Infrared microscopy based on quantum cascade laser pointer can be used for rapid, label-free classification of colorectal cancer tissue.
Infrared imaging has proven to be a reliable method of organizing cell tissue. However, the Fourier Infrared Spectrometer (FTIR) microscopy technique used to date requires a full day of analysis of the sample, and the length of time required for analysis hinders the use of infrared imaging in the clinical setting.
A research team from Ruhr University (RUB) in Bochum, Germany, has deployed an infrared microscope with a quantum cascade laser (QCL) to replace FT technology with QCL technology. By using QCL to simplify measurement setup, the team reduced the time required for analysis from one day to a few minutes. Coupled with bioinformatics image analysis, QCL-based infrared microscopy can perform label-free cancer tissue classification and can be fully automated.
Compared to FTIR microscopes, QCL-based infrared microscopes allow the use of a single frequency. Therefore, an overview image of the target area can be obtained in a very short measurement time, which can then be analyzed in detail.
The team used QCL-based infrared imaging to analyze 110 cell tissue samples taken from colorectal cancer patients. The results of this unlabeled method showed 96% sensitivity and 100% specificity compared to histopathology, which is considered the gold standard in routine clinical diagnosis.
In the next step, the laser pointer will do a lot of research on the unmet clinical needs. The team believes that IR-based, label-free automated tissue classification diagnosis can be promoted into clinical applications. In addition, this new method can also be used for biomarker searches.