery strategy via electrohydrodynamic coating of PLGA microparticles onto microneedles

Ukrit Angkawinitwong, Aaron J. Courtenay, Aoife Rodgers, Eneko Larraneta, Helen O. Mccarthy, Steve Brocchini, Ryan F. Donnelly, Gareth R. Williams

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)
37 Downloads (Pure)


Transdermal delivery of biological therapeutics is emerging as a potent alternative to intravenous or subcutaneous injections. The latter possess major challenges including patient discomfort, the necessity for trained personnel, specialized sharps disposal, and risk of infection. The microneedle (MN) technology circumvents many of the abovementioned challenges, delivering biological materials directly into the skin and allowing sustained release of the active ingredient both in animal models and in humans. This study describes the use of electrohydrodynamic atomization (EHDA) to coat ovalbumin (OVA)-loaded PLGA nanoparticles onto hydrogel-forming MN arrays. The particles showed extended release of OVA over ca. 28 days. Microscopic analysis demonstrated that EHDA could generate a uniform particle coating on the MNs, with 30% coating efficiency. Furthermore, the coated MN array manifested similar mechanical characteristics and insertion properties to the uncoated system, suggesting that the coating should have no detrimental effects on the application of the MNs. The coated MNs resulted in no significant increase in anti-OVA-specific IgG titres in C57BL/6 mice in vivo as compared to the untreated mice (paired t-test, p > 0.05), indicating that the formulations are nonimmunogenic. The approach of using EHDA to coat an MN array thus appears to have potential as a novel noninvasive protein delivery strategy.

Original languageEnglish
Pages (from-to)12478-12488
Number of pages11
JournalACS Applied Materials & Interfaces
Issue number11
Early online date18 Feb 2020
Publication statusPublished (in print/issue) - 18 Mar 2020

Bibliographical note

Funding Information:
This work was supported in part by Wellcome Trust grant number WT094085MA. The authors gratefully acknowledge Dr Andrew Weston (UCL School of Pharmacy) for assistance with SEM and TEM measurements and John Frost (UCL School of Pharmacy) for his help with designing and manufacturing equipment for electrospraying.

Publisher Copyright:
Copyright © 2020 American Chemical Society.

Copyright 2020 Elsevier B.V., All rights reserved.


  • PLGA
  • electrohydrodynamic atomisation
  • microneedle
  • microparticles
  • ovalbumin
  • transdermal drug delivery


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