Titanium Surface Synergy: Strontium Incorporation and Controlled Disorder Nanotopography Optimize Osteoinduction.

Osteoporotic fractures and arthritis represent a major socioeconomic health burden. Fragility fracture fixation and joint replacement are often undertaken using titanium (Ti) or Ti alloy implants. Ideally these should induce bone formation and reduce osteoclast formation.

Mesenchymal stem cell-derived extracellular vesicles may promote breast cancer cell dormancy.

Disseminated breast cancer cells have the capacity to metastasise to the bone marrow and reside in a dormant state within the mesenchymal stem cell niche. Research has focussed on paracrine signalling factors, such as soluble proteins, within the microenvironment. However, it is now clear extracellular vesicles secreted by resident mesenchymal stem cells into this microenvironment also play a key role in the initiation of dormancy.

Synthesis and cellular penetration properties of new phosphonium based cationic amphiphilic peptides.

A new category of phosphonium based cationic amphiphilic peptides has been developed and evaluated as potential antimicrobial peptides and cell penetrating peptides. The required building blocks were conveniently accessible from cysteine and could be applied in a solid phase peptide synthesis protocol for incorporation into peptide sequences. Evaluation of the antimicrobial properties and cellular toxicity of these phosphonium based peptides showed that these "soft" cationic side-chain containing peptides have poor antimicrobial properties and most of them were virtually non toxic (on HEK cells tested at 256 and 512 μM) and non-haemolytic (on horse erythrocytes tested at 512 μM), hinting at an interesting potential application as cell penetrating peptides.

Osteoblast response to disordered nanotopography.

The ability to influence stem cell differentiation is highly desirable as it would help us improve clinical outcomes for patients in various aspects. Many different techniques to achieve this have previously been investigated. This concise study, however, has focused on the topography on which cells grow.

Microtopographical cues promote peripheral nerve regeneration via transient mTORC2 activation.

Unlabelled: Despite microsurgical repair, recovery of function following peripheral nerve injury is slow and often incomplete. Outcomes could be improved by an increased understanding of the molecular biology of regeneration and by translation of experimental bioengineering strategies. Topographical cues have been shown to be powerful regulators of the rate and directionality of neurite regeneration, and in this study we investigated the downstream molecular effects of linear micropatterned structures in an organotypic explant model.

Bone and cartilage differentiation of a single stem cell population driven by material interface.

Adult stem cells, such as mesenchymal stem cells, are a multipotent cell source able to differentiate towards multiple cell types. While used widely in tissue engineering and biomaterials research, they present inherent donor variability and functionalities. In addition, their potential to form multiple tissues is rarely exploited.

Thermoresponsive Polymer Micropatterns Fabricated by Dip-Pen Nanolithography for a Highly Controllable Substrate with Potential Cellular Applications.

We report a novel approach for patterning thermoresponsive hydrogels based on N,N-diethylacrylamide (DEAAm) and bifunctional Jeffamine ED-600 by dip-pen nanolithography (DPN). The direct writing of micron-sized thermoresponsive polymer spots was achieved with efficient control over feature size. A Jeffamine-based ink prepared through the combination of organic polymers, such as DEAAm, in an inorganic silica network was used to print thermosensitive arrays on a thiol-silanized silicon oxide substrate.

Nanopit-induced osteoprogenitor cell differentiation: The effect of nanopit depth.

We aimed to assess osteogenesis in osteoprogenitor cells by nanopits and to assess optimal feature depth. Topographies of depth 80, 220 and 333 nm were embossed onto polycaprolactone discs. Bone marrow-derived mesenchymal stromal cells were seeded onto polycaprolactone discs, suspended in media and incubated.

Three-dimensional CaP/gelatin lattice scaffolds with integrated osteoinductive surface topographies for bone tissue engineering.

Surface topography is known to influence stem cells and has been widely used as physical stimuli to modulate cellular behaviour including adhesion, proliferation and differentiation on 2D surfaces. Integration of well-defined surface topography into three-dimensional (3D) scaffolds for tissue engineering would be useful to direct the cell fate for intended applications. Technical challenges are remaining as how to fabricate such 3D scaffolds with controlled surface topography from a range of biodegradable and biocompatible materials.

Elucidating the function of penetratin and a static magnetic field in cellular uptake of magnetic nanoparticles.

Nanotechnology plays an increasingly important role in the biomedical arena. In particular, magnetic nanoparticles (mNPs) have become important tools in molecular diagnostics, in vivo imaging and improved treatment of disease, with the ultimate aim of producing a more theranostic approach. Due to their small sizes, the nanoparticles can cross most of the biological barriers such as the blood vessels and the blood brain barrier, thus providing ubiquitous access to most tissues.

Osteogenic lineage restriction by osteoprogenitors cultured on nanometric grooved surfaces: the role of focal adhesion maturation.

The differentiation of progenitor cells is dependent on more than biochemical signalling. Topographical cues in natural bone extracellular matrix guide cellular differentiation through the formation of focal adhesions, contact guidance, cytoskeletal rearrangement and ultimately gene expression. Osteoarthritis and a number of bone disorders present as growing challenges for our society.

Cell interactions at the nanoscale: piezoelectric stimulation.

Nanometric movements of the substrate on which endothelial cells are growing, driven by periodic sinusoidal vibration from 1 Hz to 50 Hz applied by piezo actuators, upregulate endothelin-1 and Kruppel-like factor 2 expression, and increase cell adhesion. These movements are in the z (vertical) axis and ranges from 5 to 50 nm and are similar in vertical extent to protrusions from the cells themselves already reported in the literature. White noise vibrations do not to produce these effects.

Embossing of micropatterned ceramics and their cellular response.

The aim of this work is to investigate the use of microtopographies in providing physical cues to modulate the cellular response of human mesenchymal stem cells on ceramics. Two microgrooved patterns (100 μm/50 μm, 10 μm/10 μm groove/pitch) were transcribed reversely onto alumina green ceramic tapes via an embossing technique followed by sintering. Characterization of the micropatterned alumina surfaces and their cellular response was carried out.

The effect of static magnetic fields and tat peptides on cellular and nuclear uptake of magnetic nanoparticles.

Magnetic nanoparticles are widely used in bioapplications such as imaging (MRI), targeted delivery (drugs/genes) and cell transfection (magnetofection). Historically, the impermeable nature of both the plasma and nuclear membranes hinder potential. Researchers combat this by developing techniques to enhance cellular and nuclear uptake.