Exploiting the potential of OLED-based photo-organic sensors for biotechnological applications

Micro- and millilitre-scale sensors have become increasingly important in modern biotechnology. Miniaturization and parallelization are also commonly employed in bio-analytical applications, environmental science and bioprocess engineering. This reduction of dimensions to the micro- and milliliter-scale stems from the demand for new sensor systems that enable non-invasive monitoring of bioprocesses in microfluidic or on-chip devices. Highly sensitive optical (bio-) sensors, with operating principles based on photoluminescence intensity or lifetime detection, hold significant promise for meeting the space-limited conditions within miniaturized biotechnological systems. In this context, the properties and applications of OLED-based organic sensors in biotechnology are discussed. The possibleuse of OLEDs as excitation sources in (analytical) biotechnological applications is also examined

Exploiting the potential of additive technologies for advanced micro-cultivation solutions for microalgae and plant cells

Due to their potential to produce a great variety of valuable products bioprocesses using plant cells and microalgae are of growing industrial interest. The cultivation of eukaryotic production systems is challenged by slow growth rates, uncontrolled formation of cell aggregates, adherence to surfaces, shear sensitivity due to their huge cell size and by maintaining the productivity. Because of the high complexity of the biological systems there is only limited knowledge about the physiological and kinetic dependencies on the cultivation conditions. Therefore, advanced micro-cultivation systems are necessary enabling a detailed investigation on the micro- (cellular-scale, e.g. viability, morphology…) and macro-scale (process-scale, e.g. product formation kinetics, substrate consumption…). Additive technologies have the potential to meet these complex biological requirements. This work describes the design of two micro-cultivation environments for suspended and immobilized microalgae and plant cells by additive technologies. First, a milliliter-scale (V = 15 mL) Flat-Panel-Airlift photobioreactor equipped with optical sensors for the real-time measurement of dry weight concentration, chlorophyll fluorescence, pH, dO2 and dCO2 is presented. As a second example, we present a method called Green Bioprinting which was derived from tissue engineering bioprinting approaches and describes the fabrication of three-dimensional hydrogel-based immobilization structures for microalgae, plant cells and even structural organized co-cultures of different cell types. It was shown that the hydrogel-environment provided excellent growth and viability conditions using Chlamydomonas reinhardtii and Ocimum basilicum. The Green Bioprinting technology enables the study of cell-cell interactions (e.g. symbiotic living organisms) or the design of three-dimensional immobilization structures to perform cascaded bioprocesses

Functionalized Bioink with Optical Sensor Nanoparticles for O<inf>2</inf> Imaging in 3D-Bioprinted Constructs

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Research on 3D bioprinting of living cells has strong focus on printable biocompatible materials and monitoring of cell growth in printed constructs, while cell metabolism is mostly measured in media surrounding the constructs or by destructive sample analyses. Bioprinting is combined with online imaging of O2 by functionalizing a hydrogel bioink via addition of luminescent optical sensor nanoparticles. Rheological properties of the bioink enable 3D printing of hydrogel layers with uniform response to O2 concentration. Co-immobilization of sensor nanoparticles with green microalgae and/or mesenchymal stem cells does not affect cell viability over several days. Interference from microalgal autofluorescence on the O2 imaging is negligible, and no leakage or photobleaching of nanoparticles is observed over 2–3 days. Oxygen dynamics due to respiration and photosynthesis of cells can be imaged online and the metabolic activity of different cell types can be discriminated in intact 3D structures. Bioinks containing chemical sensor particles enable noninvasive mapping of cell metabolism and spatiotemporal dynamics of their chemical microenvironment in 3D-printed structures. This major advance now facilitates rapid evaluation of cell activity in printed constructs as a function of structural complexity, metabolic interactions in mixed species bioprints, and in response to external incubation conditions