A research team led by Kelvin Yeung from Department of Orthopedics and Traumatology, School of Clinical Medicine, LKS School of Medicine, University of Hong Kong (HKUMed) have designed a new microneedle patch that provides an effective non-antibiotic approach to treatment. from skin infections.
The design engineered with ultrasound-responsive metal-organic framework (MOF) zinc-based antibacterial nanoparticles promises painless delivery to treat bacterial infections of skin tissue and facilitate skin repair at the same time. The new microneedles are about 50 microns in diameter, similar to normal hair. These findings have been published in Science Advances.
Acne is a common skin disease worldwide that affects more than 80% of adolescents and young adults. This causes excessive lipid secretion which clogs the hair follicles, thus creating a hypoxic microenvironment in the skin tissue. This causes proliferation Propionibacterium acnes bacteria.
This not only causes physical and emotional distress to the patient, but can also develop into a chronic inflammatory condition without proper treatment. Clinical management usually includes over-the-counter medications (ie, benzoyl peroxide and salicylic acid), or oral or topical administration of antibiotics. However, such treatments may be ineffective or have side effects.
Sometimes, the drug can pass through the skin tissue. Also, treatment becomes less effective when the bacteria are resistant to the drug or when they migrate to the subcutaneous tissue.
Also, P. acnes bacteria can secrete extracellular polysaccharides to form biofilms that block attacks initiated by antibacterial agents or immune cells.
Most of the microneedle products on the market use pharmaceutical ingredients to treat acne. However, repeated use of antibiotics can reduce the sensitivity of bacteria to drugs. Patients who have had acne for a long time will find that the effects of the same treatment product can be significantly reduced after prolonged use.
Research methods and findings
The HKUMed team has devised a new microneedle patch that facilitates transdermal delivery of ultrasound-responsive antibacterial nanoparticles to treat skin infections caused by P. acnes with a minimally invasive approach. In the current design, an ultrasound responsive antibacterial nano material is introduced to the microneedle patch which responds quickly and efficiently to bacterial infection. The use of drugs is avoided in treatment. The modified nanoparticles composed of ZnTCPP and ZnO are capable of generating large amounts of reactive oxygen species (ROS) subject to ultrasound stimulation which can effectively oxidize major cellular macromolecules of bacteria.
The results showed that ROS-mediated killing of P. acnes bacteria could reach 99.73% after 15 minutes of ultrasound stimulation. Also, levels of inflammatory markers, including tumor necrosis factor-a (TNF-α), interleukins (ILs), and matrix metalloproteinases (MMPs) were significantly reduced. In addition, zinc ions released can increase DNA replication related genes, thereby adding more fibroblasts towards better skin repair.
A new approach to treating skin infections
Kelvin Yeung Wai-kwok said: “The new microneedle patch which enables the formation of ROS through ultrasound stimulation, considered as a non-antibiotic and transdermal approach, can not only effectively treat infections caused by P. acnes bacteria, but also facilitate skin repair due to the release of zinc ion. Due to the specific ROS killing mechanism, we believe that this design is also capable of treating other skin infections caused by fungi, parasites or viruses, such as tinea pedis.”
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