Real-time, noninvasive monitoring of nitric oxide (NO) on intact plant and fruit tissues is limited by NO's short lifetime and the lack of soft, conductive, adhesive interfaces for irregular surfaces. A detachable electrode-tissue bridge is introduced by integrating a catechol-functionalized carbon-nanotube polyacrylamide hydrogel (CNT-DA-PAM) with a commercial screen-printed carbon electrode, enabling on-demand electrochemical NO sensing on leaves and fruit peels. The hydrogel provides reversible adhesion, mechanical robustness, and a percolating CNT network for efficient charge transfer. The modified electrode exhibits characteristic NO oxidation signals, a broad linear range (0.1 μM-10 mM), a detection limit of 0.49 μM, good selectivity, and 14-day storage stability. On living leaves, thermal and mechanical stimuli induce graded, minute-scale NO responses, whereas on fruit peels, NO signals increase over 0-48 h and scale with damage severity. This soft, reversible interface enables minimally perturbative NO sensing across organs and time scales without invasive probes.

Multifunctional hydrogel patch for wearable colorimetric sensing and oral ulcer therapy.

Anaplastic thyroid cancer (ATC) is a highly lethal malignancy characterized by rapid progression and therapeutic resistance. This study uncovers the pivotal role of extracellular matrix (ECM) stiffness in driving ATC aggressiveness through mechanotransduction mediated by the Integrin α6β4/Focal Adhesion Kinase (FAK) axis. By engineering collagen-coated polyacrylamide hydrogels with tunable rigidity, we demonstrated that high ECM stiffness (60 kPa) markedly enhanced ATC cell proliferation, clonogenicity, migration, and invasion. Mechanistically, stiff matrices induced cytoskeletal reorganization, activated RhoA/Rac1/Cdc42 signaling, and upregulated Integrin α6β4-FAK pathway components, as validated by transcriptomic, proteomic, and functional assays. Pharmacological inhibition of FAK reversed stiffness-dependent tumor-promoting effects in vitro. In vivo, mice injected with tumor cells pre-cultured on high-stiffness ECM-mimicking hydrogels exhibited accelerated subcutaneous tumor growth and increased lung metastatic burden, which were significantly attenuated by FAK-targeted therapy. These findings establish ECM stiffness as a biomechanical determinant of ATC progression and metastasis, offering novel insights into microenvironment-driven malignancy and highlighting FAK as a promising therapeutic target to disrupt mechanosignaling in ATC.

MXene-enhanced paper/hydrogel bilayer moisture-driven generator for long-term energy output.

Stiff matrix promotes lung cancer cell migration through down-regulating the Piezo1 channel expression to facilitate Ca2+-dependent filopodia formation

The widespread use of portable electronic devices has sparked interest in zinc-ion hybrid capacitors as an ecofriendly, safe, and cost-efficient energy storage solution. However, balancing the mechanical properties and high ionic conductivity of zinc-ion hybrid capacitor electrolytes presents a significant challenge. This study introduces a polyacrylamide hydrogel (PAM) electrolyte containing nanoparticle Laponite (Lap), demonstrating outstanding mechanical properties and high ionic conductivity. Furthermore, when ZnSO4 is introduced into the gel electrolyte, it reduces system dependence and decreases the water freezing point, expanding the hydrogel's operational temperature range. Consequently, the prepared gel electrolyte has a high ionic conductivity of 45.3 mS·cm-1 and excellent flexibility and can operate stably in both zinc-ion hybrid capacitors and sensors. This research provides an effective approach for developing hydrogel electrolytes with broad voltage windows, high ionic conductivity, and favorable mechanical characteristics.

The rheology of soft materials is routinely measured at low strain rates to extract constitutive laws necessary for understanding and modeling their behavior. High-frequency rheology, however, remains difficult to access. Consequently, the mechanical properties of soft materials at MHz strain rates are largely unknown. Ultrasound-driven microbubbles, widely used in biomedical imaging, drug delivery, and therapy, act as efficient mechanical actuators at MHz frequencies. Their dynamics depend on nonlinear resonance behavior, the viscoelasticity of their stabilizing shells, and the viscoelastic properties of the surrounding medium. Here, we make use of (nonlinear) bubble dynamics to characterize the rheology of polyacrylamide (PAM) hydrogels at strain rates exceeding 106 s-1. Narrow resonance curves of single coated microbubbles embedded in PAM, obtained through high-speed imaging, were compared to a Rayleighâ€"Plesset-type model. The results show that the shear modulus is similar in both the Hz and MHz regimes, while the loss modulus behaves very differently, exhibiting an effective shear viscosity at MHz frequencies comparable to that of water. These findings demonstrate a new approach for probing the high-frequency rheology of viscoelastic media.

