Polyacrylamide Hydrogel Research Articles

MicroRNA sensing using integrating DNA-functionalized hydrogels with aggregation-induced emission of silver nanoclusters

Here, a platform consisting of a fluorescent DNA-functionalized hydrogel was created for the measurement of miRNA-141. In the presence of the target, the closed cytosine-rich loop of the three-segment branched DNA structure is formed as a useful template to create fluorescent silver nanoclusters (AgNCs). Then, aggregation-induced emission of AgNCs occurs in the hydrogel, and enhanced fluorescence is observed. Instead of acrylate-modified DNA, we used unmodified penta-adenine (A5) DNA strands for incorporation into polyacrylamide hydrogel in this method. By raising the concentration of target microRNA 141 (miR-141) under optimal conditions, the silver nanocluster's fluorescence intensities increased linearly from 5 pM to 100 nM, with a detection limit (LOD) of 2 pM. In addition, a selectivity analysis against the target demonstrates that the proposed analytical technique has good selectivity for miR-141. Since the creation of nanoclusters only occurs in the presence of the target sequence, this technique has shown significant potential for sensitive, selective, and label-free miRNA detection for clinical disease diagnosis and biomedical applications.

Non-isothermal decomposition kinetics of commercial polyacrylamide hydrogel using TGA and DSC techniques

The thermal decomposition method was employed to analysis the non-isothermal kinetics of commercial polyacrylamide hydrogel. Malek model-based methods and Vyazovkin model-free advanced converter methods were used to analyze the non-isothermal kinetics of hydrogel decomposition using DSC and TGA data. Thermal decomposition takes place in two stages. FTIR diagrams showed that ammonia gas and CO2 were likely released during the first and second stages of decomposition, respectively. By breaking the main chain in the second stage, the polymer loses a significant amount of weight. The Sestak-Berggren model describes the reaction process. The activation energies for the first and second stages were calculated to be (40±3 kJ/mol) and (59±3 kJ/mol), respectively. Finally, a commercial polyacrylamide hydrogel decomposition explicit rate equation was derived. The increase in surface porosity with the progress of the degradation process can be evidence of autocatalysis effects.

Large Polyacrylamide Hydrogels for Large-Batch Cell Culture and Mechanobiological Studies.

The rigidity of a cell's substrate or extracellular matrix plays a vital role in regulating cell and tissue functions. Polyacrylamide (PAAm) hydrogels are one of the most widely used cell culture substrates that provide a physiologically relevant range of stiffness. However, it is still arduous and time-consuming to prepare PAAm substrates in large batches for high-yield or multiscale cell cultures. In this communication, a simple method to prepare PAAm hydrogels with less time cost and easily accessible materials is presented. The hydrogel is mechanically uniform and supports cell culture in a large batch. It is further shown that the stiffness of the hydrogel covers a large range of Young's modulus and is sensed by cells, regulating various cell features including changes in cell morphology, proliferation, and contractility. This method improves the reproducibility of mechanobiology studies and can be easily applied for mechanobiology research requiring large numbers of cells or experimental groups.

High Performance and Multifunction Moisture-Driven Yin-Yang-Interface Actuators Derived from Polyacrylamide Hydrogel.

High actuation performance of a moisture actuator highly depends on the presence of a large property difference between the two layers, which may cause interfacial delamination. Improving interfacial adhesion strength while increasing the difference between the layers is a challenge. In this study, a moisture-driven tri-layer actuator with a Yin-Yang-interface (YYI) design is investigated in which a moisture-responsive polyacrylamide (PAM) hydrogel layer (Yang) is combined with a moisture-inert polyethylene terephthalate (PET) layer (Yin) using an interfacial poly(2-ethylhexyl acrylate) (PEA) adhesion layer. Fast and large reversible bending, oscillation, and programmable morphing motions in response to moisture are realized. The response time, bending curvature, and response speed normalized by thickness are among the best compared with those of previously reported moisture-driven actuators. The excellent actuation performance of the actuator has potential multifunctional applications in moisture-controlled switches, mechanical grippers, and crawling and jumping motions. The Yin-Yang-interface design proposed in this work provides a new design strategy for high-performance intelligent materials and devices.

