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Science Advances Feb 2023We report multifunctional tendon-mimetic hydrogels constructed from anisotropic assembly of aramid nanofiber composites. The stiff nanofibers and soft polyvinyl alcohol...
We report multifunctional tendon-mimetic hydrogels constructed from anisotropic assembly of aramid nanofiber composites. The stiff nanofibers and soft polyvinyl alcohol in these anisotropic composite hydrogels (ACHs) mimic the structural interplay between aligned collagen fibers and proteoglycans in tendons. The ACHs exhibit a high modulus of ~1.1 GPa, strength of ~72 MPa, fracture toughness of 7333 J/m, and many additional characteristics matching those of natural tendons, which was not achieved with previous synthetic hydrogels. The surfaces of ACHs were functionalized with bioactive molecules to present biophysical cues for the modulation of morphology, phenotypes, and other behaviors of attached cells. Moreover, soft bioelectronic components can be integrated on ACHs, enabling in situ sensing of various physiological parameters. The outstanding mechanics and functionality of these tendon mimetics suggest their further applications in advanced tissue engineering, implantable prosthetics, human-machine interactions, and other technologies.
Topics: Humans; Tissue Scaffolds; Hydrogels; Tissue Engineering; Polyvinyl Alcohol; Tendons; Nanofibers
PubMed: 36800416
DOI: 10.1126/sciadv.ade6973 -
Clinical Neuroradiology Mar 2022Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid... (Review)
Review
BACKGROUND
Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure.
MATERIAL AND METHODS
This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes.
RESULTS
Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts.
CONCLUSION
All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.
Topics: Animals; Central Nervous System Vascular Malformations; Decapodiformes; Dimethyl Sulfoxide; Embolization, Therapeutic; Humans; Intracranial Arteriovenous Malformations; Polyvinyls; Treatment Outcome
PubMed: 34324005
DOI: 10.1007/s00062-021-01066-6 -
British Dental Journal Sep 2020
Topics: Iodine; Povidone-Iodine
PubMed: 32917988
DOI: 10.1038/s41415-020-2127-0 -
Science Advances Apr 2022Extracellular contractile injection systems (eCISs) are widespread bacterial nanomachines that resemble T4 phage tail. As a typical eCIS, virulence cassette (PVC) was...
Extracellular contractile injection systems (eCISs) are widespread bacterial nanomachines that resemble T4 phage tail. As a typical eCIS, virulence cassette (PVC) was proposed to inject toxins into eukaryotic cells by puncturing the cell membrane from outside. This makes it an ideal tool for protein delivery in biomedical research. However, how to manipulate this nanocomplex as a molecular syringe is still undetermined. Here, we identify that one group of N-terminal signal peptide (SP) sequences are crucial for the effector loading into the inner tube of PVC complex. By application of genetic operation, cryo-electron microscopy, in vitro translocation assays, and animal experiments, we show that, under the guidance of the SP, numerous prokaryotic and eukaryotic proteins can be loaded into PVC to exert their functions across cell membranes. We therefore might customize PVC as a potent protein delivery nanosyringe for biotherapy by selecting cargo proteins in a broad spectrum, regardless of their species, sizes, and charges.
Topics: Animals; Cryoelectron Microscopy; Photorhabdus; Polyvinyl Chloride; Protein Sorting Signals; Virulence
PubMed: 35486720
DOI: 10.1126/sciadv.abm2343 -
British Dental Journal Jun 2020
Topics: Povidone-Iodine
PubMed: 32541700
DOI: 10.1038/s41415-020-1725-1 -
International Journal of Molecular... Jan 2023As an energy storage technology, supercapacitors (SCs) have become an important part of many electronic systems because of their high-power density, long cycle life, and...
As an energy storage technology, supercapacitors (SCs) have become an important part of many electronic systems because of their high-power density, long cycle life, and maintenance-free characteristics. However, the widespread development and use of electronics, including SCs, have led to the generation of a large amount of e-waste. In addition, achieving compatibility between stability and biodegradability has been a prominent challenge for implantable electronics. Therefore, environmentally friendly SCs based on polypyrrole (PPy)-stabilized polypeptide (FF) are demonstrated in this study. The fully degradable SC has a layer-by-layer structure, including polylactic acid/chitosan (PLA-C) support layers, current collectors (Mg), FF/PPy composite layers, and a polyvinyl alcohol/phosphate buffer solution (PVA/PBS) hydrogel. It has the advantages of being light, thin, flexible, and biocompatible. After 5000 cycles in air, the capacitance retention remains at up to 94.7%. The device could stably operate for 7 days in a liquid environment and completely degrade in vitro within 90 days without any adverse effect on the environment. This work has important implications for eco-friendly electronics and will have a significant impact on the implantable biomedical electronics.
