Biology subjects

Childs, P.

Publications and source records attributed to Childs, P..

5 recordsLinked to original sources

bioRxiv2026

Mechanical evolution of 3T3 fibroblastic cells exposed to nanovibrational stimulation

Cells are mechanosensitive, responding to external mechanical stimulation. Nanovibrational stimulation has been shown to enhance cell contractility and actin stress fibre formation. These changes in morphology occur quickly, alongside associated mechanical changes. Here, the relationship between acute morphological and mechanical changes in NIH 3T3 fibroblastic cells in response to nanovibrational stimulation is presented. A 1 kHz, 30 nm vibration is applied continuously for 72 hours. Atomic force microscopy (AFM) quantifies mechanical properties of the nucleus and cytoplasm at multiple timepoints, while immunofluorescence tracks morphological changes. Within 3 hours of stimulation, both nuclear and cytoplasmic stiffness increase significantly, accompanied by a decrease in the cellular fluid exponent, suggesting a shift of the cell towards more solid-like behaviour. These changes correlate with increased nuclear area. Actin polymerisation also increases within 24 hours, although variably. To understand the role of the cytoskeleton, actin polymerisation and contraction are inhibited using cytochalasin D and blebbistatin. Results show that inhibition prevents stiffness increases and results in a higher fluid exponent, indicating a more fluid-like state. These findings demonstrate that actin-myosin dynamics mediate cell stiffening under nanovibrational stimulation. Interestingly, prolonged stimulation appears to reverse this effect, suggesting that temporal optimisation of stimulation may enhance long-term mechanotransducive responses.

cell biology↗

bioRxiv2025

Nanovibrational stimulation of osteogenesis engages non-canonical Wnt signalling and NF-κB regulator BCL3 as a mechanotransducer

Enhancing osteogenesis in mesenchymal stromal (stem) cells is essential for advancing cellular therapies that target and alleviate skeletal pathologies. By employing a bespoke bioreactor capable of delivering nano-amplitude vibration (30 nm, 1kHz) to human adipose-derived mesenchymal stromal cells, we observed osteo-specific differentiation. We related this to the mechanotransductive mechanism by showing that inhibition of intracellular tension results in the loss of cytoskeletal organisation and myosin activation driven by nanovibration. Further, we dissect the mechanism of osteogenesis using a panel of Wnt agonists and antagonists and highlight the role of non-canonical Wnt. Then, using Bcl3-/- cells and by stimulating with BCL3 peptide, we show that non-canonical Wnt, osteogenesis-related inflammation and osteogenesis itself are all regulated by BCL3. This is important as nanoscale direct cell-stimulation is gaining interest, and there is an emerging consensus that such signals can be osteogenic. While prior research has only broadly hinted at how nanovibrational signals convert to an osteogenic phenotype, this new work pinpoints critical mechanistic insights, thereby advancing our understanding of this promising avenue in musculoskeletal cell therapy.

bioengineering↗

bioRxiv2020

PEA polymer-coated nanotopography delivers solid-state BMP2, enhances mesenchymal stem cell adhesion, prevents bacterial biofilm formation and protects cells from quorum sensing virulence factors

Post-operative infection is a major complication in patients recovering from orthopaedic surgery. As such, there is a clinical need to develop biomaterials for use in regenerative surgery that can promote mesenchymal stem cell (MSC) osteospecific differentiation and that can prevent infection caused by biofilm-forming pathogens. Nanotopographical approaches to pathogen control are being identified, including in orthopaedic materials such as titanium and its alloys. These topographies use high aspect ratio nanospikes or nanowires to prevent bacterial adhesion but these features puncture adhering cells, thus also reducing MSC adhesion. Here, we use a poly(ethyl acrylate) (PEA) polymer coating on titanium nanowires to spontaneously organise fibronectin (FN) and to deliver bone morphogenetic protein 2 (BMP2) to enhance MSC adhesion and osteospecific signalling. This nanotopography when combined with the PEA coating enhanced osteogenesis and reduced adhesion of Pseudomonas aeruginosa in culture. Using a novel MSC-Pseudomonas aeruginosa co-culture, we also show that the coated nanotopographies protect MSCs from cytotoxic quorum sensing and signalling molecules. We conclude that the PEA polymer-coated nanotopography can both support MSCs and prevent pathogens from adhering to a biomaterial surface, thus protecting from biofilm formation and bacterial infection and supporting osteogenic repair.

bioengineering↗

bioRxiv2020

Nanovibrational stimulation of mesenchymal stem cells induces therapeutic reactive oxygen species and inflammation for 3D bone tissue engineering

There is a pressing clinical need to develop cell-based bone therapies due to a lack of viable, autologous bone grafts and a growing demand for bone grafts in musculoskeletal surgery. Such therapies can be tissue engineered and cellular, such as osteoblasts combined with a material scaffold. Because mesenchymal stem cells (MSCs) are both available and fast growing compared to mature osteoblasts, therapies that utilise these progenitor cells are particularly promising. We have developed a nanovibrational bioreactor that can convert MSCs into bone-forming osteoblasts in 2D and 3D but the mechanisms involved in this osteoinduction process remain unclear. Here, to elucidate this mechanism, we use increasing vibrational amplitude, from 30 nm (N30) to 90 nm (N90) amplitudes at 1000 Hz, and assess MSC metabolite, gene and protein changes. These approaches reveal that dose-dependent changes occur in MSCs responses to increased vibrational amplitude, particularly in adhesion and mechanosensitive ion channel expression, and that energetic metabolic pathways are activated, leading to low-level reactive oxygen species (ROS) production and to low-level inflammation, as well as to ROS- and inflammation-balancing pathways. These events are analogous to those that occur in the natural bone-healing processes. We have also developed a tissue engineered MSC-laden scaffold designed using cells mechanical memory, driven by the stronger N90 stimulation. These new mechanistic insights and cell-scaffold design are underpinned by a process that is free of inductive chemicals.

bioengineering↗

bioRxiv2020

The use of nanovibration to discover specific and potent bioactive metabolites that stimulate osteogenic differentiation in mesenchymal stem cells

Bioactive metabolites have wide-ranging biological activities and are a potential source of future research and therapeutic tools. Here, we use nanovibrational stimulation to induce the osteogenic differentiation of MSCs, in the absence of off-target differentiation. We show that this differentiation method, which does not rely on the addition of exogenous growth factors to the culture media, provides an artefact-free approach to identifying bioactive metabolites that specifically and potently induce osteogenesis. We first identify a highly specific metabolite as the endogenous steroid, cholesterol sulphate. Next, a screen of other small molecules with a similar steroid scaffold identified fludrocortisone acetate as being both specific and having highly potent osteogenic-inducing activity. These findings demonstrate that physical priciples can be used to identify bioactive metabolites and then metabolite potency can be optimised by examining structure-function relationship.

bioengineering↗