Sensors in the blood

Scientists from China have developed a water-soluble zinc-based fluorescent sensor to detect pyrophosphate in blood that isn't affected by the environment and can be used in real blood samples. 

Pyrophosphate plays an important role in metabolic processes in the body but a lack of the compound can lead to calcium deposits in arteries - called Mönckeberg's arteriosclerosis. Too much pyrophosphate causes calcium pyrophosphate deposition disease, where calcium pyrophosphate dihydrate crystals accumulate in connective tissues.  More...

http://www.rsc.org/chemistryworld/News/2011/January/11011101.asp