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Silane modification has been proposed as a powerful biomaterial surface modification tool. This is the first comprehensive investigation into the effect of silane chain length on the resultant properties of -NH silane monolayers and the associated osteoinductive properties of the surface. A range of -NH presenting silanes, chain length 3-11, were introduced to glass coverslips and characterized using water contact angles, atomic force microscopy, X-ray photoelectron spectroscopy, and Ninhydrin assays. The ability of the variation in chain length to form a homogenous layer across the entirety of the surfaces was also assessed. The osteoinductive potential of the resultant surfaces was evaluated by real-time polymerase chain reaction, immunocytochemistry, and von Kossa staining. Control of surface chemistry and topography was directly associated with changes in chain length. This resulted in the identification of a specific, chain length 11 (CL11) which significantly increased the osteoinductive properties of the modified materials. Only CL11 surfaces had a highly regular nano-topography/roughness which resulted in the formation of an appetite-like layer on the surface that induced a significantly enhanced osteoinductive response (increased expression of osteocalcin, CBFA1, sclerostin, and the production of a calcified matrix) across the entirety of the surface. © 2018 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1862-1877, 2018.

Optimising cell/tissue constructs so that they can be successfully accepted and integrated within a host body is essential in modern tissue engineering. To do this, adult stem cells are frequently utilised, but there are many aspects of their environment in vivo that are not completely understood. There is evidence to suggest that circadian rhythms and daily circadian temporal cues have substantial effects on stem cell activation, cell cycle, and differentiation. It was hypothesised that the circadian rhythm in human adult stem cells differs depending on the source of tissue and that different entraining signals exert differential effects depending on the anatomical source. Dexamethasone and rhythmic mechanical stretch were used to synchronise stem cells derived from the bone marrow, tooth dental pulp, and abdominal subcutaneous adipose tissue, and it was experimentally evidenced that these different stem cells differed in their circadian clock properties in response to different synchronisation mechanisms. The more primitive dental pulp-derived stem cells did not respond as well to the chemical synchronisation but showed temporal clock gene oscillations following rhythmic mechanical stretch, suggesting that incorporating temporal circadian information of different human adult stem cells will have profound implications in optimising tissue engineering approaches and stem cell therapies.

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Accelerating the integration of a joint replacement or the healing of a bone fracture, particularly a complicated non-union fracture, would improve patient welfare and decrease healthcare costs. Currently, an autologous bone graft is the gold standard method for the treatment of complicated non-union fractures, but it is not always possible to harvest such a graft. A proactive highly inductive so-called smart material approach is pertinent in these cases. In this study, the surface chemistry of a previously approved material with desirable bulk material properties was modified to investigate its potential as an economical and effective alternative. The objective was to create stable synthetic chemical coatings that could guide cells along the osteogenic lineage required to generate mineralised tissue that would induce and accelerate bone healing. Primary human osteoblast-like cells were cultured in vitro for 7, 14 and 28 days on amine-terminated (chain length in the range 3–11) silane-modified glass surfaces with controlled nanotopography, to determine how surface chemistry and nanotopography change osteoblast function. The materials were characterised using atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle (WCA) and a novel ninhydrin assay. The cells were analysed using qRT-PCR, von Kossa tinctural staining for mineralisation, and visualised using both transmitted white light and electron microscopy. Bone-like nodules, quantified using microscopy, only formed on the short-chain (chain length 3 and 4) amines after 7 days, as did the up-regulation of sclerostin, suggestive of a more mature osteoblast phenotype. In this paper, we report more rapid nodule formation than has previously been observed, without the addition of exogenous factors in the culture medium. This suggests that the coating would improve the integration of implants with bone or be the basis of a smart biomaterial that would accelerate the bone regeneration process.Electronic supplementary materialThe online version of this article (doi:10.1007/s00223-016-0202-y) contains supplementary material, which is available to authorized users.

Many biological systems have evolved circadian rhythms based on the daily cycles of daylight and darkness on Earth. Such rhythms are synchronised or entrained to 24-h cycles, predominantly by light, and disruption of the normal circadian rhythms has been linked to elevation of multiple health risks. The skin serves as a protective barrier to prevent microbial infection and maintain homoeostasis of the underlying tissue and the whole organism. However, in chronic non-healing wounds such as diabetic foot ulcers (DFUs), pressure sores, venous and arterial ulcers, a variety of factors conspire to prevent wound repair. On the other hand, keloids and hypertrophic scars arise from overactive repair mechanisms that fail to cease in a timely fashion, leading to excessive production of extracellular matrix (ECM) components such as such as collagen. Recent years have seen huge increases in our understanding of the functions of microRNAs (miRNAs) in wound repair. Concomitantly, there has been growing recognition of miRNA roles in circadian processes, either as regulators or targets of clock activity or direct responders to external circadian stimuli. In addition, miRNAs are now known to function as intercellular signalling mediators through extracellular vesicles (EVs). In this review, we explore the intersection of mechanisms by which circadian and miRNA responses interact with each other in relation to wound repair in the skin, using keratinocytes, macrophages and fibroblasts as exemplars. We highlight areas for further investigation to support the development of translational insights to support circadian medicine in the context of these cells.

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Myalgic Encephalomyelitis (ME) /Chronic Fatigue Syndrome (CFS) is a severely debilitating and complex illness of uncertain aetiology, affecting the lives of millions and characterised by prolonged fatigue. The initiating factors and mechanisms leading to chronic debilitating muscle fatigue in ME/CFS are unknown and are complicated by the time required for diagnosis. Both mitochondrial dysfunction and inflammation have been proposed to be central to the pathogenesis of ME/CFS. This original and extensive study demonstrated that although there was little dysfunction evident in the muscle mitochondria of patients with ME/CFS, particular blood plasma and skeletal muscle cytokines, when adjusted for age, gender and cytokine interactions could predict both diagnosis and a number of measures common to patients with ME/CFS. These included MVC and perceived fatigue as well as cognitive indices such as pattern and verbal reaction times. We employed advanced multivariate analyses to cytokine profiles that leverages covariation and intrinsic redundancy to identify patterns of immune signaling that can be evaluated for their predictions of disease phenotype. The current study identified discriminatory cytokine profiles that can be sufficiently used to distinguish HCs from patients with ME/CFS and provides compelling evidence that a limited number of cytokines are associated with diagnosis and fatigue. Moreover, this study demonstrates significant potential of using multiplex cytokine profiles and bioinformatics as diagnostic tools for ME/CFS, potentiating the possibility of not only diagnosis, but also being able to individually personalise therapies.