A5068495630- Force Microscopy Techniques and Applications
- Mechanical and Optical Resonators
- Photochromic and Fluorescence Chemistry
- Cellular Mechanics and Interactions
- Luminescence and Fluorescent Materials
- Analytical Chemistry and Sensors
- Drug Transport and Resistance Mechanisms
- Polydiacetylene-based materials and applications
- Vibrio bacteria research studies
- Lipid Membrane Structure and Behavior
- Clostridium difficile and Clostridium perfringens research
- Gut microbiota and health
- Bacterial biofilms and quorum sensing
- Porphyrin and Phthalocyanine Chemistry
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Photoreceptor and optogenetics research
- Crystallography and molecular interactions
- Radical Photochemical Reactions
- Photoacoustic and Ultrasonic Imaging
- Aquaculture disease management and microbiota
- Nanofabrication and Lithography Techniques
- Bacterial Genetics and Biotechnology
California Institute of Technology
2018-2023
Indiana University Bloomington
2019-2021
Pasadena City College
2020
Technical University of Munich
2019
University of Turku
2019
University of Kashan
2019
Bielefeld University
2019
Gilead Sciences (Canada)
2019
University of Rostock
2019
Institute of Cancer Research
2019
We report a bis-naphthopyran mechanophore that exhibits force-dependent changes in visible absorption. A series of polymers incorporating chain-centered was synthesized and mechanically activated using ultrasonication. By varying the length polymer chains, force delivered to is modulated systematically. demonstrate relative distribution two distinctly colored merocyanine products altered predictably with different magnitudes applied force, resulting gradient multicolor mechanochromism. The...
We introduce the concept of mechanochemically gated photoswitching. Mechanical regulation a photochemical reaction is exemplified using newly designed mechanophore based on cyclopentadiene–maleimide Diels–Alder adduct. Ultrasound-induced mechanical activation photochemically inert in polymers generates diarylethene photoswitch via retro-[4 + 2] cycloaddition that photoisomerizes between colorless and colored states upon exposure to UV visible light. Control experiments demonstrate thermal...
External control of chemical reactions in biological settings with spatial and temporal precision is a grand challenge for noninvasive diagnostic therapeutic applications. While light conventional stimulus remote activation, its penetration severely attenuated tissues, which limits applicability. On the other hand, ultrasound biocompatible energy source that highly penetrant offers wide range functional tunability. Coupling to activation specific under physiological conditions, however,...
Structure–activity relationships for strategic substitution of the naphthopyran mechanophore scaffold enable polymeric materials with tunable mechanochromic behavior.
We report the discovery of a 2H-naphtho[1,2-b]pyran mechanophore that produces permanent merocyanine dye upon mechanochemical activation, in contrast to reversible product generated photochemically. Experiments suggest irreversibility mechanically is due unique reaction which scission an ester C-O bond reveals β-hydroxy ketone locks through intramolecular H-bonding interaction. In addition demonstrating reactivity using solution-phase ultrasonication, generation also achieved solid polymeric...
The ability to accurately and quantitatively characterize structure–mechanochemical activity relationships is important for informing the fundamental understanding of mechanochemical reactivity and, in turn, successful advancement rapidly growing field polymer mechanochemistry. Ultrasound-induced mechanical activation polymers remains one most general methods studying mechanophore reactivity; however, rates scissile mechanophores are still routinely deduced from changes size using gel...
Multimodal mechanophores that exhibit complex mechanochromic behavior beyond the typical binary response are capable of distinguishing between multiple stress states through discrete changes in color. Naphthodipyran photoswitches contain two pyran rings fused to a central naphthalene core and represent potentially promising framework for multimodal reactivity. However, concurrent ring opening both moieties has previously proven inaccessible via photochemical activation. Here, we demonstrate...
Understanding structure-mechanochemical reactivity relationships is important for informing the rational design of new stimuli-responsive polymers. To this end, establishing accurate reaction kinetics mechanophore activation a key objective. Here, we validate an initial rates method that enables and rapid determination rate constants ultrasound-induced mechanochemical transformations. Experimental profiles are well-aligned with theoretical models, which support effectively deconvolutes...
In contrast to common angular naphthopyrans that exhibit strong photochromic and mechanochromic behavior, constitutionally isomeric linear are typically not photochromic, due the putative instability of completely dearomatized merocyanine product. The photochemistry is thus relatively understudied compared naphthopyrans, while mechanochromism remains unexplored. Here we demonstrate incorporation a polarizing dialkylamine substituent enables behavior from polymers containing novel...
A 2 H -bis-napthopyran (2 -BNP) mechanophore generates an unusually stable bis-merocyanine product upon mechanical activation.
Abstract Naphthopyrans are molecular switches that produce highly colored merocyanine dyes upon photochemical or mechanochemical activation in polymers. The mechanochromic behavior of these force probes enables the straightforward visualization stress and/or strain materials. To date, research on mechanochemistry naphthopyran has largely focused 3 H ‐naphtho[2,1‐ b ]pyran (3 ) scaffold, whereas isomeric 2 ‐naphtho[1,2‐ ]pyrans (2 exhibit complementary properties as suggested from their...
Mechanophores are molecules that undergo productive, covalent chemical transformations in response to mechanical force. Over the last decade, a variety of mechanochromic mechanophores have been developed enable direct visualization stress polymers and polymeric materials through changes color chemiluminescence. The recent introduction mechanochemically gated photoswitching extends repertoire polymer mechanochromism by decoupling activation from visible response, enabling history be recorded...
ABSTRACT The gut microbiota synthesize hundreds of molecules, many which are known to impact host physiology. Among the most abundant metabolites secondary bile acids deoxycholic acid (DCA) and lithocholic (LCA), accumulate at ~500 μM block C. difficile growth 1 , promote hepatocellular carcinoma 2 modulate metabolism via GPCR TGR5 3 . More broadly, DCA, LCA their derivatives a major component recirculating pool 4 ; size composition this target therapies for primary biliary cholangitis...
The quorum-sensing signaling systems in Vibrio bacteria converge to control levels of the master transcription factors LuxR/HapR, a family highly conserved proteins that regulate gene expression for bacterial behaviors. A compound library screen identified 2-thiophenesulfonamide compounds specifically inhibit campbellii LuxR but do not affect cell growth. We synthesized panel 50 thiophenesulfonamide examine structure-activity relationship effects on quorum sensing. most potent molecule...
Multimodal mechanophores that exhibit complex mechanochromic behavior beyond the typical binary response are capable of distinguishing between multiple stress states through discrete changes in color. Naphthodipyran photoswitches contain two pyran rings fused to a central naphthalene core and represent potentially promising framework for multimodal reactivity. However, concurrent ring opening both moieties has previously proven inaccessible via photochemical activation. Here, we demonstrate...
Abstract Vibrio bacteria are pathogens of fish, shellfish, coral, and humans due to contaminated seafood consumption. virulence factors controlled by the cell-to-cell communication called quorum sensing, thus this signaling system is a promising target for therapeutic design. We screened compound library identified nine compounds, including several 2-thiophenesulfonamides, that inhibit master sensing transcription factor LuxR in campbellii but do not affect cell growth. synthesized panel 50...