Nanotopography mediated osteogenic differentiation of human dental pulp derived stem cells

Advanced medical devices, treatments and therapies demand an understanding of the role of interfacial properties on the cellular response. This is particularly important in the emerging fields of cell therapies and tissue regeneration. In this study, we evaluate the role of surface nanotopography on the fate of human dental pulp derived stem cells (hDPSC). These stem cells have attracted interest because of their capacity to differentiate to a range of useful lineages but are relatively easy to isolate. We generated and utilized density gradients of gold nanoparticles which allowed us to examine, on a single substrate, the influence of nanofeature density and size on stem cell behavior. We found that hDPSC adhered in greater numbers and proliferated faster on the sections of the gradients with higher density of nanotopography features. Furthermore, greater surface nanotopography density directed the differentiation of hDPSC to osteogenic lineages. This study demonstrates that carefully tuned surface nanotopography can be used to manipulate and guide the proliferation and differentiation of these cells. The outcomes of this study can be important in the rational design of culture substrates and vehicles for cell therapies, tissue engineering constructs and the next generation of biomedical devices where control over the growth of different tissues is required

Surface nanotopography guides kidney-derived stem cell differentiation into podocytes

Abstract not availableMelanie MacGregor-Ramiasa, Isabel Hopp, Akash Bachhuka, Patricia Murray, Krasimir Vasile

Surface Functionalization of Exposed Core Glass Optical Fiber for Metal Ion Sensing

One of the biggest challenges associated with exposed core glass optical fiber-based sensing is the availability of techniques that can be used to generate reproducible, homogeneous and stable surface coating. We report a one step, solvent free method for surface functionalization of exposed core glass optical fiber that allows achieving binding of fluorophore of choice for metal ion sensing. The plasma polymerization-based method yielded a homogeneous, reproducible and stable coating, enabling high sensitivity aluminium ion sensing. The sensing platform reported in this manuscript is versatile and can be used to bind different sensing molecules opening new avenues for optical fiber-based sensing

The Role of Controlled Surface Topography and Chemistry on Mouse Embryonic Stem Cell Attachment, Growth and Self-Renewal

The success of stem cell therapies relies heavily on our ability to control their fate in vitro during expansion to ensure an appropriate supply. The biophysical properties of the cell culture environment have been recognised as a potent stimuli influencing cellular behaviour. In this work we used advanced plasma-based techniques to generate model culture substrates with controlled nanotopographical features of 16 nm, 38 nm and 68 nm in magnitude, and three differently tailored surface chemical functionalities. The effect of these two surface properties on the adhesion, spreading, and self-renewal of mouse embryonic stem cells (mESCs) were assessed. The results demonstrated that physical and chemical cues influenced the behaviour of these stem cells in in vitro culture in different ways. The size of the nanotopographical features impacted on the cell adhesion, spreading and proliferation, while the chemistry influenced the cell self-renewal and differentiation

Field Deployable Method for Gold Detection Using Gold Pre-Concentration on Functionalized Surfaces

Gold in a rock is usually associated with other elements, forms nuggets, or is hosted within the crystal lattice of a mineral (e.g., pyrite) and is often heterogeneously distributed and trapped inside the rock matrix even after crushing. Gold can be liberated from these rock matrices by chemical leaching, but then their concentration becomes too low for detection by a portable method due to the dilution effect of the leaching process. In this paper, we present a proof-of-concept method for gold pre-concentration to enable the detection of gold in rock at low levels using a portable technique. Two coating methods, plasma polymerization (PP) and wet chemistry (WC), were utilized to generate surface coatings, which were then compared for their effectiveness in binding gold ions. Laser-induced breakdown spectroscopy (LIBS) was used as a portable technique for the detection of immobilized gold on these modified surfaces. The detection limit for pure gold ions in solution incubated on PP and WC coatings was determined to be as low as 80 ppb. To demonstrate the real-life capability of the method, it was tested for rock sample leachates bearing 300–500 ppb gold

Innate Immunity and Biomaterials at the Nexus: Friends or Foes

Biomaterial implants are an established part of medical practice, encompassing a broad range of devices that widely differ in function and structural composition. However, one common property amongst biomaterials is the induction of the foreign body response: an acute sterile inflammatory reaction which overlaps with tissue vascularisation and remodelling and ultimately fibrotic encapsulation of the biomaterial to prevent further interaction with host tissue. Severity and clinical manifestation of the biomaterial-induced foreign body response are different for each biomaterial, with cases of incompatibility often associated with loss of function. However, unravelling the mechanisms that progress to the formation of the fibrotic capsule highlights the tightly intertwined nature of immunological responses to a seemingly noncanonical "antigen." In this review, we detail the pathways associated with the foreign body response and describe possible mechanisms of immune involvement that can be targeted. We also discuss methods of modulating the immune response by altering the physiochemical surface properties of the biomaterial prior to implantation. Developments in these areas are reliant on reproducible and effective animal models and may allow a "combined" immunomodulatory approach of adapting surface properties of biomaterials, as well as treating key immune pathways to ultimately reduce the negative consequences of biomaterial implantation.Susan N. Christo, Kerrilyn R. Diener, Akash Bachhuka, Krasimir Vasilev, and John D. Haybal

Surface Modification by Allylamine Plasma Polymerization Promotes Osteogenic Differentiation of Human Adipose-Derived Stem Cells

Tuning the material properties in order to control the cellular behavior is an important issue in tissue engineering. It is now well-established that the surface chemistry can affect cell adhesion, proliferation, and differentiation. In this study, plasma polymerization, which is an appealing method for surface modification, was employed to generate surfaces with different chemical compositions. Allylamine (AAm), acrylic acid (AAc), 1,7-octadiene (OD), and ethanol (ET) were used as precursors for plasma polymerization in order to generate thin films rich in amine (−NH₂), carboxyl (−COOH), methyl (−CH₃), and hydroxyl (−OH) functional groups, respectively. The surface chemistry was characterized by X-ray photoelectron spectroscopy (XPS), the wettability was determined by measuring the water contact angles (WCA) and the surface topography was imaged by atomic force microscopy (AFM). The effects of surface chemical compositions on the behavior of human adipose-derive stem cells (hASCs) were evaluated <i>in vitro</i>: Cell Count Kit-8 (CCK-8) analysis for cell proliferation, F-actin staining for cell morphology, alkaline phosphatase (ALP) activity analysis, and Alizarin Red S staining for osteogenic differentiation. The results show that AAm-based plasma-polymerized coatings can promote the attachment, spreading, and, in turn, proliferation of hASCs, as well as promote the osteogenic differentiation of hASCs, suggesting that plasma polymerization is an appealing method for the surface modification of scaffolds used in bone tissue engineering