Engineered PDMS microtopography: Precision regulation of tendon stem cell behavior for tendon regeneration.

Microtopography critically regulates tendon stem cell (TSC) migration for repair, yet its precise roles remain unclear. We engineered polydimethylsiloxane (PDMS) scaffolds with precisely defined micron-scale pits and columns (diameters 7-21 μm, spacings 13-47 μm) via ultraviolet lithography and etching. High-throughput screening to promote TSC viability identified six optimal topographies: three pit-based topographies (diameters/spacings: 7 μm/47 μm, 11 μm/18 μm, 21 μm/26 μm) and three column-based topographies (diameters/spacings: 8 μm/14 μm, 13 μm/13 μm, 18 μm/18 μm).

In vitro regulation of collective cell migration: Understanding the role of physical and chemical microenvironments.

Collective cell migration is the primary mode of cellular movement during embryonic morphogenesis, tissue repair and regeneration, and cancer invasion. Distinct from single-cell migration, collective cell migration involves complex intercellular signaling cascades and force transmission. Consequently, cell collectives exhibit intricate and diverse migration patterns under the influence of the microenvironment in vivo.

Promising application of pulsed electromagnetic fields on tissue repair and regeneration.

Tissue repair and regeneration is a vital biological process in organisms, which is influenced by various internal mechanisms and microenvironments. Pulsed electromagnetic fields (PEMFs) are becoming a potential medical technology due to its advantages of effectiveness and non-invasiveness. Numerous studies have demonstrated that PEMFs can stimulate stem cell proliferation and differentiation, regulate inflammatory reactions, accelerate wound healing, which is of great significance for tissue regeneration and repair, providing a solid basis for enlarging its clinical application.

Regulation of Tendon Stem Cell Behavior by Designed Nanoporous Topography of Microfibers.

Nano scale topography scaffold is more bioactive and biomimetic than smooth fiber topographies. Tendon stem cells (TSCs) play important roles in the tendinogenesis of tendon tissue engineering, but the effects and mechanisms of nano topography on TSC behavior are still unclear. This study determined whether the morphology, proliferation, cytoskeleton, and differentiation of TSCs are affected by topography of scaffold in vitro.

The regulation of tendon stem cell distribution, morphology, and gene expression by the modulus of microfibers.

The mechanical properties of a stem cell culture substrate significantly impact cell adhesion, survival, migration, proliferation, and differentiation in vitro. A major challenge in engineering artificial stem cell substrate is to properly identify the relevant physical features of native stem cell niches, which are likely different for each stem cell type. The behavior of tendon stem cells has potentially significant implications for tendon repair.

A study of degradation behaviour and biocompatibility of Zn-Fe alloy prepared by electrodeposition.

Zinc is a biodegradable metal, which exhibits more moderate biodegradability than magnesium and iron, so that it has great application potential in the field of biomedical materials. Alloying of zinc and iron may lead to producing a new type of implant material Zn-Fe alloy, which might be able to meet the requirements for a moderate degradation rate. However, due to the huge difference in the melting point between zinc and iron, the preparation of Zn-Fe alloy is quite challenging and hence rarely reported.

Erratum to "The Possibility of Changing the Wettability of Material Surface by Adjusting Gravity".

[This corrects the article DOI: 10.34133/2020/2640834.].

The Possibility of Changing the Wettability of Material Surface by Adjusting Gravity.

The contact angle, as a vital measured parameter of wettability of material surface, has long been in dispute whether it is affected by gravity. Herein, we measured the advancing and receding contact angles on extremely low contact angle hysteresis surfaces under different gravities (1-8G) and found that both of them decrease with the increase of the gravity. The underlying mechanism is revealed to be the contact angle hysteresis and the deformation of the liquid-vapor interface away from the solid surface caused by gradient distribution of the hydrostatic pressure.

A Novel Approach to Accumulate Superparamagnetic Particles in Aqueous Environment Using Time-Varying Magnetic Field.

Objective: Magnetic drug targeting (MDT) has attracted a lot of attention in recent years as a treatment to reduce side effects and improve efficacy. To realize successful MDT, a magnet system that can create suitable magnetic field is necessary. However, the existing technology has some shortcomings such as low targeting efficiency and unsatisfactory targeting effect.

A periodic magnetic field as a special environment for scientific research created by rotating permanent magnet pairs.

A magnetic field is an often-encountered physical environment that can affect many processes, including chemical, physical, and biochemical processes. Utilization of magnetic fields is thus very helpful in a wide variety of applications, such as scientific research in various disciplines, materials processing (e.g.

Electrospun Heparin-Loaded Core-Shell Nanofiber Sutures for Achilles Tendon Regeneration In Vivo.

