H 8100

Transmission electron microscopy (TEM) (Hitachi H-8100) was used to characterize the surface morphology of CNPs and GNs. Raman spectra were measured with a SENTERRA dispersive Raman microscope spectrometer (Bruker Optics). A SHIMADZU UV-1800 spectrophotometer was used for UV-Vis measurements. MALDI-TOF-MS analyses were carried out using a 4800 MALDI TOF/TOF analyzer (AB SCIEX) equipped with a pulsed Nd:YAG laser at an excitation wavelength of 355 nm. For each MS spectrum 1250 laser shots were fired (50 sub-spectra, 25 shots per sub-spectrum). The mass spectra analyzed using Data Explorer 4.9 software (AB SCIEX). GlycoWorkbench software was employed for MS data interpretation.

Exosome bound beads were resuspended in 200 μL 1× cold PBS solution and washed 2 times with pure water followed by the fixation in a 2% EMS-quality paraformaldehyde aqueous solution for electron microscopic imaging. A 5 μL sample was added to cleaned silicon chips and immobilized after air dry in a ventilation hood. Samples on silicon chips were mounted on a SEM stage by carbon paste. A ~5 nm coating of gold-palladium alloy was applied to improve SEM image background. The SEM imaging was performed under low beam energies (7 kV) on a Hitachi SU8230 filed emission scanning electron microscope. For immune staining TEM imaging, a solution of 1× PBS and 0.1% BSA (1 mL) was prepared, then a 50 μL of the solution was mixed with ~2.5 μL gold conjugated CD63 antibody (6 nM) and the prepared exosome sample grid in a clean 1.5 mL Eppendorf tube. This was incubated for 1 h at room temperature. Afterwards, the sample grid was be soaked in 100 μL MilliQ pure water for 30 sec. and transferred onto filter paper to remove all liquid and dried at room temperature for 20 min. Five minutes of negative staining with 2% aqueous uranyl acetate was followed by distilled water washes. Images were acquired at 75 kV using a Hitachi H-8100 transmission electron microscope.