Led by Stefan Wilhelm, Ph.D., assistant professor in the Stephenson School of Biomedical Engineering at the University of Oklahoma, a team of researchers from the OU Gallogle School of Engineering, the OU Health Sciences Center and Yale University published an article in ACS Nano which describes their development of a super-resolution imaging platform technology to improve understanding of how nanoparticles interact within cells.
As technology-based capabilities in engineering and healthcare continue to grow, scientists and engineers are working to develop new technologies to advance the future of health. One such field, nanomedicine, is exploring the use of nanoparticles to deliver drugs into the body to fight infectious diseases or cancer. Evaluation of these nanomedicines in cells, tissues, and organs is often done by optical imaging, which can have a limited quality of imaging resolution. New imaging techniques are needed to see nanoparticles in the context of the 3D ultrastructure within biological tissues.
“To see nanomedicine in biological samples, researchers use either electron microscopy, which provides excellent spatial resolution but lacks 3D imaging capabilities, or optical microscopy, which achieves excellent 3D imaging, but displays relatively low spatial resolution,” Wilhelm said. “We demonstrate that we can perform 3D imaging of biological samples with electron microscope-like resolution. This technique, called super-resolution imaging, allows us to see nanomedicines inside individual cells. With this new super-resolution imaging method, we can now begin to track and monitor nanoparticles.” inside cells, which is a prerequisite for designing nanomedicines that are safer and more effective in reaching specific areas within cells.”
The researchers applied a super-resolution 3D imaging technique known as expansion microscopy that involves embedding cells inside swollen hydrogels. Like the water-absorbent materials used in diapers, hydrogels actually expand up to 20 times their original size when in contact with water.
“This expansion allows imaging of cells with a lateral resolution of approximately 10 nanometers using a conventional optical microscope,” said Wilhelm. “We combined this method with a method for imaging metal nanoparticles inside cells. Our method exploits the inherent ability of metal nanoparticles to scatter light. We used scattered light to image and quantify intracellular nanoparticles without the need for any additional nanoparticle labels.”
The authors suggest that ultra-high-resolution imaging platform technology can be used to improve the engineering of safer and more effective nanomedicines to enhance the translation of these technologies into the clinic.