The rapid growth of wearable and implantable electronics has led to a search for power systems that are safe for the body and can disappear when no longer needed. Glycine-based piezoelectric nanogenerators (PENGs) have become a leading option in this area because they naturally generate electricity from movement, have a simple structure, and are fully biodegradable. This review provides a detailed look at glycine PENGs, moving from basic crystal science to their use in tissue engineering. We first look at how glycine turns mechanical energy into electricity, focusing on its different crystal forms and how they are built into structures such as tiny tubes, reinforced materials, and fibrous materials. A major part of this discussion is how these devices can both sense body movement and actively help tissues heal. Beyond just collecting energy, we explain how glycine itself helps the body, such as by controlling immune responses and protecting cells. We also study how the mechanodynamic processes of these devices, specifically how their physical motion and resulting electricity guide cell growth and regulate mechanotransduction signaling. Finally, we show examples of how this technology helps regenerate nerves, muscles, skin, and bone, while discussing the practical steps needed to ensure their biocompatibility in the body. This review positions glycine PENGs as one of the key technologies for future self-powered medical devices for tissue healing and regenerative purposes.
We report a strategy for synthesizing crack-free carbon aerogel (CA) composites by rationally matching the carbonization shrinkage of viscose fiber felts (VFs) with that of a phenolic resin (PR) aerogel matrix. The VFs were pretreated at elevated temperatures to induce controlled pre-shrinkage, followed by an in situ sol-gel transition and ambient-pressure drying of the PR precursor to produce large monolithic organic aerogels. By selecting a pretreatment temperature of 265 °C, the fibers and the matrix showed nearly identical subsequent carbonization shrinkages (26.2
Dielectric resonance arises from the collective oscillation of local electrons between adjacent, non-contacting particles under an external alternating electric field. Adjusting the spacing between particles to induce a dielectric response is crucial for electromagnetic wave (EMW) absorption capability. This work introduces an innovative cold press sintering (CSP) technique conducive to generating dielectric resonance; this method effectively anchors rare-earth (RE) magnetic nanoparticles onto a two-dimensional (2D) Mo-MXene conductive substrate while allowing for the controllable adjustment of the spacing between nanoparticles. Furthermore, compared to high-temperature sintering, low-temperature CSP mitigates the oxidation of Mo-MXene nanosheets, preserves their high electrical conductivity, and facilitates electron supply to the loaded magnetic nanoparticles. Experimental results and theoretical simulations demonstrate that Mo-MXene/ReFeOx (Re = Ce, Er, Gd) exhibits distinct dielectric resonance characteristics, thereby enabling the modulation of dielectric resonance-type loss in RE magnetic materials. Additionally, Mo-MXene/ReFeOx maintains excellent magnetic stability across various temperatures. This technique demonstrates versatility, as dielectric resonance phenomena, and the resulting superior EMW absorption performance, are observed in Mo-MXene/CeFeOx, Mo-MXene/ErFeOx, and Mo-MXene/GdFeOx sintered bodies, with reflection loss (RL) values of -49.69 dB, -33.18 dB, and − 40.13 dB, respectively. Radar cross-section (RCS) simulations indicate that Mo-MXene/ReFeOx sintered bodies inherit practical potential for radar stealth applications. In summary, this work breaks through the traditional paradigm of relaxation loss modulation and offers a novel perspective for the design of dielectric resonance-type EMW absorption materials.
The growing threat of antimicrobial resistance and viral infections has intensified the demand for adaptive biomaterials that combine intrinsic bioactivity with controlled therapeutic delivery. In parallel, the development of sustainable polymeric materials from abundant and underutilized feedstocks has become an increasingly important objective. Elemental sulfur, an industrial byproduct produced on a megaton scale, represents a highly attractive yet largely untapped building block for functional polymer synthesis. Herein, we report a one-pot, catalyst- and solvent-free copolymerization of glycidol with elemental sulfur to generate poly(glycerol-sulfur) (hPG-Sn), comprising polyglycerol and polysulfide segments. This approach provides a modular route to sulfur-containing polymers while valorizing elemental sulfur as a sustainable feedstock. The resulting polymers spontaneously form nanoscale networks (200–500 nm) in aqueous media. Importantly, the dynamic S–S bonds within the polysulfide segments impart a stimuli-responsive architecture that enables reversible opening and closing of the network pores, thereby facilitating drug loading and subsequent encapsulation and release. Tetracycline-loaded hPG-Sn networks exhibited a ten-fold enhancement in antibacterial efficacy compared with the free drug, while maintaining low cytotoxicity toward human cells. The chemical modularity of the polysulfide domains further enables facile post-functionalization through thiol-disulfide exchange. Functionalization with 11-mercaptoundecanesulfonate (MUS) generated negatively charged nanoparticles ( 550 nm, ζ = −30 mV) that exhibited pronounced antiviral activity against herpes simplex virus (HSV), including both inhibitory and virucidal effects. Thus, hPG-Sn combines sustainable sulfur utilization, dynamic and reversible pore modulation, efficient therapeutic cargo loading, and facile surface functionalization within a single polymer platform. These features highlight its potential as an adaptable nanomaterial for controlled antimicrobial and antiviral delivery.
Helicoidal structures mimic nature and are evident in plant cell walls, lamellar bone, and the shell structures of mantis shrimp and beetles. These nature-inspired helicoidal composites are widely used in impact-resistant applications. Traditional hand-layup methods for producing layered helicoidal composites can introduce defects such as gaps, overlaps, and wrinkles, which can be mitigated using Automated Fiber Placement (AFP). Optimizing AFP process parameters, including pressure, temperature, and layup speed, is crucial. While experimental optimization is costly and time-consuming, Artificial Intelligence (AI)-based design offers a more efficient alternative. This narrative review explores the inspiration behind helicoidal structures and their application fields. It also covers advanced manufacturing of hybrid long-fiber layered composites using AFP + autoclave/hot press, ceramic filler-based nanocomposites using direct ink writing (DIW), and multi-walled carbon nanotube (MWCNT)-based nanocomposites using digital micromirror device (DMD). Furthermore, it discusses the roles of machine learning and deep learning, coupled with finite element modeling, in minimizing process-induced defects. Compared with conventional AFP inspection techniques such as laser profilometry and thermography, a defect-detection algorithm based on PointNet + + , a convolutional neural network (CNN), can be tailored for 3D point cloud segmentation, offering a cost-effective, user-friendly alternative. Next, the mechanical and microstructural properties of helicoidal composites, compared with those of traditional laminates, are discussed to evalaute impact performance. Helicoidal composites with low inter-ply angles up to 20° consistently outperform conventional lay-ups under quasi-static and impact loading, due to a crack-twisting mechanism and superior out-of-plane properties. Incorporating nylon 6 powder microparticles into carbon/epoxy and glass/epoxy helicoidal composites subjected to impact loading significantly improves their toughness through self-healing, compared with virgin helicoidal composites. Carbon/epoxy helicoidal composites with low inter-ply angles of up to 9° are prone to extensive matrix cracking and minor fiber damage, while self-healing in carbon/epoxy composites also helps minimize matrix cracking but does not reduce fiber damage. In contrast, self-healing significantly decreases overall damage in glass/epoxy composites. Self-healing is more effective at eliminating damage in glass/epoxy than in carbon/epoxy, primarily because the former exhibits higher ductility (
