A self-elastic chitosan sponge reinforced with lauric acid-modified quaternized chitosan and attapulgite to treat noncompressible hemorrhage and facilitate wound healing.

The development of self-elastic sponges with enhanced hemostatic and antibacterial properties to treat noncompressible hemorrhage and facilitate wound healing remains challenging. Herein, we prepared a chitosan sponge reinforced with lauric acid-modified quaternized chitosan (LQC) and attapulgite, features a porous structure, high self-elasticity, and rapid shape recovery. The incorporation of LQC conferred the sponge with an enhanced capacity to promote the adhesion, aggregation, and activation of blood cells, and resistance to infection by Staphylococcus aureus, Escherichia coli, and Methicillin-resistant Staphylococcus aureus; the incorporation of attapulgite enhanced the hydrophilicity and mechanical strength of the sponge, and its ability to activate the intrinsic and extrinsic coagulation pathways.

Proteomic analysis of the pyrenoid-traversing membranes of reveals novel components.

Pyrenoids are algal CO-fixing organelles that mediate approximately one-third of global carbon fixation and hold the potential to enhance crop growth if engineered into land plants. Most pyrenoids are traversed by membranes that are thought to supply them with concentrated CO. Despite the critical nature of these membranes for pyrenoid function, they are poorly understood, with few protein components known in any species.

SAGA1 and MITH1 produce matrix-traversing membranes in the CO-fixing pyrenoid.

Approximately one-third of global CO assimilation is performed by the pyrenoid, a liquid-like organelle found in most algae and some plants. Specialized pyrenoid-traversing membranes are hypothesized to drive CO assimilation in the pyrenoid by delivering concentrated CO, but how these membranes are made to traverse the pyrenoid matrix remains unknown. Here we show that proteins SAGA1 and MITH1 cause membranes to traverse the pyrenoid matrix in the model alga Chlamydomonas reinhardtii.

Biogenesis, engineering and function of membranes in the CO -fixing pyrenoid.

Approximately one-third of global CO assimilation is performed by the pyrenoid , a liquid-like organelle found in most algae and some plants . Specialized membranes are hypothesized to drive CO assimilation in the pyrenoid by delivering concentrated CO , but their biogenesis and function have not been experimentally characterized. Here, we show that homologous proteins SAGA1 and MITH1 mediate the biogenesis of the pyrenoid membrane tubules in the model alga and are sufficient to reconstitute pyrenoid-traversing membranes in a heterologous system, the plant .

Multi-omics analysis of green lineage osmotic stress pathways unveils crucial roles of different cellular compartments.

Maintenance of water homeostasis is a fundamental cellular process required by all living organisms. Here, we use the single-celled green alga Chlamydomonas reinhardtii to establish a foundational understanding of osmotic-stress signaling pathways through transcriptomics, phosphoproteomics, and functional genomics approaches. Comparison of pathways identified through these analyses with yeast and Arabidopsis allows us to infer their evolutionary conservation and divergence across these lineages.

Biodegradable quaternized silk fibroin sponge with highly uniform pore structure for traumatic hemostasis and anti-infection.

Developing a biodegradable sponge with rapid shape recovery and potent antibacterial and coagulation properties for traumatic hemostasis and anti-infection remains challenging. Herein, we fabricated quaternized silk fibroin (SF) sponges by freeze-drying under a constant cooling rate and modification with quaternary ammonium groups. We found the constant cooling rate enabled the sponges with a highly uniform pore structure, which provided excellent self-elasticity and shape recovery.

A self-elastic chitosan sponge integrating active and passive hemostatic mechanisms for effectively managing uncontrolled coagulopathic hemorrhage.

Developing a self-elastic sponge integrating active and passive hemostatic mechanisms for the effective management of uncontrolled coagulopathic hemorrhage remains a challenge. We here developed a chitosan-based sponge by integrating freeze-drying, chemical decoration of alkyl chains and phosphate groups, and physical loading of thrombin. The sponge exhibited high mechanical strength, self-elasticity, and rapid shape recovery.

