Current tumour identification through histopathology follows an established process.
Tissue biopsies are stained with haematoxylin and eosin dyes (H&E staining). Slides are then viewed by a histo-pathologist, who provides a qualitative and subjective diagnosis.
Every component of a biological specimen (cell or tissue) is characterized by a vibrational spectrum that reflects its molecular structure and provides an endogenous and chemically specific signature for its identification.
Tissues display characteristic vibrational spectra “fingerprint” - “chemical signature” tumor identification with 90-100% sensitivity and specificity! Non-invasive (no staining, no labelling)
Tumour identification by Spontaneous Raman Spectroscopy offers high sensitivity and specificity for disease in many parts of the body, but low acquisition speed.
Spontaneous Raman Spectroscopy is an established technique for imaging, but is very slow. Coherent Raman Spectroscopy enables much faster imaging as the signal strength is much greater:
Stimulated Raman Scattering (SRS) detects small variations of the pump/Stokes frequencies.
Coherent Raman scattering requires synchronized tunable picosecond lasers. Such systems are bulky, expensive and require tuning by an expert operator. The size and cost of the laser system limit the application of coherent Raman scattering to medical diagnostics.
Graphene is an atomically thin layer of carbon atoms with unique mechanical, electrical and optical properties.
Because of its massless Dirac fermions, graphene is the only material that absorbs light at every wavelength. Graphene behaves like a fast switch that transmits light only for a very short time (picoseconds) enabling the generation of ultra-fast laser pulses. Using two laser cavities we can produce inherently synchronized picosecond laser pulses that make fast CARS imaging possible.
Fiber lasers are compact, low-cost and alignment free making them ideal for use in biomedical diagnostics. CRIL is developing ultra fast and inherently synchronised fiber lasers based on graphene. These lasers will drastically simplify Coherent Raman Scattering systems enabling rapid and low cost label free imaging. This technology enables new applications in medical technology where speed, ease of use and low cost are essential.