What is Tris(2,2'-Bipyridyl)Ruthenium(II) Chloride Hexahydrate?

Tris (2,2’-bipyridyl) dichlororuthenium hexahydrate (RTDP, Ru (BPY) 3) is an oxygen-sensitive fluorescent stain. It can be used to measure the oxygen concentration of microfluidic chips. The combination of K7[H4PW18O62]•18H2O(PW18) and Tris(2,2'-bipyridine)dichlororuthenium(II) hexahydrate can prepare a new oxidase-based biodetector hybrid material. Silica nanoparticles doped with Tris(2,2'-bipyridine)dichlororuthenium(II) hexahydrate make them fluorescent, radiopaque and paramagnetic.

Tris(2,2'-bipyridine)dichlororuthenium(II) hexahydrate is a catalyst used in light-induced redox reactions, and is an important catalyst in studies towards photochemical water splitting. This product can be used as a catalyst in pharmaceutical research. Tris(2,2'-bipyridine)dichlororuthenium(II) hexahydrate is widely applied in fields of photoelectrical chemical components, photovoltaic cells, smart biosensors[1-3].

Fig 1. Chemical structure formula and three-dimensional structure of Tris(2,2'-Bipyridyl)Ruthenium(II) Chloride Hexahydrate

Fluorescence lifetime imaging microscopy offers a non-invasive method for quantifying local oxygen concentrations. However, existing methods are either invasive, require custom-made systems, or show limited spatial resolution. Therefore, these methods are unsuitable for investigation of pericellular oxygen concentrations. This study describes an adaptation of commercially available equipment which has been optimized for quantitative extracellular oxygen detection with high lifetime accuracy and spatial resolution while avoiding systematic photon pile-up. The oxygen sensitive fluorescent dye, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate [Ru(bipy)3]2+, was excited using a two-photon excitation laser. Lifetime was measured using a Becker & Hickl time-correlated single photon counting, which will be referred to as a TCSPC card. [Ru(bipy)3]2+ characterization studies quantified the influences of temperature, pH, cellular culture media and oxygen on the fluorescence lifetime measurements. This provided a precisely calibrated and accurate system for quantification of pericellular oxygen concentration based on measured lifetimes. 

Using this technique, quantification of oxygen concentrations around isolated viable chondrocytes, seeded in three-dimensional agarose gel, revealed a subpopulation of cells that exhibited significant spatial oxygen gradients such that oxygen concentration reduced with increasing proximity to the cell. This technique provides a powerful tool for quantifying spatial oxygen gradients within three-dimensional cellular models.

The triboluminescence of tris(2,2’-bipyridyl)ruthenium(II) dichloride hexahydrate complex is detected during the mechanical grinding. The intense lines of N2 in the UV region and a band at 619 nm appeared due to luminescence of [Ru(bpy)3]2+ ion and coincided with the photoluminescence spectrum of the crystals are observed in the emission spectrum in air.

References

[1] Khramov, A. N.; Collinson, M. M. Electrogenerated Chemiluminescence of Tris(2,2'-bipyridyl)ruthenium(II) Ion-Exchanged in Nafion-Silica Composite Films. Anal. Chem. 2000, 72, 2943-2948.
[2] Moon, H. C.; Lodge, T. P.; Frisbie, C. D. Solution-Processable Electrochemiluminescent Ion Gels for Flexible, Low-Voltage, Emissive Displays on Plastic. J. Am. Chem. Soc. 2014, 136 (9), 3705-3712.
[3] Parajuli, S.; Miao, W. Sensitive Determination of Hexamethylene Triperoxide Diamine Explosives, Using Electrogenerated Chemiluminescence Enhanced by Silver Nitrate. Anal. Chem. 2009, 81 (13), 5267-5272.
[4] D.G. Whitten Acc. Chem. Res. 13, 83, (1980) 2. M. Grätzel Pure Appl. Chem. 54, 2369, (1982)