Publications

Bioelectrical cues are essential for cardiac function and regeneration, yet current electrostimulation strategies rely on invasive electrodes that limit spatial control and clinical translation. Here, we report magnetoelectric nanocomposite hydrogels that combine core-shell CoFe2O4@BiFeO3 magnetoelectric nanoparticles (ME NPs) with a photo-cross-linked methacrylated gelatin (GelMA) network, enabling wireless electroactivity through externally applied magnetic fields within a soft, biomimetic three-dimensional scaffold. Structural and physicochemical analyses confirmed the successful synthesis of crystalline core-shell ME NPs with strong interfacial coupling, as demonstrated by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and magnetic hysteresis measurements showing exchange bias effects. Homogeneous incorporation of ME NPs within GelMA produced highly porous and interconnected hydrogels, as revealed by scanning electron microscopy and microcomputed tomography. The presence of nanoparticles reduced equilibrium swelling and refined pore architecture, suggesting increased effective cross-linking density and nanoparticle-polymer interactions. Mechanical testing showed soft elastomeric behavior with compressive moduli compatible with cardiac tissue. Under dynamic magnetic stimulation, magnetoelectric hydrogels significantly enhanced cardiac cell viability, proliferation, and morphological organization compared with pristine GelMA controls. After 10 days, the metabolic activity of cells cultured on GelMA-ME NP hydrogels under stimulation was approximately 3-fold higher than that of unstimulated GelMA. These results demonstrate that magnetoelectric hydrogels provide an effective platform for wireless electrostimulation, offering promising opportunities for cardiac tissue engineering and implantable bioelectronic therapies without wired electrodes.

JTD Keywords: Cardiac tissue engineering, Core-shell nanoparticles, Fields, Gelma hydrogels, Magnetoelectric nanocomposites, Tissue, Wireless electrostimulation

Epithelial tissues undergo complex morphogenetic transformations driven by cellular and cytoskeletal dynamics. To understand the emergent tissue mechanics resulting from sub-cellular mechanisms, we formulate a fully nonlinear continuum theory for epithelial shells that coarse-grains an underlying 3D vertex model, whose surfaces are in turn patches of active viscoelastic gel undergoing turnover. Our theory relies on two ingredients. First, we relate the deformation of apical, basal and lateral surfaces of cells to the continuum deformation of the tissue mid-surface and a thickness director field. We explore two variants of the theory, a Cosserat theory accommodating through-thickness tilt of cells, and a Kirchhoff theory assuming that lateral cell surfaces remain perpendicular to the mid-surface. Second, by adopting a variational formalism of irreversible thermodynamics, we construct an effective Rayleighian functional of the tissue constrained by the cellular-continuum kinematic relations, which therefore depends on continuum fields only. This functional allows us to obtain the governing equations of the continuum theory and is the basis for efficient finite element simulations. Verification against explicit 3D cellular model simulations demonstrates the accuracy of the proposed theory in capturing epithelial buckling dynamics. Furthermore, we show that the Cosserat theory is required to model tissues exhibiting apicobasal asymmetry of active tension. Our work provides a general framework for further studies integrating refined subcellular models into continuum descriptions of epithelial mechanobiology.

JTD Keywords: Active gels, Cortex, Epithelial mechanics, Mechanobiology, Monolayers, Morphogenesis, Thin shells, Vertex models

Although an increasing number of micro/nanomotors have been designed for environmental remediation in the past decade, the construction of contaminants-fueled nanomotors for synergistically degrading multiple pollutants simultaneously remains a challenge. Herein, laccase-powered Fe3O4@silica nanomotors are fabricated, assisted with lipase enzyme for the enhanced degradation of multiple contaminants using the contaminants themselves as fuels. Notably, we demonstrate that representative industrial phenols and polycyclic aromatic pollutants possess the ability of triggering the enhanced Brownian motion of laccase nanomotors (De of 1.16 mu m(2)/s in 220 mu M biphenol A (BPA), 1.40 mu m(2)/s in 375 mu M Congo red (CR)). Additionally, the k(cat) value of lipase-assisted laccase-powered nanomotors increased over 1.4 times, enhancing their Brownian motion, while leading to the efficient degradation of multiple contaminants such as BPA, CR, and triacetin droplets within 40 min, simultaneously. Ultimately, the lipase-assisted laccase nanomotors exhibit great advantages over free laccase, free lipase, lipase nanomotors, or laccase nanomotors in K-m, k(cat), catalytic stability, recycling property, and the degradation efficiency of contaminants. Therefore, our work further broadens the library of enzyme-powered nanomotors and provides deep insights in synergistical enzymatic catalysis, thus paving avenues for environmental remediation based on enzyme-powered micro/nanomotors. (C) 2022 Elsevier Ltd. All rights reserved.

JTD Keywords: core, dye, environmental remediation, enzyme catalysis, hybrid, light, microspheres, motors, pollutants removal, propulsion, removal, self-propulsion, shell, Core, Dye, Environmental remediation, Enzyme catalysis, Hybrid, Light, Micro/nanomotors, Micromotors, Microspheres, Motors, Pollutants removal, Propulsion, Removal, Self-propulsion, Shell