Polyvinyl alcohol (PVA) hydrogels are synthetic polymers which can be used as scaffolds for tissue engineering due to their biocompatibility and large water content. To improve their biodegradation properties, partial oxidation of PVA is achieved by means of different oxidizing agents, such as potassium permanganate, bromine and iodine. The effect of this process on hydrogels mechanical performance has not been fully investigated in view of tissue engineering applications. In this work, the time-dependent mechanical behavior of unmodified and partially oxidized PVA hydrogels is evaluated by means of uniaxial tensile and stress relaxation tests, to evaluate the effect of different oxidizing agents on the viscoelastic response. Tensile tests show an isotropic and almost-incompressible behavior, with a stiffness reduction after PVA oxidation. The time-dependent response of oxidized PVA is comparable to the one of unmodified PVA and is modeled as a quasi-linear viscoelastic behavior. Finite Element (FE) models of PVA samples are developed and numerical analyses are used to evaluate the effect of different strain rates on the mechanical response under uniaxial tension. This model can be exploited to predict the time-dependent mechanical behavior of partially oxidized PVA in tissue engineering application under tensile loading.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104966 | DOI Listing |
Connect Tissue Res
January 2025
Graduate School of Engineering, Kogakuin University, Hachioji, Tokyo, Japan.
Objective: This study aimed to investigate the collagen fiber structure of the subcutaneous fascia, a connective tissue layer between the skin and epimysium.
Methods: Fascia samples with varying extensibility were examined using biochemical and microscopic methods.
Results: Loose fascia, the more extensible type, displayed sparsely distributed collagen fibers, while dense fascia showed tightly packed collagen fiber bundles.
Nat Comput Sci
January 2025
Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
How complex phenotypes emerge from intricate gene expression patterns is a fundamental question in biology. Integrating high-content genotyping approaches such as single-cell RNA sequencing and advanced learning methods such as language models offers an opportunity for dissecting this complex relationship. Here we present a computational integrated genetics framework designed to analyze and interpret the high-dimensional landscape of genotypes and their associated phenotypes simultaneously.
View Article and Find Full Text PDFJ Prosthodont
January 2025
Prosthodontist, Implant Dentistry Associates of Arlington, Arlington, Texas, USA.
Purpose: The purpose of this study was to analyze gingival fibroblast proliferation on additively manufactured polymethylmethacrylate (PMMA) groups with different surface characteristics namely no treatment group (NTG) and customized 250 µm diameter porosity (AM-250G) group.
Materials And Methods: 3D-printed NTG was compared for its influence on growth of cells to a additively manufactured surface with porosity (AM-250G). For each group (NTG, AM-250G) 20 samples of material were tested.
Sci Rep
January 2025
Department of Occupational Pneumology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka, 807-8555, Japan.
Polyacrylic acid (PAA) with different concentrations of cross-linker was instilled into the trachea of rats to examine the effect of PAA crosslink density on lung disorders. Methods: F344 rats were intratracheally exposed to low and high doses of PAA with cross-linker concentrations of 0.1, 1.
View Article and Find Full Text PDFNat Commun
January 2025
Key Laboratory of Bioactive Materials for the Ministry of Education, College of Life Sciences, State Key Laboratory of Medicinal Chemical Biology, and Frontier of Science Center for Cell Response, Nankai University, Tianjin, 300071, China.
Nanozymes play a pivotal role in mitigating excessive oxidative stress, however, determining their specific enzyme-mimicking activities for intracellular free radical scavenging is challenging due to endo-lysosomal entrapment. In this study, we employ a genetic engineering strategy to generate ionizable ferritin nanocages (iFTn), enabling their escape from endo-lysosomes and entry into the cytoplasm. Specifically, ionizable repeated Histidine-Histidine-Glutamic acid (9HE) sequences are genetically incorporated into the outer surface of human heavy chain FTn, followed by the assembly of various chain-like nanostructures via a two-armed polyethylene glycol (PEG).
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