Hot off the press: Elastin-derived peptide-based hydrogels as a potential drug delivery system

Keng has published a new paper out with Dr Othman Al Musaimi and co-workers. In this paper, we report the development of a self-assembling hydrogel formulation based on peptide sequences derived from elastin.

Elastin is a naturally occurring protein found in many connective tissues in the body, including the skin and blood vessels. These peptide sequences have been selected carefully to promote self-assembly of the hydrogels and confer the desired mechanical properties to the hydrogel. This hydrogel can be an interesting drug delivery system. The ability for the hydrogel to self-assemble at room temperature makes it easier to incorporate drugs into the hydrogel matrix. The mechanical properties will determine the rate at which the drugs can then be released from the hydrogel.

The paper is open access and free to read, so head over there now to read the full text for free.

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).

Group photos and social

We probably should do this more as a group.

Don’t get me wrong, we do socialise daily, but we don’t document it the way we document our experiments meticulously. So, before people start to disappear for their summer breaks, Wing had the brilliant idea of a lab photo and a meal together.

It was a shame that we couldn’t get everyone in one photo, but people deserve to take their holidays when they want them! So, we gathered up the boffins on two separate occasions and collected photographic evidence of them in full PPE (personal protective equipment, for the uninitiated), thoroughly committed to their research and enjoying it. We then headed off for a meal and a afternoon chat filled with laughter, talking mostly about ‘safe hobbies’.

We really should do this more.

Hot off the press: In vitro evaluation of microneedle strength: a comparison of test configurations and experimental insights

We test our microneedles a lot to examine how they fail. The most common technique we use to quantify the mechanical strength of the microneedles is by applying axial compression (crushing the microneedles from the tip towards the base) on a texture analyser, and pinpointing the minimum force that results in microneedle failure. We’re fortunate that our lab is well equipped to perform these tests. We get a live video feed of what’s happening to each microneedle as it’s being compressed. We can also playback the videos and analyse them synchronously with the force-displacement data. This technique has proved invaluable in making sure our microneedles perform as they should.

Hence, when Dr Choon Fu Goh invited me (Keng) to contribute to this paper on the mechanical testing of microneedle strength, I jumped at the opportunity. This is our first paper together and I really enjoyed working on this. I hope the microneedle community finds it useful.

Welcome Bohan!

Bohan Zhou, who spent several weeks as a research intern in our lab last year, has rejoined us to study a PhD in microneedle biosensing. We have a very interesting project lined up. Welcome back, Bohan!

Grace passes PhD viva without corrections!

Many congratulations to Grace Young who has passed her PhD viva – without corrections, I might add. This is an incredible feat. Congratulations, Dr Young! This is very well deserved.

Thanks, Professor Brendan Gilmore and Dr Chien-yi Chang, for conducting the examination.

Grace was supervised by Dr Wing Man Lau, Professor Nick Jakubovics and myself. The title of her thesis is “Development of a novel antimicrobial and drug delivery strategy to combat biofilm”.

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!

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!

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

APS PharmSci 2023

I was at the APS PharmSci conference in Reading. The veterans among us may remember the British Pharmaceutical Conference many, many years ago. That morphed into the APS PharmSci conference, which remains one of the major pharmaceutical science conferences to this day.

Of course I didn’t go there empty-handed. Our group presented two posters—one on a microneedle fabrication method (by Emma), the other on an impedimetric microneedle immunosensor (by Rach).

You can’t say that about many things nowadays, but the conference was both informative and enjoyable. There were many talks on 3D printing, which is a current passion of mine. It was also great to catch up with many old friends, colleagues and mentors, whom I had missed since moving away from Reading. I have only two regrets: I couldn’t attend the parallel sessions simultaneously, and I didn’t take enough photos. I did manage one tweet, and I deem that a notable achievement.

It was a fantastic conference, and I look forward to the next one.

Research trip to The Hong Kong Polytechnic University

Previously, I wrote that we’d started a research collaboration into 3D-printed microneedles with The Hong Kong Polytechnic University (PolyU). In the spring of 2023, we visited our collaborators at PolyU for 2 weeks to complete the second part of the research exchange. For final-year MPharm students, Jasmine and Liv, who were in Hong Kong for the first time, this was an excellent overseas experience, both academically and culturally.

We will share the results of the research in due course. For now, suffice it to say that this has been a most fruitful research collaboration. Jasmine and Liv wrote after the visit:

This Easter break we were lucky enough to be given the opportunity to visit Hong Kong as part of our final year research project. We spent some time at the Hong Kong Polytechnic University working with some of the Biomedical Engineering students and staff, getting to know them personally and admiring the engineering work they do. Our work consisted of 3D printed moulds and 3D printed structures all relating to microneedles. But it wasn’t all work! The cultural side of the city was something we had never experienced before. From giant Buddha statues to the street food we ate in Mong Kok, it was truly amazing. We also got a chance to watch the amazing Hong Kong 7s tournament! When we touched down back in Newcastle (after a very, very long flight), we didn’t want it to be over.

No doubt, they enjoyed themselves. I’ll let the pictures do the talking:

I think they enjoyed themselves alright.

They went on to say:

If we could go back and do it all again, we would. If a similar opportunity arises in the future, we encourage every pharmacy student with interest to apply to work on such multi-discipline projects, it really was worth it.

Indeed, we’re going back next year with two other final-year MPharm students, so stay tuned for more updates!