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Polymers Oct 2023MXene exhibits impressive characteristics, including flexibility, mechanical robustness, the capacity to cleanse liquids like water through MXene membranes,... (Review)
Review
MXene exhibits impressive characteristics, including flexibility, mechanical robustness, the capacity to cleanse liquids like water through MXene membranes, water-attracting nature, and effectiveness against bacteria. Additionally, bacterial cellulose (BC) exhibits remarkable qualities, including mechanical strength, water absorption, porosity, and biodegradability. The central hypothesis posits that the incorporation of both MXene and bacterial cellulose into the material will result in a remarkable synthesis of the attributes inherent to MXene and BC. In layered MXene/BC coatings, the presence of BC serves to separate the MXene layers and enhance the material's integrity through hydrogen bond interactions. This interaction contributes to achieving a high mechanical strength of this film. Introducing cellulose into one layer of multilayer MXene can increase the interlayer space and more efficient use of MXene. Composite materials utilizing MXene and BC have gained significant traction in sensor electronics due to the heightened sensitivity exhibited by these sensors compared to usual ones. Hydrogel wound healing bandages are also fabricated using composite materials based on MXene/BC. It is worth mentioning that MXene/BC composites are used to store energy in supercapacitors. And finally, MXene/BC-based composites have demonstrated high electromagnetic interference (EMI) shielding efficiency.
PubMed: 37896311
DOI: 10.3390/polym15204067 -
International Ophthalmology Sep 2023We developed model eyes using six polymer materials to determine which materials were most appropriate in simulating real human sclera and extraocular muscle (EOM).
PURPOSE
We developed model eyes using six polymer materials to determine which materials were most appropriate in simulating real human sclera and extraocular muscle (EOM).
METHODS
Five three-dimensional (3-D) printed polymers (FlexFill, PolyFlex, PCTPE, Soft PLA, and NinjaFlex) and one silicone material were systematically tested by board-certified ophthalmologists and senior ophthalmology residents. Material testing included scleral passes with 6-0 Vicryl sutures through each eye model. Participants completed a survey designed to collect demographic data, subjective assessment of each material's accuracy in simulating real human sclera and EOM, and a ranking for each polymer material to identify which would be most suitable for an ophthalmic surgery training tool. The Wilcoxon signed-rank test was conducted to determine if there was a statistically significant difference in the distribution of ranks between the polymer materials.
RESULTS
The distribution of ranks for silicone material's "sclera" and "EOM" components were statistically significantly higher than that of all other polymer materials (all p < 0.05). Silicone material received the highest rank for both "sclera" and "EOM" components. Survey results indicated that the silicone material effectively simulated real human tissue.
CONCLUSION
Silicone model eyes performed better than 3-D printed polymers as an educational tool for incorporation into a microsurgical training curriculum. Silicone models provide a low-cost teaching tool that allows for independent practice of microsurgical techniques without requiring a wet-laboratory facility.
Topics: Humans; Internship and Residency; Polymers; Clinical Competence; Ophthalmology; Silicones
PubMed: 37217809
DOI: 10.1007/s10792-023-02736-9 -
Nanomaterials (Basel, Switzerland) Mar 2024Vanadium dioxide (VO) stands out for its versatility in numerous applications, thanks to its unique reversible insulator-to-metal phase transition. This transition can... (Review)
Review
Vanadium dioxide (VO) stands out for its versatility in numerous applications, thanks to its unique reversible insulator-to-metal phase transition. This transition can be initiated by various stimuli, leading to significant alterations in the material's characteristics, including its resistivity and optical properties. As the interest in the material is growing year by year, the purpose of this review is to explore the trends and current state of progress on some of the applications proposed for VO in the field of sensors and actuators using literature review methods. Some key applications identified are resistive sensors such as strain, temperature, light, gas concentration, and thermal fluid flow sensors for microfluidics and mechanical microactuators. Several critical challenges have been recognized in the field, including the expanded investigation of VO-based applications across multiple domains, exploring various methods to enhance device performance such as modifying the phase transition temperature, advancing the fabrication techniques for VO structures, and developing innovative modelling approaches. Current research in the field shows a variety of different sensors, actuators, and material combinations, leading to different sensor and actuator performance input ranges and output sensitivities.
PubMed: 38607118
DOI: 10.3390/nano14070582 -
Advanced Science (Weinheim,... Jul 2023Information processing using material's own properties has gained increasing interest. Mechanical metamaterials, due to their diversity of deformation modes and wide...
