Editors Letter Cite This: ACS Chem. Biol. 2018, 13, 1695−1696
Special Issue on Sensors in Biology
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cence methods due to the fact that ion concentrations can vary with cell morphology or between different cell types. Ratiometric approaches, which are based on the ratio between two fluorescence intensities, measure emission shifts rather than intensity changes and allow for the imaging of analytes sensitive to environmental dynamics. An article from Chris Chang (University of California, Berkeley), led by first author Shang Jia, delineates how small structural changes can be used to prepare a family of copper-responsive dyes based on a rhodol fluorophore scaffold. A report from Yan Qin and lead author Dylan Fudge (University of Denver) describes the development of a series of genetically encoded, zinc-responsive FRET reporters that are optimized to measure changes in the labile zinc pool in the mitochondrial matrix. Masato Niwa and Tasuku Hirayama (Gifu Pharmaceutical University) report the development of a membrane-anchoring fluorescent sensor for Fe(II) and its application to fluorescent imaging of Fe(II) release in endosomes following uptake of transferrin. A critical application of biosensing includes the development of diagnostics for the detection of analytes or aberrant activities that signal disease states. Kamalpreet Singh, Adrian Rotaru, and Andrew Beharry (University of Toronto) provide an overview of various classes of fluorescent chemosensors and their targets for cancer detection. Jefferson Chan and firstauthor Hailey Knox (University of Illinois at Urbana− Champaign) describe the development of N-oxide functionalized BODIPY dyes as photoacoustic probes for imaging of tumor hypoxia. David Wilson and Eric Kool (Stanford University) summarize numerous fluorescent probes for sensing DNA repair activity in living systems, as a means for detecting disease states associated with the DNA damage response. While dyes and probes have provided crucial insight into the inner workings of the cell, there remain many unique tools for sensing in biological systems. A review from William Peveler (University of Glasgow) and Russ Algar (University of British Columbia) highlights “unconventional” fluorescent sensor architectures, including multifluorophore FRET networks, nanomaterials such as quantum dots, temporal multiplexing, logic sensors, and more. Ganglin Wang, Zhi Li, and Nan Ma (Soochow University) review DNA-functionalized quantum dots for biosensing and bioimaging. Beyond imaging, analytical methods are also highly useful for sensing. Mario Modena and Andreas Hierlemann review methods for monitoring cell culture systems, including electrochemical sensing platforms, acoustic-wave sensors and actuators, surface plasmon resonance sensors, and more. Nancy Allbritton, David Lawrence, and lead author Brianna Vickerman (University of North Carolina, Chapel Hill) offer a comprehensive review of chemical cytometry, covering a variety of molecular sensors for detecting cellular analytes. Theodore Zwang, Edmund Tse, and Jacqueline Barton review methods for leveraging DNA
issues, cells, and cellular components such as organelles, DNA, and protein comprise an intricate array of complex, interactive processes that support life. For many years, chemical details of many of these processes have been opaque. Chemical biologists have led the development of sensors, probes, dyes, and diagnostics capable of detecting, often with tremendous precision and detail, various aspects of the inner workings of the cell. The ability to sense single molecules, enzymatic activity, signaling events, and disease states has illuminated our view of the cell and enhanced our understanding of biological systems. In this special issue, we highlight some of the recent advances in biological sensing and imaging and future directions for the field. Small molecule fluorescent probes have long been a staple of the chemical biologist’s toolbox for detecting and monitoring cellular processes. A Review from Wen Chyan and Ronald Raines (Massachusetts Institute of Technology) outlines recent advances in the use of fluorogenic probes for monitoring various types of enzyme activity in cellular systems. Itaru Hamachi and Shigeki Kiyonaka (Kyoto University) report the construction of fluorophore-labeled AMPA-type glutamate receptors (AMPARs) that act as turn-on sensors for AMPAR ligands in live cells. Hui Ling Chang and Bengang Xing (Nanyang Technological University) report the synthesis and characterization of a fluorescent probe for selective sensing of the β-lactamase AmpC to detect drug-resistant bacteria, including Gram-negative P. aeruginosa and Gram-positive E. faecium. Baoli Dong, Xiuqi Kong, and Weiying Lin (University of Jinan) review recent progress in the development of small molecule fluorescent probes to detect nitroxyl in cells. Robert Campbell and lead author Jiahui Wu (University of Alberta) engineer fluorescent protein-based genetically encoded neurotransmitter indicators capable of sensing glutamate in cells, with opportunities for multicolor imaging. Bioluminescent platforms, based on naturally occurring luciferases and luciferins, are powerful tools for imaging live cells and organisms. A major advantage of bioluminescence imaging is the emission wavelength of firefly luciferase (560 nm), which can be imaged several centimeters deep within tissue and enables imaging of tissues and organs. Stephen C. Miller, David Mofford, and Spencer Adams review new advances in the development of luciferin-based bioluminescent probes. A research article from Takeharu Nagai, led by Md Nadim Hossain (Osaka University), offers a new approach for detecting calcium dynamics in the sarco/endoplasmic reticulum using bioluminescent protein-based genetically encoded Ca2+ indicators. Andrew Dippel and Ming Hammond (University of California, Berkeley) developed a chemiluminescent biosensor for the detection of cyclic di-GMP by combining split luciferase complementation with bioluminescence resonance energy transfer. Sensors for detecting ionic analytes provide key insights into mechanisms of cellular homeostasis. Sensing dynamic changes in cellular pH, voltage potential, and intracellular ion concentrations can be a challenge using traditional fluores© 2018 American Chemical Society
Special Issue: Sensors Published: July 20, 2018 1695
DOI: 10.1021/acschembio.8b00593 ACS Chem. Biol. 2018, 13, 1695−1696
ACS Chemical Biology
Editors Letter
charge transport chemistry to electrically sense changes to DNA that disrupt base pair stacking, including lesions and protein binding. Yimon Aye and first author Sanjina Surya (Cornell University) use the T-REX platform developed in their laboratory to characterize small heat shock protein B7 (HSPB7) as a sensor for reactive electrophilic signals (RES) in striated muscle, due to a single reactive cysteine residue able to covalently bind RES ligands. Our privileged view into the cell would not be possible without the discoveries of Roger Tsien, whose Nobel Prizewinning work on green-fluorescent protein paved the way for modern bioimaging. Our Spotlight highlights not only his brilliant career, but also his relationships with his students, colleagues, and family. The topics covered in this special issue show that the future of biological sensing and imaging remains exciting, innovative, and most of all, bright.
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Alyson G. Weidmann Dan Yang, Guest Editor AUTHOR INFORMATION
ORCID
Alyson G. Weidmann: 0000-0003-3876-2847 Dan Yang: 0000-0002-1726-9335 Notes
Views expressed in this editorial are those of the authors and not necessarily the views of the ACS.
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DOI: 10.1021/acschembio.8b00593 ACS Chem. Biol. 2018, 13, 1695−1696
