Microscopy has played a crucial role in exploring the microscopic world, allowing scientists to delve into the inner workings of cells and uncovering details previously unseen. However, each microscopy technique comes with its limitations, whether it be the need for fluorescent labeling or the inability to observe live samples. In a groundbreaking development, a team of researchers at the University of Tokyo have revolutionized mid-infrared microscopy, achieving a remarkable 30-fold improvement in resolution compared to conventional methods.
Traditional microscopy techniques, such as super-resolution fluorescent microscopy and electron microscopy, have been instrumental in revealing the intricate details of cells and molecular structures. However, these methods have their drawbacks. Super-resolution fluorescent microscopy requires specimens to be labeled with fluorescence, which can be harmful to samples and lead to sample bleaching with prolonged light exposure. On the other hand, electron microscopy provides exceptional details but necessitates samples to be placed in a vacuum, making it impossible to study live samples.
Mid-infrared microscopy offers a unique advantage in providing both chemical and structural information about live cells without the need for labeling or damaging the samples. Despite its potential, mid-infrared microscopy has been limited by its lower resolution capabilities compared to other microscopy techniques. Typically, mid-infrared microscopy could achieve a resolution of around 3 microns, significantly lower than super-resolution fluorescent microscopy which can narrow down images to tens of nanometers.
The researchers at the University of Tokyo overcame the resolution limitations of conventional mid-infrared microscopy by achieving an unprecedented spatial resolution of 120 nanometers. Professor Takuro Ideguchi from the Institute for Photon Science and Technology at the University of Tokyo explained that this remarkable improvement was made possible by using a “synthetic aperture” technique, combining multiple images taken from various illuminated angles to create a more detailed picture.
To enhance resolution and image clarity, the research team utilized a single lens setup and a silicon plate for sample placement, which reflected visible light and transmitted infrared light. This configuration allowed for better illumination of the sample with mid-infrared light and enabled the researchers to observe the intracellular structures of bacteria with exceptional clarity. The team used bacterial samples, including E. coli and Rhodococcus jostii RHA1, to demonstrate the capabilities of their improved mid-infrared microscope.
The enhanced resolution of mid-infrared microscopy opens up new possibilities for research in various fields, including infectious diseases and antimicrobial resistance. With the ability to observe samples at a scale of 120 nanometers, researchers can delve deeper into the mechanisms of antimicrobial resistance and other critical issues facing healthcare. Additionally, the researchers at the University of Tokyo believe that further improvements in the technique, such as using better lenses and shorter wavelengths of visible light, could push the spatial resolution below 100 nanometers in the future.
The breakthrough in mid-infrared microscopy by the University of Tokyo represents a significant advancement in the field of microscopy. By pushing the boundaries of resolution and image clarity, researchers have paved the way for exploring the intricate structures inside living bacteria with unprecedented precision. This breakthrough not only benefits biological research but also holds promise for advancements in various scientific disciplines in the future.