IST’s new infrared microscopy technique allows for the detailed imaging of biomolecules in cells, supporting advancements in biotechnology and cellular therapies.
In an effort to advance biotechnology innovations, scientists are working to develop faster, more quantitative, and more accessible ways to observe biomolecules in living cells.
Now, researchers at the National Institute of Standards and Technology (NIST) have developed a new method that allows the use of infrared (IR) light to capture clear images of biomolecules inside cells, something that was previously not possible due to the tendency of the water in cells to absorb infrared radiation.
NIST’s new method removes the obscuring effects of water in IR-based measurements and allows researchers to determine the amounts of key biomolecules in cells, such as the proteins that direct cell function. The ability to measure changes in living cells could speed up advances in biomanufacturing, cell therapy development, drug development, and more.
Their findings have been published in Analytical Chemistry.
Understanding Infrared Microscopy and Its Challenges
Infrared radiation is light that is just beyond what is visible to the human eye. Although we cannot see IR light, we can feel it as heat. In IR microscopy, a material of interest absorbs radiation from a range of wavelengths in the IR spectrum. Scientists measure and analyze the IR absorption spectrum of a sample, producing a set of “fingerprints” to identify molecules and other chemical structures. However, water, the most abundant molecule both inside and outside cells, absorbs infrared strongly and masks the infrared absorption from other biomolecules in cells.
One way to understand this optical masking effect is to compare it to when an airplane passes overhead next to the Sun. With the naked eye, it’s hard to see the airplane because of the Sun, but if you use a special Sun-blocking filter, then you can easily see the airplane in the sky.
“In the spectrum, water absorbs infrared so strongly, and we want to see the absorption spectrum of proteins through the thick water background, so we designed the optical system to uncloak the water contribution and reveal the protein signals,” said NIST chemist Young Jong Lee.
Advancing Cellular Analysis with SAC-IR
Lee developed a patented technique that uses an optical element to compensate for water absorption from IR. Called solvent absorption compensation (SAC), the technique was used with a hand-built IR laser microscope to image cells that support the formation of connective tissue, called fibroblast cells. Over a 12-hour observation period, researchers were able to identify groups of biomolecules (proteins, lipids, and nucleic acids) during stages of the cell cycle, such as cell division. While this may seem like a long time, the method is ultimately faster than current alternatives, which require beam time at a large synchrotron facility.
This new method, called SAC-IR, is label-free, meaning it does not require any dyes or fluorescent markers, which can harm cells and also produce less consistent results across labs.
The SAC-IR method enabled NIST researchers to measure the absolute mass of proteins in a cell, in addition to nucleic acids, lipids, and carbohydrates. The technique could help establish a foundation for standardizing methods for measuring biomolecules in cells, which could prove useful in biology, medicine, and biotechnology.
“In cancer cell therapy, for example, when cells from a patient’s immune system are modified to better recognize and kill cancer cells before being reintroduced back to the patient, one must ask, ‘Are these cells safe and effective?’ Our method can be helpful by providing additional insight with respect to biomolecular changes in the cells to assess cell health,” said Lee.
Other potential applications include using cells for drug screening, either in the discovery of new drugs or in understanding the safety and efficacy of a drug candidate. For example, this method could help to assess the potency of new drugs by measuring absolute concentrations of various biomolecules in a large number of individual cells or to analyze how different types of cells react to the drugs.
Future Applications and Improvements
The researchers hope to develop the technique further so it can measure other key biomolecules, such as DNA and RNA, with greater accuracy. The technique could also help provide detailed answers to fundamental questions in cell biology, such as what biomolecule signatures correspond with cell viability — in other words if the cell is alive, dying, or dead.
“Some cells are preserved in a frozen state for months or years, then thawed for later use. We don’t yet fully understand how best to thaw the cells while maintaining maximum viability. With our new measurement capabilities, we may be able to develop better processes for cell freezing and thawing by looking at their infrared spectra,” said Lee.
Reference: “Benchtop IR Imaging of Live Cells: Monitoring the Total Mass of Biomolecules in Single Cells” by Yow-Ren Chang, Seong-Min Kim and Young Jong Lee, 4 September 2024, Analytical Chemistry.
