Bio & Medicine

A team of researchers has created 2D ultrasound-responsive antibacterial nano-sheets to efficiently treat bone tissue infection.

A technology that effectively reduces methicillin-resistant Staphylococcus aureus (MRSA) infection in bony tissue has been developed by a research team led by Professor Kelvin Yeung Wai-kwok from the Department of Orthopaedics and Traumatology, School of Clinical Medicine, LKS Faculty of Medicine, the University of Hong Kong (HKUMed). This technology does not require the use of antibiotics and is non-invasive.

When subjected to ultrasound stimulation, the novel antibacterial nanosheets are able to release a significant amount of reactive oxygen species (ROS). The nanosheets are able to effectively eliminate 99.72 percent of the MRSA bacteria that are buried deep within bony tissue by engulfing the neutrophil membrane (NM). Advanced Materials has published the research.

An infection of the bone or bone marrow caused by bacteria, fungi, or other microorganisms is known as osteomyelitis. MRSA is the most prevalent pathogen that causes disease. Patients at risk of amputation or even life-threatening sepsis can develop severe infections. In clinical settings, antibiotics and surgical debridement to remove infected bone or tissue are typically used to treat infections of bone tissue.

“Our design has made a quantum leap by transforming the ROS catalytic site in the sonosensitizer from zero-dimensional to two-dimensional. This invention has the potential to significantly enhance bactericide production (ROS). In the future, we may investigate extending our technology to the prevalent post-operative bacterial infection encountered in bone cancer patients, as well as patients with cystitis and peritonitis.”

Professor Kelvin Yeung Wai-kwok .

Antibiotic overuse, on the other hand, may unavoidably lead to the emergence of drug-resistant pathogens and compromise the host’s innate immune system. As of late, phototherapy (including photodynamic and photothermal treatment) has been applied as an anti-toxin-free technique to handle bacterial diseases. Due to its limited penetration power, conventional phototherapy, on the other hand, is unable to treat bone-deep tissue infections.

The specialists accordingly sought an elective anti-microbial-free methodology saddled with the entrance force of ultrasound in human tissues.

Ti3C2-SD(Ti3+) nano-sheets, a brand-new two-dimensional (2D) sonosensitizer, were developed by the HKUMed research team. ROS generation is limited by a conventional zero-dimensional sonosensitizer’s efficiency.

When triggered by an ultrasound signal, the novel 2D sonosensitizer, which has a lot of planar catalytic sites, can effectively produce a lot of reactive oxygen species. The NM-Ti3C2-SD(Ti3+) nano-sheets (NM-nano-sheets) can actively locate the MRSA bacteria in ultrasound-stimulated bony tissue after being covered with a neutrophil membrane (NM).

In contrast to the antibiotic therapy (Vanco), which is ineffective, the novel nano-sheets have eliminated the MRSA bacteria in bones in more than 99.72 percent of cases in an animal model. After the infection in the bony tissue has been controlled, the NM-nanosheets can also aid in bone repair and reduce tissue inflammation. Additionally, there are no immediate biosafety concerns with the NM-coated nanosheets.

“Our design has achieved a qualitative leap in that the ROS catalytic site in sonosensitizer has transformed from zero-dimensional to two-dimensional,” Professor Kelvin Yeung Wai-kwok noted. The production of bactericide (ROS) can be significantly increased by this invention. In the future, we may also think about applying this invention to patients with cystitis and peritonitis or the common bacterial infection after surgery in bone cancer patients.”

More information: Congyang Mao et al, Realizing Highly Efficient Sonodynamic Bactericidal Capability through the Phonon–Electron Coupling Effect Using Two‐Dimensional Catalytic Planar Defects, Advanced Materials (2022). DOI: 10.1002/adma.202208681

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