Our invited manuscript on the use of hydrophobic fluorescent probes to study the nature of the non-covalent interactions prevalent in the inner core of PAMAM dendrimers, a class of water-soluble cationic polyelectrolytes, has been published in the Israel Journal of Chemistry. The manuscript will be part of Fluorescent Molecular Probes and Fluorescence-based Chemical Sensing special issue of the journal, guest-edited by Prof. David Margulies (Weizmann Institue of Science) and Prof. Mindy Levine (Ariel University).
Our recent collaboration with the Papish and Kim groups at UA, and others, has been published in Inorganic Chemistry. Our contribution to this work related to the photophysics of these ruthenium - diimine complexes, namely measuring the energies of the 3MLCT excited state through steady state luminescence experiments on the protonated vs. deprotonated metal complexes. The work also relates this energetic change to the mechanism of formation of singlet oxygen, which results in the complexes' cytotoxicity and use as anti-cancer agents.
Michael Ihde and Dr. Bonizzoni both presented talks at the Bays and Bayous Symposium, supported by the Mississippi-Alabama Sea Grant Consortium, on analytical approaches to contaminants in high-salinity environments (intracoastal brackish waters, seawater, the Gulf). The symposium transitioned online due to COVID restrictions.
Pattern-based chemical recognition systems often struggle with mixtures of analytes: even if a system is trained to recognize two pure compounds, its response to their mixtures may not be directly predictable. This hinders the application of these sensing systems, giving rise to the "problem of mixtures". In our manuscript accepted by Analytical Chemistry Michael Ihde, a graduate student in our group, reported on a general approach and conditions leading to predictable response to mixtures of trained-for analytes. We also applied our approach to the pattern-based detection of metal ions, which often occur in mixtures. This will hopefully open promising further applications of these systems.
Our manuscript describing array sensing methods for the detection of azo dyes, common pollutants in industrial wastewaters, was accepted for publication in ACS Sensors. The work was conducted by Michael Ihde in our group, in collaboration with Josh Tropp in the Azoulay research group from the School of Polymer Science and Engineering at the University of Southern Mississippi. The method relies on purpose-built emissive fluorene conjugated co-polymers. These materials were decorated with pendant arms that changed the position and intensity of the polymers' absorption bands, producing a family of highly fluorogenic materials whose fluorescence modulation by non-specific interactions with dye analytes through the inner-filter effect (IFE) led to the successful discrimination of 12 chemically similar azo dyes in water.
Our chemical fingerprinting method to discriminate polycyclic aromatic hydrocarbons (PAHs), persistent pollutants with significant health and environmental consequences, has been accepted for publication in Chemical Science. The method was developed by Nick White and Michael Ihde in our group, using polymers developed by Joshua Tropp and Dr. Jason Azoulay at the School of Polymers at the University of Southern Mississippi. Our method, based on detecting how PAHs affect the fluorescence of fluorene-based conjugated polymers through the inner-filter effect (IFE), was able to discriminate between 16 PAH compounds identified as priority pollutants by the US Environmental Protection Agency (EPA).
Yifei, and Xiyuan, graduate students in the group, are organizing a student-led symposium at the upcoming Fall ACS meeting in San Diego (August 2019). They are lining up some really interesting speakers, so plan to stop by if you are at the conference!
Carbohydrate sensing in water is very challenging. In collaboration with the Kharlampieva group at UAB, Xiaoli Liang in our group was recently able to improve the solubility of boronic acds in water and the affinity of their interaction with carbohydrates, by connecting phenylboronic acid moieties to a hydrophilic poly(methacrylic acid) polymer to generate a water-soluble copolymer that can be used as a supramolecular receptor. Coupled with an indicator displacement assay, this polymer was able to differentiate both monosaccharides and disaccharides in neutral aqueous solution.
This work was recently published in ACS Applied Polymer Materials where it was featured on the cover (left).
Gabrielle Covey, an experienced undergraduate researcher in our group, presented a talk at the ACS Southeastern Undergraduate Research Conference (SURC 2019) held this year at the University of Tennessee - Martin. She spoke on her research on metal complexation by modified rhodamine dyes carried out in collaboration with the Wallace Group at the University of Southern Mississippi.