Dynamic Responses of Human Skin and Fascia to an Innovative Stimulation Device-Shear Wave Stimulation.

Exposure to mechanical stimuli such as pressure and stretching prompts the skin to undergo physiological adaptations to accommodate and distribute applied forces, a process known as mechanotransduction. Mechanotherapy, which leverages mechanotransduction, shows significant promise across various medical disciplines. Traditional methods, such as massage and compression therapy, effectively promote skin healing by utilizing this mechanism, although they require direct skin contact.

Contactless mechanical stimulation of the skin using shear waves.

The skin, the outermost organ of the human body, is vital for sensing and responding to stimuli through mechanotransduction. It is constantly exposed to mechanical stress. Consequently, various mechanical therapies, including compression, massage, and microneedling, have become routine practices for skin healing and regeneration.

Key topographic parameters driving surface adhesion of Porphyromonas gingivalis.

Dental implant failure is primarily due to peri-implantitis, a consequence of bacterial biofilm formation. Bacterial adhesion is strongly linked to micro-/nano-topographies of a surface; thus an assessment of surface texture parameters is essential to understand bacterial adhesion. In this study, mirror polished titanium samples (Ti6Al4V) were irradiated with a femtosecond laser (fs-L) at a wavelength of 1030 nm (infrared) with variable laser parameters (laser beam polarization, number, spacing and organization of the impacts).

Polarization of Femtosecond Laser for Titanium Alloy Nanopatterning Influences Osteoblastic Differentiation.

Ultrashort pulse lasers have significant advantages over conventional continuous wave and long pulse lasers for the texturing of metallic surfaces, especially for nanoscale surface structure patterning. Furthermore, ultrafast laser beam polarization allows for the precise control of the spatial alignment of nanotextures imprinted on titanium-based implant surfaces. In this article, we report the biological effect of beam polarization on human mesenchymal stem cell differentiation.

Ultrafast Laser Processing of Nanostructured Patterns for the Control of Cell Adhesion and Migration on Titanium Alloy.

Femtosecond laser texturing is a promising surface functionalization technology to improve the integration and durability of dental and orthopedic implants. Four different surface topographies were obtained on titanium-6aluminum-4vanadium plates by varying laser processing parameters and strategies: surfaces presenting nanostructures such as laser-induced periodic surface structures (LIPSS) and 'spikes', associated or not with more complex multiscale geometries combining micro-pits, nanostructures and stretches of polished areas. After sterilization by heat treatment, LIPSS and spikes were characterized to be highly hydrophobic, whereas the original polished surfaces remained hydrophilic.

In vitro histomechanical effects of enzymatic degradation in carotid arteries during inflation tests with pulsatile loading.

In this paper, the objective is to assess the histomechanical effects of collagen proteolysis in arteries under loading conditions reproducing in vivo environment. Thirteen segments of common porcine carotid arteries (8 proximal and 5 distal) were immersed in a bath of bacterial collagenase and tested with a pulsatile tension/inflation machine. Diameter, pressure and axial load were monitored throughout the tests and used to derive the stress-stretch curves and to determine the secant circumferential stiffness.

Laser-Based Hybrid Manufacturing of Endosseous Implants: Optimized Titanium Surfaces for Enhancing Osteogenic Differentiation of Human Mesenchymal Stem Cells.

Additive manufacturing (AM) is becoming increasingly important in the orthopedic and dental sectors thanks to two major advantages: the possibility of custom manufacturing and the integration of complex structures. However, at smaller scales, surface conditions of AM products are not mastered. Numerous non-fused powder particles give rise to roughness values (Sa) greater than 10 μm, thus limiting biomedical applications since the surface roughness of, e.

Comparison of four methods of surface roughness assessment of corneal stromal bed after lamellar cutting.

Corneal lamellar cutting with a blade or femtosecond laser (FSL) is commonly used during refractive surgery and corneal grafts. Surface roughness of the cutting plane influences postoperative visual acuity but is difficult to assess reliably. For the first time, we compared chromatic confocal microscopy (CCM) with scanning electron microscopy, atomic force microscopy (AFM) and focus-variation microscopy (FVM) to characterize surfaces of variable roughness after FSL cutting.

Macrotopographic closure promotes tissue growth and osteogenesis in vitro.

Unlabelled: While the impact of substrate topographies at nano- and microscale on bone cell behavior has been particularly well documented, very few studies have analyzed the role of substrate closure at a tissular level. Moreover, these have focused on matrix deposition rather than on osteoblastic differentiation. In the present work, mouse calvaria cells were grown for 15days on hydroxyapatite (HA) ceramics textured with three different macrogrooves shapes (100µm): 1 sine and 2 triangle waveforms.

Femtosecond laser nano/micro patterning of titanium influences mesenchymal stem cell adhesion and commitment.

Surface improvement of implants is essential for achieving a fast osseo-integration. Technically, the creation of a precise pattern on a titanium alloy surface is challenging. Here, the femtosecond laser was chosen as an innovative technology for texturing with accuracy a nano-micro topography.

Multiscale grooved titanium processed with femtosecond laser influences mesenchymal stem cell morphology, adhesion, and matrix organization.

The femtosecond laser processing enabled the structuring of six types of surfaces on titanium-6aluminium-4vanadium (Ti-6Al-4V) plates. The obtained hierarchical features consisted of a combination of microgrooves and oriented nanostructures. By adjusting beam properties such as laser polarization, the width of the microgrooves (20 or 60 μm) and the orientation of the nanostructures (parallel or perpendicular to the microgrooves) can be precisely controlled.

Extracellular matrix produced by osteoblasts cultured under low-magnitude, high-frequency stimulation is favourable to osteogenic differentiation of mesenchymal stem cells.

The effects of low-magnitude, high-frequency (LMHF) mechanical stimulation on osteoblastic cells are poorly understood. We have developed a system that generates very small (15-40 με), high-frequency (400 Hz, sine) deformations on osteoblast cultures (MC3T3-E1). We investigated the effects of these LMHF stimulations mainly on extracellular matrix (ECM) synthesis.

The effect of dual frequency cyclic compression on matrix deposition by osteoblast-like cells grown in 3D scaffolds and on modulation of VEGF variant expression.

As a strategy to optimise osteointegration of biomaterials by inducing proper extracellular matrix synthesis, and specifically angiogenic growth factor production and storage, we tested the effects of cyclic mechanical compression on 3D cultures of human osteoblast-like cells. MG-63 cells were seeded into 3D porous hydroxyapatite ceramics under vacuum to enable a homogenous cellular distribution. A four-day culture period allowed cell proliferation throughout the scaffolds.