Biodegradable active composite hydrogel packaging for postharvest climacteric bananas preservation.

Climacteric bananas are susceptible to endogenous ethylene and temperature, resulting in dehydration, accelerated senescence and deterioration. The widely-used plastic cling films is particularly complicated due to their high consumption and non-degradability. Herein, this study proposed to fabricate a carboxymethyl cellulose/polyvinyl alcohol/pyrazoic acid (CPP) hydrogel for postharvest banana preservation. The hydrogel demonstrated excellent potential as a packaging film, including natural degradability (complete degradation within 50 days), high tensile performance, transparent visibility and biosafety. As a validation experiment, bananas in a 30 °C environment confirmed the effectiveness of CPP hydrogels in banana postharvest preservation. Compared with the blank control and CP hydrogel, CPP packaging film delayed the processes of browning, dehydration, softening, nutrients loss, ripening and senescence in bananas, thereby maintaining their commercial value. Accordingly, this study demonstrates the potential of hydrogel materials as an alternative strategy to climacteric fruit preservation and plastic film.

Corrigendum to "Development of methods for detecting the fate of mesenchymal stem cells regulated by bone bioactive materials" [Bioact. Mater. 6(3) (2021) 613-626].

[This corrects the article DOI: 10.1016/j.bioactmat.2020.08.035.].

3D Printing of PLLA/Biomineral Composite Bone Tissue Engineering Scaffolds.

Tissue engineering is one of the most effective ways to treat bone defects in recent years. However, current highly active bone tissue engineering (BTE) scaffolds are mainly based on the addition of active biological components (such as growth factors) to promote bone repair. High cost, easy inactivation and complex regulatory requirements greatly limit their practical applications. In addition, conventional fabrication methods make it difficult to meet the needs of personalized customization for the macroscopic and internal structure of tissue engineering scaffolds. Herein, this paper proposes to select five natural biominerals (eggshell, pearl, turtle shell, degelatinated deer antler and cuttlebone) with widely available sources, low price and potential osteo-inductive activity as functional particles. Subsequently compounding them into L-polylactic acid (PLLA) biomaterial ink to further explore 3D printing processes of the composite scaffold, and reveal their potential as biomimetic 3D scaffolds for bone tissue repair. The research results of this project provide a new idea for the construction of a 3D scaffold with growth-factor-free biomimetic structure, personalized customization ability and osteo-inductive activity.

Determination of an Initial Stage of the Bone Tissue Ingrowth Into Titanium Matrix by Cell Adhesion Model.

For achieving early intervention treatment to help patients delay or avoid joint replacement surgery, a personalized scaffold should be designed coupling the effects of mechanical, fluid mechanical, chemical, and biological factors on tissue regeneration, which results in time- and cost-consuming trial-and-error analyses to investigate the in vivo test and related experimental tests. To optimize the fluid mechanical and material properties to predict osteogenesis and cartilage regeneration for the in vivo and clinical trial, a simulation approach is developed for scaffold design, which is composed of a volume of a fluid model for simulating the bone marrow filling process of the bone marrow and air, as well as a discrete phase model and a cell impingement model for tracking cell movement during bone marrow fillings. The bone marrow is treated as a non-Newtonian fluid, rather than a Newtonian fluid, because of its viscoelastic property. The simulation results indicated that the biofunctional bionic scaffold with a dense layer to prevent the bone marrow flow to the cartilage layer and synovia to flow into the trabecular bone area guarantee good osteogenesis and cartilage regeneration, which leads to high-accuracy in vivo tests in sheep . This approach not only predicts the final bioperformance of the scaffold but also could optimize the scaffold structure and materials by their biochemical, biological, and biomechanical properties.

Synthesis and Insecticidal Activity Evaluation of Virtually Screened Phenylsulfonamides.

The fastest and most effective way to control pests is to use pesticides. However, with the accumulation of pesticide resistance and the difficulties of rapidly producing new pesticides, it is of great significance to create new pesticides through new synthetic methods. In this study, we report a computer-aided drug design (CADD)-assisted method to obtain two lead sulfonamides by homology modeling and virtual screening. On this basis, the lead compounds were synthesized from p-chlorocresol by four steps of esterification, sulfonation, sulfonamidation, and amidation. Further, 71 derivatives were synthesized by optimizing the lead compounds, and their insecticidal activities against Mythimna separata were evaluated by the leaf-dipping method. Notably, seven sulfonamides (5a, 5g, 5h, 5m, 6b, 6g, and 6m) with excellent insecticidal activity were obtained, and the possible binding modes between receptors and active groups in sulfonamides were verified by structure-activity relationship and docking simulation, which provided theoretical support for the subsequent development of these novel candidate insecticides.

Dual directions to address the problem of aseptic loosening via electrospun PLGA @ aspirin nanofiber coatings on titanium.

