5420 atomic force microscope

The synthesized conjugates (20 µg mL⁻¹) were tested with UV-vis spectroscopy in a 1 cm quartz cell by using Shimadzu UV-2600 spectrometer. Then the fluorescent emission spectra of the same samples were recorded by Horiba Jobin Yvon Fluorolog-3 with slit width 5 nm for both excitation and emission. The solid FTIR study was performed on a PerkinElmer FTIR (Frontier) spectrometer using the attenuated total reflection (ATR) technique which uses the ATR prism alone as the background. The matrix-assisted laser desorption ionization time of flight (MALDI-TOF) was measured by a Bruker autoflex speed spectrometer. Transmission electron microscopic (TEM) studies were conducted with the JEOL 1200X TEM and atomic force microscopic (AFM) studies were done by an Agilent 5420 atomic force microscope using the tapping mode. Each characterization study was repeated with different batches of C-dots-conjugates to verify the consistency of the data and the stability of the complexes.

The UV/Vis absorption spectra of three CDs fractions were obtained by using a Cary 100 UV/Vis spectrophotometer and a 1cm optical cell. A Fluorolog (Horiba Jobin Yvon) spectrometer was used to record the fluorescence emission spectra of sample with a slit width of 5 nm used for both excitation and emission. As for the determination of fluorescence quantum yield, a Varian Cary Eclipse spectrometer was used to record the fluorescence spectra of samples and standards. Fourier-transform infrared (FTIR) spectroscopy data were obtained with a PerkinElmer FTIR (Frontier) spectrometer by using the attenuated total reflection (ATR) technique with air as background. XPS data was acquired using a Perkin-Elmer PHI 560 system with a double-pass cylindrical mirror analyzer operated using a Mg Kα anode with a hʋ = 1253.6 eV photon energy operated at 250 Watts and 13 kV. Zeta potential measurements were made by using a nano series Malvern Zetasizer. AFM images were obtained with an Agilent 5420 atomic force microscope by using the tapping mode. TEM was performed by using a JEOL 1200X TEM.