Get ready to dive into the world of biosensors and discover a groundbreaking innovation! We've developed a game-changing green calcium biosensor that shines brightly throughout its entire dynamic range. This sensor, named G-Ca-FLITS, is a true game-changer for precise calcium measurements.
In the world of biosensors, most sensors toggle between a bright and a dim state, which can lead to measurement errors. But G-Ca-FLITS is different. It maintains a consistent brightness, ensuring accurate and reliable measurements across its entire range.
We engineered this sensor by optimizing a bacterial screening method, resulting in a biosensor with a strong lifetime contrast. The key to its success lies in its ability to remain bright in both the calcium-free and calcium-saturated states. This unique feature sets it apart from traditional biosensors and opens up new possibilities for imaging low calcium concentrations and subsequent increases in mammalian cells, including mitochondria.
But here's where it gets controversial: G-Ca-FLITS challenges the conventional wisdom of biosensors. While most sensors have a (very) dim state when calcium levels are low, G-Ca-FLITS remains bright, making it an ideal tool for robust quantification of low and intermediate calcium concentrations.
And this is the part most people miss: the minimal change in intensity between the two states of G-Ca-FLITS results in a similar signal-to-noise ratio for both states. This means that the measurement precision is comparable in both low and high calcium concentrations, a significant advantage over traditional biosensors.
We put G-Ca-FLITS to the test and found that it performs exceptionally well. It showed negligible sensitivity to pH in the physiological range, just like its turquoise parent. Using fluorescence lifetime imaging (FLIM), we measured calcium concentrations in various organelles and observed transient and spatially heterogeneous calcium elevations in mitochondria of HeLa cells.
Furthermore, we evaluated the use of G-Ca-FLITS and its turquoise predecessor for two-photon FLIM in Drosophila brains. The results were impressive, with all three fluorophores exhibiting calcium-dependent signals in an intact brain.
So, what do you think? Is G-Ca-FLITS the future of calcium biosensors? We invite you to share your thoughts and opinions in the comments below. Let's spark a discussion and explore the potential of this innovative biosensor together!
