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Bioinspired Simultaneous Changes in Fluorescence Color, Brightness, and Shape of Hydrogels Enabled by AIEgens
摘要： Development of stimuli-responsive materials with complex practical functions is significant for achieving bioinspired artificial intelligence. It is challenging to fabricate stimuli-responsive hydrogels showing simultaneous changes in fluorescence color, brightness, and shape in response to a single stimulus. Herein, a bilayer hydrogel strategy is designed by utilizing an aggregation-induced emission luminogen, tetra-(4-pyridylphenyl)ethylene (TPE-4Py), to fabricate hydrogels with the above capabilities. Bilayer hydrogel actuators with the ionomer of poly(acrylamide-r-sodium 4-styrenesulfonate) (PAS) as a matrix of both active and passive layers and TPE-4Py as the core function element in the active layer are prepared. At acidic pH, the protonation of TPE-4Py leads to fluorescence color and brightness changes of the actuators and the electrostatic interactions between the protonated TPE-4Py and benzenesulfonate groups of the PAS chains in the active layer cause the actuators to deform. The proposed TPE-4Py/PAS-based bilayer hydrogel actuators with such responsiveness to stimulus provide insights in the design of intelligent systems and are highly attractive material candidates in the fields of 3D/4D printing, soft robots, and smart wearable devices.
关键词： stimuli-responsive hydrogels,complex shape,simultaneous changes,fluorescence,aggregation-induced emission luminogens
更新于2025-09-19 17:13:59
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Development of Plasmonic Chitosan-Squarate Hydrogels via Bio-Inspired Nanoparticle Growth
摘要： We report on the bio-inspired growth of gold nanoparticles (GNPs) in biocompatible hydrogels to develop plasmonic hybrid materials. The new hydrogel (CS-Sq) is prepared from chitosan and diethylsquarate and is formed via non-covalent interactions rising between the in-situ formed ionic squaric acid derivatives and chitosan. Interestingly, when the hydrogel is prepared in the presence of HAuCl4, GNPs with controlled sizes between 15 and 50 nm are obtained which are homogeneously distributed within the plasmonic hydrogels (GNPs-CS-Sq). We found that the supramolecular nature and the composition of the CS-Sq hydrogels are key for the GNPs growth process where the squaric derivatives act as reducing agents and the chitosan hydrogel network provides nucleation points and supports the GNPs. Accordingly, the hydrogel acts as a bio-inspired reactor and permits to gain certain control on the GNPs size by adjusting the concentration of chitosan and HAuCl4. Besides the intrinsic and tunable plasmonic properties of the GNPs-CS-Sq hydrogels, it was found that the gels could be useful as heterogeneous catalysts for organic reactions. Furthermore, cell viability studies indicate that the new hydrogels exhibit suitable biocompatibility. Thus, the proposed method for obtaining GNPs-CS-Sq hydrogels has the potential to be applied for the development of a wide variety of other hybrid chitosan materials useful for catalysis, biosensing, cell culture, tissue engineering, and drug delivery applications.
关键词： Chitosan,Hybrid Materials,Hydrogels,Squaric Acid,Gold Nanoparticles
更新于2025-09-12 10:27:22
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Recent development of g-C3N4-based hydrogels as photocatalysts: A minireview
摘要： Solar-driven photocatalysis using graphitic carbon nitride (g-C3N4) is considered the most promising approach for the generation of H2 from water, degradation of organic pollutants, and reduction of CO2. However, bulk g-C3N4 exhibits several drawbacks, such as low specific surface area, high defect density, and fast charge recombination, which result in low photocatalytic performance. Construction of 3D porous hydrogels for g-C3N4 through nanostructural engineering is a rapid, feasible, and cost-effective technique to improve the adsorption capability, stability, and separability of the hydrogel composite; to increase the number of active sites; and to create an internal conductive path for facile charge transfer and high photocatalytic activity. This minireview summarizes the recent progresses in photocatalytic water splitting and dye degradation using g-C3N4-based hydrogels with respect to the state-of-the-art methods of synthesis, preparation, modification, and multicomponent coupling. Furthermore, comprehensive outlooks, future challenges, and concluding remarks regarding using g-C3N4-based hydrogels as highly efficient photocatalysts are presented.
