Abstract. Fluorescence bioimaging is one of the most important technologies in the biomedical field. The most serious issue concerning current fluorescence bioimaging systems is the use of short wavelength light, UV or VIS, for the excitation of phosphors such as fluorescent proteins or quantum dots. The authors propose a fluorescence bioimaging system excited by near infrared light using rare-earth doped ceramic nanophosphors. The requirements for the nanophosphors are a designed emission scheme under the near infrared excitation, a controlled size between 10 and 200 nm and surface modification of the particles with a biofunctional polymer, which prevents particle agglomeration and non-specific interaction to nontargeting substances and gives them a specific interaction for the targeted objects. The preparation of the bioimaging probe and demonstrative imaging work are reported
