We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
PURITAN MEDICAL

Download Mobile App




Fine-Tuned Microscopy Offers Breakthrough Resolution of Melanoma

By LabMedica International staff writers
Posted on 17 Mar 2017
Print article
Image: A melanoma on a patient\'s skin (Photo courtesy of the National Cancer Institute).
Image: A melanoma on a patient\'s skin (Photo courtesy of the National Cancer Institute).
Researchers have refined a classic Raman-based technique and succeeded in imaging the two dominant melanin molecules, which could lead to new understandings and, critically, early detection of melanoma.

People with fair skin have higher concentration of pheomelanin in their skin, and a corresponding higher risk of developing melanoma – particularly the difficult-to-detect subtype amelanotic melanoma. In high concentrations, pheomelanin is responsible for the orange-reddishness in hair, but is essentially invisible in skin. While the brown-black pigment eumelanin found in most melanomas can be easily seen, the light colored pheomelanin is difficult to detect even with current advances in modern microscopy.

Massachusetts General’s chief of dermatology Dr. David Fischer had initially approached Prof. Conor Evans of Harvard University (MA, USA), who took on the pheomelanin imaging challenge with his team. Their research centers on using coherent anti-Stokes Raman Scatterings (CARS) microscopy, a variant Raman spectroscopy. In general, CARS microscopy utilizes two lasers focused on a sample whose energy difference is “tuned” to specific molecular vibrations to generate high-resolution imaging information.

While another optical technology, transient absorption microscopy, does offer possibilities for studying pheomelanin, this method is complex and does not easily lend itself to clinical practice. “We started to look through the Raman literature,” said Prof. Evans, “Raman spectroscopy is a very mature technique that allows you to detect molecules by their unique chemical vibrations, which are themselves derived from the structure of the molecules. CARS microscopy is a coherent Raman tool that is akin to using a tuning fork to specifically detect molecular structures.”

“We started to look at the molecular structure [of pheomelanin] and noticed there was a corresponding unique molecular vibration that might be useful for imaging the pigment with CARS microscopy.” CARS microscopy proved successful for imaging pheomelanin, a breakthrough for detecting and studying this elusive molecule in skin.

Dr. Sam Osseiran and Dr. Tracy Wang, researchers in the group led by Prof. Evans, led the way in developing and refining CARS microscopy for imaging pheomelanin. “The work led by Tracy was really rather novel application of CARS microscopy to target this biomolecule which no one else has tried to do before,” said Dr. Osseiran, “We adjusted our system and aligned and tuned everything so that we could specifically target this one melanin pigment, pheomelanin.”

Serendipitously, while developing their CARS imaging method, the group found a complementary method, sum-frequency absorption (SFA) microscopy, that could be used for the simultaneously detection of eumelanin. SFA makes use of a signal modulation scheme that can detect both species of melanin. This additional imaging tool is important, as most humans produce both species within skin, making mapping the distribution and quantity of both pigments important.

“SFA imaging allows you to visualize where all the melanin absorbers are within tissue,” said Prof. Evans, “As both CARS and SFA can be carried out at the same time, these two techniques can be used together to simultaneously image both melanin pigments.” Drs. Wang and Osseiran believe their CARS and SFA method could be very helpful for future research and treatment of melanoma, including for observing changes that occur with melanin species in different states.

The study’s original motivator, Dr. Fischer, believes that another important benefit of the work might be its potential role in diagnosing cancer: “This may offer a brand-new tool for early diagnosis for some of the most lethal melanomas, possibly at a stage when they might still be curable,” he said, “Time and time again, it is proven that early diagnosis saves lives.”

Dr. Osseiran will present their findings at the OSA Biophotonics Congress: Optics in the Life Sciences meeting (April 2-5; San Diego, CA, USA).

Platinum Member
COVID-19 Rapid Test
OSOM COVID-19 Antigen Rapid Test
One Step HbA1c Measuring System
GREENCARE A1c
POCT Fluorescent Immunoassay Analyzer
FIA Go
New
Gold Member
Fully Automated Cell Density/Viability Analyzer
BioProfile FAST CDV

Print article

Channels

Clinical Chemistry

view channel
Image: Reaching speeds up to 6,000 RPM, this centrifuge forms the basis for a new type of inexpensive, POC biomedical test (Photo courtesy of Duke University)

POC Biomedical Test Spins Water Droplet Using Sound Waves for Cancer Detection

Exosomes, tiny cellular bioparticles carrying a specific set of proteins, lipids, and genetic materials, play a crucial role in cell communication and hold promise for non-invasive diagnostics.... Read more

Molecular Diagnostics

view channel
Image: The study showed the blood-based cancer screening test detects 83% of people with colorectal cancer with specificity of 90% (Photo courtesy of Guardant Health)

Blood Test Shows 83% Accuracy for Detecting Colorectal Cancer

Colorectal cancer is the second biggest cause of cancer deaths among adults in the U.S., with forecasts suggesting 53,010 people might die from it in 2024. While fewer older adults are dying from this... Read more

Hematology

view channel
Image: The Gazelle Hb Variant Test (Photo courtesy of Hemex Health)

First Affordable and Rapid Test for Beta Thalassemia Demonstrates 99% Diagnostic Accuracy

Hemoglobin disorders rank as some of the most prevalent monogenic diseases globally. Among various hemoglobin disorders, beta thalassemia, a hereditary blood disorder, affects about 1.5% of the world's... Read more

Microbiology

view channel
Image: The new platform is designed to perform blood-based diagnoses of nontuberculosis mycobacteria (Photo courtesy of 123RF)

New Blood Test Cuts Diagnosis Time for Nontuberculous Mycobacteria Infections from Months to Hours

Breathing in nontuberculous mycobacteria (NTM) is a common experience for many people. These bacteria are present in water systems, soil, and dust all over the world and usually don't cause any problems.... Read more

Industry

view channel
Image: These new assays are being developed for use on the recently introduced DxI 9000 Immunoassay Analyzer (Photo courtesy of Beckman Coulter)

Beckman Coulter and Fujirebio Expand Partnership on Neurodegenerative Disease Diagnostics

Beckman Coulter Diagnostics (Brea, CA, USA) and Fujirebio Diagnostics (Tokyo, Japan) have expanded their partnership focused on the development, manufacturing and clinical adoption of neurodegenerative... Read more
Copyright © 2000-2024 Globetech Media. All rights reserved.