Inorganic phosphate nanorods are a novel fluorescent label in cell biology

Nanotechnology, the creation of new objects in nanoscale dimensions, is a cutting edge technology having important applications in modern biomedical research [1-7]. Because the dimension of nanoscale devices is similar to cellular components such as DNA and proteins [8,9], tools developed through nanotechnology may be utilized to detect or monitor several diseases at the molecular level [3,10,11]. Bio-imaging with inorganic fluorescent nanorods probes have recently attracted widespread interest in biology and medicine [1-4,12-14] compared to nanospheres. According to the reported literature [15], there is a drastic reduction of the plasmon dephasing rate in nanorods compared to small nanospheres due to a suppression of interband damping [15]. These rods show very little radiation damping due to their small volumes. These findings imply large local-field enhancement factors and relatively high light-scattering efficiencies, making metal nanorods extremely interesting for optical applications. Therefore, we are highly interested to examine the possibility of using inorganic fluorescent nanorods, especially lanthanide ortho phosphate LnPO4·H2O [Ln = Eu or Tb], as fluorescent labels in cell biology. On the otherhand, in comparison to organic dyes (including Fluorescein, Texas Red？, Lissamine Rhodamine B, and Tetramethylrhodamine) and fluorescent proteins (Green fluorescent protein, GFP), inorganic fluorescent nanoparticles have several unique optical and electronic properties including size- and composition-tunable emission from visible to infrared wavelengths, a large stokes shift, symmetric emission spectrum, large absorption coefficients across a wide spectral range, simultaneous excitation of multiple fluorescent colors, very high levels of brightness, [4,13], high resistance to photobleaching, and an exceptional resistance to photo- and chemical degradation [2-5,13,16,17] ].Bio-conjugated inorganic nanoparticles have raised new possibilities for the ultrasensitive