Microneedle arrays for vaccine delivery: the possibilities, challenges and use of nanoparticles as a combinatorial approach for enhanced vaccine immunogenicity

ABSTRACT

Introduction: Vaccination is one of the greatest breakthroughs of modern preventative medicine. Despite this, there remain problems surrounding delivery, efficacy and compliance. Thus, there is a pressing need to develop cost-effective vaccine delivery systems that could expand the use of vaccines, particularly within developing countries. Microneedle (MN) arrays, given their ease of use, painlessness and ability to target skin antigen presenting cells, provide an attractive platform for improved vaccine delivery and efficacy. Studies have demonstrated enhanced immunogenicity with the use of MN in comparison to conventional needle. More recently, dissolving MN have been used for efficient delivery of nanoparticles (NP), as a means to enhance antigen immunogenicity.

Areas covered: This review introduces the fields of MN technology and nanotechnology, highlighting the recent advances which have been made with these two technologies combined for enhanced vaccine delivery and efficacy. Some key questions that remain to be addressed for adoption of MN in a clinical setting are also evaluated.

Expert opinion: MN-mediated vaccine delivery holds potential for expanding access to vaccines, with individuals in developing countries likely to be the principal beneficiaries. The combinatorial approach of utilizing MN coupled with NP, provides opportunities to enhance the immunogenicity of vaccine antigens.

KEYWORDS:

• Antigen
• microneedle (MN)
• nanoparticle (NP)
• skin
• vaccine

Article highlights

• The invention of vaccination is one of the greatest triumphs of modern preventative medicine;

• At present, most vaccines are administered intramuscularly or subcutaneously via needle and syringe with associated disadvantages including pain, needle phobia, poor patient compliance and risk of needle-stick injuries;

• Most vaccines also require storage at specific temperatures, referred to as the cold chain, which has associated cost challenges in low-resource settings;

• MN arrays offer the possibility to circumvent many of the abovementioned challenges while also offering the possibility for improved vaccine immunogenicity through direct targeting of the dense network of antigen presenting cells in the skin;

• The use of nanoparticles in combination with microneedle arrays offers the possibility for enhanced vaccine immunogenicity. Specifically, by increasing antigen delivery and allowing for sustained release, they enhance the immune response to antigens;

• Key considerations that require attention include formulation, manufacture and production. Manufacturing approaches will need to be considered if MN are to be mass-produced and industry will be required to invest significantly in appropriate equipment.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer Declaration of Interests

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.