Chemically Triggered Hydrogel Transformations through Covalent Adaptable Networks and Applications in Cell Culture

Abstract

In this article, we report a "smart" hydrogel system, which can be remodeled into multiple architectures through dynamic covalent adaptable networks. The topological changes in hydrogel structures yield dynamically tunable properties through the reformation of covalent chemical linkages via amine−thiol scrambling, thiol−thiol exchange, decoupling reaction, and disulfide formation. The stiffness of the hydrogels can be regulated via dynamic covalent bonding, with some hydrogels displaying selfhealing and shear thinning properties, as demonstrated by rheological measurements. Significantly, the dramatic structural transformations are achieved under neutral aqueous conditions at room temperature. These "smart" hydrogels show good biocompatibility, which can induce cell growth in two-dimensional cell culture and effectively serve as a scaffold for encapsulating and releasing human mesenchymal stem cells in three-dimensional cell culture. Thus, the developed "smart" hydrogel system holds great potential in biomedical applications such as tissue engineering and cell therapy.

A ring‐controlled fluorescent platform for visualizing polymer degradation

“…In certain scenarios, rapid degradation properties would be in high demand in plastics, [ 12 ] hydrogels, [ 13 ] as well as other categories of medical polymers. [ 14 ] Visualization and quantitation of polymer degradation extent are of great importance for tracking and control of material properties.…”

“…1 H and 13 C NMR spectra were recorded on 400 MHz JEOL NMR spectrometer, Bruker Avance-400 and 600 MHz NMR spectrometer. The NMR spectra were referenced to solvent and the spectroscopic solvents (chloroform-d, DMSO-d 6 ) were purchased from Cambridge Isotope Laboratories and Energy Chemical.…”

Fluorometric detection of volatile amines using an indanonalkene platform

“…33 The molecule contains bis-vinylogous thioester active moieties, which are reactive towards amine derivatives. 32,34 The chemical reaction enables the design of a reaction-based chemosensor through amine-thiol scrambling, with the release of methylmercaptan. Firstly using UV-Vis absorbance spectroscopy, kinetic tracking of the photophysicochemical reaction between CA-SCH 3 (10 μM) and ammonia (0.0125%) over 0-180 min resulted in a ratiometric change, with a decrease at λ abs = 366 nm an increase at λ abs = 336 nm and isosbestic point at 345 nm in a H 2 O/DMSO (1%/ 99%) system (Fig.…”

Tailoring Dynamic Hydrogels by Controlling Associative Exchange Rates

“…Meldrum's acidderived dithioalkylidenes have been incorporated into chemicallyresponsive hydrogels, but stress relaxation (if present) was not characterized. [28][29][30] Thioesters, which exchange through an associative mechanism, have been used as dynamic cross-links in stress-relaxing hydrogels, but thioester exchange is extremely slow (t½ > 30 h) at physiological pH in the absence of a catalyst, leading to slow stress relaxation. [31][32][33][34] Figure 1.…”