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International Dental Journal Feb 2023The term bioactivity is being increasingly used in medicine and dentistry. Due to its positive connotation, it is frequently utilised for advertising dental restorative... (Review)
Review
The term bioactivity is being increasingly used in medicine and dentistry. Due to its positive connotation, it is frequently utilised for advertising dental restorative materials. However, there is confusion about what the term means, and concerns have been raised about its potential overuse. Therefore, FDI decided to publish a Policy Statement about the bioactivity of dental restorative materials to clarify the term and provide some caveats for its use in advertising. Background information for this Policy Statement was taken from the current literature, mainly from the PubMed database and the internet. Bioactive restorative materials should have beneficial/desired effects. These effects should be local, intended, and nontoxic and should not interfere with a material's principal purpose, namely dental tissue replacement. Three mechanisms for the bioactivity of such materials have been identified: purely biological, mixed biological/chemical, or strictly chemical. Therefore, when the term bioactivity is used in an advertisement or in a description of a dental restorative material, scientific evidence (in vitro or in situ, and preferably in clinical studies) should be provided describing the mechanism of action, the duration of the effect (especially for materials releasing antibacterial substances), and the lack of significant adverse biological side effects (including the development and spread of antimicrobial resistance). Finally, it should be documented that the prime purpose, for instance, to be used to rebuild the form and function of lost tooth substance or lost teeth, is not impaired, as demonstrated by data from in vitro and clinical studies. The use of the term bioactive dental restorative material in material advertisement/information should be restricted to materials that fulfil all the requirements as described in the FDI Policy Statement.
Topics: Humans; Dental Restoration, Permanent; Dental Caries; Policy; Dental Materials; Composite Resins
PubMed: 36577639
DOI: 10.1016/j.identj.2022.11.012 -
Journal of the Mechanical Behavior of... Sep 2022Numerical simulations are a valuable tool in the field of tissue engineering for cartilage repair and can help to understand which mechanical properties affect the...
Numerical simulations are a valuable tool in the field of tissue engineering for cartilage repair and can help to understand which mechanical properties affect the behavior of chondrocytes and contribute to the success or failure of surrogate materials as implants. However, special attention needs to be paid when identifying corresponding material parameters in order to provide reliable numerical predictions of the material's response. In this study, we identify hyperelastic material parameters for numerical simulations in COMSOL Multiphysics® v. 5.6 for human articular cartilage and two surrogate materials, commercially available ChondroFiller, and oxidized alginate-gelatin (ADA-GEL) hydrogels. We consider several hyperelastic isotropic material models and provide separate parameter sets for the unconditioned and the conditioned material response, respectively, based on previously generated experimental data including both compression and tension experiments. We compare a direct parameter identification approach assuming homogeneous deformation throughout the specimen and an inverse approach, where the experiments are simulated using a finite element model with realistic boundary conditions in COMSOL Multiphysics® v. 5.6. We demonstrate that it is important to consider both compression and tension data simultaneously and to use the inverse approach to obtain reliable parameters. The one-term Ogden model best represents the unconditioned response of cartilage, while the conditioned response of cartilage and ADA-GEL is equally well represented by the two-term Ogden and five-term Mooney-Rivlin models. The five-term Mooney-Rivlin model is also most suitable to model the unconditioned response of ADA-GEL. For ChondroFiller, we suggest using the five-term Mooney-Rivlin or two-term Ogden model for the unconditioned and the two-term Ogden model for the conditioned material response. These results will help to choose appropriate material models and parameters for simulations of whole joints or to advance mechanical-stimulation assisted cartilage tissue engineering in the future.
Topics: Cartilage, Articular; Chondrocytes; Elasticity; Finite Element Analysis; Gelatin; Humans; Hydrogels; Stress, Mechanical; Tissue Engineering
PubMed: 35689988
DOI: 10.1016/j.jmbbm.2022.105292 -
Preparation and Performance of Water-Active Polyurethane Grouting Material in Engineering: A Review.Polymers Nov 2022Polyurethane foam materials have broad application prospects in practical engineering as flame retardants, waterproof coatings, and grout repair materials due to... (Review)
Review
Polyurethane foam materials have broad application prospects in practical engineering as flame retardants, waterproof coatings, and grout repair materials due to advantages such as light weight, quick forming, and good durability. Due to water's low cost and convenience, water-reactive Polyurethane foam materials are widely used in engineering. The content of the water has a significant effect on the performance of polyurethane foams after molding. Polyurethane foams with anti-seepage and reinforcement effects are used in complex water environments for long durations. This study analyzed the effects of water content on properties and the diffusion mechanism of polyurethane foam materials in water. Additionally, the effect of the water environment on the polyurethane grouting material's properties was summarized. Finally, this study discussed the future research directions of polyurethane foam materials in a water environment.
