Deciphering the dual role of persistent luminescence materials: Toxicity and photoreception effects on rice development.

Studies on the toxicity of micro- and nanomaterials in plants have primarily focused on their intrinsic effects. However, there is often oversight when considering the potential perceptual responses that plants may exhibit in response to these materials. In this investigation, we assessed the impact of three commercially available persistent luminescence materials (PLMs) that emit red, green, or blue light under various environmental conditions. We subjected rice (Oryza sativa L.), a short-day plant, to nine distinct treatments, including exposure to particles in isolation, their nocturnal afterglow, or a combination of both. We thoroughly examined rice seedling morphology, photosynthesis patterns, metabolite dynamics, and flowering gene expression to determine the biological responses of plants to these particles. These findings demonstrated that PLMs stably interact with rice, and their emitted afterglow precisely matches the perceptual bandwidth of rice photoreceptors. Notably, the nocturnal afterglow from the red and blue PLMs enhanced the vegetative growth of rice seedlings while inhibiting their reproductive development. The blue PLMs exhibited the most pronounced positive effects, while the red PLMs exhibited inhibitory effects. When exposed to a combination of red and blue PLMs, rice displays enhanced growth and development. The observed alterations in the expression patterns of genes responsible for flowering supported these effects. We concluded that PLMs influence rice growth and development due to their inherent properties and intermittent illumination during dark periods. Both factors collectively shape rice growth and development.

Ultra-strong and tough cellulose-based conductive hydrogels via orientation inspired by noodles pre-stretching.

Due to the unsatisfactory mechanical properties of natural polymer-based conductive hydrogels, their applications are limited. Shaanxi Biangbiang noodles can be toughened by applying external mechanical forces through stretching and beating movements; this process provides inspiration for the preparation of high-strength hydrogels. In this paper, we propose a strategy for the preparation of ultrastrong and ultratough conductive hydrogels by directional prestretching and solvent exchange. Neatly arranged fiber bundles containing many intermolecular hydrogen bonds and metal ion coordination bonds are successfully constructed inside the prepared hydrogels. The hydrogel has exceptional mechanical properties, with a fracture stress exceeding 50 MPa, fracture strain approaching 105 %, fracture toughness exceeding 30 MJ m-3, and high conductivity reaching 11.738 ± 0.06 mS m-1. Impressively, the hydrogel can maintain its high mechanical properties after being frozen at an ultralow temperature of -80 °C for 7 days. Compared with other tough hydrogels, natural tendons and synthetic rubbers, the hydrogel exhibits excellent mechanical properties. The cellulose-based conductive hydrogel prepared in this study can be applied to robotic soft tissues (such as the Achilles tendon) that require high strength and are operated in extreme environments.

Rapid self-healing carboxymethyl chitosan/hyaluronic acid hydrogels with injectable ability for drug delivery.

In this study, the quaternized carboxymethyl chitosan (QCMCS), oxidized hyaluronic acid (OHA), 3,3'-dithiobis-(propionohydrazide) (DTP) were used as raw materials for the synthesis of hydrogels with excellent properties as carriers for drug release. The hydrogels were prepared by a simple "one-pot" method without external stimuli on the basis of interactions between formed dynamic covalent bonds (imine bonds, acylhydrazone bonds, disulfide bonds) and hydrogen bonds. The hydrogels had rapid self-healing properties, with a self-healing rate of 96 % after 30 min, as well as good pH responsiveness and excellent cytocompatibility (up to 98 % cell survival). The compressive stress of the hydrogels reached 423 kPa. Moreover, a representative drug (acetylsalicylic acid) demonstrated sustained release in the hydrogels (>72 h). The drug release behaviour was shown to be consistent with the Fick diffusion mechanism by kinetic modelling. Collectively, the findings demonstrate that the QCMCS + OHA + DTP injectable self-healing hydrogels are a potential material for the construction of pH-controlled drug delivery platforms.

Injectable multifunctional carboxymethyl chitosan/hyaluronic acid hydrogel for drug delivery systems.

Injectable hydrogels with notable mechanical properties and self-healing ability are promising carriers for use as a drug delivery system. Here, adipic acid dihydrazide (ADH) and calcium ions (Ca2+) were introduced into quaternary ammonium carboxymethyl chitosan and aldehyde-modified hyaluronic acid hydrogels (QCS + OHA). The hydrogels were synthesized through the interaction of the Schiff bases (imine bonds, acylhydrazone bonds) and coordination bonds via a facile one-step approach. The gelation time (∼54 s) ensured excellent injectability. The QCS + OHA + ADH + Ca2+ hydrogel had notable mechanical properties (compressive stress up to 896.30 KPa), good self-healing ability (up to 94 %), good pH responsiveness, and excellent antibacterial properties. In addition, the QCS + OHA + ADH + Ca2+ hydrogel had a high drug loading capacity (121.3 mg/g) and sustained drug release behaviour (≥120 h). The results of cytotoxicity tests showed a high cell proliferation rate (up to 98 %) and good cytocompatibility. In summary, this work presents an injectable and self-healing pH-responsive hydrogel that can be used as a carrier for drug delivery systems.

An injectable and self-healing cellulose nanofiber-reinforced alginate hydrogel for bone repair.

Biomedical materials are in high demand for transplantation in cases of diseased or damaged bone tissue. Hydrogels are potential candidates for bone defect repair; however, traditional hydrogels lack the necessary strength and multiple functions. Herein, we effectively synthesized a cellulose nanofiber (CNF)-reinforced oxidized alginate (OSA)/gelatin (Gel) semi-interpenetrating network hydrogel through a facile one-step approach without a cross-linker by using the synergistic effects of dynamic imine bonds and hydrogen bonds. The OSA/Gel/CNF sample showed a notable compressive modulus (up to 361.3 KPa). The gelation time (~150 s) ensured excellent injectability. Self-healing exhibited a high efficiency of up to 92 %, which would enable minimally invasive, dynamic adjustments and personalized therapies. Furthermore, the OSA/Gel/CNF hydrogel showed excellent biomineralization (Ca/P ratio ~ 1.69) and enhanced preosteoblast cell (MC3T3-E1) viability (over 96 %), proliferation, and osteogenic differentiation. Thus, this multifunctional hydrogel has promising potential for using in the bone tissue repairs.

Significantly enhanced UV luminescence by plasmonic metal on ZnO nanorods patterned by screen-printing.

A smart synthetic method is conceived to construct large batches of ZnO nanostructures to meet market demand for light-emitting diodes. Utilizing the localized surface plasmon resonance of metal nanoparticles (NPs) facilitates the recombination of electron-hole pairs and the release of photons. Compared to raw ZnO nanorods (NRs), ZnO NRs@HfO2@Al NPs show a ∼120× enhancement in ultraviolet (UV) photoluminescence (PL), while ZnO NRs@HfO2@Ag NPs show a six-fold enhancement. Because the surface plasmon energy of Al is nearer the ZnO band gap, the PL enhancement of ZnO NRs covered with Al is stronger than that of those covered with Ag. Based on this analysis, three-dimensional graphical ZnO NR arrays were manufactured by screen-printing, a mass production technique. After covering the arrays with layers of HfO2 and Al NPs, the UV PL intensities of the corresponding substrates were increased by approximately 16×. This indicates the potential to mass-produce highly efficient optoelectronic devices.