Over the past decade, genetically encoded biosensors have proved to be powerful reporters of cellular activities, as shown using a variety of model organisms. They are highly amenable to customized designs to suit experimental needs, as they vary in fluorescence range, kinetics, and cellular compartmental targeting. They can be incorporated into a variety of cell types to support research into multiple physiological systems and processes. Although there are many immortalized human cell lines available, tissue-specific cell types that are not immortalized in vitro offer many experimental advantages, including retention of innate cellular functionalities that more accurately reflect in vivo human cellular functions.
At Tempo Bioscience, we developed a set of calcium and voltage biosensors that target different cellular compartments. We have incorporated these biosensors into human induced pluripotent stem cell (iPSC-) derived cell types, such as neural stem cells, astrocytes, and other neural cell types. Here, we report a new set of biosensor assays and show how they can be used for basic research, drug discovery, and chemical compound screening.
Currently, chemical dyes/sensors demonstrate difficulties targeting to specific cellular organelles and tend to compartmentalize randomly, before getting extruded from the cell during lengthy recording experiments (e.g., accumulation in cellular organelles). Genetically based biosensors can be tunable and more precisely targeted, using rational molecular and structural designs. The intensity changes at Excitation/Emission (Ex/Em) wavelengths are greater in magnitude for single-fluorophore reporters than traditional FRET-based biosensors. Unlike chemical biosensors, such as Fura-2, there is no ratiometric response, thereby making single-fluorophore biosensors more sensitive as reporters. This is advantageous for calibration and quantitative imaging measurements.