Nav: Home

Fluorescence imaging technique goes from micro to macro, moves closer to clinic

June 26, 2018

WASHINGTON -- Researchers have scaled up a powerful fluorescence imaging technique used to study biological processes on the cellular level. Previously limited to samples just millimeters in area, the expanded approach can analyze samples with areas up to 4 square centimeters. With further development the new approach could find use in the clinic as a sensitive and precise method for identifying the edges of tumors during surgery.

The new macroscale imaging approach is based on a biological imaging technique known as fluorescence lifetime imaging microscopy (FLIM). "Our macro-FLIM system can not only obtain a sample's structural information, but also allows observation of certain biochemical processes taking place within the sample," said senior research scientist Vladislav Shcheslavskiy, Becker & Hickl, GmbH, Germany. "Although our goal is to develop this for clinical use, it could also be very useful in fundamental studies for probing biological processes as disease develops or investigating biological responses to different types of therapy."

In The Optical Society (OSA) journal Optics Letters, the researchers demonstrate the first confocal microscopy based macro-FLIM system with cellular resolution and high molecular sensitivity. They used it to observe the metabolic processes inside a whole tumor in a live mouse, a feat that isn't possible with current FLIM systems. The new system was produced through a close collaboration between engineers and physicists from Becker & Hickl GmbH, Germany, and biologists from Privolzhskiy Research Medical University, Russia.

In addition to biological and clinical samples, the new macro-FLIM system could be used to analyze other samples with large areas. For example, it could offer a non-destructive method for determining the media used in paintings that need restoring.

Getting more information from fluorescence

FLIM involves precise measurements of the fluorescence decay rate, or lifetime, of a naturally fluorescent molecule or a fluorescent tag or "label" that has been added to tissue. Because the lifetime depends on characteristics of a molecule's environment such as temperature and pH as well as on its interaction with other surrounding molecules, FLIM can be used to obtain information about the properties of the molecule and its micro-environment.

Typically, FLIM is performed using laser scanning confocal microscopy, which achieves high resolution by scanning a laser beam across a fluorescent sample to form an image. To obtain FLIM information on a macro scale, the researchers developed a confocal macroscopy system that incorporates lasers with extremely short pulses -- only picoseconds in length -- and very sensitive detectors to sense the fluorescence. The system also included electronics that count the photons and plot their distribution in relation to the time since the laser pulse and the position of the laser beam on the sample.

Shcheslavskiy continued "Careful optical design along with the picosecond lasers, sensitive and fast detectors and fast single photon counting electronics allowed us to record fluorescence decay with high precision at macroscale."

Confocal microscopy is typically limited to an imaging area of just millimeters but placing the samples in the macroscanner's intermediate image plane allowed the researchers to image larger samples. They then plotted the photon distributions across a large area of the sample to acquire macro-scale fluorescence lifetime information.

Testing in cancerous tissue

To demonstrate the cellular resolution of the macro-FLIM system, the researchers used it to image fluorescent microbeads with a diameter of 14.6 microns and live cultured cancer cells labeled with fluorescent dye.

They then used the macro-FLIM system to analyze an entire tumor in a live mouse. They did this by simultaneously measuring the fluorescence lifetime of a genetically encoded red fluorescent protein, which identified the location of the tumor, and nicotinamid adenine dinucleotide (NADH), a molecule responsible for energy production in living cells.

"The sensitivity of our system was high enough to observe fluorescence of intrinsic tissue components such as NADH without any labeling," said Shcheslavskiy. "In addition to being used to study metabolism in a tumor, macro-FLIM could be used to follow cell death or oxygen status of tumors on a macroscale with cellular resolution."

To develop the system for clinical applications, the researchers are working to improve its flexibility and mobility. They also want to combine the macro-FLIM system with a scanning stage that would move the sample to allow FLIM to be performed on areas as large as 10 by 10 centimeters.
-end-
Paper: V. I. Shcheslavskiy, M. V. Shirmanova, V. V. Dudenkova, K. A. Lukyanov, A. I. Gavrina, A. V. Shumilova, E. V. Zagaynova, W. Becker. "Fluorescence Time-Resolving Macroimaging,"Opt. Lett., Volume 43, Issue 13, page 3152-3155 (2018). DOI: 10.1364/OL.43.003152.

About Optics Letters

Optics Letters offers rapid dissemination of new results in all areas of optics with short, original, peer-reviewed communications. Optics Letters covers the latest research in optical science, including optical measurements, optical components and devices, atmospheric optics, biomedical optics, Fourier optics, integrated optics, optical processing, optoelectronics, lasers, nonlinear optics, optical storage and holography, optical coherence, polarization, quantum electronics, ultrafast optical phenomena, photonic crystals and fiber optics.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.

Media Contact:

Rebecca B. Andersen
The Optical Society
randersen@osa.org
+1 202.416.1443

Azalea Coste
The Optical Society
ACoste@osa.org
+1 202.416.1435

The Optical Society

Related Tumor Articles:

Tumor progression depends on the tumor microenvironment
Researchers from Tokyo Medical and Dental University (TMDU) and Niigata University identified a novel mechanism by which tumors progress.
How do tumor cells divide in the crowd?
Scientists led by Dr. Elisabeth Fischer-Friedrich, group leader at the Excellence Cluster Physics of Life (PoL) and the Biotechnology Center TU Dresden (BIOTEC) studied how cancer cells are able to divide in a crowded tumor tissue and connected it to the hallmark of cancer progression and metastasis, the epithelial-mesenchymal transition (EMT).
Finding a way to STING tumor growth
The immune protein STING has long been noted for helping protect against viruses and tumors by signaling a well-known immune molecule.
Assembly within the tumor center
Number of macrophages in tumor tissue enables prognosis of lung tumor progression.
Mirror image tumor treatment
Our immune system ought to be able to recognize and kill tumor cells.
Traces of immortality in tumor DNA
To gain an infinite lifespan, cancer cells need to maintain the ends of their chromosomes, known as telomeres.
Peering into the genome of brain tumor
Scientists at Osaka University have created a machine learning method for classifying the mutations of glioma brain tumors based on MR images alone.
Glutamine-blocking drug slows tumor growth and strengthens anti-tumor response
A compound developed by Johns Hopkins researchers that blocks glutamine metabolism can slow tumor growth, alter the tumor microenvironment and promote the production of durable and highly active anti-tumor T cells.
Cancer genes and the tumor milieu
In a recent study published in Cancer Research, researchers demonstrate the role of an oncogene in altering the immediate environment of tumors.
Mechanism of tumor metastasis and tumor-suppressive role of UDP-glucose revealed
Scientists from Dalian Institute of Chemical Physics (DICP) and Shanghai Institute of Biochemistry and Cell Biology (SIBCB) of the Chinese Academy of Sciences revealed that UDP-glucose accelerates SNAI1 mRNA decay and impairs lung cancer metastasis.
More Tumor News and Tumor Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.