Cancer is on its way to becoming the leading cause of death all over the world. The demand for earlier and more accurate detection of cancer is now greater than ever before. The key to this challenge lies in detecting cancer cells within the tissues, and cancer cells circulating in the bloodstream. Using existing detection methods, these cancer cells remain elusive. Konica Minolta has therefore focused its research on the proteins that are characteristic of cancer cells.
We focused on the fact that, by making fluorescent materials bond chemically with the specific proteins, and then detecting the fluorescence, the presence and behaviour of cancer cells can be shown up more clearly. In other words, the elusive cancer cells are detected by lighting them up. This method can also be applied in detecting minute quantities of viruses that have invaded the body.
Highly-sensitive detection of the proteins associated with disease by using fluorescent markers presents two challenges. One is developing fluorescent materials that emit brighter fluorescence. The other is finding a more efficient way to detect the light they emit.
In 2008, Dr. Osamu Shimomura, Distinguished Invited Professor at Nagoya University, won the Nobel Prize in Chemistry for the discovery and development of the green fluorescent protein now commonly known as GFP. This marked the beginning of detection techniques using fluorescent materials, which are currently the focus of attention in the fields of medicine and life sciences. These techniques are being used in R&D on cell imaging and bioimaging.
One of these fluorescence detection techniques uses fluorescent dyes. Conventional marker techniques using fluorescent dyes are subject to two problems, the first being photobleaching, and the second, low sensitivity and low quantitative capability.
Konica Minolta addressed these problems by applying techniques used in its own silver halide particle development operations. By developing fluorescent nanoparticles emitting light in a range of colours, Konica Minolta solved the problems of photobleaching and low sensitivity. Our technology binds antibodies to high-brightness, highly-photostable fluorescent nanoparticles, so it has the potential to help to improve quantitative capability in cancer tissue diagnosis.
Konica Minolta is currently developing an immunoassay technique based on surface plasmon field-enhanced fluorescence spectroscopy (SPFS). This technique works by detecting the fluorescence signal of fluorophore markers which are held in place by an antigen-antibody reaction. These fluorophore markers are excited most efficiently by near-field light induced on the surface of a thin layer of gold. This is known as surface plasmon resonance (SPR).
To perform high-sensitivity detection, this technique relies on advanced sensing technology, combined with materials technology that creates an adequate immune reaction site. Konica Minolta's strengths lie in sensing technologies for detecting weak fluorescence, materials technologies cultivated through working with photographic materials, and technologies for manufacturing precision optics. By combining these strengths, we have made it possible to detect blood proteins with a high degree of sensitivity.