Hydrogels are widely used in flexible sensors and energy devices due to their excellent flexibility, conductivity, and biocompatibility. However, achieving a hydrogel design that simultaneously offers high toughness, low hysteresis, and outstanding electrochemical performance remains a significant challenge. Herein, zwitterionic microgels with a special chemical design were synthesized from monomer 3-(1-(4-vinylbenzyl)-1H-benzo[d]imidazol-3-ium-3-yl)propane-1-sulfonate (VBIPS), which were further incorporated into a highly entangled polyacrylamide (PAM) network to fabricate a tough, low-hysteresis hydrogel. The penetrated pVBIPS microgels acted as cross-linking domains, promoting toughness through efficient stress transmission and crack resistance with restricted energy dissipation. The obtained PAM/pVBIPS hydrogel showed high toughness (1450.8 kJ/m3) with no significant degradation in mechanics after loading 100 cycles at 100% strain. Besides, due to the zwitterionic nature of pVBIPS domains, the PAM/pVBIPS-ZnSO4 hydrogel showed good conductivity (52.9 mS cm-1) and exhibited excellent sensitivity (GF = 4.48) when applied as a strain sensor. Additionally, it demonstrates good electrochemical stability when applied in a zinc-ion hybrid capacitor, retaining ∼92.23% capacitance after 24 h in static conditions. These results collectively highlight the pivotal role of zwitterionic microgels in reinforcing the mechanical integrity and electrochemical functionality of the conventional PAM hydrogels.

Amphiphilic quantum dots embedded in polyacrylamide hydrogels as fluorescent sensors for simultaneous rapid selective detection of Hg2+ and Pb2+ ions

Polyacrylamide (PAM)-based hydrogels are commonly acknowledged as promising contenders for replacing cartilage. Nevertheless, their restricted mechanical strength and puncture resistance greatly impeded their ability to be used in biological applications. The current investigation aimed to increase the strength of polyacrylamide hydrogels by including carbon nanotubes (CNTs) and graphene oxide (GO) in various concentrations in a PAM matrix. Combining CNT and GO nanoparticles with PAM results in a synergistic effect and a strong interfacial bonding. This leads to high compressive strength and elastic modulus. The PAM-CNT and PAM-GO composite hydrogels exhibited remarkable self-healing characteristics, bioactivity, and cytocompatibility. This was evidenced by a cell survival rate of over 99%. The incorporation of GO markedly improved the hydrophilicity of the composites, resulting in a contact angle of 40°. The swelling characteristics of the hydrogels were assessed, revealing that PAM-GO1 (0.3 g L-1) and PAM-GO2 (0.5 g L-1) exhibited the greatest stability. In vitro degradation tests showed that both PAM-GO1 (0.3 g L-1) and PAM-GO2 (0.5 g L-1) preserved approximately 90% of their gel mass following 20 days of immersion in PBS. Compression tests revealed that PAM-GO1 (0.3 g L-1) has the greatest compressive strength (≈0.31 MPa) and highest elastic modulus (1.653 MPa). Furthermore, the PAM-GO hydrogels demonstrated exceptional cell survival, almost surpassing 100%. The best antimicrobial activity was found in PAM-GO1. In attaining new insights into the structural [interfacial interactions recognized by the noncovalent interactions (NCIs) and van der Waals (vdW) interactions], stability/strength, energetic [binding energy (BE)], and electronic [HOMO-LUMO gap and charge transfer (CT)] features of both composites, an in-silico approach has been applied. The PAM-GO composite model was found to be more stable than the PAM-CNTCOOH composite model. The BE, HOMO-LUMO gap, some selected QTAIM-based parameters, dipole moment, and CT-related parameters supported the experiment-based outcomes. In summary, the PAM-GO1 (0.3 g L-1) hydrogel composite, characterized by enhanced mechanical characteristics, bioactivity, and robust adhesion, has considerable potential as an advanced hydrogel material for cartilage repair applications.

Elastic moduli and strain-dependent lateral strain to axial strain ratio in semi-dilute polyacrylamide hydrogels.

Robust removal of thallium(I) from water with nano-MnO2 implanted zwitterionic porous hydrogel.

Optimised formula of Fufang Biejia Ruangan tablets alleviates renal fibrosis by suppressing matrix-stiffness-induced fibroblast activation via inhibition of integrin αVβ1 binding.

