Polyethylenimine-carbon nanotube nanohybrids for siRNA-mediated gene silencing at cellular level

Carbon nanotubes (CNTs) covalently modified with low molecular weight polyethylenimine (PEI) are able to bind and deliver siRNA to cells with higher efficacy than a reference lipidic carrier. The performances of the nanohybrid are rationalized by the combination of the cell penetration and endosomal escape properties of CNTs and PEI, respectively.     

Studies of bacterial adhesion on TiN, SiO2-TiO2 and hydroxyapatite thin layers deposited on titanium and Ti6Al4V alloy for medical applications

The Staphylococcus epidermidis biofilm formation on titanium or titanium alloy, coated with TiN, SiO₂-TiO₂ and electrodeposited hydroxyapatite, was tested. Surfaces of titanium, Ti6Al4V alloy or TiN, modified with SiO₂-TiO₂ layer, were found to be highly resistant to bacterial adhesion. Only small amounts of bacterial cells were observed on matrices coated by thin hydroxyapatite films, deposited on both SiO₂-TiO₂ and TiN + SiO₂-TiO₂ interlayers. Biological tests showed that the biofilm formed massively on polished and ground titanium and titanium alloy surfaces, also those covered with TiN, but not on those modified with SiO₂-TiO₂ nanofilm.     

Functionalization of electrospun fibers of poly(ε-caprolactone) with star shaped NCO-poly(ethylene glycol)-<Emphasis Type="Italic">stat</Emphasis>-poly(propylene glycol) for neuronal cell guidance

Microfibers produced with electrospinning have recently been used in tissue engineering. In the development of artificial implants for nerve regeneration they are of particular interest as guidance structures for cell migration and axonal growth. Using electrospinning we produced parallel-orientated biocompatible fibers in the submicron range consisting of poly(ε-caprolactone) (PCL) and star shaped NCO-poly(ethylene glycol)-stat-poly(propylene glycol) (sPEG). Addition of the bioactive peptide sequence glycine-arginine-glycine-aspartate-serine (GRGDS) or the extracellular matrix protein fibronectin to the electrospinning solution resulted in functionalized fibers. Surface characteristics and biological properties of functionalized and non-functionalised fibers were investigated. Polymer solutions and electrospinning process parameters were varied to obtain high quality orientated fibers. A polymer mixture containing high molecular weight PCL, PCL-diol, and sPEG permitted a chemical reaction between hydroxyl groups of the diol and isocyanante groups of the sPEG. Surface analysis demonstrated that sPEG at the fiber surface minimized protein adhesion. In vitro experiments using dorsal root ganglia explants showed that the cell repellent property of pure PCL/sPEG fibers was overcome by functionalization either with GRGDS peptide or fibronectin. In this way cell migration and axonal outgrowth along fibers were significantly increased. Thus, functionalized electrospun PCL/sPEG fibers, while preventing non-specific protein adsorption, are a suitable substrate for biological and medical applications.     

Growth and exopolysaccharide yield of Lactobacillus delbrueckii ssp. bulgaricus DSM 20081 in batch and continuous bioreactor experiments at constant pH

Some Lactobacillus delbrueckii ssp. bulgaricus strains are able to synthesize exopolysaccharides (EPS) and are therefore highly important for the dairy industry as starter cultures. The aim of this study was to investigate the nutritional requirements for growth and EPS production of Lactobacillus delbrueckii ssp. bulgaricus DSM 20081. A medium was developed from a semi-defined medium (SDM) in which glucose was replaced by lactose and different combinations of supplements (nucleobases, vitamins, salts, sodium formate and orotic acid) were added. Constant pH batch fermentation with the modified medium resulted in an EPS yield of approximately 210 mg glucose equivalents per liter medium. This was a 10-fold increase over flask cultivation of this strain in SDM. Although not affecting cell growth, the mixture of salts enhanced the EPS synthesis. Whereas EPS production was approximately 12 mg/g dry biomass without salt supplementation, a significantly higher yield (approximately 20 mg/g dry biomass) was observed after adding the salt mixture. In continuous fermentation, a maximal EPS concentration was obtained at a dilution rate of 0.31/h (80 mg EPS/L), which corresponded to a specific EPS production of 49 mg/g dry biomass.     

Identification of Candidate Biomarker and Drug Targets for Improving Endometrial Cancer Racial Disparities

Racial disparities in incidence and survival exist for many human cancers. Racial disparities are undoubtedly multifactorial and due in part to differences in socioeconomic factors, access to care, and comorbidities. Within the U.S., fundamental causes of health inequalities, including socio-economic factors, insurance status, access to healthcare and screening and treatment biases, are issues that contribute to cancer disparities. Yet even these epidemiologic differences do not fully account for survival disparities, as for nearly every stage, grade and histologic subtype, survival among Black women is significantly lower than their White counterparts. To address this, we sought to investigate the proteomic profiling molecular features of endometrial cancer in order to detect modifiable and targetable elements of endometrial cancer in different racial groups, which could be essential for treatment planning. The majority of proteins identified to be significantly altered among the racial groups and that can be regulated by existing drugs or investigational agents are enzymes that regulate metabolism and protein synthesis. These drugs have the potential to improve the worse outcomes of endometrial cancer patients based on race.