title: A Switch-On NIR Probe for Specific Detection of Hg2+Ion in Aqueous Medium and in Mitochondria.
abstract: A new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based probe molecule (L) is synthesized for specific binding to Hg2+ion in physiological condition with an associated luminescence ON response in the near-IR region of the spectrum. Appropriate functionalization in the 5-position of each of two pyrrole moieties with styryl functionality in a BODIPY core helped us in achieving the extended conjugation and a facile intramolecular charge transfer transition with a narrow energy gap for frontier orbitals. This accounted for a poor emission quantum yield for the probe molecule L. Binding to Hg2+helped in interrupting the facile intramolecular charge transfer (ICT) process that was initially operational for L. This resulted in a hypsochromic shift of absorption band and a turn-on luminescence response with λMaxEmsof 650 nm on specific binding to Hg2+. Observed spectral changes are rationalized based on quantum chemical calculations. Interestingly, this reagent is found to be localized preferentially in the mitochondria of the live human colon cancer (Hct116) cells. Mitochondria is one of the major targets for localization of Hg2+, which actually decreases the mitochondrial membrane potential and modifies various proteins having sulfudryl functionality(ies) to cause cell apoptosis. Considering these, ability of the present reagent to specifically recognize Hg2+in the mitochondrial region of the live Hct116 cells has significance.
authors.affiliation: Organic Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Hridesh
authors.initials: H
authors.lastname: Agarwalla
authors.affiliation: Organic Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Pankaj S
authors.initials: PS
authors.lastname: Mahajan
authors.affiliation: Computation and Simulation Unit (Analytical Discipline and Centralized Instrument Facility), CSIR-Central Salt and Marine Chemicals Research Institute , Bhavnagar 364002, India.
authors.forename: Debashis
authors.initials: D
authors.lastname: Sahu
authors.affiliation: Chromatin and Disease Biology Lab, National Centre for Cell Science ; Pune 411007, India.
authors.forename: Nandaraj
authors.initials: N
authors.lastname: Taye
authors.affiliation: Computation and Simulation Unit (Analytical Discipline and Centralized Instrument Facility), CSIR-Central Salt and Marine Chemicals Research Institute , Bhavnagar 364002, India.
authors.forename: Bishwajit
authors.initials: B
authors.lastname: Ganguly
authors.affiliation: Organic Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Santosh B
authors.initials: SB
authors.lastname: Mhaske
authors.affiliation: Chromatin and Disease Biology Lab, National Centre for Cell Science ; Pune 411007, India.
authors.forename: Samit
authors.initials: S
authors.lastname: Chattopadhyay
authors.affiliation: Organic Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India.|CSIR-Central Salt & Marine Chemicals Research Institute , Bhavnagar 364002, Gujarat, India.
authors.forename: Amitava
authors.initials: A
authors.lastname: Das
mesh_terms: D045325:HCT116 Cells; D006801:Humans; D008628:Mercury / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D015335:Molecular Probes; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D015335:Molecular Probes; D014867:Water; D008628:Mercury