Design principles of fluorescent molecular sensors for cation recognition

The brain is a singular organ of unique biological complexity that serves as the command center for cognitive and motor function. As such, this specialized system also possesses a unique chemical composition and reactivity at the molecular level. In this regard, two vital distinguishing features of the brain are its requirements for the highest concentrations of metal ions in the body and the highest per-weight consumption of body oxygen. In humans, the brain accounts for only 2% of total body mass but consumes 20% of the oxygen that is taken in through respiration. As a consequence of high oxygen demand and cell complexity, distinctly high metal levels pervade all regions of the brain and central nervous system. Structural roles for metal ions in the brain and the body include the stabilization of biomolecules in static (e.g., Mg2+ for nucleic acid folds, Zn2+ in zinc-finger transcription factors) or dynamic (e.g., Na+ and K+ in ion channels, Ca2+ in neuronal cell signaling) modes, and catalytic roles for brain metal ions are also numerous and often of special demand.

Metals in Neurobiology: Probing Their Chemistry and Biology with Molecular Imaging

Fluorescent detection of zinc in biological systems: recent development on the design of chemosensors and biosensors

Biomedical Diagnostics. Edited by Tuan Vo-Dinh Edited by Tuan VoDinh. CRC Press 20142014. Pages 311–356. Print ISBN: 978-1-42008514-3. eBook ISBN:. Bjorn Kemper is a senior researcher at the Biomedical Technology Center of the Srirang Manohar is an associate professor of biomedical photonic imaging. This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications.

https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-9/issue-5/0000/Book-Review-Biomedical-Photonics-Handbook/10.1117/1.1776177.pdf

Biomedical Photonics Handbook

Flipping the light switch 'on'--the design of sensor molecules that show cation-induced fluorescence enhancement with heavy and transition metal ions.

Seventy-eight metal species are examined for fluorescence properties of their chelates with 8-hydroxyquinoline-5-sutfonic acid (HQS); 42 of these fluoresce, many intensely. The optimum pH, determined by ligand ionization vs. hydroxo compiex formation, iles between 5 and 8. Cadmlum forms the most fluorescent complex In a purely aqueous solution. Fluorescence Is enhanced for many metals in surfactant (hexadecyltrlmethyiammonlum ion, HTA') containing media and in a water:dimethytformamide solvent. A number of metal ions quench the fluorescence of other metal-HQS chelates, Fe(II1) being by far the most effective, and such quenching is accentuated in media contalnlng HTA'. The fluorescence propertles can be exploited by introducing the ligand through a postcolumn reactor or by Incorporating it in the eluent in a chromatographic system. Subpicomole detection limits are attainable for Cd, Mg, and Zn.

Fluorescence Properties of Metal Complexes of 8-Hydroxyquinoline-5-sulfonic Acid and Chromatographic Applications

Fluorescence enhancement of 8-hydroxyquinoline-5-sulfonic acid complexes of Mg, Ca, Sr, Ba, Al, Zn and Cd were studied in micellar and hydroorganic solvents Al is extraordinarily amenable to both types of fluorescence enhancement, an order of magnitude to two order of magnitude enhancement of fluorescence intensity has been observed with aqueous hexadecyltrimethylammonium chloride (HTAC) and certain mixed aqueous-organic solvents Fe(III) appears to be an unusually powerful fluorescence quencher in these systems — the effect is noticeable in low micromolar concentrations and is greatly amplified by cationic surfactants such as HTAC

Denise A. Phillips

Papers

Fluorescence Properties of Metal Complexes of 8-Hydroxyquinoline-5-sulfonic Acid and Chromatographic Applications

Enhancement and quenching of fluorescence of metal chelates of 8-hydroxyquinoline-5-sulfonic acid