A research team led by Kelvin Yeung from the Department of Orthopaedics and Traumatology, School of Clinical Medicine, LKS Faculty of Medicine, the University of Hong Kong (HKUMed) has designed a new microneedle patch that provides an effective non-antibiotic approach for the treatment of skin infections.
The design engineered with ultrasound-responsive zinc-based metal-organic framework (MOF) antibacterial nanoparticles promises pain-free delivery to treat bacterial infection on skin tissue and facilitate skin repair at the same time. The novel microneedle is around 50 microns in diameter, similar to a typical hair. The findings have been published in Science Advances.
Background
Acne is a common skin disease worldwide affecting more than 80% of teenagers and young adults. This leads to excessive lipid secretion that clogs the hair follicles, thereby establishing a hypoxic microenvironment in skin tissue. This leads to the proliferation of Propionibacterium acnes bacteria.
It not only causes patients physical and emotional distress, but may also develop into chronic inflammatory conditions without proper treatment. The clinical management normally includes non-prescription treatment (i.e., benzoyl peroxide and salicylic acid), or the administration of antibiotics orally or topically. However, such treatments can be ineffective or have side effects.
Sometimes, drugs can pass through the skin tissue. Also, the treatment becomes less effective when bacteria are drug resistant or when they migrate to subcutaneous tissue.
Also, P. acnes bacteria can secrete extracellular polysaccharides to form biofilm that blocks out the attacks initiated by antibacterial agents or immune cells.
Most microneedle products on the market use pharmaceutical ingredients to treat acne. However, repeated applications of antibiotics may reduce the sensitivity of bacteria to drugs. Patients who have been affected by acne for a long time will know that the effects of the same treatment products can be significantly reduced after long-term use.
Research method and findings
The HKUMed team has invented a new microneedle patch that facilitates the transdermal delivery of ultrasound-responsive antibacterial nanoparticles to treat the skin infection induced by P. acnes at minimal invasive approach. In the current design, ultrasound-responsive antibacterial nanomaterials are introduced to the microneedle patch that respond to bacterial infection quickly and efficiently. The use of drugs is avoided in the treatment. The modified nanoparticles comprised of ZnTCPP and ZnO are able to produce a substantial amount of reactive oxygen species (ROS) subject to ultrasound stimulation that can effectively oxidize the key cellular macromolecules of the bacteria.
The results demonstrated that the killing of P. acnes bacteria mediated by ROS can reach 99.73% after 15 minutes of ultrasound stimulation. Also, the levels of inflammatory markers, including tumor necrosis factor-a (TNF-α), interleukins (ILs), and matrix metalloproteinases (MMPs) are significantly reduced. Also, the zinc ions released can elevate the DNA replication-related genes, thereby augmenting more fibroblasts towards better skin repair.
A new approach for addressing skin infections
Kelvin Yeung Wai-kwok said: “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. 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.”
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