Photopolymerizable hydrogels have been investigated extensively for biomedical applications, specifically in the area of tissue engineering. While fabrication approaches have shown promise in designing hydrogel scaffolds that guide cell function, the ability to spatially control localization in three-dimensions has been limited. We have developed a method for generating two-dimensional and three-dimensional (3D) patterns within multilayered poly(ethylene glycol) diacrylate (PEG-DA) hydrogels. Covalently attached hydrogel layers are formed using precursor solutions with a 10:1 mole ratio of PEG-DA to PEG-aminoacrylate (Acr-PEG-NH2). Upon illumination of the precursor with visible light (wavelength = 514 nm), a hydrogel layer forms with pendant amine groups induced by the presence of Acr-PEG-NH2 macromer. Pendant amine groups are further functionalized with free carboxyl groups present on the visible light photoinitiator eosin, allowing for the formation of subsequent hydrogel layers. Using noncontact photolithography, the prepolymer solution is polymerized through a photomask, resulting in hydrogel structures with distinct pattern formation in each layer. Unreacted regions immobilized with eosin can be subsequently filled with a different PEG hydrogel. The technique presented shows a great potential for tissue engineering applications, for biosensors, and in the formation of cell and protein patterning for biotechnology.
This work aims at monitoring air quality in indoor environments through the integration of several sensing technologies into a single robust, reliable and cheap detection platform, which shares air pre-conditioning and electronics. Target gases and detection limits have been set according to recommendations of different agencies in Europe and the US. The system has reached detection limits stated by the OSHA (Occupational Safety and Health Administration) for benzene. The pre-conditioning fluidic platform has also been designed, simulated, fabricated and tested with sensors so the gas flow has been optimized. Field tests in real buildings are being carried out to contrast current measurement procedures and results with the obtained using the device under development. The main aim of the system is to control HVAC (Heat Ventilation and Air Conditioning) in energy-efficient way while keeping a high air quality standard inside the building.
HighlightsA system to control indoor air quality is being designed, fabricated and tested. Conductometric sensors based on nanostructured ZnO are developed for the system. A fluidic unit is being developed to improve the performance of the sensors. Field studies in buildings are carried out to be contrasted with the developed system.
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