https://video.igem.org/videos/watch/1a5991a4-a47a-4d83-920a-bed3211c8733 Title: DigiCAT：A Multi-Threshold Biosensor for Monitoring of Feline Diabetic Ketoacidosis Description: Biological sensors usually convert continuous molecular inputs into continuous outputs, which limits their ability to make clear, programmable decisions. Our project develops a modular biological analogue-to-digital converter that transforms graded biochemical signals into discrete, multi-level outputs through tunable genetic thresholds. The system combines an upstream sensing module with recombinase-based comparators. By tuning promoter and ribosome-binding-site strengths, different recombinases are activated at distinct input concentrations, allowing a single molecular signal to be classified into defined ranges. These threshold modules can then drive different reporters or downstream genetic programs, creating a reusable framework for concentration-dependent decision making in living cells. To demonstrate the platform, we use β-hydroxybutyrate sensing as a proof of concept. BHB is first converted into acetoacetate by β-hydroxybutyrate dehydrogenase, then detected by the AtoS/AtoC system. Molecular docking, molecular dynamics simulations, and AI-assisted enzyme engineering are used to optimize signal transduction, while mathematical modeling guides threshold selection and circuit design. Official Page Sat, 29 Aug 2026 17:17:21 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://video.igem.org https://video.igem.org/client/assets/images/icons/icon-1500x1500.png https://video.igem.org/videos/watch/1a5991a4-a47a-4d83-920a-bed3211c8733 All rights reserved, unless otherwise specified in the terms specified at https://video.igem.org/about and potential licenses granted by each content's rightholder.