Sct 320

To characterize nIRCats after synthesis, the full visible and nIR absorption spectrum was taken for each nanosensor batch (UV-VIS-nIR spectrophotometer, Shimadzu UV-3600 Plus) or UV-VIS (Thermo Fisher Scientific Genesys 20). SWNT concentrations of as-made nanosensor batches were determined using absorbance at 632 nm (UV-VIS) with an extinction coefficient of ε = 0.036 (mg/liter)⁻¹ cm⁻¹. Full spectrum absorbance measurements were made with UV-VIS-nIR after dilution to an SWNT concentration of 5 mg/liter in 100 mM NaCl. For fluorescence spectroscopy, each sensor batch was diluted to a working concentration of 5 mg/liter in 100 mM NaCl, and aliquots of 198 μl were placed in each well of a 96-well plate (Corning). Fluorescence measurements were obtained with a 20× objective on an inverted Zeiss microscope (Axio Observer D1) coupled to a Princeton Instruments spectrograph (SCT 320) and a liquid nitrogen–cooled Princeton Instruments InGaAs linear array detector (PyLoN-IR). A 721-nm laser (Opto Engine LLC) was used as the excitation light source for all characterization experiments.

nIR fluorescence spectra were measured with a 20× objective on an inverted Zeiss microscope (Axio Observer.D1) coupled to a spectrograph (SCT 320, Princeton Instruments) and liquid nitrogen–cooled InGaAs linear array detector (PyLoN-IR, Princeton Instruments). A 721-nm laser (OptoEngine LLC) was used as the excitation light source for all spectroscopy and imaging studies. The absorption spectra were measured with a UV-3600 Plus absorption spectrophotometer (Shimadzu). Our custom nIR spectrometer and microscope have been described in detail in previous works (45 , 46 (link)).