Parkinson's disease (PD) is one of the most common neurological disorders associated with later life, and its prevalence rises sharply with age. It affects the brain systems that control movement, often causing tremor, stiffness, slowness and problems with balance, all of which can reduce independence and quality of life in older adults. The condition is mainly linked to the gradual loss of dopamine-producing nerve cells. Current treatment usually relies on medicines such as levodopa, which can improve symptoms, especially in the earlier stages, but their benefit may become less consistent over time. For some patients, deep brain stimulation (DBS) offers another option, yet this involves surgery to place electrodes deep inside the brain.
These limitations continue to motivate the search for neuromodulation approaches that are both precise and less invasive. Prof. Lei SUN, Professor of the Department of Biomedical Engineering and Sports Technology and Director, Research Centre for Non-invasive Brain Computer Interface at The Hong Kong Polytechnic University, and his research team address the need for such approaches by combining low-intensity ultrasound with engineered hollow silica nanostructures (HSN) to achieve chronic, localised brain stimulation in mice, as well as therapeutic benefit in parkinson's disease models. The research titled, “Sono-mechanical nanostructures-enabled sustained precise ultrasound brain stimulation,” was published in Nature Communications.
The principal advancement of this work is the demonstration that ultrasound neuromodulation can be made both spatially precise and durable through the use of stable, sonoresponsive nanostructures. Conventional transcranial ultrasound is attractive because it penetrates deeply and can be delivered non-invasively, but its spatial resolution is typically limited to millimetre or centimetre scales, making selective activation of small neuronal populations difficult. Earlier nanoparticle- or nanobubble-assisted approaches improved localisation, but their in vivo instability limited usefulness for chronic applications. In contrast, the HSN developed by Prof. Sun and his team persisted in the mouse brain for more than nine weeks while remaining functionally responsive to ultrasound. This enabled repeated stimulation of targeted regions, including the motor cortex, striatum, ventral tegmental area (VTA) and subthalamic nucleus (STN), without genetic modification and without repeated intracranial administration.
To understand how the treatment worked, the team examined dopamine activity in brain circuits linked to movement. Ultrasound stimulation of the HSN-targeted STN increased dopamine signalling, suggesting that the approach activated pathways affected in Parkinson’s disease. Treated mice also showed better preservation of dopamine-related neurons. Similar benefits were seen in a second Parkinson’s model, indicating that this ultrasound-based method may achieve some DBS-like effects without implanted electrodes.
This research provides a compelling proof of concept for chronic, localised and minimally invasive neuromodulation using ultrasound and hollow silica nanostructures. The work is particularly relevant to age-related neurological disease because it addresses a central translational challenge: how to stimulate deep brain circuits precisely, repeatedly and safely without implanted hardware or genetic manipulation. For parkinson's disease and, potentially, other chronic neurological disorders, it suggests a future in which engineered nanomaterials and focused acoustic energy may complement or in some cases reduce reliance on, conventional invasive neuromodulation strategies.
Prof. Sun has 25 years of research and development experience in medical ultrasound technology, including in system development, signal/image processing and biomedical applications. He holds more than ten US and Chinese patents, either granted or filed. In recognition of Prof. Sun's outstanding research achievements in the field of biomedical engineering, he was awarded a fellowship under the Research Grants Council's (RGC) Senior Research Fellow Scheme (SRFS) 2025/26.
Source: Innovation Digest 8