关键词： water splitting,hydrogels,photocatalysts,dye degradation,g-C3N4
更新于2025-09-10 09:29:36
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Biomaterials and Regenerative Medicine in Ophthalmology || An introduction to ophthalmic biomaterials and their role in tissue engineering and regenerative medicine
摘要： The ultimate goal of the research and development of materials (other than drugs) for applications in medicine, which we call biomaterials, has always been to emulate natural materials. Since the natural target for biomaterials, ie, our body’s tissues and organs, is exceedingly complex, it is not surprising that in many instances the laboratory-made materials cannot match in their performance the natural entities they are meant to augment or replace. This is obviously different from the development of materials for industrial applications, which usually perform better than their natural counterparts (if the latter exist), and also evolve relatively fast, unhindered by the biological constraints inherent to living systems. For too long, an acceptable end performance in the short term was the main requirement from a biomaterial, with little attention paid to changing its bulk and/or surface properties through the manipulation of composition and/or structure, in order to maximize the clinical outcome. Over the past six decades or so, however, the progress in bringing the properties and functionality of biomaterials close to those of their biological targets has been remarkable. While the previous statements are valid for the ophthalmic biomaterials too, their development has shown some particular features. The general developments in the field of biomaterials have customarily been gauged through the achievements in the branches of orthopaedic biomaterials and, to a lesser extent, biomaterials for cardiology or dentistry, while the progress of biomaterials for the eye has usually been ignored or seldom presented.
关键词： ophthalmic biomaterials,artificial cornea,poly(methyl methacrylate),contact lenses,hydrogels,cornea,regenerative medicine,tissue engineering
更新于2025-09-10 09:29:36
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Synthesis, characterization, swelling-deswelling properties of Novel nanoparticle-hydrogel containing core chitosan and their cyclohexanone-crosslinked counterparts
摘要： Novel Chitosan-cyclohexanone Mannich based hydrogel nanoparticles (CCMb1-4) were prepare via the reaction of chitosan with different concentration of 2, 6-bis (piperidin-1-ylmethyl) cyclohexanone. 2HCl (1%, 5%, 10% and 15% wt/wt) at 70–80°C for 7 h. These hydrogels were subjected to equilibrium swelling studies at room temperature in solutions of pH 2, 4, 6 and 8. The (CCMb1-4) showed maximum percent swellability at pH = 2.0. Furthermore, the swelling of the (CCMb1-4) followed Fickian diffusion. This preliminary investigation of chitosan-based interpolymeric hydrogels showed that they may be exploited to expand the utilization of these systems in drug delivery applications.
关键词： Chitosan,mannish base,hydrogels,drug delivery,swellability
更新于2025-09-10 09:29:36
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Alginate-graphene oxide hydrogels with enhanced ionic tunability and chemomechanical stability for light-directed 3D printing
摘要： Nanocomposite hydrogels that incorporate 2D carbon nanomaterials could enable augmented and responsive behaviors not observed with polymeric matrices alone. In particular, non-covalent interactions could facilitate enhanced mechanical performance that can be self-recovered with external stimuli. Here, we demonstrate alginate-graphene oxide (GO) hydrogels using a non-covalent, ionic crosslinking mechanism compatible with light-directed 3D printing. We show that alginate-GO hydrogels exhibit improved mechanical performance in shear, compression, and tension, including a two-fold increase in shear modulus, a three-fold decrease in inelastic deformation, and a nine-fold increase in fracture energy relative to alginate-only hydrogels. Moreover, alginate-GO hydrogels are stabilized by hydrogen bonding between nanosheets and remain intact after removal of ionic crosslinkers by chelation. As a consequence, the shear modulus of these nanocomposite hydrogels can be tuned by over 500-fold via external ion concentration. We demonstrate that alginate-GO can be stereolithographically printed into robust, freestanding and overhanging 3D structures. These designer material architectures exhibit outstanding stability and superoleophobicity in high salt solution, which can be used to repel and manipulate a variety of oils. Overall, such nanocomposite hydrogels with engineered non-covalent interactions could enable “smart” multiresponsive and multifunctional devices for aqueous and marine environments.
关键词： Superoleophobicity,Ionic crosslinking,Chemomechanical stability,Graphene oxide,3D printing,Alginate,Nanocomposite hydrogels,Mechanical performance
更新于2025-09-10 09:29:36
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A Second-Generation Chameleon N-Heterocyclic Carbene–Borane Coinitiator for the Visible-Light Oxygen-Resistant Photopolymerization of Both Organic and Water-Compatible Resins
摘要： N-Heterocyclic carbene?boranes (NHC-boranes, NHCBs) were recently described as efficient coinitiators for the visible light photopolymerization of hydroxyethyl methacrylate (HEMA) in the presence of water. In this work, a new, more water-soluble, NHC-borane—2,4-dimethyl-1,2,4,5-tetrazol-3-ylidene borane—has been synthesized, and its efficiency in three-component systems (dye (Acridine Orange), disulfide, and NHC-borane coinitiators) for the polymerization of methacrylate resins under visible light under air has been studied. In fluid resins this new photoinitiating system (PIS) gives better results than the one previously studied. More importantly, this system is competitive with the widely used type II system—camphorquinone/4-(dimethylamino)benzonitrile (DMABN)—for the polymerization of methacrylate resins but better for the photopolymerization of poly(2-hydroxyethyl methacrylate) leading to hydrogels, where the former PIS fails. The excellent ability of the NHC-boranes, and especially the new one, to be used as photopolymerization coinitiators has been analyzed by laser flash photolysis (LFP). The rate constants for elementary reactions of the three boranes and their derived NHC-boryl radicals obtained by LFP correlated well with the molecular modeling data and show that the key for the observed reactivity is the ability of the tetrazolydinyl NHC-borane to repair the peroxyl radicals formed by the reactions of the macroradicals with oxygen.
