Nanotechnology-based antimicrobial and antiviral formulations can prevent SARS-CoV-2 viral dissemination, and highly sensitive biosensors and detection platforms may contribute to the detection and ...diagnosis of COVID-19.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The fiber-matrix interface properties play an important role in determining the overall mechanical performance of the fiber reinforced brittle matrix composites. This study is to evaluate the effects ...of wettability, chemical characterization and nanometric roughness of two different fibers, polypropylene (PPF) and micro steel fibers (MSF), superposed by shrinkage of fly ash based geopolymer binder on fiber-matrix interaction and the consequent mechanical properties of the corresponding composites. The fiber incorporation in geopolymer matrix was performed by 0.5, 1, 2, 3 and 4% of the total volume of each type of fibers. The results show that MSF has strong contact with the geopolymer paste since it tends to behave as a hydrophilic material that resulted in significant improvement in energy absorption and flexural strength of the composite; while PPF led to fiber-matrix debonding due to hydrophobic characteristics of the fiber compounds by geopolymer shrinkage that weakened the mechanical performances of the composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
3.
Sheath-run artificial muscles Mu, Jiuke; Jung de Andrade, Mônica; Fang, Shaoli ...
Science (American Association for the Advancement of Science),
07/2019, Volume:
365, Issue:
6449
Journal Article
Peer reviewed
Open access
Although guest-filled carbon nanotube yarns provide record performance as torsional and tensile artificial muscles, they are expensive, and only part of the muscle effectively contributes to ...actuation. We describe a muscle type that provides higher performance, in which the guest that drives actuation is a sheath on a twisted or coiled core that can be an inexpensive yarn. This change from guest-filled to sheath-run artificial muscles increases the maximum work capacity by factors of 1.70 to 2.15 for tensile muscles driven electrothermally or by vapor absorption. A sheath-run electrochemical muscle generates 1.98 watts per gram of average contractile power-40 times that for human muscle and 9.0 times that of the highest power alternative electrochemical muscle. Theory predicts the observed performance advantages of sheath-run muscles.
Given their durability and long‐term stability, self‐healable hydrogels have, in the past few years, emerged as promising replacements for the many brittle hydrogels currently being used in ...preclinical or clinical trials. To this end, the incompatibility between hydrogel toughness and rapid self‐healing remains unaddressed, and therefore most of the self‐healable hydrogels still face serious challenges within the dynamic and mechanically demanding environment of human organs/tissues. Furthermore, depending on the target tissue, the self‐healing hydrogels must comply with a wide range of properties including electrical, biological, and mechanical. Notably, the incorporation of nanomaterials into double‐network hydrogels is showing great promise as a feasible way to generate self‐healable hydrogels with the above‐mentioned attributes. Here, the recent progress in the development of multifunctional and self‐healable hydrogels for various tissue engineering applications is discussed in detail. Their potential applications within the rapidly expanding areas of bioelectronic hydrogels, cyborganics, and soft robotics are further highlighted.
Self‐healable hydrogels hold great promise in preclinical and clinical trials, owing to their durability and long‐term stability. This study delves into the development of multifunctional and self‐healable hydrogels for tissue regeneration, mainly focused on the synergy between toughness and dynamic self‐repairing capability. Specifically, some of the uncharted potential of these materials are discussed, and their applications within the newly emerging areas of cyborganics and soft robotics are highlighted.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•The ionic liquid route to synthesize rich FGO at the moderate temperature.•The high degree of 66.4 wt.% fluorination on graphene oxide surfaces.•The high curcumin-loading efficiency ...(78.43%) on FGO to deliver the anti-cancer drug.
Fluorination of graphene nanomaterials has multitude merits owing to the peculiar temperament of the carbon-fluorine (C-F) bond. However, the current synthesis modalities of fluorinated graphene (FG) are based on the usage of toxic materials at high temperatures, which are problematic to be used. The methods to overcome these problems are challenging for chemists. Ionic liquids (ILs) have been used in several chemical processes as auxiliaries and eco-friendly alternatives instead of volatile organic solvents because of their properties. Consequently, herein we exploited a highly effective and green process for the synthesis of FG at mild temperature (80 °C) by using ammonium fluoride salt as fluorine agent and a synthesized acidic IL (TEA+TFA–) as a solvent. Our goal was to synthesize enriched FG with a high degree of fluorination (66.4 wt.% of F) and F/C ratio (2.2), which measured and confirmed by XPS analysis. Subsequently, the obtained FG was used as a nanocarrier for delivery of curcumin to cancerous cells. The in-vitro results showed that these nanosheets possessed a higher Cur-loading efficiency (78.43%) than commercial FG (52.12%) due to the sheet-like structure with folded edges. This, in turn, translated into an excellent in-vitro anti-cancer effect when tested against cancerous cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Highly flexible biocompatible materials that are both thermally conductive and electrically insulating are important for implantable and wearable bioelectronics applications. The ability to thermally ...process these materials into useful structures using additive manufacturing approaches opens up new opportunities for its use in bespoke structures. Here we investigate the three-dimensional (3D) printing of a medical-grade thermoplastic polyurethane (PU) elastomer, which is thermally insulating and enhance its thermal and mechanical properties through the incorporation of boron nitride (BN) as a filler. Via a simple solution compounding approach, a highly flexible and thermally conductive BN nanoparticle/ PU composite has been developed and subsequently processed into simple bio-scaffolds structures via a 3D pneumatic melt extrusion printing process. The addition of up to 20% w/w of BN to the PU significantly enhances the tensile modulus by 659%, from 1.74 to 13.2 MPa, while supporting high mechanical flexibility. The thermal conductivity of 20% w/w BN/PU composite increases by 74% with respect to the unmodified PU. The 3D printed BN/PU composite scaffolds exhibit good biocompatibility and cell attachment enhancement with L929 fibroblast cells.
