Tag: microneedles

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Engineering and in vitro evaluation of semi-dissolving, hydrogel-forming polymeric microneedles for sustained-release drug delivery

Abdelghany TM, Vo N, Vukajlovic D, Smith E, Wong JZ, Jackson E, Hilkens CMU, Lau WM, Ng KW, Novakovic K. Engineering and in vitro evaluation of semi-dissolving, hydrogel-forming polymeric microneedles for sustained-release drug delivery. Int J Pharm. 2025:125932. https://doi.org/10.1016/j.ijpharm.2025.125932

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In our latest paper, we describe a microneedle formulation that utilises two polymeric domains: a soluble one and an insoluble one. The insoluble domain is chemically crosslinked and traps the soluble polymer, along with the drug, within it. This combination creates a microneedle array patch that can release a drug for over 2 months.

It can contain a significantly larger dose than microneedles where the drug is contained within the microneedle tips only (e.g., detachable microneedles). The drug reservoir in the backplate makes this possible to support extended release. It uses one-pot synthesis, a mild hydroalcoholic solvent system and mild temperatures to aid manufacturability and drug stability.

For the first time, we were able to see, on video, how the microneedles released the drug and swell as they hydrated. These videos are buried in the supplementary files for the paper, but I thought it worthy of sharing more widely here:

Videos from Abdelghany et al. (2025). Reused under a Creative Commons licence.

We would like to thanks everyone who’s contributed to this paper. Big thanks to the EPSRC and Innovate UK for funding this work.

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Assessing the integrity and mechanical properties of commercial microneedles: innovation or fad?

Citation: Lee JY, Dong SH, Ng KW, Goh CF. Assessing the integrity and mechanical properties of commercial microneedles: innovation or fad? Drug Deliv Transl Res. 2025. doi: 10.1007/s13346-025-01888-8

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In this collaborative paper—our second with the Malaysian team led by Dr Choon Fu Goh—we examine some commercially available cosmetic products and ask what lessons we can learn from them to enhance pharmaceutical microneedle product translation and commercialisation.

We have known, for a long time, that the regulatory hurdles for pharmaceutical products are much greater than those for cosmetic products. Still, it’s interesting to see how cosmetic microneedle products have surged years (if not decades) ahead of their pharmaceutical counterparts, particularly in the Asian market. A low regulatory hurdle could spur innovation, but it could equally grow fad. How can one tell which it is? We examined a selection of commercially available cosmetic microneedle products to find out, and report our findings in this paper.

This has been an interesting paper to work on. I have admired Goh’s tenacity collecting microneedle patches from pharmacies on his various international trips across Asia for this study. Last year, I hosted him in Newcastle to conduct parts of the study, including some microscopy work and the optical coherence tomography (OCT) analysis on microneedle penetration in ex vivo pig skin. It’s rewarding to see those efforts pay off.

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ULTRA microneedle patch technology featured on Serbian national TV

We have been working with Professor Katarina Novakovic‘s team for several years now to develop long-acting microneedle patch formulations based on our ULTRA technology. ULTRA stands for Ultra-long and Tunable Release of Actives. It is a polymeric composite material that confers exceptional sustained release properties.

Our work in this area is yet unpublished, but it has already attracted the attention of RTS (Radio Television of Serbia), which featured the ULTRA microneedle technology in a segment of the documentary series, A Guide to the Future (Vodič kroz budućnost). The full-length documentary is available on YouTube and is mostly in Serbian (Wing and I speak about the ULTRA microneedle technology in English). The segment about our ULTRA microneedle technology starts around the 17-minute mark.

Thanks to RTS and their crew for their invaluable time and efforts in creating this fantastic coverage.

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Hot off the press: Mathematical modelling of genipin-bovine serum albumin interaction using fluorescence intensity measurements

Hydrogels are a popular drug delivery vehicle. You can encapsulate drugs including large biological macromolecules like proteins in them, to be released in the body. Some hydrogels use chemical crosslinking to create the hydrogel matrix – with the drug in it. Can protein drugs encapsulated this way participate in those crosslinks? What if they do? How will that affect their subsequent release?

We started asking these questions when attempting to deliver protein drugs by encapsulating them in hydrogel-forming microneedle array patches. These were important questions, and now we have the answers.

In this paper, we address these questions using bovine serum albumin as a model drug, and a genipin-chitosan hydrogel as the drug delivery vehicle. Using a combination of empirical fluorometry data and mathematical modelling, we investigate the kinetics of the interactions of the protein drug and genipin (the crosslinker).

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Micromoulding microneedle array patches under vacuum, hands-free!

Our hands-free, ‘vac-and-fill’ micromoulding technique prevented air entrapment and bubble formation in viscous formulations when degassed under vacuum. Image from Smith E, et al. Int J Pharm 2024;650:123706. Licence: CC BY 4.0 Deed.

Our latest paper, Vac-and-fill: A micromoulding technique for fabricating microneedle arrays with vacuum-activated, hands-free mould-filling, has been published in the International Journal of Pharmaceutics. It’s open access, so head over there to read the full-text article for free!

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This paper reports the solution to a problem that took us several months to solve. We were trying to mould a microneedle array patch. There are basically two ways to do it: you fill the mould with the liquid formulation and either centrifuge it or degas it under vacuum. Both techniques are widely reported in the literature. They have been designed to force any air out of the microcavities in the mould, so that the formulation can enter them to form the microneedles. We didn’t have the right rotor to go with the centrifuge, so we opted for the vacuum degassing technique, fully expecting it to be a walk in the park. What a disappointment that turned out to be! We discovered that our formulation was too viscous to allow the air to escape. We ended up with a lot of air bubbles trapped in the liquid formulation.

