Molecular diffusion, trapping and reaction of polymeric catalysts at the solution-solid interface investigated by single molecule fluorescence microscopy

• Grant number: 18/22159-5
• Support Opportunities: Scholarships abroad - Research
• Effective date (Start): July 06, 2019
• Effective date (End): June 05, 2020
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Marcelo Henrique Gehlen
• Grantee: Marcelo Henrique Gehlen
• Host Investigator: Daniel Schwartz
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Research place: University of Colorado Boulder, United States

Abstract

In this research project, the surface transport properties, interface behavior, trapping and localization of polymeric catalysts (PCat) and their chemical reactivity under special conditions will be designed, prepared, and investigated by advanced fluorescence microscopy methods with single molecule (SM) resolution. Polymeric catalysts may include artificial polymer chain with active chemical groups for acid and base catalysis, natural enzymes and special prepared nano-particle (NP). The scope of the project is divided in two interchanged branches. In the first one, a study of the surface mobility of the labeled polymeric catalysts (PCat) using advanced single-molecule tracking based on mapping with accumulated probe trajectories (MAPT) method will be conducted. In this part, adsorption and desorption rates, surface diffusion coefficients, and self-association process will be mapped at SM level owing applications of PCat in concomitant thermal and photochemical reactions. The second part is the investigation of the chemical reactivity of the polymeric catalyst in specific reactions with discrete single molecule production. Using free and surface bound polymeric catalyst (PCat) previously characterized, a designed organic or enzymatic reaction forming a fluorescent dye product is accompanied at SM level using one and two-color measurements. Such studies will allow deep understanding of the effect of free and restricted mobility of PCat in the underlying mechanism and determination of the turnover rates by stochastic analysis of the single molecule fluorescence time-traces.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GEHLEN, MARCELO H.. The centenary of the Stern-Volmer equation of fluorescence quenching: From the single line plot to the SV quenching map. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS, v. 42, MAR 2020. (18/22159-5)

GEHLEN, MARCELO H.; FOLTRAN, LARISSA S.; KIENLE, DANIEL F.; SCHWARTZ, DANIEL K.. Single-Molecule Observations Provide Mechanistic Insights into Bimolecular Knoevenagel Amino Catalysis. Journal of Physical Chemistry Letters, v. 11, n. 22, p. 9714-9724, NOV 19 2020. (18/17660-7, 18/22159-5)