Graphical abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study demonstrates a cost-effective portable fabrication system for 3D printing complex structures from polydimethylsiloxane (PDMS). Material development and characterisation allowed for the ...design and production of a 3D printer that is capable of fabricating PDMS structures using a photo-initiator and a LED curing process. A 3D model of a participant’s ear was captured using a handheld scanner. These data were used to directly 3D print an ear. Micro-extrusion direct deposition of PDMS at room temperature is demonstrated via a custom designed 3D printer, with in situ UV cross-linking to facilitate curing of the PDMS during the 3D printing process. This 3D printer has great potential to be used as a fast and facile fabrication approach to create facial and other prosthesis. Future developments will also focus on other application areas such as microfluidics, flexible electronics, and other biomedical applications.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The effects of polymer concentration and electrospinning parameters on the diameter of electrospun polymethyl methacrylate (PMMA) fibers were experimentally investigated. It was also studied how the ...controlled factors would affect the output with the intention of finding the optimal electrospinning settings in order to obtain the smallest PMMA fiber diameter. Subsequently the solution feed rate, needle gauge diameter, supply voltage, polymer concentration and tip-to-collector distance were considered as the control factors. To achieve these aims, Taguchi’s mixed-level parameter design (L18) was employed for the experimental design. Optimal electrospinning conditions were determined using the signal-to-noise (S/N) ratio that was calculated from the electrospun PMMA fiber diameter according to “the-smaller-the-better” approach. Accordingly, the smallest fiber diameter observed was 228 (±76) nm and it was yielded at 15 wt% polymer concentration, 20 kV of supply voltage, 1 ml/h feed rate, 15 cm tip-to-distance and 19 needle gauge. Moreover, the S/N ratio response showed that the polymer concentration was the most effective parameter on determination of fiber diameter followed by feed rate, tip-to distance, needle gauge and voltage, respectively. The Taguchi design of experiments method has been found to be an effective approach to statistically optimize the critical parameters used in electrospinning so as to effectively tailor the resulting electrospun fiber diameters and morphology.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Abstract Adverse body reactions to blood-contacting medical devices endanger patient safety and impair device functionality, with events invariably linked to nonspecific protein adsorption due to ...suboptimal material biocompatibility. To improve the safety and durability of such devices, herein we propose a strategy for introducing stable zwitterionic grafts onto polymeric surfaces via plasma functionalization. The resulting zwitterion-grafted substrates exhibit long-lasting superhydrophilicity, enabling antifouling and anti-thrombogenic properties. We demonstrate the successful modification of the surface elemental composition, morphology, and hydrophilicity, while retaining the underlying mechanical properties of the polymeric substrate. Furthermore, we optimise the fabrication process to ensure long-lasting modifications at least three months after fabrication. This strategy decreases fibrinogen adsorption by approximately 9-fold, and thrombosis by almost 75% when applied to a commercial polyurethane. Moreover, this process is universally applicable to a wide range of polymeric materials, even those with stable chemistry such as polytetrafluoroethylene.
A comparative study on the in vitro osteogenic potential of electrospun poly-L-lactide/hydroxyapatite/collagen (PLLA/HA/Col, PLLA/HA, and PLLA/Col) scaffolds was conducted. The morphology, chemical ...composition, and surface roughness of the fibrous scaffolds were examined. Furthermore, cell attachment, distribution, morphology, mineralization, extracellular matrix protein localization, and gene expression of human mesenchymal stromal cells (hMSCs) differentiated on the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA were also analyzed. The electrospun scaffolds with a diameter of 200-950 nm demonstrated well-formed interconnected fibrous network structure, which supported the growth of hMSCs. When compared with PLLA/H%A and PLLA/Col scaffolds, PLLA/Col/HA scaffolds presented a higher density of viable cells and significant upregulation of genes associated with osteogenic lineage, which were achieved without the use of specific medium or growth factors. These results were supported by the elevated levels of calcium, osteocalcin, and mineralization (P<0.05) observed at different time points (0, 7, 14, and 21 days). Furthermore, electron microscopic observations and fibronectin localization revealed that PLLA/Col/HA scaffolds exhibited superior osteoinductivity, when compared with PLLA/Col or PLLA/HA scaffolds. These findings indicated that the fibrous structure and synergistic action of Col and nano-HA with high-molecular-weight PLLA played a vital role in inducing osteogenic differentiation of hMSCs. The data obtained in this study demonstrated that the developed fibrous PLLA/Col/HA biocomposite scaffold may be supportive for stem cell based therapies for bone repair, when compared with the other two scaffolds.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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