Chloroplast phosphate transporter CrPHT4-7 regulates phosphate homeostasis and photosynthesis in Chlamydomonas.

In eukaryotic cells, phosphorus is assimilated and utilized primarily as phosphate (Pi). Pi homeostasis is mediated by transporters that have not yet been adequately characterized in green algae. This study reports on PHOSPHATE TRANSPORTER 4-7 (CrPHT4-7) from Chlamydomonas reinhardtii, a member of the PHT4 transporter family, which exhibits remarkable similarity to AtPHT4;4 from Arabidopsis (Arabidopsis thaliana), a chloroplastic ascorbate transporter.

A chloroplast protein atlas reveals punctate structures and spatial organization of biosynthetic pathways.

Chloroplasts are eukaryotic photosynthetic organelles that drive the global carbon cycle. Despite their importance, our understanding of their protein composition, function, and spatial organization remains limited. Here, we determined the localizations of 1,034 candidate chloroplast proteins using fluorescent protein tagging in the model alga Chlamydomonas reinhardtii.

Controlling Pore Size of Electrospun Vascular Grafts by Electrospraying of Poly(Ethylene Oxide) Microparticles.

Electrospinning has become a popular polymer processing technique for application in vascular tissue engineering due to its unique capability to fabricate porous vascular grafts with fibrous morphology closely mimicking the natural extracellular matrix (ECMs). However, the inherently small pore sizes of electrospun vascular grafts often inhibit cell infiltration and impede vascular regeneration. Here we describe an effective and controllable method to increase the pore size of electrospun poly(ε-caprolactone) (PCL) vascular graft.

Microchannelled alkylated chitosan sponge to treat noncompressible hemorrhages and facilitate wound healing.

Developing an anti-infective shape-memory hemostatic sponge able to guide in situ tissue regeneration for noncompressible hemorrhages in civilian and battlefield settings remains a challenge. Here we engineer hemostatic chitosan sponges with highly interconnective microchannels by combining 3D printed microfiber leaching, freeze-drying, and superficial active modification. We demonstrate that the microchannelled alkylated chitosan sponge (MACS) exhibits the capacity for water and blood absorption, as well as rapid shape recovery.

Biomimetic Design of Mitochondria-Targeted Hybrid Nanozymes as Superoxide Scavengers.

Development of enzyme mimics for the scavenging of excessive mitochondrial superoxide (O ) can serve as an effective strategy in the treatment of many diseases. Here, protein reconstruction technology and nanotechnology is taken advantage of to biomimetically create an artificial hybrid nanozyme. These nanozymes consist of ferritin-heavy-chain-based protein as the enzyme scaffold and a metal nanoparticle core as the enzyme active center.

Role of the Calcified Cartilage Layer of an Integrated Trilayered Silk Fibroin Scaffold Used to Regenerate Osteochondral Defects in Rabbit Knees.

The repair of osteochondral defects remains challenging, given the complexity of native osteochondral tissue and the limited self-repair capacity of cartilage. Osteochondral tissue engineering is a promising strategy. Here, we fabricated a biomimetic osteochondral scaffold using silk fibroin and hydroxyapatite, including a calcified cartilage layer (CCL).

Assembly of the algal CO-fixing organelle, the pyrenoid, is guided by a Rubisco-binding motif.

Approximately one-third of the Earth's photosynthetic CO assimilation occurs in a pyrenoid, an organelle containing the CO-fixing enzyme Rubisco. How constituent proteins are recruited to the pyrenoid and how the organelle's subcompartments-membrane tubules, a surrounding phase-separated Rubisco matrix, and a peripheral starch sheath-are held together is unknown. Using the model alga , we found that pyrenoid proteins share a sequence motif.

Biomimetic angle-ply multi-lamellar scaffold for annulus fibrosus tissue engineering.

Constructing a biomimetic scaffold that replicates the complex architecture of intervertebral disc annulus fibrosus (AF) remains a major goal in AF tissue engineering. In this study, a biomimetic angle-ply multi-lamellar polycaprolactone/silk fibroin (PCL/SF) AF scaffold was fabricated. Wet-spinning was used to obtain aligned PCL/SF microfiber sheets, and these were excised into strips with microfibers aligned at +30° or -30° relative to the strip long axis.

