P-37 Intrinsic Fluorescence Quantum Yield of PAMAM Dendrimers

Ryan T. Hayes, Andrews University
Anthony Miller, Andrews University
Ansel Nam, Andrews University

Undergraduate Research Scholarship, Office of Research and Creative Scholarship

Andrews ChemServices (Berrien Springs, MI)

Presentation Abstract

Despite their lack of conjugation, polyamidoamine (PAMAM) dendrimers emit a blue fluorescence in aqueous solutions. This intrinsic fluorescence has been reported in literature, but the nature and efficiency of this emission remains to be fully explained and quantified. Previous reports show G4-PAMAM-amine dendrimer fluorescence increases in increasingly acidic solutions and larger dendrimers. This current project evaluated the fluorescence of PAMAM dendrimers with a variety polar surface groups, sizes, and solution pHs. We report on the characteristic features of dendrimer excitation and emission spectra along with a fluorescent quantum yield obtained by comparison to the well characterized fluorescein emission. Our initial results demonstrate that the PAMAM dendrimer’s fluorescence is quite weak in comparison to fluorescein, but PAMAM dendrimers experience limited quenching even at very high dendrimer concentrations. PAMAM dendrimer’s intrinsic fluorescence provides a unique opportunity to track their location in biological procedures, such as transfection and drug delivery, without attaching additional chromophores. Understanding and manipulating this fluorescence could provide the knowledge for developing a colorful range of novel, nanosized imaging agents for in vitro assays.

 
Oct 26th, 2:00 PM Oct 26th, 3:00 PM

P-37 Intrinsic Fluorescence Quantum Yield of PAMAM Dendrimers

Despite their lack of conjugation, polyamidoamine (PAMAM) dendrimers emit a blue fluorescence in aqueous solutions. This intrinsic fluorescence has been reported in literature, but the nature and efficiency of this emission remains to be fully explained and quantified. Previous reports show G4-PAMAM-amine dendrimer fluorescence increases in increasingly acidic solutions and larger dendrimers. This current project evaluated the fluorescence of PAMAM dendrimers with a variety polar surface groups, sizes, and solution pHs. We report on the characteristic features of dendrimer excitation and emission spectra along with a fluorescent quantum yield obtained by comparison to the well characterized fluorescein emission. Our initial results demonstrate that the PAMAM dendrimer’s fluorescence is quite weak in comparison to fluorescein, but PAMAM dendrimers experience limited quenching even at very high dendrimer concentrations. PAMAM dendrimer’s intrinsic fluorescence provides a unique opportunity to track their location in biological procedures, such as transfection and drug delivery, without attaching additional chromophores. Understanding and manipulating this fluorescence could provide the knowledge for developing a colorful range of novel, nanosized imaging agents for in vitro assays.