Alginate/polyacrylamide host-guest supramolecular hydrogels with enhanced adhesion

Although injectable hydrogels with minimally invasive delivery have garnered significant interest, their potential applications have been restricted by a singular property. In this study, a supramolecular hydrogel system with improved adhesion was constructed through host-guest interactions between alginate and polyacrylamide. The maximum tensile adhesion strength between the β-cyclodextrin and dopamine-grafted alginate/adamantane-grafted polyacrylamide (Alg-βCD-DA/PAAm-Ad, namely AβCDPA) hydrogels and pigskin reached 19.2 kPa, which was 76 % stronger than the non-catechol-based control hydrogel (β-cyclodextrin-grafted alginate/adamantane-grafted polyacrylamide, Alg-βCD/PAAm-Ad). Moreover, the hydrogels demonstrated excellent self-healing, shear-thinning, and injectable properties. The required pressure to extrude the AβCDPA2 hydrogel from a 16G needle at a rate of 2.0 mL/min was 67.4 N. As the polymer concentration and adamantane substitution degree increased, the hydrogels exhibited higher modulus, stronger network structure, and lower swelling ratio and degradation rate. Encapsulating and culturing cells within these hydrogels demonstrated good cytocompatibility. Therefore, this hydrogel can serve as a viscosity extender or bioadhesive, and as a carrier material to deliver encapsulated therapeutic substances into the body through minimally invasive injection methods.

Sustainable β-cyclodextrin modified polyacrylamide hydrogel for highly efficient solar-driven water purification

Solar-driven water purification is considered as an efficient and green method to solve water scarcity. However, creating a hydrogel evaporator with both long-lasting evaporation performance and an efficient reduction in water vaporization enthalpy remains a significant challenge. Herein, a hydrogel with low water vaporization enthalpy was prepared by introducing β-cyclodextrin (β-CD) to polyacrylamide. The three-dimensional network structure was obtained via a simple freeze-drying process, and the addition of β-CD enhanced its hydrophilicity. Due to the hydration of hydroxyl groups on β-CD, the hydrogel facilitated the formation of intermediate water, substantially reducing the water vaporization enthalpy to 1428 J/g. It enabled the hydrogel to achieve a high evaporation rate of 2.65 kg/m2/h under 1 sun irradiation. Furthermore, the hydrogel demonstrated excellent hydration properties and abundant water transport channels for salt rejection in long-term desalination. After 50 cycles of testing in 3.5% brine, the evaporation rate remained high at 2.38 kg/m2/h. This work provides a sustainable way to develop a highly efficient solar evaporator for clean water production.

Preparation of magnetic polyacrylamide hydrogel with chitosan for immobilization of glutamate decarboxylase to produce γ-aminobutyric acid

Gamma-aminobutyric acid (GABA) is an vital neurotransmitter, and the reaction to obtain GABA through biocatalysis requires coenzymes, which are therefore limited in the production of GABA. In this study, polyacrylamide hydrogels doped with chitosan and waste toner were synthesized for glutamate decarboxylase (GAD) and coenzyme co-immobilization to realize the production of GABA and the recovery of coenzymes. Enzymatic properties of immobilized GAD were discussed. The immobilized enzymes have significantly improved pH and temperature tolerance compared to free enzymes. In terms of reusability, after 10 repeated reuses of the immobilized GAD, the residual enzyme activity of immobilized GAD still retains 100% of the initial enzyme activity, and the immobilized coenzyme can also be kept at about 32%, with better stability and reusability. And under the control of no exogenous pH, immobilized GAD showed good performance in producing GABA. Therefore, in many ways, the new composite hydrogel provides another way for the utilization of waste toner and promises the possibility of industrial production of GABA.

Hydrosoluble diacetone acrylamide as an electrolyte additive for high-capacity Zn-ion hybrid supercapacitors

Rational optimization of electrolytes is of great concern for the improvement of Zn-ion hybrid supercapacitors. Polyacrylamide hydrogels as gel electrolytes, usually suffer from slow electromigration of the hydrated Zn2+ ions limited by the complexation of acylamino groups with the hydrated Zn2+ ions. We propose a new strategy of adding hydrosoluble diacetone acrylamide (DAAM) as an electrolyte additive into the Zn(CF3SO3)2 electrolyte to boost the electrochemical performances of the MnO2//AC Zn-ion hybrid supercapacitors. Theoretically, the formation of double hydrogen bonds between DAAM and H2O can induce the structural transformation of the hydrated Zn2+ ion from [Zn(H2O)6]2+ to [Zn(H2O)5]2+, which can reduce the thickness of the electric double layer to boost the electric double layer capacitance. The theoretical calculation on the Gibbs free energy change can confirm the formation of DAAM/H2O and [Zn(H2O)5]2+ from DAAM and [Zn(H2O)6]2+, indicating the effect of DAAM on the structural transformation of the hydrated Zn2+ ion. The MnO2//AC Zn-ion hybrid supercapacitor with the Zn(CF3SO3)2/DAAM (1 M) electrolyte shows the higher specific capacitances at 0.4 A g−1 and 0.5 A g−1 than the supercapacitor with the Zn(CF3SO3)2 electrolyte, probably due to the effect of DAAM on the structural transformation of the hydrated Zn2+ ion. This supercapacitor can provide the cycling stability of 80.2% (after 10,000 cycles) and the energy density of 35.6 Wh kg−1 (at 0.44 kW kg−1). The wise utilization of DAAM as an electrolyte additive, opens up new avenues for developing high-capacity Zn-foil-free Zn-ion hybrid supercapacitors.