Peri-implant aseptic inflammation and osteolysis can cause aseptic loosening, leading to the failure of implants. Therefore, aseptic loosening of orthopedic implants remains an imminent problem for the development of durable and effective implants. In this work, a common anti-inflammatory drug (aspirin, ASA) was loaded in poly(lactic-co-glycolic acid) (PLGA) to construct nanofiber coatings on titanium (Ti) via electrospinning. The adhesion of the nanofiber coatings to Ti was ensured by polydopamine (PDA) modification. A stable and sustainable release of aspirin from the nanofiber coatings could last up to 60 days. Such electrospun PLGA@ASA nanofiber coatings could promote proliferation and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) as well as inhibit M1 polarization and RANKL-induced osteoclast differentiation of macrophages in vitro. These results indicated that this facile formulation of the PLGA@ASA nanofiber coatings for long-term drug release could be expected to address the problem of aseptic loosening effectively in dual directions of both anti-inflammation and improving osseointegration simultaneously. Notably, the in vivo experiments demonstrated that PLGA@ASA nanofiber coatings did promote osseointegration ability of Ti implants significantly, even in challenging condition with wear particles, and also effectively inhibited Ti particle induced osteolysis around the implants. This work indicates a promising way for the development of durable and effective implants by using PLGA@ASA-PDA-Ti to address the problem of aseptic loosening in dual directions.

Cell Seeding Process Experiment and Simulation on Three-Dimensional Polyhedron and Cross-Link Design Scaffolds.

Cell attachment to a scaffold is a significant step toward successful tissue engineering. Cell seeding is the first stage of cell attachment, and its efficiency and distribution can affect the final biological performance of the scaffold. One of the contributing factors to maximize cell seeding efficiency and consequently cell attachment is the design of the scaffold. In this study, we investigated the optimum scaffold structure using two designs - truncated octahedron (TO) structure and cubic structure - for cell attachment. A simulation approach, by ANSYS Fluent coupling the volume of fluid (VOF) model, discrete phase model (DPM), and cell impingement model (CIM), was developed for cell seeding process in scaffold, and the results were validated with in vitro cell culture assays. Our observations suggest that both designs showed a gradual lateral variation of attached cells, and live cell movements are extremely slow by diffusion only while dead cells cannot move without external force. The simulation approaches supply a more accurate model to simulate cell adhesion for three-dimensional structures. As the initial stages of cell attachment in vivo are hard to observe, this novel method provides an opportunity to predict cell distribution, thereby helping to optimize scaffold structures. As tissue formation is highly related to cell distribution, this model may help researchers predict the effect of applied scaffold and reduce the number of animal testing.

Antifungal, anti-inflamatory and neuritogenic activity of newly-isolated compounds from Disporopsis aspersa.

A new ester (1) and a terpenoid (2) were isolated from the dried whole plant of Disporopsis aspersa (HUA) ENGL. ex DIELS for the first time and their structures were elucidated, as well as their biological activities are described. The two compounds all showed good antifungal activities, especially furanone (2) exhibited better antifungal activity against Pseudoperonospora cubensis and Phytophthora infestans with EC50 value of 22.82, 18.90 µg/mL, respectively. Compound 1 exhibited a significant promotion on the neurite outgrowth in NGF-induced PC-12 cells, and moderate inhibition on the NO production induced by lipopolysaccharide (LPS) in BV-2 microglial cells.

Correction: Robust magnetic double-network hydrogels with self-healing, MR imaging, cytocompatibility and 3D printability.

Correction for 'Robust magnetic double-network hydrogels with self-healing, MR imaging, cytocompatibility and 3D printability' by Fangli Gang et al., Chem. Commun., 2019, 55, 9801-9804.

3D Printing of Conductive Tissue Engineering Scaffolds Containing Polypyrrole Nanoparticles with Different Morphologies and Concentrations.

Inspired by electrically active tissues, conductive materials have been extensively developed for electrically active tissue engineering scaffolds. In addition to excellent conductivity, nanocomposite conductive materials can also provide nanoscale structure similar to the natural extracellular microenvironment. Recently, the combination of three-dimensional (3D) printing and nanotechnology has opened up a new era of conductive tissue engineering scaffolds exhibiting optimized properties and multifunctionality. Furthermore, in the case of two-dimensional (2D) conductive film scaffolds such as periosteum, nerve membrane, skin repair, etc., the traditional preparation process, such as solvent casting, produces 2D films with defects of unequal bubbles and thickness frequently. In this study, poly-l-lactide (PLLA) conductive scaffolds incorporated with polypyrrole (PPy) nanoparticles, which have multiscale structure similar to natural tissue, were prepared by combining extrusion-based low-temperature deposition 3D printing with freeze-drying. Furthermore, we creatively integrated the advantages of 3D printing and solvent casting and successfully developed a 2D conductive film scaffold with no bubbles, uniform thickness, and good structural stability. Subsequently, the effects of concentration and morphology of PPy nanoparticles on electrical properties and mechanical properties of 3D conductive scaffolds and 2D conductive films scaffolds have been studied, which provided a new idea for the design of both 2D and 3D electroactive tissue engineering scaffolds.

