Secondary structure of rhBMP-2 in a protective biopolymeric carrier material

Efficient delivery of growth factors is one of the great challenges of tissue engineering. Polyelectrolyte multilayer films (PEM) made of biopolymers have recently emerged as an interesting carrier for delivering recombinant human bone morphogenetic protein 2 (rhBMP-2 noted here BMP-2) to cells in a matrix-bound manner. We recently showed that PEM made of poly(l-lysine) and hyaluronan (PLL/HA) can retain high and tunable quantities of BMP-2 and can deliver it to cells to induce their differentiation in osteoblasts. Here, we investigate quantitatively by Fourier transform infrared spectroscopy (FTIR) the secondary structure of BMP-2 in solution as well as trapped in a biopolymeric thin film. We reveal that the major structural elements of BMP-2 in solution are intramolecular β-sheets and unordered structures as well as α-helices. Furthermore, we studied the secondary structure of rhBMP-2 trapped in hydrated films and in dry films since drying is an important step for future applications of these bioactive films onto orthopedic biomaterials. We demonstrate that the structural elements were preserved when BMP-2 was trapped in the biopolymeric film in hydrated conditions and, to a lesser extent, in dry state. Importantly, its bioactivity was maintained after drying of the film. Our results appear highly promising for future applications of these films as coatings of biomedical materials, to deliver bioactive proteins while preserving their bioactivity upon storage in dry state.This work was supported by the French Ministry of Research through an ANR-EmergenceBIO grant (ANR-09-EBIO-012-01), by the European Commission (FP7 program) via a European Research Council starting grant (BIOMIM, GA 259370), and by GRAVIT (081012_FIBIOS). C.P. is grafetul to IUF for financial support

Nanostructured 3D Constructs Based on Chitosan and Chondroitin Sulphate Multilayers for Cartilage Tissue Engineering

Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and chondroitin sulphate (CS) on either bidimensional glass surfaces or 3D packet of paraffin spheres. 2D CHT/CS multi-layered constructs proved to support the attachment and proliferation of bovine chondrocytes (BCH). The technology was transposed to 3D level and CHT/CS multi-layered hierarchical scaffolds were retrieved after paraffin leaching. The obtained nanostructured 3D constructs had a high porosity and water uptake capacity of about 300%. Dynamical mechanical analysis (DMA) showed the viscoelastic nature of the scaffolds. Cellular tests were performed with the culture of BCH and multipotent bone marrow derived stromal cells (hMSCs) up to 21 days in chondrogenic differentiation media. Together with scanning electronic microscopy analysis, viability tests and DNA quantification, our results clearly showed that cells attached, proliferated and were metabolically active over the entire scaffold. Cartilaginous extracellular matrix (ECM) formation was further assessed and results showed that GAG secretion occurred indicating the maintenance of the chondrogenic phenotype and the chondrogenic differentiation of hMSCs

Free-standing polyelectrolyte membranes made of chitosan and alginate

Free-standing films have increasing applications in the biomedical field as drug delivery systems for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce a thick membrane and to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any postprocessing step. The dry thickness was varied over a large range from 4 to 35 μm. A 2-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free-standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side.This work was financially supported by Foundation for Science and Technology (FCT) through the Scholarship SFRH/BD/64601/2009 granted to S.G.C. C.M. is indebted to Grenoble INP for financial support via a postdoctoral fellowship. This work was supported by the European Commission (FP7 Program) via a European Research Council starting grant (BIOMIM, GA 259370 to C.P.). C.P. is also grateful to Institut Universitaire de France and to Grenoble Institute of Technology for financial support. We thank Isabelle Paintrand for her technical help with the confocal apparatus and Patrick Chaudouet for his help with SEM imaging