An anti-infective hydrogel adhesive with non-swelling and robust mechanical properties for sutureless wound closure.

A non-swelling hydrogel adhesive is urgently needed in clinical application for wound closure; however, preparing a non-swelling hydrogel adhesive with superior mechanical and tissue adhesion properties remains a challenge. In this study, we developed a new family of non-swelling hydrogel adhesives composed of Pluronic F127 diacrylate, poly(ethylene glycol) diacrylate, modified sodium alginate, and tannic acid. Physical and biological properties of the hydrogels were systematically evaluated in vitro/vivo.

The pyrenoid.

Wang and Jonikas take a look at an unconventional organelle, the pyrenoid.

Construction of vascular graft with circumferentially oriented microchannels for improving artery regeneration.

Design and fabrication of scaffolds with three-dimensional (3D) topological cues inducing regeneration of the neo-tissue comparable to native one remains a major challenge in both scientific and clinical fields. Here, we developed a well-designed vascular graft with 3D highly interconnected and circumferentially oriented microchannels by using the sacrificial sugar microfiber leaching method. The microchannels structure was capable of promoting the migration, oriented arrangement, elongation, and the contractile phenotype expression of vascular smooth muscle cells (VSMCs) in vitro.

Anti-Infective and Pro-Coagulant Chitosan-Based Hydrogel Tissue Adhesive for Sutureless Wound Closure.

Multifunctional tissue adhesives with excellent adhesion, antibleeding, anti-infection, and wound healing properties are desperately needed in clinical surgery. However, the successful development of multifunctional tissue adhesives that simultaneously possess all these properties remains a challenge. We have prepared a novel chitosan-based hydrogel adhesive by integration of hydrocaffeic acid-modified chitosan (CS-HA) with hydrophobically modified chitosan lactate (hmCS lactate) and characterized its gelation time, mechanical properties, and microstructure.

Injectable hydrogel composed of hydrophobically modified chitosan/oxidized-dextran for wound healing.

An injectable hydrogel dressing with multifunctional properties of superior hemostasis, antibacterial activity, tissue adhesive and cytocompatibility is desirable candidate in wound healing. In this study, we developed a novel hydrogel dressing composed of hydrophobically modified chitosan (hmCS) and oxidized dextran (OD). The gelation time, microstructure, injectability, self-healing and rheological properties were characterized.

A Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology in .

A phase-separated, liquid-like organelle called the pyrenoid mediates CO fixation in the chloroplasts of nearly all eukaryotic algae. While most algae have 1 pyrenoid per chloroplast, here we describe a mutant in the model alga that has on average 10 pyrenoids per chloroplast. Characterization of the mutant leads us to propose a model where multiple pyrenoids are favored by an increase in the surface area of the starch sheath that surrounds and binds to the liquid-like pyrenoid matrix.

[Preparation and evaluation of carboxymethyl chitosan/sodium alginate hydrogel for cartilage tissue engineering].

Objective: This study aimed to optimize the preparation of carboxymethyl chitosan/sodium alginate (CMCS/OSA) compound hydrogels. This study also aimed to investigate the applicability of the hydrogels in cartilage tissue engi-neering.

Methods: Three groups of CMCS/OSA composite hydrogels with amino-to-aldehyde ratios of 2∶1, 1∶1 and 1∶2 were prepared.

Multifunctional Hydrogel Patch with Toughness, Tissue Adhesiveness, and Antibacterial Activity for Sutureless Wound Closure.

A multifunctional hydrogel patch with a combination of high toughness, superior adhesion, and good antibacterial effect is a highly desired surgical material. In this study, we developed a novel hydrogel patch composed of poly(ethylene glycol) diacrylate/quaternized chitosan/tannic acid (PEGDA/QCS/TA) based on mussel-inspired chemistry. The physical and biological properties of the hydrogel patch were systematically evaluated in vitro and in vivo.