Achilles tendon reconstruction surgery is the primary clinical method for repairing acute Achilles tendon ruptures. However, the efficacy of the postoperative healing process and the recovery of physiological function are inadequate. This study examines the healing mechanism of ruptured rat Achilles tendons seamed with heparin-loaded core-shell fiber sutures fabricated via near-field electrospinning.

A novel layer-structured scaffold with large pore sizes suitable for 3D cell culture prepared by near-field electrospinning.

Electrospinning is a powerful method for preparing porous materials that can be applied as biomedical materials for implantation or tissue engineering or as scaffolds for 3D cell culture experiments. However, this technique is limited in practical applications because the pore size of 3D scaffolds directly prepared by conventional electrospinning is usually less than several tens of micrometres, which may not be suitable for 3D cell culture and tissue growth. To allow for satisfactory 3D cell culture and tissue engineering, the pore size of the scaffold should be controllable according to the requirement of the specific cells to be cultured.

Silk fibroin/chitosan thin film promotes osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells.

As a biodegradable polymer thin film, silk fibroin/chitosan composite film overcomes the defects of pure silk fibroin and chitosan films, respectively, and shows remarkable biocompatibility, appropriate hydrophilicity and mechanical properties. Silk fibroin/chitosan thin film can be used not only as metal implant coating for bone injury repair, but also as tissue engineering scaffold for skin, cornea, adipose, and other soft tissue injury repair. However, the biocompatibility of silk fibroin/chitosan thin film for mesenchymal stem cells, a kind of important seed cell of tissue engineering and regenerative medicine, is rarely reported.

From 2D to 3D: The morphology, proliferation and differentiation of MC3T3-E1 on silk fibroin/chitosan matrices.

It has been widely accepted that cell culture in two-dimensional (2D) conditions may not be able to represent growth in three-dimensional (3D) conditions. Systematic comparisons between 2D and 3D cell cultures are needed to appropriately use the existing 2D results. In this work, we conducted a comparative study between 2D and 3D cell cultures of MC3T3-E1 using the same type of material (a mixture of silk fibroin (SF) and chitosan (CS)).

Silk fibroin/chitosan scaffold with tunable properties and low inflammatory response assists the differentiation of bone marrow mesenchymal stem cells.

The physical and chemical properties of the scaffold are known to play important roles in three-dimensional (3D) cell culture, which always determine the cellular fate or the results of implantation. To control these properties becomes necessary for meeting the requirements of a variety of tissue engineering applications. In this study, a series of silk fibroin/chitosan (SF/CS) scaffolds with tunable properties were prepared using freeze-drying method, and the rat bone marrow-derived mesenchymal stem cells (BM-MSCs) were seeded in these scaffolds to evaluate their availability of use in tissue engineering.

A novel rotating experimental platform in a superconducting magnet.

This paper introduces a novel platform designed to be used in a strong static magnetic field (in a superconducting magnet). The platform is a sample holder that rotates in the strong magnetic field. Any samples placed in the platform will rotate due to the rotation of the sample holder.

The preparation, characterization, and pharmacokinetic studies of chitosan nanoparticles loaded with paclitaxel/dimethyl-β-cyclodextrin inclusion complexes.

A novel biocompatible and biodegradable drug-delivery nanoparticle (NP) has been developed to minimize the severe side effects of the poorly water-soluble anticancer drug paclitaxel (PTX) for clinical use. PTX was loaded into the hydrophobic cavity of a hydrophilic cyclodextrin derivative, heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD), using an aqueous solution-stirring method followed by lyophilization. The resulting PTX/DM-β-CD inclusion complex dramatically enhanced the solubility of PTX in water and was directly incorporated into chitosan (CS) to form NPs (with a size of 323.

HAp/Ti2Ni coatings of high bonding strength on Ti-6Al-4V prepared by the eutectic melting bonding method.

Eutectic melting bonding (EMB) method is a useful technique for fabricating bioactive coatings with relatively high crystallinity and bonding strength with substrate on titanium substrates. Using the EMB method, hydroxyapatite/Ti2Ni coatings were prepared on the surface of Ti-6Al-4V at a relatively low temperature (1,050 °C) in a vacuum furnace. The coatings were then characterized in terms of phase components, microstructure, bonding strength and cytotoxicity.

Correlation between protein sequence similarity and x-ray diffraction quality in the protein data bank.

As the most widely utilized technique to determine the 3-dimensional structure of protein molecules, X-ray crystallography can provide structure of the highest resolution among the developed techniques. The resolution obtained via X-ray crystallography is known to be influenced by many factors, such as the crystal quality, diffraction techniques, and X-ray sources, etc. In this paper, the authors found that the protein sequence could also be one of the factors.