Metal-carbonyls complexes and colloids have been explored for biomedical applications, such as CO delivery, biosensored, and cancer therapy.Particularly,the IR absorption of the CO groups at the wavenumbers between 1800 and 2200 cm is biologically transparent. it is therefore an advantage to use MC derivatives as vibrational IR or raman probes for cell imaging and bioassay. However,the intensity of the IR absorption is not high enough for possible applications in a diluted solution. Attachment of MC compounds on the surface of plasmonic or dielectric nanoparticles has been reported to enhance the CO vibration signals via surface enhanced raman scattering and surface enhanced IR absorption.