We present the development of microbioreactors (MBRs) based on poly(dimethylsiloxane) (PDMS) segmented waveguides (SWG) for local absorbance measurements. Two different MBRs were studied, either using symmetric or asymmetric SWG (being defined as MBR-S and MBR-A, respectively). Their optical and fluidic performances were numerically analyzed, showing robustness from an optical point of view and distinct fluid flow profile. The optical characterization was done in two steps. Initially, the experimental limit of detection (LOD) and the sensitivity were determined for two different analytes (fluorescein and methylorange). With both systems, a similar limit of detection for both analytes was obtained, being in the micromolar level. Their sensitivities were 20.2±0.3 (×10⁻³) A.U./μM and 5.5±0.2 (×10⁻³) A.U./μM for fluorescein and methylorange, respectively. Once validated its applicability for local absorbance measurements, a continuous cultivation of Saccharomyces cerevisiae was done to test the viability of the proposed systems for photonic MBRs. Concretely, the cell growth was locally monitored inside the MBR during 33 h. Spectral analysis showed that the determination of the culture parameters were wavelength dependant, with a growth rate of 0.39±0.02 h⁻¹ and a doubling time of 1.65±0.09 h at an optimal wavelength of 469.9±0.3 nm. Besides the easy and monolithic integration of the SWG into poly(dimethylsiloxane) microfluidic systems, the results presented here are very promising for the application in any disposable photonic lab-on-a-chip systems used for online analysis or photonic MBRs.
Local therapeutic action and targeted drug release are promising approaches compared to traditional systemic drug administration. This is especially relevant for nitric oxide (NO), as its effects change dramatically depending on concentration and cellular context. Materials capable of releasing NO in deep tissues in a controlled manner might open new therapeutic opportunities.
Background: NeoDura (Medprin Biotech Gmbh) is an absorbable dural repair patch consisting of degradable poly-L-lactic acid and porcine gelatin that provides a hermetic closure of the dura mater (Medprin Biotech. Neodura. Dural Repair Patch [Brochure].
Coal mined in the shut-down Raša mine in Istria, Croatia had a high organic sulphur content. What has remained of its local combustion is a coal and ash waste (legacy site) whose trace element and radionuclide composition in soil has enduring consequences for the environment. The aim of this study was to follow up on previous research and investigate the potential impact on surrounding soil and local residents by characterising the site's ash and soil samples collected in two field campaigns.
Unlabelled: Molecular crowding influences DNA mechanics and DNA - protein interactions and is ubiquitous in living cells. Quantifying the effects of molecular crowding on DNA supercoiling is essential to relating experiments to DNA supercoiling. We use single molecule magnetic tweezers to study DNA supercoiling in the presence of dehydrating or crowding co-solutes.
Aerosol-producing global catastrophes such as nuclear war, super-volcano eruption, or asteroid strike, although rare, pose a serious threat to human survival. Light-absorbing aerosols would sharply reduce temperature and solar radiation reaching the earth's surface, decreasing crop productivity including for locally adapted traditional crop varieties, i.e.
