The Macromolecular, Supramolecular and Nanochemistry (MSN) Program in the Chemistry Division supports Professor Bradley Smith of the University of Notre Dame to prepare and study a series of dyes and organized molecular assemblies that can absorb relatively harmless laser light and generate localized heating. The process is known as photothermolysis and can be incorporated into a wide range of modern research methods and frontier technologies such as advanced materials, healthcare, and biotechnology. The project develops new methods of producing photothermolysis over a very small area, or under specific environmental conditions. The research activities train students, including those from historically underrepresented groups, in synthetic chemistry, quantitative photophysical measurements, membrane science, and multimedia presentation of scientific results to expert and non-expert audiences. Professor Smith and his students are also producing an electronic book (ebook) describing the most effective synthetic receptors for biological molecules. Professional and global distribution of the ebook ensures that it effectively reaches Science, Technology, Engineering, and Math (STEM) students. The ebook is expected to educate a wide range of STEM students who are new to supramolecular chemistry and thus have a global educational impact.
The research plan builds on preliminary results showing that a new class of near-infrared absorbing dyes is extremely well-suited for many laser photothermolysis applications. The work investigates nanoscale photothermolysis as a new way of producing highly localized bilayer membrane disruption events without causing bulk heating of the sample. Another major theme is the broadly applicable supramolecular design concept of activated photothermolysis. Dye-containing assemblies are fabricated in a chromophore state that does not absorb near-infrared laser light at neutral pH. Changing to acidic pH triggers pseudorotaxane formation, a supramolecular complexation event that greatly enhances laser absorption and photothermal heating. The general concept of activated photothermolysis can likely be expanded to include various chemical and biochemical reactions to switch on laser absorption by organic dyes.
