Transition metal ions are important regulators of various biological processes in living systems. However, disturbances in the homeostatic regulation of transition metal ions can lead to toxic effects on the cellular machinery. Manganese (Mn) is one such trace yet biologically essential metal ion. Mn2+ serves as a cofactor for several enzymes besides relieving the cell of oxidative stress.[1] On the other hand, occupational and environmental overexposure to Mn results in a neurological disorder, Manganism which has symptoms similar to Parkinson's Disease and is characterized by Mn2+ accumulation in the brain.[2] In order to obtain insights into the molecular mechanisms underlying manganese regulation we need to quantify Mn2+ pools live, in vivo, for which chemical tools for probing Mn2+ are required. One approach toward live quantification is optical imaging of Mn2+ pools using fluorescent probes. However, Mn2+ being paramagnetic can quench the emission of fluorescent probes, which makes optical sensing of Mn2+ challenging. Hence, only few Mn2 + sensors have been reported till date with mostly optical quenching and displacement based assays.[3] Our approach is to develop 'turn-on' fluorescent sensors which can afford a selective fluorescence enhancement upon Mn2+ binding. The sensor design includes a protein-inspired Mn2+ selective scaffold linked to a fluorophore such that the fluorophore is quenched before Mn2+ binding and 'turns-on' specifically in the Mn2+bound form. The underlying sensor design principles, synthesis, and the fluorescence response and selectivity of the sensor will be presented.[1] K. Barnese et al., PNAS, 2012  , 109, 6892-6897.[2] E. J. Martinez-Finley et al., Free Rad. Biol. Med., 2013  , 62, 65-75.[3] F. Gruppi, et al., Chem. Comm., 2012  , 48, 10778-10780.

�Turn-on� optical probes for Mn<sup>2+</sup>

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

�Turn-on� optical probes for Mn2+

�Turn-on� optical probes for Mn²⁺