Matrix stiffness-induced platelet activation determines immunomodulation of macrophages.

Although various bone defect repair materials have been used clinically, the influence of the material properties on bone repair and regeneration as well as the underlying mechanisms are not fully understood. We hypothesize that the material stiffness affects initial platelet activation during hemostasis phase, which in turn mediates subsequent osteoimmunomodulation of macrophages, finally determining clinical outcomes. To verify the hypothesis, the present work used polyacrylamide hydrogels with different stiffness (10, 70, and 260kPa) as model materials to investigate matrix stiffness induced platelet activation behavior and its mediation on osteoimmunomodulation of macrophages. The results showed that the matrix stiffness was positively related with activation degree of platelets. However, the extracts of platelets incubated on middle-stiff matrix polarized macrophages to pro-healing M2 phenotype when compared with that on soft and stiff matrixes. ELISA results showed when compared with that on soft and stiff matrixes, the platelets incubated on middle-stiff matrix released more TGF-β and PGE2, both of which could polarize macrophages to M2 phenotype. The M2 macrophages could promote angiogenesis of endothelial cells and osteogenesis of bone marrow mesenchymal stem cells, two important and coupled processes involved in bone repair and regeneration. These findings suggest bone repair materials with 70kPa stiffness can mediate proper platelet activation, which can polarize macrophages to pro-healing M2 phenotype, potentially contributing to bone repair and regeneration.

Flame‐retardant, flexible, and breathable smart humidity sensing fabrics based on hydrogels for respiratory monitoring and non‐contact sensing

AbstractSmart sensing fabrics are becoming increasingly attractive in the emerging wearable areas of medical and military so far. Here, for the first time, we present a smart humidity sensing fabric (SHSF) based on a moisture‐sensitive polyacrylamide hydrogel for respiratory monitoring and non‐contact sensing. Fabricated by in situ cross‐linking of the hydrogel precursors on the fibers of the fabric, the flexible SHSF shows excellent sensitivity, outstanding flame retardance, air permeability, water retention capacity, and stability after treatment with lithium bromide solution. Specifically, its conductance increases more than 311 times as humidity increased from 11% to 98%. Besides, the humidity sensor features good repeatability and the ability to work normally under folding due to its flexible nature. As a clothing material, hydrogel–fabric composite exhibits 4.3 times the burning time compared to cotton fabric, illustrating better flame retardance. The SHSF is used to monitor human breathing and non‐contact finger approaching in real time, demonstrating its flexibility in practical applications. This work provides strategies for preparing high‐performance, flame‐retardant SHSF for emerging wearable electronic devices.

3 Year results from a prospective study of polyacrylamide hydrogel for knee osteoarthritis

3 Year results from a prospective study of polyacrylamide hydrogel for knee osteoarthritis

Water-dispersible and stable polydopamine coated cellulose nanocrystal-MXene composites for high transparent, adhesive and conductive hydrogels

High conductive and transparent hydrogels with adhesion function are ideal candidates for soft electronic devices. However, it remains a challenge to design appropriate conductive nanofillers to endow hydrogels with all these characteristics. The 2D MXene sheets are promising conductive nanofillers for hydrogels due to excellent electricity and water-dispersibility. However, MXene is quite susceptible to oxidation. In this study, polydopamine (PDA) was employed to protect the MXene from oxidation and meanwhile endow hydrogels with adhesion. However, PDA coated MXene (PDA@MXene) were easily flocculated from dispersion. 1D cellulose nanocrystals (CNCs) were employed as steric stabilizers to prevent the agglomeration of MXene during the self-polymerization of dopamine. The obtained PDA coated CNC-MXene (PCM) sheets display outstanding water-dispersible and anti-oxidation stability and are promising conductive nanofillers for hydrogels. During the fabrication of polyacrylamide hydrogels, the PCM sheets were partially degraded into PCM nanoflakes with smaller size, leading to transparent PCM-PAM hydrogels. The PCM-PAM hydrogels can self-adhere to skin, and possess high transmittance of 75 % at 660 nm, superior electric conductivity of 4.7 S/m with MXene content as low as 0.1 % and excellent sensitivity. This study will facilitate the development of MXene based stable, water-dispersible conductive nanofillers and multi-functional hydrogels.

