A recent study published in Science Advances introduces an innovative and groundbreaking acne treatment.¹ A microneedle patch, embedded with ultrasound-responsive antibacterial nanoparticles, has been developed by a team of researchers from the Department of Orthopaedics and Traumatology, School of Clinical Medicine, LKS Faculty of Medicine, the University of Hong Kong (HKUMed).¹ This treatment effectively eradicates acne-causing bacteria, providing a painless, non-antibiotic approach for treating this common skin condition.¹ Remarkably, the novel treatment also simultaneously facilitates skin repair.¹

Acne is a common, chronic inflammatory skin disease caused by anaerobic Propionibacterium acnes (P. acnes), with a prevalence of up to 91.3% among adolescents.² The condition is characterized by seborrhea, comedones, papules, pustules, nodules, and cysts, which can lead to permanent scars and keloids in severe cases.² The psychological impact of moderate-to-severe acne can be significant in adolescents, particularly with regard to self-esteem and their long-term personal growth.² Currently, the first-line treatment approach for moderate-to-severe acne involves the use of systemic antibiotics, often in combination with topical therapies such as retinoids.³ However, there are challenges with the adoption of these conventional treatments.⁴ Due to the presence of skin barrier, topical agents are often formulated to adequately penetrate the skin, thus reducing their therapeutic effectiveness.⁴ In addition, the frequent use of oral antibiotics could disrupt the normal gut flora and cause various adverse effects (AEs).⁴ A further concern is the potential of P. acnes developing resistance to antibiotics over time due to prolonged usage.⁴ Hence, an alternative for acne treatment is warranted.

The new microneedle patch, invented by HKUMed researchers, utilizes ultrasound-responsive nanoparticles as a cure.⁴ It is composed of zinc porphyrin-based (ZnTCPP) metal-organic frameworks (MOF) and zinc oxide (ZnO), which can quickly and effectively eradicate bacteria, also contributing to skin repair.⁴ Facilitated by sodium hyaluronate, these microneedles can dissolve into the dermis, subsequently releasing the nanoparticles.⁴ In response to the excitation by ultrasound that can penetrate more than 5cm beneath the human skin and connective tissue, the ultrasound-responsive materials can generate reactive oxygen species (ROS) to kill bacteria through oxidizing their key cellular macromolecules, regardless of whether the bacteria are Gram-positive or Gram-negative.⁴ Furthermore, the zinc ions released from the nanomaterials can up-regulate metallothioneins (MTs) in skin fibroblasts, promoting fibroblast proliferation and skin repair.⁴

In this study, the antibacterial effect of these novel microneedles was demonstrated.⁴ Results showed that 99.73% of P. acnes were eradicated after 15 minutes of ultrasound stimulation, which were achieved by rupture of bacterial cell membrane mediated by ROS.⁴ Additionally, to verify the antibacterial effect of the microneedles against other drug-resistant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) was selected, with the result showing the antibacterial efficiency reaching 99.64%.⁴

Upon performing 15 minutes of ultrasound irradiation, the concentration of inflammatory markers, such as tumor necrosis factor-a (TNF-α), interleukins (ILs), and matrix metalloproteinases (MMPs), was notably diminished.¹ Moreover, the release of zinc ions was shown to stimulate genes relating to deoxyribonucleic acid (DNA) replication.¹ This resulted in an increase in fibroblasts, leading to enhanced skin repair.¹

Professor Yeung, Wai-Kwok Kelvin, a key researcher of the study, conveyed that these microneedles embedded with ultrasound-responsive nanoparticles offer a rapid, effective, non-antibiotic, and transdermal approach for patients also suffering from acne caused by P. acnes.¹ He also highlighted that this novel treatment has the potential to manage other infections caused by fungi, parasites, or viruses.¹