Design of 1,25 dihydroxyvitamin D3 coupled quantum dots, a novel imaging tool.

1,25 dihydroxyvitamin D3 (Calcitriol), one of the active forms of Vitamin D, plays a vital role not only in calcium absorption but also during neuromuscular function and regulation of inflammation. Epidemiological studies suggest a preventive effect of Calcitriol in breast, colon and prostate cancer, however high concentrations of Calcitriol are necessary. Therefore targeted biologically active probes must be designed to determine Calcitriol distribution and dynamics in vitro and in vivo. Our Calcitriol probe remained stable over 2 days at 37 degrees C. When added to live C2C12 cells, the Calcitriol probe can be seen entering the nucleus within 2 hours and the probe activated the expression of the Vitamin D Response Element (VDRE), one of the major transcription elements. The Calcitriol probe provides a novel imaging tool that can be used to view Calcitriol localization and dynamics.