Carboxymethylcellulose reinforced, double-network hydrogel-based strain sensor with superior sensing stability for long-term monitoring

Hydrogel-based strain sensors have garnered significant attention for their potential for human health monitoring. However, its practical application has been hindered by water loss, freezing, and structural impairment during long-term motion monitoring. Here, a strain sensor based on double-network (DN) hydrogel of polyacrylamide (PAAm)/carboxymethylcellulose (CMC) was developed in a ternary solvent system of lithium chloride (LiCl)/ethylene glycol (EG)/H2O through a facile one-pot radical polymerization strategy. The incorporation of EG effectively mitigated the hydration of lithium salts by generating stable ion clusters with Li+ and stronger hydrogen bonds within the polymer matrix. The sensor demonstrated excellent mechanical properties, including a stretchability of 1858 %, toughness of 1.80 MJ/m3, and recoverability of 102 %. Furthermore, the LiCl/EG/H2O ternary system resulted in high conductivity, excellent anti-freezing performance, and superior sensing stability. In addition, the sensor exhibited remarkable sensitivity, enabling the monitoring of human movements ranging from subtle to significant deformations, including throat motion and bending of the elbow, wrist, finger, and lower limb. This study presents a viable approach for constructing hydrogel-based strain sensors with exceptional sensing stability for long-term tracking of human motions.

The effect of three types of cross-linked hydrogels and volume fraction of polyacrylamide on the swelling and thermal behavior using molecular dynamics simulation

The technology of hydrogels is three-dimensional polymer networks with transverse connections that can adsorb water or biofluids. These compounds can adsorb water without dissolving. Natural hydrogels are considered due to their variety, abundance, cheapness, non-toxicity, and biocompatibility with synthetic hydrogels. In this research, the effect of three types of cross-linked hydrogels polyacrylamide (PAM), polyvinyl alcohol (PVA), and polyethylene glycol (PEG) hydrogels), and volume fraction (5–15%) of PAM on the swelling, and thermal behavior (TB) of simulated samples were studied using molecular dynamics (MD) simulations. The results show that among the simulated hydrogels, the structure of PAM had better atomic behavior and TB. PAM hydrogel had the highest swelling, heat flux (HF), and thermal conductivity (TC), with a numerical value of 342,722 Å3, 1583 W/m2, and 0.57 W/m.K after 10 ns. In the following, by increasing the volume fraction of PAM hydrogel from 5% to 15%, swelling increased to 377,986 Å3, and the TC with 10% of PAM increased from 0.53 (W/m.K) to 0.66 (W/m.K). Furthermore, HF of the sample with 15% of PAM was increased from 1423 (W/m2) to 1761 (W/m2) after 10 (ns). Consequently, by increasing the volume fraction of PAM hydrogel, TB of simulated structure was improved.

Tough and Transparent Photonic Hydrogel Nanocomposites for Display, Sensing, and Actuation Applications

Thermosensitive hydrogels with periodic dielectric structures displaying tunable structural color by temperature stimuli have attracted much research interest recently. However, reported thermosensitive photonic hydrogels either using the poly(N-isopropylacrylamide) (PNIPAM) bulk hydrogel as the responsive matrix or using PNIPAM microgels as the photonic building blocks have poor mechanical strength. Moreover, the expensive and time-consuming preparation process also limits their further application. In this work, a different strategy for preparing PNIPAM-based photonic hydrogel nanocomposite films with strong mechanical strength is proposed by incorporating a PNIPAM microgel film with the polyacrylamide (PAM) hydrogel. The preparation process is simple but efficient, and the obtained nanocomposite films have tunable mechanical strength by changing the crosslinking degree of the PAM hydrogels. More interestingly, the structural color of the nanocomposite films can be retained up to 80 °C (at least), much higher than those of previously reported PNIPAM-based photonic materials. In addition to being thermochromic, the film is sensitive to humidity, and the structural color-changing process is similar to the molting process of cicadas. Furthermore, the nanocomposite films have synchronous shape deformations and color changes and can be used as color-tunable soft actuators. The microgel film-capped photonic hydrogels provide a new strategy for the preparation of thermoresponsive photonic hydrogels and structural color-tunable actuators.