A versatile strategy for constructing background fluorescence-free and dual-mode hydrogel nanosensor for sensitive detection of amikacin.

Bifunctional mechanism of immobilized organic molecule to steer Zn2+ and polyiodides transport kinetics toward ultra-stable aqueous ZnI2 batteries.

P0073 Increased Tissue Stiffness Promotes Colitis-Associated Colorectal Cancer Progression via Disruption of Intestinal Barrier Function

Hydrogen peroxide (H2O2) is a key redox signaling molecule that plays a vital regulatory role in diverse physiological processes. However, existing tools for near-real-time H2O2 detection are often constrained by limited applicability in dynamic biological environments. To address these challenges, we developed a point-of-care aptamer-functionalized nanozyme-hydrogel kit (Apt-ngel-kit) that integrates nanozyme-based homogeneous catalytic fluorescence with digital signal processing, enabling highly sensitive, quantitative, and near-real-time monitoring of in situ H2O2 secretion. The system leverages the exceptional enzymatic activity of ferromanganese silicate nanozymes (FMSN), which were immobilized in a polyacrylamide hydrogel coloaded with the catalytic substrate o-Phenylenediamine (OPD) to create a homogeneous, stable, and reproducible catalytic nanoplatform. Furthermore, to detect the near-real-time secretion of H2O2 within cells, we conjugated Apt to the nanogel surface to improve the biocompatibility of the Apt-ngel-kit. It is noteworthy that this system not only achieves an ultralow in situ detection limit of 8.32 × 10-23 M, but also quantifies H2O2 released by individual cells and distinguishes the secretion characteristics between cancer patients and healthy individuals, demonstrating its potential as a rapid and effective tool for early disease diagnosis.

Addressing water pollution with sustainable and eco-friendly strategies is a significant global challenge. Traditional methods of decontaminating water via enzyme catalysis have limitations, particularly due to the mass transfer resistance resulting from enzyme immobilization. In this study, we report a novel approach in which biochar (BC), a biomass-derived porous material rich in surface functional groups, is integrated with polyacrylamide hydrogels to encapsulate the enzyme horseradish peroxidase (HRP). The resulting Gel/BC-HRP composite hydrogel exhibits superior biocatalytic activity for the oxidation of phenolic contaminants in the presence of hydrogen peroxide (H2O2). Our findings demonstrate that the Gel/BC-HRP composite greatly enhances mass transfer efficiency, achieving a reaction rate 91.4 times faster than the biochar-free control, together with exceptionally high turnover frequency (TOF) values. The composite maintains approximately 60% efficiency for phenol removal even after eight reaction cycles. Mechanisticinvestigations suggest that the polyacrylamide gel creates electron-rich domains, while the biochar segments provide electron-deficient domains, leading to the formation of an optimal microenvironment that concentrates both H2O2 and phenol in the vicinity of the HRP, thereby significantly accelerating the oxidation process. The innovative integration of biochar with hydrogel-immobilized biocatalysts offers a promising and environmentally friendly solution for the degradation of organic pollutants in water remediation.

The design of a solar-driven interfacial evaporator applied to the process of seawater desalination has attracted great attention due to sustainable renewable solar energy. The underlying mechanisms linking the evaporator structure to its functional performance have yet to be comprehensively established. In this study, we prepared a three-dimensional (3D) porous structured molybdenum disulfide (MoS2) evaporator aerogel by using MoS2 nanosheets as photothermal materials and polyacrylamide hydrogel as immobilization carriers. And MoS2 evaporator aerogel was systematically characterized using various methods. We detailly investigated the influence of the structure characteristics (i.e., the vertical pore channels, the LAR value (which refers to the ratio of light area to effective evaporation area) and volume size) of the 3D evaporators on the evaporation rate and salt resistance performance. The results implied that the MoS2 evaporator aerogel could make full use of the environment energy. Smaller LAR and volume could improve the evaporation performance of the evaporator. In 3.5 wt % salt water, MoS2 evaporator aerogel was evaporated at the rate of 4.07 kg·m-2·h-1 and the photothermal conversion efficiency was 91.84%, without salt crystals produced on its surface. These findings will be helpful to get a deeper understanding of the correlation between the structural characteristics of an evaporator and its evaporation performance for the design of the solar-driven interfacial evaporator applied to the process of seawater desalination.

Water-in-Salt Electrolytes Embedded in Polyacrylamide Hydrogels: A First Step toward Deformable Sodium-Ion Batteries