First generation nanoparticles were tens of nanometers in diameter and uncoated.  Successor particles are less than eight nm diameter so that they can be cleared through the kidneys. Please refer to Bradbury article.

At HST, we refer to the fluorescent silica nanoparticles as “C•spec® particles”. The terms following the • help users identify key architectural features or “specs”.  For example, the full name conveys information about the encapsulated dye and its size. The product C•TRITC•I•25nm is a nanoparticle encapsulating a TRITC dye and has a nominal diameter of 25nm. The process used to encapsulate this nanoparticle is referred to as “I”. 

C•spec® particles - Series I

The C•spec® particles above are supplied in quanties of 2 ml at a 2 mg/ml concentration.

A variety pack of different size C•TRITC particles is
also available:
1 ml of each size for $ 240 (three sizes, uncoated) and $ 300 (three sizes, coated)

The encapsulated rhodamine dyes (TRITC has Excitation at 544 and Emission at 572) can be supplied as neat particles (no coating) in diameters of 25 nm, 45 nm and 75 nm. They are stable in water and alcohol, but actual shelf life has yet to be determined; six months is a good number to use until longer term studies are complete.

C•spec® particles will be characterized for size, size dispersity, brightness (dye-equivalent/particle) where available, and spectral characteristics.

HST can perform an additional step of coating the particles with a PEG (we do this for parties interested in in vivo applications). The coating also helps avoid opsonization during
in vivo administration.