PubMed: 36501494
DOI: 10.3390/polym14235099 -
Frontiers in Bioengineering and... 2022After bone defects reach a certain size, the body can no longer repair them. Tantalum, including its porous form, has attracted increasing attention due to good... (Review)
Review
After bone defects reach a certain size, the body can no longer repair them. Tantalum, including its porous form, has attracted increasing attention due to good bioactivity, biocompatibility, and biomechanical properties. After a metal material is implanted into the body as a medical intervention, a series of interactions occurs between the material's surface and the microenvironment. The interaction between cells and the surface of the implant mainly depends on the surface morphology and chemical composition of the implant's surface. In this context, appropriate modification of the surface of tantalum can guide the biological behavior of cells, promote the potential of materials, and facilitate bone integration. Substantial progress has been made in tantalum surface modification technologies, especially nano-modification technology. This paper systematically reviews the progress in research on tantalum surface modification for the first time, including physicochemical properties, biological performance, and surface modification technologies of tantalum and porous tantalum.
PubMed: 36177183
DOI: 10.3389/fbioe.2022.983695 -
Analytical and Bioanalytical Chemistry Jan 2022Urinary tract infections (UTIs) make up a significant proportion of the global burden of disease in vulnerable groups and tend to substantially impair the quality of... (Review)
Review
Urinary tract infections (UTIs) make up a significant proportion of the global burden of disease in vulnerable groups and tend to substantially impair the quality of life of those affected, making timely detection of UTIs a priority for public health. However, economic and societal barriers drastically reduce accessibility of traditional lab-based testing methods for critical patient groups in low-resource areas, negatively affecting their overall healthcare outcomes. As a result, cellulose-based materials such as paper and thread have garnered significant interest among researchers as substrates for so-called frugal analytical devices which leverage the material's portability and adaptability for facile and reproducible diagnoses of UTIs. Although the field may be only in its infancy, strategies aimed at commercial penetration can appreciably increase access to more healthcare options for at-risk people. In this review, we catalogue recent advances in devices that use cellulose-based materials as the primary housing or medium for UTI detection and chart out trends in the field. We also explore different modalities employed for detection, with particular emphasis on their ability to be ported onto discreet casings such as sanitary products.
Topics: Bacteria; Cellulose; Colorimetry; Culture Media; Electrochemical Techniques; Fungi; Humans; Lab-On-A-Chip Devices; Menstrual Hygiene Products; Paper; Urinary Tract Infections
PubMed: 34668042
DOI: 10.1007/s00216-021-03671-3 -
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 -
Additively manufactured unimorph dielectric elastomer actuators: Design, materials, and fabrication.Frontiers in Robotics and AI 2022Dielectric elastomer actuator (DEA) is a smart material that holds promise for soft robotics due to the material's intrinsic softness, high energy density, fast...
Dielectric elastomer actuator (DEA) is a smart material that holds promise for soft robotics due to the material's intrinsic softness, high energy density, fast response, and reversible electromechanical characteristics. Like for most soft robotics materials, additive manufacturing (AM) can significantly benefit DEAs and is mainly applied to the unimorph DEA (UDEA) configuration. While major aspects of UDEA modeling are known, 3D printed UDEAs are subject to specific material and geometrical limitations due to the AM process and require a more thorough analysis of their design and performance. Furthermore, a figure of merit (FOM) is an analytical tool that is frequently used for planar DEA design optimization and material selection but is not yet derived for UDEA. Thus, the objective of the paper is modeling of 3D printed UDEAs, analyzing the effects of their design features on the actuation performance, and deriving FOMs for UDEAs. As a result, the derived analytical model demonstrates dependence of actuation performance on various design parameters typical for 3D printed DEAs, provides a new optimum thickness to Young's modulus ratio of UDEA layers when designing a 3D printed DEA with fixed dielectric elastomer layer thickness, and serves as a base for UDEAs' FOMs. The FOMs have various degrees of complexity depending on considered UDEA design features. The model was numerically verified and experimentally validated through the actuation of a 3D printed UDEA. The fabricated and tested UDEA design was optimized geometrically by controlling the thickness of each layer and from the material perspective by mixing commercially available silicones in non-standard ratios for the passive and dielectric layers. Finally, the prepared non-standard mix ratios of the silicones were characterized for their viscosity dynamics during curing at various conditions to investigate the silicones' manufacturability through AM.