Independent control over cell patterning and adhesion on hydrogel substrates for tissue interface mechanobiology

Tissue boundaries and interfaces are engines of morphogenesis invivo. However, despite a wealth of micropatterning approaches available to control tissue size, shape, and mechanical environment invitro, fine-scale spatial control of cell positioning within tissue constructs remains an engineering challenge. To address this, we augment DNA "velcro" technology for selective patterning of ssDNA-labeled cells on mechanically defined photoactive polyacrylamide hydrogels. Hydrogels bearing photopatterned single-stranded DNA (ssDNA) features for cell capture are then co-functionalized with extracellular matrix (ECM) proteins to support subsequent adhesion of patterned tissues. ECM protein co-functionalization does not alter ssDNA pattern fidelity, cell capture, or hydrogel elastic stiffness. This approach enables mechanobiology studies and measurements of signaling activity at dynamic cell interfaces with precise initial patterning. Combining DNA velcro patterning and ECM functionalization provides independent control of initial cell placement, adhesion, and mechanics, constituting a new tool for studying biological interfaces and for programming multicellular interactions in engineered tissues.

Fishing Net‐Inspired Mutiscale Ionic Organohydrogels with Outstanding Mechanical Robustness for Flexible Electronic Devices

AbstractMechanically robust and electrically conductive organohydrogels/hydrogels are increasingly required in flexible electronic devices, but it remains a challenge to achieve organohydrogels/hydrogels with integrated high performances. Herein, inspired by the geometric deformability and robustness of fishing nets, multiscale ionic organohydrogels with outstanding isotropic mechanical robustness are developed. The organohydrogels are prepared by introducing polyacrylamide (PAM) hydrogel, Zn2+ and a binary solvent of glycerol‐water into a crosslinked fibrous mat which is electrospun from poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA). Because of the unique structure, the resultant organohydrogels, being mentioned as PAA‐PVA/PAM/Zn2+ organohydrogels, exhibit outstanding tensile strength (9.45 MPa), high stretchability, excellent anti‐fatigue property, skin‐like mechanical behaviors and ionic conductivity. Importantly, the organohydrogels are promising in flexible electronic devices capable of operating properly over a wide temperature range and under harsh mechanical conditions, such as mechanical‐electrical signal transducing materials in flexible mechanosensors and robust electrolytes in zinc ion hybrid supercapacitors. Not only the multiscale design strategy will provide a clue to improve the mechanical properties of soft materials, but also the organohydrogels offer promising materials for future flexible electronic devices.

V12-05 THE CYSTOSCOPIC RECONSTRUCTION OF EXTERNAL URETHRAL SPHINCTER TECHNIQUE (CREST) WITH POLYACRYLAMIDE HYDROGEL FOR STRESS URINARY INCONTINENCE