关键词： laser flash photolysis,methacrylate resins,N-Heterocyclic carbene?boranes,hydrogels,visible light photopolymerization
更新于2025-09-09 09:28:46
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Multi-Triggered Supramolecular DNA/Bipyridinium Dithienylethene Hydrogels Driven by Light, Redox and Chemical Stimuli for Shape-Memory and Self-Healing Applications
摘要： Multi-triggered DNA/bipyridinium-dithienylethene (DTE) hybrid carboxymethyl cellulose (CMC) based hydrogels are introduced. DTE exhibits cyclic and reversible photoisomerization properties, switching between the closed state (DTEc), the electron acceptor, and the open isomer (DTEo) that lacks electron acceptor properties. One system includes the synthesis of CMC chains modified with electron donor dopamine sites and self-complementary nucleic acid tethers. In the presence of DTEc and the CMC scaffold, a stiff hydrogel, cooperatively stabilized by dopamine/DTEc donor-acceptor interactions and by the duplex nucleic acids is formed. The cyclic and reversible formation and dissociation of the supramolecular donor-acceptor interactions, through light-induced photoisomerization of DTE, or via the oxidation and subsequent reduction of the dopamine sites, leads to hydrogels of switchable stiffness. Another system introduces a stimuli-responsive hydrogel triggered by one of the three alternative signals. The stiff multi-triggered hydrogel consists of CMC chains crosslinked by the dopamine/DTEc donor-acceptor interactions, and by supramolecular K+-stabilized G-quadruplexes. The G-quadruplexes are reversibly separated in the presence of 18-crown-6 ether and reformed upon the addition of K+. The stiff hydrogel undergoes reversible transitions between high-stiffness and low-stiffness states triggered by light, redox agents or K+/crown ether. The hybrid donor-acceptor/G-quadruplex crosslinked hydrogels show shape-memory and self-healing features. By using three different triggers and two alternative memory-codes, e.g. the dopamine/DTEc or the K+-stabilized G-quadruplexes, the guided shape-memory formation of the hydrogel matrices are demonstrated.
关键词： hydrogels,self-healing,chemical stimuli,DNA,redox,shape-memory,light,Multi-triggered,bipyridinium-dithienylethene
更新于2025-09-09 09:28:46
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Synthesis of Inorganic/Organic Hybrid Materials via Vapor Deposition onto Liquid Surfaces
摘要： Hybrid materials have a multitude of uses in electronics, catalysis, and drug delivery. Here, we combine sputter deposition and initiated chemical vapor deposition onto low-vapor-pressure liquids to fabricate inorganic/organic hybrid materials. We demonstrate that polymer nanoparticles can be decorated with metal nanoparticles and nanoparticle dispersions can be encapsulated within polymer shells or within gel beads. The generality of our synthetic route allows for a variety of hybrid materials to be fabricated by tuning the viscosity of the liquid, solubility of the monomer, and surface tension of the polymer and liquid.
关键词： encapsulation,polymer,hybrid,nanoparticles,hydrogels,synthesis
更新于2025-09-09 09:28:46
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Micro-patterned cell orientation of cyanobacterial liquid-crystalline hydrogels
摘要： Control of cell extension direction is crucial for the regeneration of tissues, which are generally composed of oriented molecules. The scaffolds of highly-oriented liquid crystalline polymer chains were fabricated by casting cyanobacterial mega-saccharides, sacran, on parallel-aligned micrometer bars of polystyrene (PS). Polarized microscopy revealed that the orientation was in transverse direction to the longitudinal axes of the PS bars. Swelling behavior of the micro-patterned hydrogels was dependent on the distance between the PS bars. The mechanical properties of these scaffolds were dependent on the structural orientation; additionally, the Young’s moduli in the transverse direction were higher than those in the parallel direction to the major axes of the PS bars. Further, fibroblast L929 cells were cultivated on the oriented scaffolds to be aligned along the orientation axis. L929 cells cultured on these scaffolds exhibited uniaxial elongation.
关键词： Cell orientation,Liquid crystal hydrogels,Micropatterned scaffolds,Cyanobacteria,Sulfated polysaccharides
更新于2025-09-09 09:28:46