Secretory phospholipase A2 pathway in various types of lung injury in neonates and infants: a multicentre translational study

Background Secretory phospholipase A2 (sPLA2) is a group of enzymes involved in lung tissue inflammation and surfactant catabolism. sPLA2 plays a role in adults affected by acute lung injury and seems a promising therapeutic target. Preliminary data allow foreseeing the importance of such enzyme in some critical respiratory diseases in neonates and infants, as well. Our study aim is to clarify the role of sPLA2 and its modulators in the pathogenesis and clinical severity of hyaline membrane disease, infection related respiratory failure, meconium aspiration syndrome and acute respiratory distress syndrome. sPLA2 genes will also be sequenced and possible genetic involvement will be analysed. Methods/Design Multicentre, international, translational study, including several paediatric and neonatal intensive care units and one coordinating laboratory. Babies affected by the above mentioned conditions will be enrolled: broncho-alveolar lavage fluid, serum and whole blood will be obtained at definite time-points during the disease course. Several clinical, respiratory and outcome data will be recorded. Laboratory researchers who perform the bench part of the study will be blinded to the clinical data. Discussion This study, thanks to its multicenter design, will clarify the role(s) of sPLA2 and its pathway in these diseases: sPLA2 might be the crossroad between inflammation and surfactant dysfunction. This may represent a crucial target for new anti-inflammatory therapies but also a novel approach to protect surfactant or spare it, improving alveolar stability, lung mechanics and gas exchange

DNA biosensor using fluorescence microscopy and impedance spectroscopy

Two types of DNA biosensors are presented. Both sensing principles are demonstrated using synthetic oligomer single-stranded DNA (ssDNA) with concentrations in the micromolar range. A first sensor type is based on the detection of fluorescently labeled ssDNA to a complementary probe that is bound to a silicon substrate by a disuccinimidyl terephtalate and aminosilane immobilization procedure. An enhanced fluorescent response is obtained using constructive interference effects in a fused silica layer deposited before immobilization onto the silicon substrate. The selectivity of different DNA probes towards complementary and non-complementary DNA targets is tested. A second type of DNA sensor is based on the impedimetric response of a solution of unlabeled 20-mer ssDNA in de-ionized water. Interdigitated microelectrodes that are 5 μm wide and separated by 5 μm gaps are microfabricated on glass substrates and the complex impedance of the system in the 100 Hz–100 MHz frequency range is investigated. The proportionality between the measured solution resistance and ssDNA concentration is demonstrated

Label-free detection of DNA with interdigitated micro-electrodes in a fluidic cell

We investigate the analytical performance of an interdigitated electrode sensor for the label-free detection of DNA, by monitoring the complex impedance of 5 µm wide interdigitated Pt microelectrodes on a glass substrate. We detect the hybridization of unlabeled 38-mer target ssDNA with a complementary probe that is bound on the glass in between the electrodes by a disuccinimidyl terephtalate and aminosilane immobilization procedure. The sensor is mounted in a microfluidic flow cell, in which hybridization is monitored and in situ compared with a reference. After hybridization, the cell is perfused with deionised water and the dependence of the measured conductance due to the immobilized target DNA layer, to target DNA concentrations down to 1 nM is demonstrated. Subsequently, we apply our sensor to the detection of pathogen DNA from Salmonella choleraesuis in dairy food