Robust magnetic double-network hydrogels with self-healing, MR imaging, cytocompatibility and 3D printability.

Herein, we have fabricated a novel robust self-healing magnetic double-network hydrogel by multiple interactions between bondable magnetic Fe3O4 and chitosan-polyolefin matrix, and the hydrogel also exhibits an excellent magnetogenic effect and MR imageability. The practical potential of the magnetic double-network hydrogel is further revealed by its 3D-printing performance.

Three-Dimensional Printing and Injectable Conductive Hydrogels for Tissue Engineering Application.

The goal of tissue engineering scaffolds is to simulate the physiological microenvironment, in which the electrical microenvironment is an important part. Hydrogel is an ideal material for tissue engineering scaffolds because of its soft, porous, water-bearing, and other extracellular matrix-like properties. However, the hydrogel matrix is usually not conductive and can hinder the communication of electrical signals between cells, which promotes researchers' attention to conductive hydrogels. Conductive hydrogels can promote the communication of electrical signals between cells and simulate the physiological microenvironment of electroactive tissues. Hydrogel formation is an important step for the application of hydrogels in tissue engineering. In situ forming of injectable hydrogels and customized forming of three-dimensional (3D) printing hydrogels represent two most potential advanced forming processes, respectively. In this review, we discuss (i) the classification, properties, and advantages of conductive hydrogels, (ii) the latest development of conductive hydrogels applied in myocardial, nerve, and bone tissue engineering, (iii) advanced forming processes, including injectable conductive hydrogels in situ and customized 3D printed conductive hydrogels, (iv) the challenges and opportunities of conductive hydrogels for tissue engineering. Impact Statement Biomimetic construction of electro-microenvironment is a challenge of tissue engineering. The development of conductive hydrogels provides possibility for the construction of biomimetic electro-microenvironment. However, the importance of conductive hydrogels in tissue engineering has not received enough attention so far. Herein, various conductive hydrogels and their tissue engineering applications are systematically reviewed. Two potential methods of conductive hydrogel forming, in situ forming of injectable conductive hydrogels and customized forming of three-dimensional printing conductive hydrogels, are introduced. The current challenges and future development directions of conductive hydrogels are comprehensively overviewed. This review provides a guideline for tissue engineering applications of conductive hydrogels.

Synthesis and insecticidal activity in vitro and vivo of novel benzenesulfonyl derivatives based on potent target subunit H of V-ATPase.

Two lead compounds with benzenesulfonamide were found through virtual screening based on the 3D structure of the subunit H of V-ATPase in previous study. 74 benzenesulfonyl derivatives were synthesized and their insecticidal activities were evaluated. The derivatives with propargyl substituents exhibit excellent insecticidal activities against Mythimna separata Walker. The LD50 values of compounds A5.7 (28.0 µg·g-1) and B5.7 (36.4 µg·g-1) were significantly less than that of Celangulin V (344.0 µg·g-1). Furthermore, Isothermal Titration Calorimetry (ITC) data indicate there is a strong binding affinity between A5.7 and V-ATPase Subunit H. These results demonstrate that it is a practical way to develop pesticides targeting at H subunit of V-ATPase.

Synthesis and bioactivities evaluation of l-pyroglutamic acid analogues from natural product lead.

A series of l-pyroglutamic acid analogues from natural product lead were designed and synthesized, as well as their antifungal activities against Phytophthora infestans, neuritogenic activities, antibacterial activities and anti-inflammatory activities are described. The bioassays and SAR study showed that the majority of l-pyroglutamic acid esters have a significant antifungal activity against P. infestans, especially 2d and 2j demonstrated the best activities with EC50 values of 1.44 and 1.21 µg mL-1, which were about seven times that of commercial azoxystrobin (7.85 µg mL-1). Moreover, compounds 2e, 2g and 4d displayed anti-inflammatory activity against LPS-induced NO production in BV-2 microglial cells; neuritogenic activity in NGF-induced PC-12 cells is the same activity. This study demonstrates that compounds 2d and 2j are potential drugs to control P. infestans.

Bioassay-Guided Isolation of Antifungal Compounds from Disporopsis aspersa (Hua) Engl. ex Diels against Pseudoperonospora cubensis and Phytophthora infestans.

Oomycetes are one type of the most highly destructive of the diseases that cause damage to some important crop plants, such as potato late blight, cucumber downy mildew, and grape downy mildew. As main approach of the ongoing search for new botanical fungicide from plant, the secondary metabolites of D. aspersa were investigated. Through efficient bioassay-guided isolation, two new (1 and 2) and 12 known compounds (3 - 14) were isolated, and their structures were determined via extensive NMR, HR-ESI-MS, and IR. They were isolated from this genus for the first time except for compounds 11 and 12. The biological properties of 1 - 14 were evaluated against Pseudoperonospora cubensis and Phytophthora infestans. Compounds 1 - 8 showed potent antifungal activity in vitro. Additionally, compound 3 has preferable control effect on cucumber downy mildew, showing dual effect of protection and treatment in vivo.