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This work describes the formulation and evaluation of dissolving microneedle patches (MNs) for intradermal delivery of heat-inactivated bacteria. Pseudomonas aeruginosa, strain PA01, was used as a model bacterium. Utilising a simple, cost effective fabrication process, P. aeruginosa was heat-inactivated and formulated into dissolving MNs, fabricated from aqueous blends of 20% w/w poly(methylvinylether/maleic acid). The resultant MNs were of sufficient mechanical strength to consistently penetrate a validated skin model Parafilm M®, inserting to a depth of between 254 and 381 µm. MNs were successfully inserted into murine skin and partially dissolved. Analysis of MN dissolution kinetics in murine ears via optical coherence tomography showed almost complete MN dissolution 5 min post-insertion. Mice were vaccinated using these optimised MNs by application of one MN to the dorsal surface of each ear (5 min). Mice were subsequently challenged intranasally (24 h) with a live culture of P. aeruginosa (2 × 10 6 colony forming units). Bacterial load in the lungs of mice vaccinated with P. aeruginosa MNs was significantly (p = 0.0059) lower than those of their unvaccinated counterparts. This proof of concept work demonstrates the potential of dissolving MNs for intradermal vaccination with heat-inactivated bacteria. MNs may be a cost effective, potentially viable delivery system, which could easily be implemented in developing countries, allowing a rapid and simplified approach to vaccinating against a specific pathogen., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

We describe, for the first time, the design, production and evaluation of large microneedle patches. Such systems, based on 16 individual microneedle arrays (needle height 600μm), were prepared from aqueous blends of 15% w/w Gantrez ® S97 and 7.5% w/w poly(ethyleneglycol) 10,000Da. Ester-based crosslinking was confirmed by FTIR and mechanical strength was good. Insertion depths in a validated skin model were approximately 500μm. Ten human volunteers successfully self-inserted the microneedles of these larger patches in their skin, following appropriate instruction, as confirmed by transepidermal water loss measurements. The mean insertion depth ranged between 300 and 450μm over the area of the large patches. That this was not significantly different to a single unit MN patch self-applied by the same volunteers is encouraging. Microneedle patch sizes much larger than the 1-2cm 2 will be required if this technology is to be successfully translated to clinic for delivery of drug substances. The work described here suggests that use of such larger patches by patients can be successful, potentially opening up the possibility for a significant expansion of the size of the market for transdermal drug delivery., (Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.)

A phage-displayed peptide approach was used to identify ligands mimicking antigenic determinants of hepatitis A virus (HAV) for the first time. Bacteriophages displaying HAV mimotopes were isolated from a phage-display peptide library by affinity selection on serum antibodies from hepatitis A patients. Selected phage-peptides were screened for reactivity with sera from HAV infected patients and healthy controls. Four cloned peptides with different sequences were identified as mimotopes of HAV; three of them showed similarity in their amino acid sequences with at least one of the VP3 and VP1 antigenic proteins of HAV. One clone was recognised by 92% of the positive sera. The phagotopes competed effectively with HAV for absorption of anti-HAV-specific antibodies in human sera, as determined by ELISA. The four phage clones induced neutralising anti-HAV antibodies in immunised mice. These results demonstrate the potential of this method to elucidate the disease related epitopes of HAV and to use these mimotopes in diagnostic applications or in the development of a mimotope-based hepatitis A vaccine without the necessity of manipulation of the virus.