Using CLF’s Octopus facility at the Lasers for Science Facility (LSF), the team created a method to precisely target neurovascular regions within the brain.
Using diesel exhaust particles as a representative air pollution exposure, the team generated three-dimensional datasets revealing nanoscale structural changes in brain tissue. The approach provides a tool for understanding how inhaled particles interact with the brain and contribute to neurodegenerative disease, including dementia.
Challenge
Growing evidence suggests that air pollution is a modifiable risk factor for dementia. Academic studies have linked pollution exposure to changes in brain structure - including analyses of UK Biobank data suggesting long-term exposure to air pollution may alter brain structure - while laboratory studies show inhaled particles can enter the bloodstream and potentially reach the brain.
However, directly observing how these particles interact with brain tissue remains challenging. Identifying specific regions of interest, such as individual blood vessels within the neurovasculature, requires navigating vastly different spatial scales. Researchers must move from whole-brain imaging to nanometre-scale cellular features.
Traditional electron microscopy techniques can provide extremely high resolution, but locating the correct region within a large sample can be time-consuming and inefficient. Without reliable targeting, researchers risk spending significant time searching for the structures they wish to analyse.
Approach
The team developed a multi-stage correlative imaging workflow to bridge these scale challenges. Using the CLF’s LSF Octopus imaging facility, researchers combined the CLF’s laser branding expertise and electron microscopy infrastructure with ConnectomX’s Katana serial block-face microtome, a technology developed by the SME and demonstrated through facility access.
The study focused on the hippocampus, a brain region associated with learning and memory and sensitive to environmental stressors. Regions of interest were first identified using light microscopy and laser branding, allowing the same location to be relocated during electron microscopy. ConnectomX’s Katana ultramicrotome enabled serial block-face scanning electron microscopy (SBF-SEM), slicing thin layers from the sample inside the SEM chamber while each surface was imaged, generating volumetric datasets that helped locate the target structures.
Once the region was identified, focused ion beam scanning electron microscopy (FIB-SEM) was used to capture nanoscale images (5–10 nm) of hippocampal neurovascular structures. Together, these steps created a pipeline linking millimetre-scale anatomy with nanometre-scale structural detail.
Benefits
The workflow provides a new way to investigate how environmental particles interact with the brain. By improving targeting accuracy, researchers can generate high-resolution datasets while reducing the time and cost of nanoscale imaging.
For public health researchers, this approach helps study how inhaled particles cross the blood-brain barrier and affect neurological health. The method shows the potential to support studies of other environmental exposures, including emerging concerns such as micro- and nanoplastics.
More broadly, the project demonstrates the value of collaborative research combining national facilities, innovative instrumentation and public health expertise. It shows how SME-developed technologies can be tested and demonstrated through facility access to support real-world research applications.
The workflow can also be adapted to be broadly applicable across diverse xenobiotics exposures and disease models, helping researchers understand how environmental exposures affect human health.
Quote
“The novel part of this workflow is dealing with scales and targeting. Serial block-face SEM bridges that middle step, allowing us to locate the exact region before moving to super-high-resolution FIB-SEM imaging.”
- Dr Edward Duckworth, Head of Software, Bio-applications at ConnectomX
