Plug-and-play metabolic transducers expand the chemical detection space of cell-free biosensors

TLDR

Cell‑free transcription–translation systems hold promise for biosensing, but their detectable chemical range remains limited. The authors propose a workflow to expand this range by integrating synthetic metabolic cascades with transcription factor‑based networks. The workflow couples metabolic conversion of target molecules to transcription factor activation within a cell‑free platform. The resulting hybrid biosensors exhibit rapid response, strong signal amplification, a wide dynamic range, and function in complex media such as beverages and human urine, enabling detection of clinically relevant small‑molecule concentrations and providing a modular platform for diverse applications.

Abstract

Abstract Cell-free transcription–translation systems have great potential for biosensing, yet the range of detectable chemicals is limited. Here we provide a workflow to expand the range of molecules detectable by cell-free biosensors through combining synthetic metabolic cascades with transcription factor-based networks. These hybrid cell-free biosensors have a fast response time, strong signal response, and a high dynamic range. In addition, they are capable of functioning in a variety of complex media, including commercial beverages and human urine, in which they can be used to detect clinically relevant concentrations of small molecules. This work provides a foundation to engineer modular cell-free biosensors tailored for many applications.