title: Excited-State Proton Transfer of Weak Photoacids Adsorbed on Biomaterials: Proton Transfer on Starch.
abstract: Steady-state and time-resolved fluorescence techniques were employed to study the excited-state proton transfer (ESPT) from a photoacid adsorbed on starch to a nearby water molecule. Starch is composed of ∼30% amylose and ∼70% amylopectin. We found that the ESPT rate of adsorbed 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS) on starch arises from two time constants of 300 ps and ∼3 ns. We explain these results by assigning the two different ESPT rates to HPTS adsorbed on amylose and on amylopectin. When adsorbed on amylose, the ESPT rate is ∼3 × 10(9 )s(-1), whereas on amylopectin, it is only ∼3 × 10(8) s(-1).
authors.affiliation: Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Ron
authors.initials: R
authors.lastname: Simkovitch
authors.affiliation: Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Huppert
mesh_terms: D000327:Adsorption; D000687:Amylopectin / Q000737:chemistry*; D000688:Amylose / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D007700:Kinetics; D011522:Protons; D011721:Pyrenes / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: C538892:8-hydroxy-1,3,6-pyrenetrisulfonic acid; D001672:Biocompatible Materials; D011522:Protons; D011721:Pyrenes; D013451:Sulfonic Acids; D000688:Amylose; D000687:Amylopectin