Plug-and-play protein biosensors using aptamer-regulated in vitro transcription
Heon Joon Lee, Tian Xie, Byunghwa Kang, Xinjie Yu, Samuel W. Schaffter, Rebecca Schulman
Abstract
Molecular biosensors that accurately measure protein concentrations without external equipment are critical for solving numerous problems in diagnostics and therapeutics. Modularly transducing the binding of protein antibodies, protein switches or aptamers into a useful output remains challenging. Here, we develop a biosensing platform based on aptamer-regulated transcription in which aptamers integrated into transcription templates serve as inputs to molecular circuits that can be programmed to a produce a variety of responses. We modularly design molecular biosensors using this platform by swapping aptamer domains for specific proteins and downstream domains that encode different RNA transcripts. By coupling aptamer-regulated transcription with diverse transduction circuits, we rapidly construct analog protein biosensors and digital protein biosensors with detection ranges that can be tuned over two orders of magnitude and can exceed the binding affinity of the aptamer. Aptamer-regulated transcription is a straightforward and inexpensive approach for constructing programmable protein biosensors that could have diverse applications in research and biotechnology. Biosensors that accurately detect proteins are critical for biological applications, but modular transduction of binding into useful outputs is a challenge. Here, authors develop a modular platform using aptamer-regulated transcription to detect proteins and process RNA outputs via molecular circuits.