PubMed: 36591410
DOI: 10.3389/frobt.2022.1034914 -
Polymers Feb 2021Biopolymers have gained tremendous attention in many daily life applications, including medical applications, in the past few years. Obstetrics and gynecology are two... (Review)
Review
Biopolymers have gained tremendous attention in many daily life applications, including medical applications, in the past few years. Obstetrics and gynecology are two fields dealing with sensitive parts of the woman's body and her newborn baby, which are normally associated with many issues such as toxicity, infections, and even gene alterations. Medical professions that use screening, examination, pre, and post-operation materials should benefit from a better understanding of each type of material's characteristics, health, and even environmental effects. The underlying principles of biopolymer-based materials for different obstetric and gynecologic applications may discover various advantages and benefits of using such materials. This review presents the health impact of conventional polymer-based materials on pregnant women's health and highlights the potential use of biopolymers as a safer option. The recent works on utilizing different biopolymer-based materials in obstetric and gynecologic are presented in this review, which includes suture materials in obstetric and gynecologic surgeries, cosmetic and personal care products, vaginal health, and drug delivery; as well as a wound dressing and healing materials. This review highlights the main issues and challenges of biopolymers in obstetric and gynecologic applications.
PubMed: 33672526
DOI: 10.3390/polym13040633 -
PloS One 2023A new type of paste filling material was created using fluorogypsum, a byproduct of hydrofluoric acid, as the raw material to address the issue of the filling material's...
A new type of paste filling material was created using fluorogypsum, a byproduct of hydrofluoric acid, as the raw material to address the issue of the filling material's high cost. The effects of five factors, including gangue, fly ash, fluorogypsum, lime content, and mass concentration on the physical and mechanical properties of filling material were also examined. In addition to analyzing slump and extension changes, the filler's mineral composition and microstructure were examined using SEM and XRD examinations. The results show that the best ratio of the developed filling material was 1000g coal gangue, 300g fly ash, 300g fluorogypsum, and 50g lime and mass concentration is 78%, and its compressive strength can reach 4-5MPa at 28 days. Raw materials such as gangue and fly ash will have a certain influence on the mechanical properties of the filling material. The hydration products of the developed filling material prepared by XRD and SEM were ettringite, calcium sulfate dihydrate, and calcium silicate hydrate gel. The new fluorogypsum-based paste filling material can be used to consolidate loose rock strata and fill goaf. It solves the problem of disposal of industrial waste fluoropgypsum and also solves the problem of coal mine gangue stacking, which has a far-reaching influence on ecological environment management.
Topics: Coal Ash; Oxides; Calcium Sulfate; Dental Materials; Coal
PubMed: 37289761
DOI: 10.1371/journal.pone.0286872 -
Advanced Science (Weinheim,... Jun 2022Engineered living materials (ELMs) are a new class of materials in which living organism incorporated into diffusive matrices uptake a fundamental role in material's...
Engineered living materials (ELMs) are a new class of materials in which living organism incorporated into diffusive matrices uptake a fundamental role in material's composition and function. Understanding how the spatial confinement in 3D can regulate the behavior of the embedded cells is crucial to design and predict ELM's function, minimize their environmental impact and facilitate their translation into applied materials. This study investigates the growth and metabolic activity of bacteria within an associative hydrogel network (Pluronic-based) with mechanical properties that can be tuned by introducing a variable degree of acrylate crosslinks. Individual bacteria distributed in the hydrogel matrix at low density form functional colonies whose size is controlled by the extent of permanent crosslinks. With increasing stiffness and elastic response to deformation of the matrix, a decrease in colony volumes and an increase in their sphericity are observed. Protein production follows a different pattern with higher production yields occurring in networks with intermediate permanent crosslinking degrees. These results demonstrate that matrix design can be used to control and regulate the composition and function of ELMs containing microorganisms. Interestingly, design parameters for matrices to regulate bacteria behavior show similarities to those elucidated for 3D culture of mammalian cells.
Topics: Animals; Bacteria; Hydrogels; Mammals
PubMed: 35404519
DOI: 10.1002/advs.202106026