Faint objects in motion: the new frontier of high precision astrometry

Funder: Istituto Nazionale di AstrofisicaSky survey telescopes and powerful targeted telescopes play complementary roles in astronomy. In order to investigate the nature and characteristics of the motions of very faint objects, a flexibly-pointed instrument capable of high astrometric accuracy is an ideal complement to current astrometric surveys and a unique tool for precision astrophysics. Such a space-based mission will push the frontier of precision astrometry from evidence of Earth-mass habitable worlds around the nearest stars, to distant Milky Way objects, and out to the Local Group of galaxies. As we enter the era of the James Webb Space Telescope and the new ground-based, adaptive-optics-enabled giant telescopes, by obtaining these high precision measurements on key objects that Gaia could not reach, a mission that focuses on high precision astrometry science can consolidate our theoretical understanding of the local Universe, enable extrapolation of physical processes to remote redshifts, and derive a much more consistent picture of cosmological evolution and the likely fate of our cosmos. Already several missions have been proposed to address the science case of faint objects in motion using high precision astrometry missions: NEAT proposed for the ESA M3 opportunity, micro-NEAT for the S1 opportunity, and Theia for the M4 and M5 opportunities. Additional new mission configurations adapted with technological innovations could be envisioned to pursue accurate measurements of these extremely small motions. The goal of this White Paper is to address the fundamental science questions that are at stake when we focus on the motions of faint sky objects and to briefly review instrumentation and mission profiles

LOCAL APPLICATION OF LOW POWER MILLIMETER INDUCES PAIN RELIEF IN CHRONIC PANCREATITIS ALLOWING PHYSICAL REHABILITATION: A CASE REPORT

International audienceAims : to report effects of local exposure to low level millimetric waves on chronical pancreatitis (PCC) related pain. Chronic pancreatitis at the initial stages, is characterized by flare-ups of acute pancreatitis, and by recurrent and chronic pain which is the main clinical expression of the disease. We report the effects of low level Presentation of the case : electromagnetic wave in the millimetric frequency (MMW, 60GHz, continuous wave) wrist exposure on PCC related typical epigastric pain (transfixing, triggered by any food intake), leading to extreme weight loss by apprehension of food intake. MMW exposure resulted in almost complete pain relief and antalgic drug suppression, this Results: allowing weight recovery and active rehabilitation. beside natural PCC evolution, different mechanisms Discussion : involved in such pain release: endorphins and/or parasympathetic pathways, neuro inflammation are presented. Conclusion : low level millimetric exposure could be proposed for PCC , and other chronical digestive painful diseases to overcome pain and thus facilitate clinical care or rehabilitation

Antalgic Properties of Millimetric Waves on Chronical Pain: Is It Possible to Distinguish between Neuroplastic and Neuropathic Pain? A Report About 2 Fibromyalgia Cases

International audienceMillimetric wave (MMW) therapy was discovered in the 1970s' in USSR countries and used clinically for their hypoalgesic properties in various pain pathologies. Subsequently, these hypoalgesic properties were related to a central nervous system response following peripheral stimulation, mainly involving secretion of endorphins, as well as other neurotransmitters such as parasympathetic, DOPA, etc... In the more recent past (after 2010), the development of miniaturized solutions has allowed the personal use of MMWs-outside medical structures-in the management of chronic pain, and in particular neuroplastic or nociplastic pain, independently of any etiology. We report here on two cases of fibromyalgia, in which these two contributions to pain are involved. In each case, the patients experienced the use of a portable, wristband designed MMW system. The deliberate use of the device was first intended for wellness or stress relief purposes. The notion of the non-specificity of MMWs on chronic pain is discussed at the end of the article

ARE PULSED MILLIMETRE WAVES FOR BIOLOGICAL/THERAPEUTIC USE SUITABLE TO AVOID THERMAL EFFECTS AND MAGNIFY SPECIFIC ELECTROMAGNETIC EFFECTS?

This paper presents a reflection (not a review) about the basic mechanisms involved in biological and therapeutic effects of millimetre waves (MMW). From articles, reviews and meta-analysis, a special interest was given to low power exposure to MMW (approximately 10 mW/cm 2 or less). Excluding thermal effects, several exclusive electromagnetic interactions were presented, with mainly membrane and volt gated calcium channel as targets (VGcc), involving calcium influxes and water contribution. It appeared that thermal effects were not necessary and could be avoided. This led to consider and discuss the use of pulsed MMW signals (not continuous waves) that could limit or avoid thermal effects, allow lower power requirement, best spectral bandwidth targeting, and specific properties related to currents onset/cut-off