Investigation of Cellular Interactions of Lipid-Structured Nanoparticles With Oral Mucosal Epithelial Cells.

Lipid-based nanosystems enable intracellular delivery of drugs in the oral cavity for the treatment of local diseases. To rationally design such systems, suitable matrix compositions and particle properties need to be identified, and manufacturing technologies that allow reproducible production have to be applied. This is a prerequisite for the reliable and predictable performance of in-vitro biological studies. Here, we showed that solid lipid nanoparticles (SLN, palmitic acid) and nanostructured lipid carriers (NLC, palmitic acid and oleic acid in different ratios) with a size of 250 nm, a negative zeta potential, and a polydispersity index (PdI) of less than 0.3 can be reproducibly prepared by high-pressure homogenization using quality by design and a predictive model. SLN and NLC were colloidally stable after contact with physiological fluid and did not form agglomerates. The in-vitro studies clearly showed that besides particle size, surface charge and hydrophobicity, matrix composition had a significant effect. More specifically, the addition of the liquid lipid oleic acid increased the cellular uptake capacity without changing the underlying uptake mechanism. Regardless of the matrix composition, caveolin-mediated endocytosis was the major route of uptake, which was confirmed by particle localization in the endoplasmic reticulum. Thus, this work provides useful insights into the optimal composition of lipid carrier systems to enhance the intracellular uptake capacity of drugs into the oral mucosa.

Yoga in the workplace and health outcomes: a systematic review.

BACKGROUND: Health promotion in the workplace is intended to enhance employee health and well-being. Yoga programmes are easy to implement and have been effective in the management of various health conditions. AIMS: To assess the evidence regarding the effectiveness of yoga programmes at work. METHODS: A search of electronic databases of published studies up until the 1st of April 2017. Inclusion criteria for the systematic review were randomized controlled trials of adult employees and yoga in the workplace. Quality appraisal was carried out using the Cochrane Collaboration's tool for assessing risk of bias in randomized trials. RESULTS: Of 1343 papers identified, 13 studies met the inclusion criteria. Nine out of 13 trials were classified as having an unclear risk of bias. The overall effects of yoga on mental health outcomes were beneficial, mainly on stress. Most of the cardiovascular endpoints showed no differences between yoga and controls. Other outcomes reported positive effects of yoga or no change. CONCLUSIONS: The findings of this study suggest that yoga has a positive effect on health in the workplace, particularly in reducing stress, and no negative effects were reported in any of the randomized controlled trials. Further larger studies are required to confirm this.

Novel injectable neutral solutions of chitosan form biodegradable gels in situ.

A novel approach to provide, thermally sensitive neutral solutions based on chitosan/polyol salt combinations is described. These formulations possess a physiological pH and can be held liquid below room temperature for encapsulating living cells and therapeutic proteins; they form monolithic gels at body temperature. When injected in vivo the liquid formulations turn into gel implants in situ. This system was used successfully to deliver biologically active growth factors in vivo as well as an encapsulating matrix for living chondrocytes for tissue engineering applications. This study reports for the first time the use of polymer/polyol salt aqueous solutions as gelling systems, suggesting the discovery of a prototype for a new family of thermosetting gels highly compatible with biological compounds.

[Bio-absorbable synthetic polyesters and tissue regeneration. A study of three-dimensional proliferation of ovine chondrocytes and osteoblasts]. / Polyesters biosynthétiques absorbables et régénération tissulaire. Etude de la prolifération tridimensionnelle de chondrocytes et ostéoblastes ovins.

The tissue engineering area henceforth calls more and more for bioabsorbable substrata made of biopolymers (collagen, laminin...) or polymers (PLA, PLGA, PGA...) to realize the three-dimensional culture of tissue equivalents. The poly (beta-hydroxybutyrate-beta-hydroxyvalerate), a biopolymer considered as being biodegradable and biocompatible, has been recently introduced for orthopaedic biomaterials and regeneration purposes. In our study, a PHB/9% HV polymer was transformed into 3D foams, then applied to the culture 3D of ovine chondrocytes (fibrous rings & growth plates) and osteoblasts (periostum). Sponges made of bovine type I collagen were used as references. Orthopaedic cells were isolated, prepared and sown by simple injection to the geometrical center of the substrata, then incubated from 0 to 35 days by changing the culture medium all 4 days. Maximal densities were reached after 21 days: 18-24.10(6) cells/g for the chondrocytes, 8-10.10(6) cells/g for the osteoblasts. The cellular proliferation was more marked, with highest cell densities, for the collagen sponges. Laser confocal microscopy shows that the cellular diffusion take place throughout the entire volume of the porous artificial substrata. Future studies will allow to apply the porous bioabsorbable substrata to high-density cell cultures, to the tissue engineering and regeneration, for example for orthopaedic tissues: cartilage, fibrocartilage and bone.

Fibroblast seeding and culture in biodegradable porous substrates.

A natural poly(hydroxybutyrate-co-9% hydroxyvalerate) copolyester was processed into a three-dimensional porous foam structure by salt leaching/solvent casting with previously sieved sodium chloride salts. Laboratory-built P(HB-9% HV) foams and commercial collagen sponges were cut into small rectangular specimens, sterilized, and prewetted using ethanol, rinsed with Dulbecco's minimum essential medium + 10% serum culture media, and seeded with fibroblasts isolated from canine anterior cruciate ligaments. The fibroblast cultures into such porous substrates were performed from 0 to 35 days by incubation (5% CO2) at 37 degrees C. It demonstrated that the P(HB-HV) sustained a cell proliferation rate similar to that observed in collagen sponges, up to at least 35 days, with a maximal cell density on the day 28 in culture. On the other hand, the P(HB-HV) materials kept their structural integrity during the culture period while the collagen foams contracted greatly. Further, the total protein production after 4 weeks in culture was found to be twice as high (190 +/- 10%) in the P(HB-9% HV) foam than in the collagen foam. Porous P(HB-HV) materials appear to be adequate polymeric substrates for cell cultures. However, further evaluations are still required to confirm such preliminary results.

Effect of plasma treatment on tribological properties of synthetic ligaments.

The objective of this study was to determine the optimal experimental conditions for plasma treatment of polyester ligaments. Two different surface modification techniques were used: tetrafluoroethylene and methane. Gas flow rate, pressure, power, and treatment period giving a thin film with low friction coefficient and low surface energy was determined. Control and plasma treated surfaces were characterized by X-ray photoelectron spectroscopy to investigate the functionalization of the treated surfaces in detail. The surface tension of control and plasma treated surfaces were determined from contact angle measurements to understand the adhesion and reactivity of films with aqueous medium. The results showed a decrease in friction coefficient from 0.45 to 0.28 and from 0.45 to 0.26 for thin films deposited respectively by tetrafluoroethylene (TFE) and methane (CH4) plasma. Contact angles increased from 63 degrees to 120 degrees for TFE plasma and from 63 degrees to 93 degrees for CH4 plasma. Large contact angles mean a weak affinity between molecules in water/material phase, so that the power to attract cells to the surface of the material is too weak. The results showed that optimal film, i.e., low static friction coefficient and large contact angle, can be obtained by a CH4 plasma treatment at high power RF. For TFE plasma treatments, a low power RF is needed to obtain a thin film with a stable chemical structure.