Information processing using material's own properties has gained increasing interest. Mechanical metamaterials, due to their diversity of deformation modes and wide design space, can be used to realize information processing, such as computing and storage. Here a mechanical metamaterial system is demonstrated for material-based encoding and storage of data through programmed reconfigurations of the metamaterial's structured building blocks. Sequential encoding and decoding are achieved in the three-dimensional (3D) printed pixelated mechanical metamaterial via kirigami-based "pixels" with programmable, temperature-dependent bistability. The mechanical metamaterial is demonstrated via a multistep deformation of encoding messages of texts and surfaces with arrays of binary data, and then decoding them by applying a predetermined stretching and heating regimen to sequentially retrieve layers of stored information and display them on its surface. This approach serves as a general framework to enable the encoding and storage of data with mechanical metamaterials.
PubMed: 37083263
DOI: 10.1002/advs.202301581 -
Nature Communications Nov 2023The forthcoming generation of materials, including artificial muscles, recyclable and healable systems, photochromic heterogeneous catalysts, or tailorable...
The forthcoming generation of materials, including artificial muscles, recyclable and healable systems, photochromic heterogeneous catalysts, or tailorable supercapacitors, relies on the fundamental concept of rapid switching between two or more discrete forms in the solid state. Herein, we report a breakthrough in the "speed limit" of photochromic molecules on the example of sterically-demanding spiropyran derivatives through their integration within solvent-free confined space, allowing for engineering of the photoresponsive moiety environment and tailoring their photoisomerization rates. The presented conceptual approach realized through construction of the spiropyran environment results in ~1000 times switching enhancement even in the solid state compared to its behavior in solution, setting a record in the field of photochromic compounds. Moreover, integration of two distinct photochromic moieties in the same framework provided access to a dynamic range of rates as well as complementary switching in the material's optical profile, uncovering a previously inaccessible pathway for interstate rapid photoisomerization.
PubMed: 37985777
DOI: 10.1038/s41467-023-43405-w -
Materials (Basel, Switzerland) Oct 2023The effectiveness of 3D concrete printing (3DCP) relies on understanding the rheological properties of cementitious materials and their time-dependent evolution. These...
The effectiveness of 3D concrete printing (3DCP) relies on understanding the rheological properties of cementitious materials and their time-dependent evolution. These materials exhibit shear-thinning viscosity, an elastic region, and both static and dynamic yield stress, which are challenging to balance in 3DCP. Layer deformation can be caused by factors such as self-weight, the weight of subsequently deposited layers, and the stress induced by the nozzle pressing. Starting at the level of a single filament, the final geometrical conformity of a 3D-printed object is the sum of individual filament conformities. Hence, the control of layer deformation during the printing process is critical. The failure of 3D-printed objects can occur due to two primary mechanisms: material failure, which occurs when the material's strength is exceeded, resulting in fracture or uncontrolled deformation; and stability failure, where the object cannot retain equilibrium of forces. These mechanisms often interact; extensive deformations resulting from material failure can lead to stability loss, or conversely, stability loss generates local excessive stresses leading to material failure. The governing mechanism depends on various factors, including material and process characteristics, as well as the transient nature of material properties, print strategy, and object design. With this in mind, this research aimed to broaden the understanding of the connection between rheological material properties-primarily yield stress-and the geometric conformability of printed objects. Experimental tests were conducted on pastes using a rheometer, and correlated mortars, allowing for the evaluation of realistic extrusion properties.
PubMed: 37959461
DOI: 10.3390/ma16216864 -
ACS Sustainable Chemistry & Engineering Apr 2024The cross-linked nature of vulcanized rubbers as used in tire and many other applications prohibits an effective closed-loop mechanical or chemical recycling. Moreover,...
The cross-linked nature of vulcanized rubbers as used in tire and many other applications prohibits an effective closed-loop mechanical or chemical recycling. Moreover, vulcanization significantly retards the material's biodegradation. Here, we report a recyclable and biodegradable rubber that is generated by the vulcanization of amorphous, unsaturated polyesters. The elastic material can be broken down solvolysis into the underlying monomers. After removal of the vulcanized repeat units, the saturated monomers, constituting the major share of the material, can be recovered in overall recycling rates exceeding 90%. Respirometric biodegradation experiments by CO tracking under environmental conditions the polyesters' diol monomer indicated depolymerization and partial mineralization of the vulcanized polyester rubbers.