DOI: 10.1021/acs.analchem.4c02108

News
By working together, cells can extend their senses beyond their direct environment
The story of the princess and the pea evokes an image of a highly sensitive young royal woman so refined, she can sense a pea under a stack of mattresses. When it comes to [...]
Overworked Brain Cells May Hold the Key to Parkinson’s
Scientists at Gladstone Institutes uncovered a surprising reason why dopamine-producing neurons, crucial for smooth body movements, die in Parkinson’s disease. In mice, when these neurons were kept overactive for weeks, they began to falter, [...]
Old tires find new life: Rubber particles strengthen superhydrophobic coatings against corrosion
Development of highly robust superhydrophobic anti-corrosion coating using recycled tire rubber particles. Superhydrophobic materials offer a strategy for developing marine anti-corrosion materials due to their low solid-liquid contact area and low surface energy. However, [...]
This implant could soon allow you to read minds
Mind reading: Long a science fiction fantasy, today an increasingly concrete scientific goal. Researchers at Stanford University have succeeded in decoding internal language in real time thanks to a brain implant and artificial intelligence. [...]
A New Weapon Against Cancer: Cold Plasma Destroys Hidden Tumor Cells
Cold plasma penetrates deep into tumors and attacks cancer cells. Short-lived molecules were identified as key drivers. Scientists at the Leibniz Institute for Plasma Science and Technology (INP), working with colleagues from Greifswald University Hospital and [...]
This Common Sleep Aid May Also Protect Your Brain From Alzheimer’s
Lemborexant and similar sleep medications show potential for treating tau-related disorders, including Alzheimer’s disease. New research from Washington University School of Medicine in St. Louis shows that a commonly used sleep medication can restore normal sleep patterns and [...]
Sugar-Coated Nanoparticles Boost Cancer Drug Efficacy
A team of researchers at the University of Mississippi has discovered that coating cancer treatment carrying nanoparticles in a sugar-like material increases their treatment efficacy. They reported their findings in Advanced Healthcare Materials. Over a tenth of breast [...]
Nanoparticle-Based Vaccine Shows Promise in Fighting Cancer
In a study published in OncoImmunology, researchers from the German Cancer Research Center and Heidelberg University have created a therapeutic vaccine that mobilizes the immune system to target cancer cells. The researchers demonstrated that virus peptides combined [...]
Quantitative imaging method reveals how cells rapidly sort and transport lipids
Lipids are difficult to detect with light microscopy. Using a new chemical labeling strategy, a Dresden-based team led by André Nadler at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) and [...]
Ancient DNA reveals cause of world’s first recorded pandemic
Scientists have confirmed that the Justinian Plague, the world’s first recorded pandemic, was caused by Yersinia pestis, the same bacterium behind the Black Death. Dating back some 1,500 years and long described in historical texts but [...]
“AI Is Not Intelligent at All” – Expert Warns of Worldwide Threat to Human Dignity
Opaque AI systems risk undermining human rights and dignity. Global cooperation is needed to ensure protection. The rise of artificial intelligence (AI) has changed how people interact, but it also poses a global risk to human [...]
Nanomotors: Where Are They Now?
First introduced in 2004, nanomotors have steadily advanced from a scientific curiosity to a practical technology with wide-ranging applications. This article explores the key developments, recent innovations, and major uses of nanomotors today. A [...]
Study Finds 95% of Tested Beers Contain Toxic “Forever Chemicals”
Researchers found PFAS in 95% of tested beers, with the highest levels linked to contaminated local water sources. Per- and polyfluoroalkyl substances (PFAS), better known as forever chemicals, are gaining notoriety for their ability [...]
Long COVID Symptoms Are Closer To A Stroke Or Parkinson’s Disease Than Fatigue
When most people get sick with COVID-19 today, they think of it as a brief illness, similar to a cold. However, for a large number of people, the illness doesn't end there. The World [...]
The world’s first AI Hospital, developed in China is transforming healthcare
Artificial Intelligence and its developments have had a revolutionary impact on society, and healthcare is not an exception. China has made massive strides in AI integrated healthcare, and continues to do so as AI [...]
Scientists Rewire Immune Cells To Supercharge Cancer-Fighting Power
Blocking a single protein boosts T cell metabolism and tumor-fighting strength. The discovery could lead to next-generation cancer immunotherapies. Scientists have identified a strategy to greatly enhance the cancer-fighting abilities of the immune system’s [...]