Unusual Sculpting of Dipeptide Particles by Ultrasound Induces Gelation

Interfacing Supramolecular Gels and Quantum Dots with Ultrasound: Smart Photoluminescent Dipeptide Gels

“…On the other hand, supramolecular gels are increasingly interesting due to the tunability of the structure of the gelators responsible for properties that are unprecedented as compared with macromolecular gels. Although the design of a proper chemical structure that will produce a gel still remains as a great challenge, this direction has already met with some success [6] as has the diversification of stimuli that can control such gelation.[7]Our recent discovery of a new dipeptide gelator that can be activated by ultrasound in alkanes and polar solvents [8] allows one to envision several unusual and unexpected applications. A striking feature of this dipeptide is the readily ultrasound-induced gelation in hexane containing CdSe/ZnS core/shell QDs.…”

“…This is in full agreement with our previously reported data regarding the mechanism of gel formation. [8] The location of the NPs was determined by transmission electron microscopy (TEM). [11] QDs of around 6 nm were clearly visible and found to be located along the peptide fibers.…”

“…Emission spectra of a gel of dipeptide 1 (10 mM, Fig. S6 of the Supporting Information) show typical fluorene emission at 320 nm illustrating that the peptide matrix is neither absorbing nor emitting photons at the actual excitation Proposed mechanism of peptide sheets restructuring by sonocrystallization [8] and QD binding to the peptide fiber alkyl chains e) by multiple weak van der Waals interactions. Xe NMR spectra: a) variable temperature spectra for a hexane xerogel of dipeptide 1 from 173 to 343 K. b) 2D-EXSY experiment at 173 K illustrating the free xenon exchange between the different adsorption sites and the gas phase (t ¼ 15 ms).…”

Nanoscale assembly of photoluminescent quantum dots on the surface of calix[8]arene microcrystals

“…In the first case, the nanocrystals were included in giant cucurbit [6]uril polymeric capsules, whereas in the second case, supramolecular gels were readily doped with QDs, which deposit on dipeptide fibers after a short exposure to ultrasound. 3 The resulting xerogels showed good porosity and bright luminescence under UV light. These materials had potential as chemical sensors, since the luminescence was sensitive to the presence of free radicals near the QD surface.…”

Transient supramolecular reconfiguration of peptide nanostructures using ultrasound

“…17 Peptides are versatile building blocks in molecular self-assembly [18][19][20][21] with recent reports revealing that ultrasound energy may be used to trigger supramolecular transitions, resulting from changes in supramolecular interactions. Mostly these studies used organic solvents, [22][23][24][25][26][27] with some reports using aqueous media. 28,29 Yokoi et al reported the dynamic re-assembly of a 16 amino-acid residue peptide in water using sonication.…”