Public Lecture Explores Microneedle Technologies

Public Lecture Explores Microneedle Technologies

UKZN’s College of Health Sciences hosted a public lecture titled, Translation of Microneedle Technologies from the Lab to the Clinic by Dr Mark R Prausnitz, Regents’ Professor in Chemical and Biomolecular Engineering at the Georgia Institute of Technology in Atlanta, US.

Prausnitz identified four main forms of microneedles, namely, solid, coated, dissolving and hollow. He said the solid microneedle could be developed into STAR particles for dermatological drug delivery; a piezoelectric microneedle electroporator that involves sending electric pulses to the skin for vaccination; and a dermal interstitial fluid sampling device that extracts fluid from the body rather than putting it in. Prausnitz reviewed the hollow microneedle as a mechanism for use in the eye and the dissolving microneedle as a means of exhibiting a vaccination patch (on the skin).

Discussing STAR particles as a literal three-pronged particle made of titanium dioxide, he said that when rubbed onto the skin, it was able to poke holes for absorption, increasing the skin’s permeability to topical drugs. The STAR particle was proven to enhance treatment for skin cancer when tested on mice and caused a tingling sensation when applied to the human skin.

Prausnitz focused on the piezoelectric microneedle electroporator for DNA and mRNA vaccination. Commenting on how the product was developed, he said it used a piezoelectric pulse found in lighters and electrodes as microneedles, producing a low-cost item due to its hand-held usability, requiring no battery or power supply. ‘We don’t want to stimulate nerves deep in the skin, as the electric field must be kept superficial and in the epidermis of skin,’ Prausnitz said.

Evaluating interstitial fluid as a liquid that makes up almost a quarter of the body’s fluid, Prausnitz said very little is known about it, which prompted the development of this solid microneedle. Blood is conventionally used to collect biomarkers in the body, but the development of solid microneedle devices to sample interstitial fluid from the skin could provide useful information because of the liquid’s inability to clot (making it suitable for repeat testing) and ability to measure glucose in diabetic patients.

Prausnitz reviewed the hollow microneedle developed for suprachoroidal injection that provides the required targeting of drugs within the eye when performed by doctors in clinical settings. He said this microneedle was designed to deliver steroids for the treatment of macular edema that calls for a targeted approach to the site of action in order to avoid glaucoma or cataract. Prausnitz said that he was happy to announce that through clinical trials, a product had been developed named XIPERE.

Demonstrating examples of the dissolving microneedle patch vaccination developed by Georgia Tech, he explained that it was created to meet public health needs, including being administrated by people with minimal training or patients themselves, as it requires no applicators and is delivered painlessly. Prausnitz said the manufacturing process is low cost and scalable, and transportation and storage of the patch works well due to its small package sizes, with the dry formula requiring little or no cold-chain storage. Highlighting the waste disposal element of the product, he said there are no sharps as the patch is able to dissolve in the human skin, making it impossible to reuse and reducing its disposal volume.

Prausnitz reflected on two clinical trials carried out to prove the patch vaccination’s efficacy, namely, the Influenza Vaccination trial at Emory University, in Georgia, US and the Measles and Rubella Vaccination trial in The Gambia, Africa. These proved effective due to the vaccines’ advantage of being delivered in the skin which has been shown to be immunogenic.

To watch the lecture, click here.

Words: Hlengiwe Khwela

Photograph: Sethu Dlamini