The term hydrogel describes a type of soft and wet material formed by cross‐linked hydrophilic polymers. The distinct feature of hydrogels is their ability to absorb a large amount of water and swell. The properties of a hydrogel are usually determined by the chemical properties of their constituent polymer(s). However, a group of hydrogels, called “smart hydrogels,” changes properties in response to environmental changes or external stimuli. Recently, DNA or DNA‐inspired responsive hydrogels have attracted considerable attention in construction of smart hydrogels because of the intrinsic advantages of DNA. As a biological polymer, DNA is hydrophilic, biocompatible, and highly programmable by Watson‐Crick base pairing. DNA can form a hydrogel by itself under certain conditions, and it can also be incorporated into synthetic polymers to form DNA‐hybrid hydrogels. Functional DNAs, such as aptamers and DNAzymes, provide additional molecular recognition capabilities and versatility. In this Review, DNA‐based hydrogels are discussed in terms of their stimulus response, as well as their applications.
Dual responsive inverse opal hydrogels were designed as autonomous sensor systems for (bio)macromolecules, exploiting the analyte‐induced modulation of the opal’s structural color. The systems that are based on oligo(ethylene glycol) macromonomers additionally incorporate comonomers with various recognition units. They combine a coil‐to‐globule collapse transition of the LCST type with sensitivity of the transition temperature toward molecular recognition processes. This enables the specific detection of macromolecular analytes, such as glycopolymers and proteins, by simple optical methods. While the inverse opal structure assists the effective diffusion even of large analytes into the photonic crystal, the stimulus responsiveness gives rise to strong shifts of the optical Bragg peak of more than 100 nm upon analyte binding at a given temperature. The systems’ design provides a versatile platform for the development of easy‐to‐use, fast, and low‐cost sensors for pathogens. 相似文献
Conducting polymer hydrogels that are capable of contacting with electrolytes at the molecular level, represent an important electrode material. However, the fabrication of self-standing hydrogels merely composed of conducting polymers is still challenging owing to the absence of reliable methods. Herein, a novel and facile macromolecular interaction assisted route is reported to fabricate self-standing hydrogels consisting of polyaniline (PANi: providing high electrochemical activity) and poly(3,4-ethylenedioxythiophene) (PEDOT: enabling high electronic conductivity). Owing to the synergistic effect between them, the self-standing hydrogels possess good mechanical properties and electronic/electrochemical performances, making them an excellent potential electrode for solid-state energy storage devices. A proof-of-concept all-hydrogel-state supercapacitor is fabricated, which exhibits a high areal capacitance of 808.2 mF cm−2, and a high energy density of 0.63 mWh cm−3 at high power density of 28.42 mW cm−3, superior to many recently reported conducting polymer hydrogels based supercapacitors. This study demonstrates a novel promising strategy to fabricate self-standing conducting polymer hydrogels. 相似文献
Novel antigen responsive hydrogels were prepared by using polymerizable antibody Fab′ fragment from monoclonal anti‐fluorescein BDC1 antibody (IgG2a). To form Fab′ containing hydrogels, the polymerizable Fab′ fragment was copolymerized with N‐isopropylacrylamide (NIPAAm) and N,N′‐methylenebis(acrylamide) (MBAAm; crosslinker) using redox initiators. The thermosensitivity of the hydrogels decreased with increasing Fab′ fragment content. The antigen responsiveness of the hydrogels depended on the Fab′ content, pH, and temperature. When the hydrogels were alternately exposed to antigens fluorescein (FL) and polyamidoamine dendrimer (PAMAM)‐fluorescein (FD), significant reversible volume changes were observed for the hydrogel containing 50% (w/w) Fab′ fragment at 33.7 and 36.8 °C in acetate buffer (10 mM , pH 5.0), respectively, but not at 27.7 °C or in PBS buffer (10 mM , pH 7.4). No noticeable reversible volume changes were observed with pure PNIPAAm hydrogel and the gel containing 10% (w/w) Fab′ fragment.
Interactive materials being responsive to a biocompatible stimulus represent a promising approach for future therapeutic applications. In this study, we present a novel biohybrid material synthesized from biocompatible components being stimulus‐responsive to the pharmaceutically approved small‐molecule novobiocin. The hydrogel design is based on the gyrase B (GyrB) protein, which is covalently grafted to multi‐arm polyethylene glycol (PEG) using a Michael‐type addition reaction. Upon addition of the GyrB‐dimerizing substance coumermycin, stable hydrogels form which can be dissolved in a dose‐adjustable manner by the antibiotic novobiocin. The switchable properties of this PEG‐based hydrogel are favorable for future applications in tissue engineering and as externally controlled drug depot. 相似文献