The interaction of cholesteryl-grafted sodium alginate derivative (CSAD) and decyl-β-D-glucopyranoside (DGP) in solution was studied through the surface tension method, fluorescence spectroscopy, electron paramagnetic resonance (EPR), and dynamic light scattering. Results showed that DGP and CSAD exhibit competitive adsorption behaviour at the water–gas interface and that this competitive behaviour can be intensified by NaCl. EPR revealed that the cholesterol groups of CSAD participate in the formation of micellar structures. The steric effect of the cholesterol groups reduces the microviscosity of the micellar structure, but high-concentration NaCl can weaken the polarity and increase the microviscosity of the formed micellar structure. In addition, at a high DGP concentration, high-concentration NaCl can facilitate DGP precipitation; this condition causes abnormal phenomena of surface tension, fluorescence spectroscopy, and EPR. For the emulsion system, analysis of particle size and rheology indicated that DGP and CSAD form a network structure between oil and water interfaces through interaction and thus enhance the non-Newtonian fluid properties of the emulsion. Owing to the competitive adsorption between CSAD and DGP at the oil–water interface, DGP gradually replaces CSAD with the increase in DGP concentration. With a further increase in DGP concentration, the stable steric effect of polymers between oil drops may disappear, and oil drops may aggregate mutually.
The measurement of microviscosity gradients across different regions of self-assembled systems is crucial for optimizing their performance in both biological and industrial applications. However, this task has long been challenging due to the spatial barrier within the self-assembled systems, the interference from polarity gradients, and the lack of region-positioned probes. To overcome these challenges, we developed three kinds of length-regulated aggregation-induced emission (AIE) probes for the spatial resolution measurement of microviscosity. These AIE probes with varying alkyl chain lengths showed high sensitivity (0.81) over a viscosity range from 2 to 435 mPa s and unaffected luminescence to environmental polarity, ensuring accurate measurements in diverse environments. Using micelles as a model of self-assembled systems, these AIE probes were able to localize selectively in different regions ranging from the hydrophobic core to the hydrophilic shell and interface. The results indicated that microviscosity was highest in the core and gradually decreased toward the outer regions. Furthermore, these AIE probes were successfully applied for monitoring microviscosity in hydrogels and food thickeners, showing a strong correlation among fluorescence intensity, tensile strength, and thickening effects. These findings underscore the potential of length-regulated AIE probes for evaluating the microviscosity in diverse applications.
Shi Junli,Chong Hui,Yang Xiaofei,Zhong Guangjie,Wu Shengnan,Gu Zehao,Tao Qi,Wang Dong-An,Xue Huaiguo,Yang Yi,Yao Hang
This study reports a viscosity-responsive fluorescent probe, BODIPY-C, designed to measure viscosity in a 3D live-cell hydrogel microenvironment using a fluorescence lifetime-based method. This method enables real-time monitoring of cell membrane viscosity changes through the fluorescent lifetime signals of the probe. Functionally, the BODIPY-C exhibits microviscosity sensitivity; the non-toxic probe enables long-term tracking with high sensitivity ( R 2 = 0.99). Structurally, the BODIPY-C features polymerizable vinyl groups that facilitate covalent conjugation to hydrogel networks via UV-initiated polymerization. This design synergistically integrates the molecular specificity of BODIPY-C-based viscosity sensing with the mechanobiology of covalent hydrogel networks. Notably, softer 3D hydrogel microenvironments extend the probe’s fluorescence lifetime due to restricted molecular motion from differential elastic collisions between polymer chains. The covalent anchoring of BODIPY-C within hydrogel networks enables in situ monitoring of viscosity dynamics in encapsulated cells, establishing a promising platform for investigating mechanobiological processes. Graphical abstract
危险品化学品经营许可证（带存储）