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A simple self-assembly platform based on squaraine-embedded CTAB micelles can readily discriminate between Cys and Hcy with different absorption and fluorescence signals. The recognition mechanism is attributed to the fact that analyte adducts trigger the CTAB micelles to undergo sphere-to-rod transition.
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http://dx.doi.org/10.1039/c3cc43223h | DOI Listing |
J Phys Chem B
April 2025
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, Anhui, China.
Temperature-responsive macromolecules can provide insights into the mechanisms of the aggregation and precipitation processes of proteins. In this study, the PEO-PPO-PEO triblock copolymer, Pluronic P123, has been utilized as a protein model to investigate the thermally induced dynamic transition behavior by ultrasensitive differential scanning calorimetry (US-DSC). The results of US-DSC reveal hysteresis in the disaggregation process of P123 micelles.
View Article and Find Full Text PDFJ Fluoresc
March 2025
Instituto de Física, Universidade Federal de Goiás, Av. Esperança s/n, Goiânia, GO, CEP 74690-900, Brazil.
In this study, the sphere-to-rod transition in sodium dodecyl sulfate (SDS) micelles was induced by increasing the ionic strength of the medium. This transition was monitored through the fluorescence of the lipophilic probe 2-amino-N-hexadecyl-benzamide (AHBA), which has a 16-carbon hydrocarbon chain and aggregates in aqueous solution. AHBA fluorescence parameters, such as emission intensity, spectral position, lifetime, and steady-state anisotropy, were monitored to understand the probe's behavior in aqueous solution as a function of ionic strength.
View Article and Find Full Text PDFPolymers (Basel)
November 2022
Physics Department, Moscow State University, 119991 Moscow, Russia.
Salt-induced structural transformation of charged hybrid surfactant/polymer micelles formed by potassium oleate and poly(4-vinylpyridine) was investigated by cryo-TEM, SANS with contrast variation, DLS, and 2D NOESY. Cryo-TEM data show, that at small salt concentration beads-on-string aggregates on polymer chains are formed. KCl induces the transformation of those aggregates into rods, which is due to the screening of the electrostatic repulsion between similarly charged beads by added salt.
View Article and Find Full Text PDFSoft Matter
May 2022
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA.
Capillary-driven thinning of a liquid bridge is commonly used to measure the extensional rheology of macromolecular solutions for assessment of material sprayability, printability, and jettability. Methods like dripping-onto-substrate (DoS) rheometry are often preferred to methods like capillary breakup extensional rheometry (CaBER) due to low required sample volume and ability to measure low-viscosity fluids; however, DoS measurements to-date have been limited to ambient temperatures. Here, an environmental control chamber is developed to enable temperature-controlled DoS (TC-DoS) measurements, and the temperature-dependent extensional rheology of a model system of poloxamer 234 (P234) in NaF brine is examined.
View Article and Find Full Text PDFLangmuir
October 2021
Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, United States.
Self-assembled wormlike micelles (WLMs) are widely studied in small-molecule surfactants due to their unique ability to break and recombine; however, less is known about the structure and dynamics of nonionic polymer WLMs. Here, solutions of seven triblock poloxamers, composed of poly(propylene oxide) (PPO) midblocks and poly(ethylene oxide) (PEO) end blocks, are comprehensively examined to determine the role of poloxamer composition, temperature, and inorganic salt type and concentration on rod formation and subsequent elongation into WLMs. Phase separation and sphere-to-rod transition temperatures were quantified via cloud point measurements and shear rheology, respectively, and corroborated with small-angle neutron scattering (SANS).
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