P3.11 - “All-in-one” cell-based biosensor for on-site monitoring of cell response

15. Dresdner Sensor-Symposium 2021
2021-12-06 - 2021-12-08
P3. (Bio-)Medizinische Sensorik
D. Özsoylu - Fachhochschule Aachen, Jülich/D, M. Schöning, T. Wagner - Forschungszentrum Jülich GmbH, Jülich/D
173 - 176


Biosensors play an important role in many areas and become part of our everyday life. They have rapidly been evolving and expanding due to the recent advances in material science, nano- and biotechnology, and microfluidics. The importance of biosensors has once again been demonstrated, particularly as a consequence of the coronavirus disease 2019 (COVID- 19). Biosensors, which utilize living cells, are called “cellbased biosensors”. This kind of biosensors can either detect the reaction of cells specific to analytes (for example, molecules or biomarkers) directly or monitor their physiologically relevant functions. The lightaddressable potentiometric sensor (LAPS) can be used as a biosensor, for which different regions (measurement sites) on the sensor surface can be addressed by light illumination. This feature represents a remarkable advantage in achieving spatial resolution in biosensing applications. For example, using a LAPS chip that has a pH-sensitive transducer layer, a desired sensing point on the sensor surface can be addressed to measure the extracellular acidification (EA) of the cells above that region. Moreover, a larger area can be addressed point-by-point in a scanning manner. In this way, the distribution of the concentration of the EA (extracellular pH (pHe)) can be visualized in form of a chemical image. Fig. 1 shows a representative schematic of the LAPS chip for cell investigations and its set-up. Despite an increased number of publications and research focusing on electrochemical cell-based biosensors to detect substances of interest such as pollutants, toxins, or viruses like SARS-CoV-2, there are only a few cell-based biosensors currently in use on the market. One important reason for this may be found in the biosensor principle, which contains a “living” component such as mammalian cells: their efficient preservation and transportation to the end-user of the sensor system in a ready-to-use concept is still a major challenge. This issue often hinders the practical applicability and commercialization. Therefore, there is a growing need for preservation methods and tools to enable ready-touse, on-site and on-demand concepts. In this study, a strategy (that is called on-sensor cryopreservation) has been developed, based on a method for preserving living components directly on a biosensor surface by freezing (-80 °C). To achieve a high cell recovery after the cryopreservation process, the rigid sensor surface (Ta2O5) was modified with elastic electrospun polymer fibers consisting of polyethylene vinyl acetate (PEVA), which has a low glass-transition temperature and a high thermal expansion coefficient. The biosensor chip is consequently integrated into a microfluidic system to obtain a cryo-chip, which is important for precise control of the microenvironment. This miniaturization ensures a fast thawing process that has a vital impact on cell survival.