In the world of biology, scientists are using advanced imaging techniques to delve into the intricate structures and processes within individual cells. By employing a combination of hard X-ray computed tomography and X-ray fluorescence imaging, researchers at the U.S. Department of Energy’s Brookhaven National Laboratory have made significant strides in visualizing the inner workings of cells without causing harm to their delicate components. Their groundbreaking work has been documented in Communications Biology.
Understanding the complexities of cellular structures, chemical interactions, and biological signaling at the nanometer scale has profound implications for various fields including medicine and agriculture. This research not only enhances our ability to visualize the inner world of cells but also lays the foundation for the development of improved biological imaging tools and technologies.
Delving into the Cell’s Core
Before embarking on the imaging process, researchers faced challenges in preparing the cell samples. Opting to study a cell from the human embryonic kidney (HEK) 293 line known for its growth ease but susceptibility to X-ray damage, the team undertook a meticulous process to fortify the samples. Using paraformaldehyde for preservation, rapid freezing with liquid ethane, and freeze-drying to maintain cellular structure, the researchers readied the samples for imaging under a microscope.
Despite the cells’ minute size (around 12-15 microns in diameter), ensuring their structural integrity during multiple X-ray measurements posed a significant hurdle. To address this, the scientists developed standardized sample holders for stability and utilized optical microscopes for precise cell location and imaging, minimizing X-ray exposure.
Utilizing Multiple Imaging Techniques
Employing X-ray computed tomography (XCT) and X-ray fluorescence (XRF) microscopy at the National Synchrotron Light Source II (NSLS-II), researchers gained insights into both the physical structure and chemical composition of the cells. XCT, operating on the FXI beamline, revealed cross-sectional views of the cells, akin to medical CT scans. XRF microscopy on the SRX beamline provided details on the distribution of chemical elements within the cells, aiding in understanding biological functions.
The combined approach of XCT and XRF imaging offered complementary information crucial for biological studies. Planning for the upcoming Quantitative Cellular Tomography (QCT) beamline, researchers aim to enhance bio-imaging capabilities with cryo-soft X-ray tomography for detailed cellular analysis.
Envisioning Future Discoveries
By delving into cellular structures, researchers not only unravel the mysteries within human cells but also gain insights into pathogen-host interactions, symbiotic relationships, and plant diseases. The ability to visualize cellular interactions at a molecular level opens doors to understanding infectious diseases, developing targeted treatments, and fortifying crops against harmful pathogens.
Collaborative efforts between national laboratories and universities are shedding light on molecular interactions in plants, such as sorghum’s defense mechanisms against pathogenic fungi. By harnessing advanced imaging technologies, scientists are uncovering the microscopic battles within cells, paving the way for tailored solutions to combat disease and enhance agricultural resilience.
This pioneering work, supported by Brookhaven’s Laboratory Directed Research and Development funds and the DOE Office of Science, demonstrates the power of synchrotron science in revealing the hidden realms of cellular biology.