We quickly realised that the vacuum degassing technique reported in the literature had used low polymer concentrations, which meant that their liquid formulations were not as viscous as ours. To micromould the microneedle array patch successfully from our viscous formulation, we had to remove the air first before filling the formulation into the mould. But how would one fill the mould under vacuum?

The answer: a modified syringe, a 3D-printed part, some painstaking calibration, and viola! The paper describes our solution in full, but here’s a peek of the contraption in action.

This is Emma’s first paper and our first together with Dr Katarina Novakovic‘s group. Congratulations, Emma, and thank you team for the hard work!

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PolyU collaborators visit Newcastle to conduct joint microneedle study

2023 seemingly left in a haste. Stepping into 2024, we welcomed our collaborators from The Hong Kong Polytechnic University (PolyU) to Newcastle, to conduct a joint study on microneedle formulation for drug delivery and diagnostics. Merab Naveed, Hubert Chan and Dr Thomas Lee from PolyU’s Biomedical Engineering Department spent nearly two weeks with us, running experiments and exchanging ideas with us. Newcastle University students, Begho Obale and Jakub Masloch, who completed their MPharm research projects with us, also lent their expertise to this joint study. Among other things, Begho made a dancing microneedle mould – the first ever reported. It was a most wonderful way to start the new year.

So how did our guests find it? I know Hubert enjoyed the unique learning experience – his words, not mine. I’m really pleased that we’re able to organise this research exchange programme. Thanks also go to Dr Wing Man Lau and Dr Hin Chung Lau of PolyU, the other two academic advisors on the project, for making this happen.

https://twitter.com/ngkengwooi/status/1745948085136584968

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Biosensors special issue: Microneedle diagnostics

I am guest-editing a special issue of the Biosensors journal with Professor Ryan Donnelly of Queens University Belfast. We would like to invite manuscripts from colleagues who work in this area. The submission deadline is 30 November 2021. Please see the special issue announcement on the journal website for details.

If your work concerns polymers for drug delivery or wound healing, then please also check out the Polymers special issue that I am guest-editing with Dr Wing Man Lau, which is still open for submission.

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Review: Microneedle-based devices for point-of-care infectious disease diagnostics

We have published a review article on microneedles as a technological platform for diagnosing infectious diseases. In this review, we enumerate the infectious diseases that could potentially be diagnosed in the skin, examine the mechanisms of existing microneedle diagnostic technologies, and evaluate their applications in infectious disease diagnosis. This publication is timely given that we’re in the middle of a infectious disease pandemic.

Figure 1: Microneedles inserted into the skin may extract or detect disease markers in situ. Diagnostic tests for infectious diseases should ideally be both specific and rapid.

Any diagnostic test has to be specific to be useful (Figure 1). For a potentially deadly diseases, the more rapid the diagnosis, the better, because it buys precious time for the patient to seek early treatment, which could save lives. However, for infectious diseases that can be transmitted by close contact, it’s also desirable that the patient can administer the test themselves without too much discomfort. Many tests do better in meeting some of these criteria at the expense of other criteria. For example, I took the PCR test for COVID-19. I am sure the test itself was highly specific, but the nasal and throat swabs were uncomfortable. The diagnosis wasn’t exactly ‘rapid’ either — I got my result several days later (mainly due to limited test capacity at that time, but that has improved significantly since). Microneedle devices are painless to administer on the skin, and tests can produce real-time or near-real-time results. Not all of these studies have been on infectious diseases, of course. The technology is still nascent but the potentials are huge.

The review article is currently in press, but a pre-proof is already available for download from Acta Pharmaceutica Sinica B. There have been a number of minor corrections to this pre-proof (mainly typographical and referencing error) which will appear in the final publication, but the pre-proof should satisfy the impatient for now.

Congratulations to everyone involved in putting this publication together.

Read the review

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Perspective: The diagnostic potential of microneedles in infectious diseases

The recent COVID-19 pandemic brought the healthcare systems in many countries to their knees. One of the key problems that became evident early on was the lack of diagnostic tools that were rapid and readily accessible to the public.

Diagnostics is what we do as a research team. Naturally, we contemplated what we could do in a situation like this. The result is a perspective article published in Precision Nanomedicine, the official journal of the European Foundation for Nanomedicine.

The conclusion? Microneedle systems excel in many ways as a diagnostic tool. Various microneedle platforms have demonstrated advantages of portability, self-administrability, affordability and scalability over other diagnostic platforms. The potential is huge but the technology is still in its infancy. We need more research to turn that potential into tangible clinical benefits, but we can’t do it alone. Cross-disciplinary collaboration and stakeholder support will be needed to drive this effort forward.

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The article is published under the Creative Commons BY-NC-SA 4.0 licence, so please feel free to distribute widely, adapt and reuse for non-commercial purposes, and share any derived work, citing:

Dixon RV, Lau WM, Moghimi SM, Ng KW (2020) The diagnostic potential of microneedles in infectious diseases. Precision Nanomedicine 3(4):629–640 . https://doi.org/10.33218/001c.13658

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Welcoming Hassan

Just as we were about to wind down our lab operations for Christmas, we welcomed postdoctoral research associate, Dr Hassan Elsana, into our team this week. Hassan will be working on an EPSRC-funded project researching microneedle-mediated drug delivery in the skin.

This project is a collaboration with Dr Wing Man Lau (School of Pharmacy) and Dr Katarina Novakovic (School of Engineering). We have high hopes for this project.

Exciting times ahead, and I don’t just mean Christmas!