Smart nanoprobes for the detection of alkaline phosphatase activity during osteoblast differentiation.

Gold nanoparticle-conjugated fluorescent hydroxyapatite (AuFHAp) was developed as a smart nanoprobe for measuring alkaline phosphatase (ALP) activity. AuFHAp showed NIR fluorescence due to the hydrolysis of its phosphate groups by ALP. In addition, gold nanoparticles help reduce the nonspecific signal by absorbing nonspecific fluorescence. Through in vitro tests, we confirmed that the AuFHAp probe was capable of detecting ALP levels related to osteoblast activity in living cells with high fluorescence intensity.