The effects of radial shock waves on gene transfer in rabbit chondrocytes in vitro

SummaryObjectiveThe purpose of this study was to develop a new technique of gene transfer utilizing radial shock waves. The effects of radial shock waves on gene transfer in rabbit chondrocytes were examined by varying the parameters of exposure conditions in vitro.MethodsChondrocytes were obtained from New Zealand white rabbits and cultured in a monolayer. A luciferase-encoding gene expression vector, or vector alone, was added to chondrocyte cell suspensions, and the cells were then exposed to radial shock waves. Parameters such as pressure amplitude, number of pulses, frequency, and DNA concentration were varied, and luciferase activity was measured 48h after transfection. Transfection efficiency of radial shock waves was compared with the FuGENE6 transfection method using a green fluorescence protein (GFP)-encoding gene vector by fluorescent-activated cell sorter (FACS) analysis.ResultsRadial shock wave exposure significantly increased luciferase activity over 140-fold as compared to the control under the optimal exposure conditions. Both pressure amplitude and number of pulses were relevant to transfection efficiency and cell viability, but frequency was not. Transfection efficiency increased in a dose-dependent manner with DNA concentration. FACS analysis showed 4.74% of GFP-encoding gene using radial shock waves. FuGENE6 transfection was almost similar in transfection efficiency to radial shock wave.ConclusionIn spite of certain degree of cell disruption, radial shock waves significantly augmented reporter gene transfection in rabbit chondrocytes in vitro. Radial shock waves may potentially contribute to the treatment of the cartilage morbidities by enhancing the potency of tissue healing and gene transfection of growth factors

Kinetic Modelling of Hydrothermal Lignin Depolymerisation

Although lignin is one of the most abundant renewable organic materials in the world, it is principally a waste product of the paper industry which is used for the production of heat and power. Hydrothermal lignin depolymerisation aids in facilitating the valorization of lignin in aqueous solutions or suspensions. For the recovery of valuable phenolic products from lignin it is crucial to understand the main reaction pathways of lignin degradation and the reaction kinetics. Batch experiments were carried out for studying the depolymerisation of an enzymatic hydrolysis lignin from spruce wood in near critical water. Phenolic products were extracted from the aqueous phase and quantified via gas chromatography. The main reaction products were grouped (lumped), the main reaction pathways of hydrothermal lignin depolymerisation were discovered and formal kinetic rate coefficients were determined. Optimization of these formal kinetic parameters yielded a satisfying approximation of the experimental yields of phenolic products and describes the most important tendencies over temperature and residence time of solid residue and gas. The model is validated by the comparison with other kinetic studies of the degradation of lignin as well as the decomposition of intermediate phenolics, such as catechols and methoxyphenols

Solvothermal Liquefaction of Corn Stalk: Physico-Chemical Properties of Bio-oil and Biochar

This study investigated the conversion of corn stalk to bio-oil by solvothermal liquefaction using ethanol as a solvent. Effect of reaction temperature, time and solvent to biomass ratio on the yield and the properties of bio-oil and biochar was studied. Analysis of corn stalk and bio-oil were done to determine the surface functional groups, existing bonds and molecular structure of specified compounds. Investigations were done to identify different compounds in bio-oil, the thermal stability, and weight loss kinetics of biochar. Study shows that percentage yield of bio-oil increases with increase in temperature and time, up to a specific level, and then starts declining. Further, the heating value, carbon content, and fixed carbon content of both bio-oil and biochar increased to 30.52, 22.8 MJ/kg, and 66.42 and 61.25%, 26.10 and 27.97% respectively from those (19.55 MJ/kg, 51.12 and 6.36%) of the corn stalk. This study suggests that the bio-oil contained mostly phenolic compounds and its derivatives. Two major DTG peaks were observed at 380 and 620 °C indicating the improvement in thermal stability of the biochar after solvolysis liquefaction process. Investigation results can be very useful in optimizing process parameters for solvothermal liquefaction