Conformational SERS Classification of K‐Ras Point Mutations for Cancer Diagnostics

Point mutations in Ras oncogenes are routinely screened for diagnostics and treatment of tumors (especially in colorectal cancer). Here, we develop an optical approach based on direct SERS coupled with chemometrics for the study of the specific conformations that single‐point mutations impose on a relatively large fragment of the K‐Ras gene (141 nucleobases). Results obtained offer the unambiguous classification of different mutations providing a potentially useful insight for diagnostics and treatment of cancer in a sensitive, fast, direct and inexpensive manner.     

Bio‐Inspired Carbon Monoxide Sensors with Voltage‐Activated Sensitivity

Carbon monoxide (CO) outcompetes oxygen when binding to the iron center of hemeproteins, leading to a reduction in blood oxygen level and acute poisoning. Harvesting the strong specific interaction between CO and the iron porphyrin provides a highly selective and customizable sensor. We report the development of chemiresistive sensors with voltage‐activated sensitivity for the detection of CO comprising iron porphyrin and functionalized single‐walled carbon nanotubes (F‐SWCNTs). Modulation of the gate voltage offers a predicted extra dimension for sensing. Specifically, the sensors show a significant increase in sensitivity toward CO when negative gate voltage is applied. The dosimetric sensors are selective to ppm levels of CO and functional in air. UV/Vis spectroscopy, differential pulse voltammetry, and density functional theory reveal that the in situ reduction of Fe^III to Fe^II enhances the interaction between the F‐SWCNTs and CO. Our results illustrate a new mode of sensors wherein redox active recognition units are voltage‐activated to give enhanced and highly specific responses.     

Trichalcogenasumanene ortho‐Quinones: Synthesis,Properties, and Transformation into Various Heteropolycycles

The regioselective transformation of heterobuckybowl trichalcogenasumanenes 1 a , b at peripheral butoxy groups afforded trichalcogenasumanene ortho ‐quinones 2 a , b . Compounds 2 a , b are distinct from 1 a , b in terms of their molecular geometry and electronic state; that is, they have a shallower bowl depth and show absorbance in the NIR region. The reaction of 2 a , b with diamines resulted in a variety of heteropolycycles, including molecular spoon 3 a – 6 a , planar π‐systems 3 b – 6 b , and highly twisted [7‐6‐6]‐fused systems 7 a , b . These new heteropolycycles had different optical/electrical properties: 4 a,b showed hole mobility of approximately 0.002 cm² V⁻¹ s⁻¹, 6 a displayed red emission in both solution and the solid state, and 7 a , b formed tight stacks of the curved π‐surface.     

Luciferases with Tunable Emission Wavelengths

We introduce luciferases whose emission maxima can be tuned to different wavelengths by chemical labeling. The luciferases are chimeras of NanoLuc with either SNAP‐tag or HaloTag7. Labeling of the self‐labeling tag with a fluorophore shifts the emission maximum of NanoLuc to that of the fluorophore. Luciferases with tunable colors have applications as reporter genes, for the construction of biosensors and in bioimaging.