Researchers at the University of Hong Kong have developed a microneedle patch for the drug-free treatment of skin infections, such as acne. Acne is often treated using antibiotics, but these have limited effectiveness over the long term and can result in drug-resistant bacteria. In an effort to develop a drug-free alternative, these researchers have created a microneedle patch that is ultrasound responsive. The patch contains zinc-based nanomaterials that produce a substantial amount of reactive oxygen species when stimulated using ultrasound. These reactive oxygen species are highly effective at killing acne-causing bacteria within the skin, and the Hong Kong team also claims that released zinc ions can stimulate fibroblasts to initiate skin repair.
Acne is incredibly common and can have both physical and psychological effects for those who experience it. Commonly caused by the bacterium Propionibacterium acnes (P. acnes), acne is often treated using antibiotics. However, this is far from ideal, with drug-resistant bacteria frequently ruining the long-term effectiveness of this approach. Moreover, contributing to the development of such bacteria on the skin is not great for patients, who are then at risk of these bacteria colonizing a wound or causing other complications.
This latest technology does not rely on antibiotics, but it can still kill acne-causing bacteria within the skin. The sodium hyaluronate microneedle patch includes nanoparticles containing a zinc porphyrin–based metal-organic framework and zinc oxide (ZnTCPP@ZnO). The microneedle design allows these nanoparticles to enter the skin and then, when stimulated using an external ultrasound probe, they create reactive oxygen species. The infective bacteria are quickly destroyed by this mechanism, even when they are present in biofilms. The researchers showed that 99.73% of P. acnes were killed after just 15 minutes of ultrasound stimulation.
Moreover, treatment with the patch also resulted in a decrease in the levels of inflammatory proteins that are typically involved in acne, including tumor necrosis factor-a (TNF-α), interleukins (ILs), and matrix metalloproteinases (MMPs). The researchers also report that the patch releases zinc ions into the skin, which may influence gene expression in fibroblasts and encourage them to repair the skin.
‘The new microneedle patch enabling ROS generation upon ultrasound stimulation, regarding as a non-antibiotic and transdermal approach, can not only effectively address the infection induced by P. acnes bacteria, but also facilitates the skin repair due to zinc ion release,” said Kelvin Yeung Wai-kwok, a researcher involved in the study. “Due to the specific killing mechanism of ROS, we believe that this design is also able to address the other skin infections induced by fungi, parasites, or viruses, such as tinea pedis.”
Study in journal Science Advances: Ultrasound-triggered interfacial engineering-based microneedle for bacterial infection acne treatment