Bangalore: There is a quiet but major revolution brewing in the medical diagnostics field. The Bangalore-based Hind High Vacuum Company Pvt Ltd. (HHV) is a significant participant in this movement.

Conventional diagnosis employs optical microscopes to detect disease-causing organisms in human tissue.  The limitation with this method is that preparing the slide for viewing requires considerable time since the pathogen has to be cultured so that there is a sufficient amount of it to be distinguished from the background of the rest of the tissue. Sometimes, the contrast is so light that even an expert eye at the microscope can miss out detecting the pathogen.

The new method exploits a phenomenon called fluorescence. There are certain dyes that  absorb incident  light which raises the energy levels of their molecules  to a brief excited state. As the dye molecules  get back to their normal state , they emit the excess energy as  fluorescent light .

Fluorescence can be used to quickly, conveniently and effectively detect  a pathogen even if it is present in a very minute quantity in the sample tissue. The actual process comprises first staining the specimen tissue with a fluorescent dye which selectively binds to the pathogen whose presence needs to be ascertained. When the specimen is exposed  to light of a particular wave length, the dye molecules coating the pathogen get excited and then  fall back to their normal energy state. Detecting the emitted fluorescent light will confirm the presence of the pathogen in the tissue sample.

At the heart of this detection process are two very special filters. One permits excitation light of a particular wavelength to strike the specimen.   The other allows the emitted  fluorescent light  of only  a particular wave length to go through.  Excitation filters are centered on the excitation peak of the dye for the maximal energy absorption, while emission filters are designed to give excellent dye discrimination and good quality images.

These filters are very special with a wave length accuracy  of 2 nanometres . The coating on these filters  can comprise as many as 50 layers of alternate low and high refractive material. Such kind of coating  requires complex thin film deposition technology which was not available in India till recently.  HHV has now  mastered the process to make these special filters and joins a select band of just about  half-a-dozen companies in the world who make these products.

Conventional medical diagnosis requires costly analysis in centralised labs with specialist personnel. The new style diagnosis utilises “point-of-care” kits and portable machines which are fitted with these special filters and enable   doctors in the field  to  detect on the spot, diseases like malaria, Bird Flu, HIV, chikungunya and even cancer,  using  very small specimen amounts. These new methods are cutting diagnosis costs by a huge margin so that even the poor can be benefited. These HHV filters are significantly below imported price.