Nerve cells culture from lumbar spinal cord on surfaces modified by plasma pyrrole polymerization

Currently, there are several techniques for modified cell culture surfaces under research to improve cell growth and adhesion. Recently, different methods have been used for surface coating, using biomolecules that enhance cell attachment and growth of nerve cells from spinal cord, such as the use of Poly-DL-Ornithine/Laminin. Plasma-polymerized pyrrole (PPy)-treated surfaces have showed improvement on surfaces biocompatibility with the cells in culture since they do not interfere with any of the biological cell functions. In the present work, we present a novel mouse nerve cell culture technique, using PPy-treated cell culture surfaces. A comparative study of cell survival using Poly-DL-Ornithine/Laminin-treated surfaces was performed. Our results of cell survival when compared with data already reported by other investigators, show that cells cultured on the PPy-modified surface increased survival up to 21 days when compared with Poly-DL-Ornithine/Laminin-coated culture, where 8 days cell survival was obtained. There were electrical and morphological differences in the nerve cells grown in the different surfaces. By comparing the peak ion currents of Poly-DL-Ornithine/Laminin-seeded cells for 8 days with cells grown for 21 days on PPy, an increase of 516% in the Na(+) current and 127% in K(+) currents in cells seeded on PPy were observed. Immunofluorescence techniques showed the presence of cell synapses and culture viability after 21 days. Our results then showed that PPy-modified surfaces are an alternative culture method that increases nerve cells survival from lumbar spinal cord cell culture by preserving its electrical and morphological features.

Determination of denitrifying sludge settleability using contact angle measurements

The adaptation of the technique for measuring the contact angle (CA) in order to follow the changes of sludge settleability of a denitrifying sludge surface is described. Denitrifying sludge was continuously fed into an upflow anaerobic sludge blanket (UASB) reactor with acetate and nitrate. The loss of settleability in the sludge was induced by decreasing the hydraulic residence time (HRT) from 1 d to 0.125 d. CA was measured with air and nitrogen bubbles. A comparison between sludge volume index (SVI) and the CA and their correlation with sludge settleability was carried out. Results showed that CA method had a high correlation with sludge settleability. Moreover the CA method showed to be simpler and less time consuming than the SVI method.