NEW YORK (360Dx) – Georgia State University researchers are developing an infrared spectroscopy method that could help clinicians avoid invasive procedures including tissue biopsies in detecting lymphoma, subcutaneous melanoma, or colitis.
The technique uses the attenuated total reflection (ATR) sampling mode of Fourier transform infrared spectroscopy (FTIR) to provide high-quality results and better spectral reproducibility than other infrared sampling modes, the researchers said.
Using FTIR spectroscopy of serum samples in ATR sampling mode and appropriate data handling frameworks, the researchers have identified and quantified unique spectral markers for each diseased condition.
Importantly, the technique could give patients an inexpensive diagnostic technique that could enable avoiding expensive and uncomfortable procedures such as colonoscopies and other procedures involving tissue biopsies, Unil Perera, one of the GSU researchers developing the ATR-FTIR method for clinical applications, said in an interview.
FTIR spectroscopy obtains an infrared spectrum of absorption or emission of a solid, liquid, or gas. In clinical research, it extracts a snapshot of molecular components within the diagnostic medium.
The FTIR technique is attractive for rapid, reliable, and affordable screening of multiple diseases, and it's been widely applied for the study of several cancers including those of the cervix, lung, breast, prostate, colon, ovary, bladder, and gastrointestinal system, the researchers noted.
Adding ATR to FTIR provides a sampling method that relies on a property called total internal reflection through which infrared beams reflect off the surfaces of a crystal. The infrared light reflecting within the crystal also creates evanescent waves that penetrate a biological sample connected to a surface of the crystal. Some of the wave's reflected energy is absorbed by the sample and detected by the diagnostic system, enabling researchers to identify spectral signatures, or absorbance peaks, associated with samples that are healthy and differentiate among those that are diseased.
In practice, the structural rearrangement associated with the development of a cancer or other disease alters the vibrational mode of the molecular functional groups of the affected tissues, and the ATR-FTIR technique picks up and analyzes the spectral signatures reflected by these rearrangements.
The researchers said that ATR sampling method in IR spectral measurement is easier for sample preparation for clinical laboratories, and it has better sample-to-sample spectral reproducibility compared with other sampling methods of FTIR spectroscopy. In addition to simplicity and reproducibility, it offers rapid detection of biochemical alteration in the diagnostic medium, they added.
Because biological samples are so complicated, with millions of different chemicals in an individual sample, it is difficult to differentiate normal from healthy samples and characterize disease by transmitting infrared light through the sample, Perera said. Using the ATR method of sampling, however, the researchers take a different approach. They control the depth of penetration of light beams in the sample and only measure the energy in evanescent reflected beams. "Although the technique is early in its development, ATR-FTIR spectroscopy accompanied with appropriate data handling frameworks is an excellent vibrational spectroscopic technique in future clinical application," Perera added.
In a study, published online this month in the Nature research journal Scientific Reports, the GSU researchers used a mouse model to demonstrate the diagnostic capability of ATR-FTIR spectroscopy for melanoma and non-Hodgkin's lymphoma by testing air-dried serum samples.
The GSU researchers used ATR-FTIR's mid-infrared spectroscopy to analyze blood serum derived from mice and to differentiate mice with non-Hodgkin's lymphoma from mice with subcutaneous melanoma, and to differentiate mice with both types of cancer from healthy mice.
The incidence rates of cutaneous melanoma have increased in many regions and populations over the last decade, including between 3 and 7 percent per year among fair-skinned populations, GSU said, and non-Hodgkin’s lymphoma accounts for 4.3 percent of new cancer cases in the US.
The available diagnostic regimen for both NHL and melanoma, which includes tissue examination and biopsy, is time-consuming, invasive, and costly, resulting in small compliance rates of eligible populations for cancer prescreening, the researchers said. Developing a rapid and reliable prescreening strategy for melanoma and lymphoma is critical, they added, because early diagnosis and treatment of these malignancies improve the patients’ chances of survival.
Although the ATR-FTIR technique is early in its development for clinical applications, Perera said that the results observed in mouse serum samples could translate to human serum samples because mice and humans have some biomarkers and chemicals in common.
Using the data collected on the biomarkers for lymphoma and melanoma, the researchers expect to be able to develop detectors that doctors could use to test patients' blood samples for these cancers. Doctors could track a patient's blood test results starting in infancy and monitor them over the years to ascertain when the numbers begin to change, the researchers said. Physicians would monitor differences for a patient from test to test and whether patients' results are within a normal range.
In addition to cancer testing, the GSU researchers published a study earlier this year in the Journal of Biophotonics that described the use of ATR-FTIR as a screening technique for testing mouse serum for colitis.
As a next step, they are focusing on obtaining human serum samples so that they can calculate spectral regions linked to disease and differentiate them from those of patients with normal samples. Perera noted that in their work on inflammatory bowel syndrome linked to acute or ulcerative colitis the researchers are looking to establish spectral limits that differentiate whether a sample is from a patient with a disease or not.
For example, they are establishing healthy and unhealthy limits for substances such as glucose and mannose that would indicate whether a patient had inflammatory bowel syndrome and could need to have a colonoscopy or could avoid having a one, he said. After the group has demonstrated the technique in a few hundred human samples, it plans to enter clinical trials, but that may be at least two years in the future, Perera said.
Infrared emerging for Dx
In a recent interview with 360Dx, Prabhas Moghe, a distinguished professor of biomedical, chemical, and biochemical engineering at Rutgers, who also is developing an infrared diagnostic system for clinical applications, said that much of the infrared technology infrastructure has been available for military applications and it is gradually moving into health systems.
Moghe along with fellow researchers at Rutgers and Singapore University of Technology and Design are developing a diagnostic technique that obtains shortwave infrared signals that identify and trace the evolution of cancer cells inside the body.
The technique, which uses nanoparticles tagged with antibodies, peptides, or drug molecules that have an affinity for cancer cells, could be available commercially in about five years to guide cancer surgeries, the researchers said.
Other researchers are also exploring the use of infrared spectroscopy for clinical use.
Rehovot, Israel-based Todos Medical said it believes the low-cost infrared-based spectroscopy tests it is developing could give it an advantage in product placements related to enabling noninvasive screening for cancers.
Todos Medical noted that its Total Biochemical Infrared Analysis system — which leverages FTIR and a proprietary technique that analyzes the spectrometer's test results — would screen for solid tumors by measuring spectra representing biochemical changes in peripheral blood mononuclear cells. The firm has said that its tests for breast and colorectal cancers are nearing commercial launch and could be on the market in 2018 in Israel and parts of Asia, with a later launch planned in the US and Europe.
Researchers working on tests to detect neurodegenerative diseases are also looking toward infrared spectroscopy within their technology platforms. Earlier this year, researchers at the University of Central Lancashire, in Preston, UK, said that they achieved accurate results using such a platform to identify Alzheimer's disease and other forms of dementia in patients' blood.
A commercial diagnostic test that uses the technique could be at least a few years away, those researchers said.
In the realm of pathogen detection, startup 3iDx is raising $5 million to accelerate development of a novel pathogen detection platform. It incorporates a fluidics component that isolates whole pathogens from blood samples and a reader that relies on infrared-based detection.
Perera noted that his team's ultimate objective is to use the infrared technique to identify a variety of diseases. “This study shows infrared spectroscopy can identify cancer," he said.
He noted that the researchers hope that one-day clinicians and patients will be able to screen for serious diseases in the same way that routine tests are now done.