You have accessJournal of UrologyCME1 Apr 2023V12-05 THE CYSTOSCOPIC RECONSTRUCTION OF EXTERNAL URETHRAL SPHINCTER TECHNIQUE (CREST) WITH POLYACRYLAMIDE HYDROGEL FOR STRESS URINARY INCONTINENCE Whitney Clearwater, Melissa Laudano, Katherine Panushka, Anna Najor, Ava Leegant, and Nicole Fleischmann Whitney ClearwaterWhitney Clearwater More articles by this author , Melissa LaudanoMelissa Laudano More articles by this author , Katherine PanushkaKatherine Panushka More articles by this author , Anna NajorAnna Najor More articles by this author , Ava LeegantAva Leegant More articles by this author , and Nicole FleischmannNicole Fleischmann More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003347.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Stress urinary incontinence (SUI) is estimated to affect more than 20 million women in the United States. Despite negatively impacting physical, psychological, social, and economic health, less than 2% of women with SUI undergo treatment. Concern for surgical complications and recovery time have been suggested as causes of this disparity. Polyacrylamid hydrogel (PAHG) is a periurethral bulking agent that was FDA approved in 2020. Previous studies report a 60% satisfaction rate and 67% objective cure rate using the standard injection site at the bladder neck. Cystoscopic Reconstruction of the External Sphincter Technique (CREST) is a novel technique for injecting PAHG into the structures of the mid to distal urethra to realign and reconstruct the natural mechanism that prevents SUI in women with all degrees of urethral hypermobility. We seek to describe CREST and present efficacy and complication data. METHODS: This is a retrospective chart review of women>18 years old who underwent CREST with PAHG bulking for management of SUI between March to August 2022 at a single tertiary care center with a single surgeon. Women with either hypermobile or non-hypermobile urethra were included as well as those with stress and mixed urinary incontinence. Women were excluded who had prior treatment for SUI, pelvic organ prolapse greater than stage I or history of radiation therapy to the pelvis. Subjective improvement was defined as self-reporting an improvement in SUI symptoms. Subjective cure was defined as >70% improvement in SUI symptoms and objective cure was defined as negative cough stress test. RESULTS: Forty-eight patients underwent CREST. Ninety-six percent (46/48) reported subjective improvement. Eighty-three percent (40/48) reported >70% improvement in SUI symptoms and 85% (41/48) had negative cough stress test. The mean number of injections was 1.2 (SD 0.4) and median follow-up 38 days (IQR 59.5). Complications included: 10% (5/48) acute urinary retention managed with short term indwelling catheter and 2% (1/48) with denovo urgency incontinence. CONCLUSIONS: CREST is a novel technique for injecting PAHG into the structures of the distal urinary sphincter to realign and reconstruct the natural mechanism that prevents stress urinary incontinence in women with all degrees of urethral hypermobility. Our data suggest this technique is efficacious with minimal complications supporting further evaluation of this technique. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e1066 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Whitney Clearwater More articles by this author Melissa Laudano More articles by this author Katherine Panushka More articles by this author Anna Najor More articles by this author Ava Leegant More articles by this author Nicole Fleischmann More articles by this author Expand All Advertisement PDF downloadLoading ...

Influence of nanofillers (Ag NPs and C. dots) on the controlled drug release profile of gelatin-grafted-polyacrylamide hydrogel: An in vitro study

Hydrogel nanocomposites, one of the essential biomaterials, because of its enhanced mechanical strength, improved swelling properties and stimuli responsiveness has recently become quite popular in the domains of drug delivery, tissue engineering, and biomedicine. In this work, silver nanoparticles (Ag NPs) / carbon dots (C. dots) embedded gelatin-grafted polyacrylamide hydrogel nanocomposites were fabricated to understand their role in drug release, a characteristics feature of the hydrogel system. Different parameters such as swelling, thermal stability, biodegradation and antibacterial properties were adopted in order to investigate the effect of incorporation of the nanofillers on pre-synthesized hydrogel. The swelling properties and thermal stability of the hydrogel were significantly improved due to the presence of nanofillers. The in vitro release of ciprofloxacin (CFX) was performed from these nanocomposite systems at different pH conditions, i.e. pH 1.2, pH 6.8 and pH 7.4. CFX release was found to be more at pH 7.4 as compared to pH 1.2. As compared to bare hydrogel, hydrogel nanocomposite systems have demonstrated more controlled release of CFX, thus making them an appealing delivery system candidate. Antibacterial studies on E. coli and S. aureus revealed that incorporation of Ag NPs imparted antibacterial property to the hydrogel system. C. dots enhanced the hydrophilicity of the system, also, it has great potential to be employed as bioimaging agent to track the drug release process.

Phase Change Hydrogels for Bio‐Inspired Adhesion and Energy Exchange Applications

AbstractThe adhesion strategies of the gecko's toe through surface adaptation of spatulas to increase contact area and the snail's epiphragm via dehydration‐induced solidification to lock interfaces are combined to design a class of adhesion‐switchable hydrogels. The hydrogels are made via incorporating CH3COONa·3H2O salt (SA) into polyacrylamide (PAM) aqueous networks to construct supersaturated and stimuli‐responsive phase change materials (PAM‐SA). The crystallization dramatically strengthens the mechanical properties, and tensile Young's moduli are 340.7 and 0.1 MPa for crystalline C‐PAM‐SA‐120% and soft PAM hydrogel. As a result, PAM‐SA‐120% shows excellent adhesive performance (adhesion strength, 348 kPa) compared with PAM hydrogel adhesive (adhesion strength, 7 kPa). The stimuli‐induced crystallization from H‐PAM‐SA‐120% phase change hydrogels releases thermal controllably, which can be utilized for thermochromic materials and thermotherapy.