Simulation of acoustic fields in fluid-, solid- and porous layers by the combined transfer matrix/angular spectrum approach with applications in bioacoustics

Louw, Tobias M.; Jackson, T. L.; Subramanian, Anuradha; Viljoen, Hendrik J.

doi:10.1016/j.wavemoti.2015.02.007

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Media was replaced every 3 days, where only half of the media was supplemented with fresh media containing 10 ng/mL of IL1β. Automated cLIUS stimulation was applied using the bioreactor [23,29,30] developed and characterized at the University of Alabama in Huntsville (UAH) at the following regimen: 14 kPa (5.0 MHz, 2.5 Vpp), 10 min/application, and four applications/day. Hydrogels were retrieved at the end of 21 days and subjected to outcome analyses as listed in Figure 1.…”

Section: Mscs Culture In Hydrogels and Clius Treatmentmentioning

confidence: 99%

“…All cytokines were purchased from R&D systems (Minneapolis, MN, USA) and were employed at a concentration of 10 ng/mL. Non-focused immersion transducers (Panametrics V300, 12.7 mm diameters, Panametrix, Waltham, MA, USA) were used to apply cLIUS to plated MSCs using procedure detailed elsewhere [23,29,30]. MSCs were exposed to cytokines and cLIUS was applied one time for 10 or 20 min at 5 MHz (2.5 Vpp) with a constant pressure amplitude of 14 kPa.…”

Section: Mscs Culture In Monolayer and Clius Treatmentmentioning

confidence: 99%

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Continuous Low-Intensity Ultrasound Preserves Chondrogenesis of Mesenchymal Stromal Cells in the Presence of Cytokines by Inhibiting NFκB Activation

2022

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Proinflammatory joint environment, coupled with impeded chondrogenic differentiation of mesenchymal stromal cells (MSCs), led to inferior cartilage repair outcomes. Nuclear translocation of phosphorylated-NFκB downregulates SOX9 and hinders the chondrogenesis of MSCs. Strategies that minimize the deleterious effects of NFκB, while promoting MSC chondrogenesis, are of interest. This study establishes the ability of continuous low-intensity ultrasound (cLIUS) to preserve MSC chondrogenesis in a proinflammatory environment. MSCs were seeded in alginate:collagen hydrogels and cultured for 21 days in an ultrasound-assisted bioreactor (5.0 MHz, 2.5 Vpp; 4 applications/day) in the presence of IL1β and evaluated by qRT-PCR and immunofluorescence. The differential expression of markers associated with the NFκB pathway was assessed upon a single exposure of cLIUS and assayed by Western blotting, qRT-PCR, and immunofluorescence. Mitochondrial potential was evaluated by tetramethylrhodamine methyl ester (TMRM) assay. The chondroinductive potential of cLIUS was noted by the increased expression of SOX9 and COLII. cLIUS extended its chondroprotective effects by stabilizing the NFκB complex in the cytoplasm via engaging the IκBα feedback mechanism, thus preventing its nuclear translocation. cLIUS acted as a mitochondrial protective agent by restoring the mitochondrial potential and the mitochondrial mRNA expression in a proinflammatory environment. Altogether, our results demonstrated the potential of cLIUS for cartilage repair and regeneration under proinflammatory conditions.

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Section: Mscs Culture In Hydrogels and Clius Treatmentmentioning

confidence: 99%

Section: Mscs Culture In Monolayer and Clius Treatmentmentioning

confidence: 99%

Continuous Low-Intensity Ultrasound Preserves Chondrogenesis of Mesenchymal Stromal Cells in the Presence of Cytokines by Inhibiting NFκB Activation

2022

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“…For instance, pressure cannot be measured using a hydrophone at the dish surface where the cell layer is present in a 2D culture model or within a porous scaffold where cells will be distributed in a 3D culture model. A few previous studies have examined variability of the pressure field in the US bioreactor and evaluated effects of geometric features [9,10]. One limitation of these prior studies was that the acoustic pressure field was simulated only in the frequency domain (which assumes continuous waves) or only for a short period of time (over a few sine waves).…”

Section: Introductionmentioning

confidence: 99%

Analysis of a Novel Bioreactor Designed for Ultrasound Stimulation of Cell-Seeded Scaffolds

Crapps

Rahimi²,

Case³

2018

Preprint

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Although daily low intensity pulsed ultrasound (LIPUS) treatment has been shown to induce cellular responses supporting bone repair, in vitro studies in 3D models, such as cellseeded scaffolds, are needed to further investigate the underlying cellular mechanisms. This requires well-controlled conditions in an US bioreactor. Computational studies are needed to investigate various effects on US wave propagation influenced by bioreactor configurations, such as reflections at interfaces and wave interference, and optimize the bioreactor design for experimental repeatability. In this study, an enclosed cylindrical sample holder that contained an inner well for placement of a scaffold immersed in culture medium was fabricated by stereolithography 3D printing and combined with an acoustic absorbent material to eliminate the presence of an air-liquid interface perpendicular to the wave propagation path. Finite element simulations conducted in the frequency domain demonstrated that weak standing waves were present within the culture medium, indicating the effects of reflections at solidliquid interfaces within the sample holder, as expected. Focusing on the acoustic pressure at the inner well surface, it was found that the spatially-averaged pressure varied from a maximum to a minimum value as the thickness of the water layer beneath the sample holder was changed. Average pressure values at antinode positions were 2-fold higher than at node positions. A volumeaveraged pressure was calculated within the culture medium corresponding to the region where a scaffold would be centrally located within the bioreactor. It was shown that the thickness of the volume analyzed had a minimal effect on the calculated average pressure. Time-dependent simulations for one complete pulse (i.e. 1 ms) showed that the acoustic pressure in volumes that would be occupied by scaffolds of two different thicknesses (diameter of 8.5 mm and thicknesses of 0.2 or 2.0 mm) reached a stable value after 45 µs, and then remained at that value until the active period of the pulse ceased. Once the active period ended, the acoustic pressure rapidly decreased to a low baseline pressure. Overall, this study showed that the proposed novel bioreactor design provided a controlled environment for the US treatment of a cell-seeded scaffold by removing the air-liquid interface using a custom-designed sample holder and an acoustic absorbent material.

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Theoretical investigation on the underwater sound absorption of a functionally graded anechoic coating under the phased arc array incidence

Dong

Zhou

Chen

et al. 2023

Applied Mathematical Modelling

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Simulation of acoustic fields in fluid-, solid- and porous layers by the combined transfer matrix/angular spectrum approach with applications in bioacoustics

Cited by 5 publications

References 27 publications

Continuous Low-Intensity Ultrasound Preserves Chondrogenesis of Mesenchymal Stromal Cells in the Presence of Cytokines by Inhibiting NFκB Activation

Continuous Low-Intensity Ultrasound Preserves Chondrogenesis of Mesenchymal Stromal Cells in the Presence of Cytokines by Inhibiting NFκB Activation

Analysis of a Novel Bioreactor Designed for Ultrasound Stimulation of Cell-Seeded Scaffolds

Theoretical investigation on the underwater sound absorption of a functionally graded anechoic coating under the phased arc array incidence

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