Silica sol-gel encapsulation of cyanobacteria: lessons for academic and applied research.

Cyanobacteria inhabit nearly every ecosystem on earth, play a vital role in nutrient cycling, and are useful as model organisms for fundamental research in photosynthesis and carbon and nitrogen fixation. In addition, they are important for several established biotechnologies for producing food additives, nutritional and pharmaceutical compounds, and pigments, as well as emerging biotechnologies for biofuels and other products. Encapsulation of living cyanobacteria into a porous silica gel matrix is a recent approach that may dramatically improve the efficiency of certain production processes by retaining the biomass within the reactor and modifying cellular metabolism in helpful ways.

Diffusion of dissolved ions from wet silica sol-gel monoliths: implications for biological encapsulation.

Divalent nickel (Ni(2+)), Cu(II)EDTA, methyl orange, and dichromate were used to investigate diffusion from hydrated silica sol-gel monoliths. The objective was to examine diffusion of compounds on a size regime relevant to supporting biological components encapsulated within silica gel prepared in a biologically compatible process space with no post-gelation treatments. With an initial sample set, gels prepared from tetraethoxysilane were explored in a factorial design with Ni(2+) as the tracer, varying water content during hydrolysis, acid catalyst present during hydrolysis, and the final concentration of silica.

Transcriptomic responses of Synechocystis sp. PCC 6803 encapsulated in silica gel.

Global gene expression of Synechocystis sp. PCC 6803 encapsulated in silica gel was examined by microarray analysis. Cultures were encapsulated in gels derived from aqueous precursors or from alkoxide precursors and incubated under constant light for 24 h prior to RNA extraction.

Evaluation of encapsulation stress and the effect of additives on viability and photosynthetic activity of Synechocystis sp. PCC 6803 encapsulated in silica gel.

Stresses imposed on the cyanobacterium Synechocystis sp. PCC 6803 by various compounds present during silica sol-gel encapsulation, including salt, ethanol (EtOH), polyethylene glycol (PEG), glycerol, and glycine betaine, were investigated. Viability of encapsulated cells and photosynthetic activity of cells stressed by immediate (2 min) and 24-h exposure to the five stress-inducing compounds were monitored by pulse amplitude modulated fluorometry.

Opioids for non-operable osteoarthritis and soft-tissue rheumatism.

Reviews of oral opioid trials have shown that many side-effects need to be considered when treating patients with non-operable osteoarthritis and soft-tissue problems. European and American guidelines recommend their use with or without paracetamol. The controversy surrounding the use of non-steroidal anti-inflammatory drugs/cyclo-oxygenase-2 inhibitors is limiting physician and patient choices.