Topics: Polymers; Pyrroles; Polyvinyl Alcohol; Peptides
PubMed: 36768819
DOI: 10.3390/ijms24032497 -
British Dental Journal Feb 2021
Topics: Dentistry; Povidone-Iodine
PubMed: 33574511
DOI: 10.1038/s41415-021-2674-z -
BioTechniques Sep 2022hybridization is a commonly used technique in molecular biology to assess the temporal and spatial expression of a given gene. As a long and labor-intensive protocol,...
hybridization is a commonly used technique in molecular biology to assess the temporal and spatial expression of a given gene. As a long and labor-intensive protocol, double hybridization, which detects two genes in series, is challenging and can require a lot of troubleshooting. Optional additives, polyvinyl alcohol and dextran sulfate, were tested in a standard hybridization protocol and several colorimetric stain pairings using double hybridization in zebrafish embryos. Optional additives can improve staining time and reduce nonspecific background. Nitro-blue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate (BCIP) + Fast Red/BCIP was the most effective stain pairing. As a proof-of-concept, this work shows that and are expressed in distinct regions of the developing zebrafish brain.
Topics: Animals; Chlorides; Dextran Sulfate; In Situ Hybridization; Polyvinyl Alcohol; Zebrafish
PubMed: 36065907
DOI: 10.2144/btn-2022-0038 -
Scientific Reports Jul 2022An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual...
An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual polypropylene (PP) fibers of polypropylene micromembrane (PPMM). The functionalized PPMM becomes hydrophilic to allow the formation of Au nuclei for subsequent electroless Au deposition. The metalized PPMM is further deposited with IrO nanoparticles, and evaluated as a flexible and porous pH sensor. Images from scanning electron microscope confirms the uniform formation of IrO nanoparticles on Au-coated PP fibers. For pH-sensing performance, the IrO-decorated metalized PPMM reveals a super-Nernstian response for a sensing slope of -74.45 mV/pH in aqueous solutions with pH value ranging between 2 and 12. In addition, the pH-sensing performance is properly maintained after 5000 bending cycles and hysteresis is modest in an acidic environment. The cell viability test indicates a negligible bio-toxicity. Our strategy of using a conductive polymeric membrane decorated with IrO nanoparticles enables possible sensing applications in wearable and implantable electronics.
Topics: Electronics; Hydrogen-Ion Concentration; Nanoparticles; Polypropylenes; Polyvinyl Alcohol
PubMed: 35810194
DOI: 10.1038/s41598-022-15961-6 -
The Journal of Extra-corporeal... Jun 2020The U.S. healthcare system generates more than five billion pounds of waste each year. Waste disposal has become a serious environmental problem facing healthcare... (Review)
Review
The U.S. healthcare system generates more than five billion pounds of waste each year. Waste disposal has become a serious environmental problem facing healthcare institutions. The operating room is the second largest source of hospital waste, and no current standards exist regarding perfusion waste reuse or recycling. A typical perfusion circuit produces approximately 15 pounds of plastic that ends up incinerated once used. Contaminated perfusion circuits consisting primarily of polyvinyl chloride (PVC) and polycarbonate are difficult to sterilize, reuse, or recycle. A literature review of Internet-based and peer-reviewed publications was conducted to identify all resources that describe sterilizing, dechlorinating, reusing, and recycling of medical-grade disposable products. There are several chemical methods available to re-harvest PVC after it has been properly decontaminated and melted down. Dichlorination by near-critical methanol shows promise in the recovery of additives such as plasticizers, stabilizers, and lubricants. The reinjection of PVC may have ecological and economic advantages. Dechlorinated PVC also creates a less toxic by-product when incinerated. Although this process is not recycling, it lessens the impact of poisonous chlorine gas release into the atmosphere. Sterilizing, dechlorinating, and recycling the perfusion circuit may be a promising avenue for reducing the ecological impact of perfusion waste. Although an economically sensitive mode of reusing, reducing, and recycling a circuit does not currently exist, this presentation will explore the perfusion waste dilemma and present potential solutions in hopes of promoting future reuse and recycling opportunities.
Topics: Medical Waste; Polyvinyl Chloride; Recycling; Refuse Disposal
PubMed: 32669740
DOI: 10.1182/ject-1900023