PubMed: 38665800
DOI: 10.1021/acssuschemeng.3c08435 -
Materials Today. Bio Jun 2024Cardiovascular diseases are a main cause of death worldwide, leading to a growing demand for medical devices to treat this patient group. Central to the engineering of... (Review)
Review
Cardiovascular diseases are a main cause of death worldwide, leading to a growing demand for medical devices to treat this patient group. Central to the engineering of such devices is a good understanding of the biology and physics of cell-surface interactions. In existing blood-contacting devices, such as vascular grafts, the interaction between blood, cells, and material is one of the main limiting factors for their long-term durability. An improved understanding of the material's chemical- and physical properties as well as its structure all play a role in how endothelial cells interact with the material surface. This review provides an overview of how different surface structures influence endothelial cell responses and what is currently known about the underlying mechanisms that guide this behavior. The structures reviewed include decellularized matrices, electrospun fibers, pillars, pits, and grated surfaces.
PubMed: 38711934
DOI: 10.1016/j.mtbio.2024.101060 -
Materials (Basel, Switzerland) Jul 2023Numerous studies have been conducted on fiber-reinforced concrete; however, comparative investigations specifically focusing on the utilization of fibers in CLSM remain...
Numerous studies have been conducted on fiber-reinforced concrete; however, comparative investigations specifically focusing on the utilization of fibers in CLSM remain limited. In this study, we conducted a systematic investigation into the mechanical properties of controlled low-strength material (CLSM) by manipulating the length and doping amount of fibers as control variables. The 7-day compressive strength (7d-UCS), 28-day compressive strength (28d-UCS), and 28-day splitting strength of CLSM were employed as indicators to evaluate the material's performance. Based on our comprehensive analysis, the following conclusions were drawn: (1) A positive correlation was observed between fiber length and material strength within the range of 0-6 mm, while conversely, a negative correlation was evident. Similarly, when the fiber doping was within the range of 0-0.3%, a positive correlation was identified between material strength and fiber doping. However, the strength of CLSM decreased when fiber doping exceeded 0.3%. (2) SEM and PCAS analyses provided further confirmation that the incorporation of fibers effectively reduced the porosity of the material by filling internal pores and interacting with hydration products, thereby forming a mesh structure. Overall, this study offers valuable insights into the manipulation of fiber length and doping amount to optimize the mechanical properties of CLSM. The findings have important implications for the practical application of CLSM, particularly in terms of enhancing its strength through fiber incorporation.
PubMed: 37569988
DOI: 10.3390/ma16155287 -
International Journal of Molecular... Sep 2023Tissue engineering for spinal cord injury (SCI) remains a complex and challenging task. Biomaterial scaffolds have been suggested as a potential solution for supporting...
Tissue engineering for spinal cord injury (SCI) remains a complex and challenging task. Biomaterial scaffolds have been suggested as a potential solution for supporting cell survival and differentiation at the injury site. However, different biomaterials display multiple properties that significantly impact neural tissue at a cellular level. Here, we evaluated the behavior of different cell lines seeded on chitosan (CHI), poly (ε-caprolactone) (PCL), and poly (L-lactic acid) (PLLA) scaffolds. We demonstrated that the surface properties of a material play a crucial role in cell morphology and differentiation. While the direct contact of a polymer with the cells did not cause cytotoxicity or inhibit the spread of neural progenitor cells derived from neurospheres (NPCdn), neonatal rat spinal cord cells (SCC) and NPCdn only attached and matured on PCL and PLLA surfaces. Scanning electron microscopy and computational analysis suggested that cells attached to the material's surface emerged into distinct morphological populations. Flow cytometry revealed a higher differentiation of neural progenitor cells derived from human induced pluripotent stem cells (hiPSC-NPC) into glial cells on all biomaterials. Immunofluorescence assays demonstrated that PCL and PLLA guided neuronal differentiation and network development in SCC. Our data emphasize the importance of selecting appropriate biomaterials for tissue engineering in SCI treatment.
Topics: Animals; Rats; Humans; Spinal Cord Regeneration; Biocompatible Materials; Tissue Engineering; Induced Pluripotent Stem Cells; Nerve Tissue; Spinal Cord Injuries
PubMed: 37686446
DOI: 10.3390/ijms241713642