Anionic and BSA Gold Tracers

Aurion Anionic Gold Tracers are used to visualize charged moieties in specimens. They bind to polycationic moieties (basic proteins e.g. histones). “Neutral” BSA coated gold tracers are useful for detecting open connections and tissue damage. Under proper conditions and with suitable microscopical techniques the tracers can also be used to follow cellular events in time. In addition BSA Gold Tracers can act as fiducial marker in electron tomography to facilitate image alignment.

The AURION Anionic Gold Tracers are designed to detect multiple positive charge moieties.

BSA Gold tracers are near neutral in charge. The BSA molecules on the surface of the gold nanoparticles protect against particle clustering when the tracer is in a buffered environment,  a pre-requisite for tracking of cellular events like endocytosis and vascular leakage. The protective layer of BSA also promotes an even distribution of the gold nanoparticles on EM specimens, making the tracer a valuable tool in image alignment in electron tomography.

Anionic Tracers
1. charge interactions are influenced by the presence of ions, di- and trivalent ions being of more influence than univalent ions. The influence is concentration dependent. Binding is stronger in low ionic-strength media.

2. charge interactions are influenced by pH. The charge of components in the specimen is dependent of their isoëlectric point, below the IEP the charge is positive, above the IEP negative. Significant binding of the anionic tracer will only occur at a pH at least one to two pH-units lower than the IEP.

Anionic tracers are negatively charged at pH >5

BSA Tracers
BSA tracers are intended for tracking fine capillaries or connecting spaces in intact tissues. BSA Tracers are generally used at physiological pH. Use undiluted – 1/5 or add BSA-gold Tracer in a 1:2 to 1:5 ratio to your sample.

Storage:
Aurion gold tracers have a guaranteed shelf life of 18 months from the date of quality control analysis. The products should be stored at 4-8°C. Freezing is not recommended.