Diinnova afm

Acquisition of AFM images was done on Bruker's diINNOVA AFM equipped with NanoDrive v8 real-time control & NanoScope Analysis system softwares. Void and formulated liposomes were diluted 10 times and were drop casted on glass slides. The samples were left to dry overnight before AFM imaging. Scanning mode used was tapping mode with scan rate of 3.41 μm/s and aspect ratio 1. Images were captured from random spots on the slides.

TEM images were taken on a JEOL JEM 2100 microscope at an accelerating voltage of 200 kV. SEM observation was performed on a JSM-6700F field emission SEM operating at 10 kV. The as-prepared UCNPs powder was characterized on an XRD-7000 diffractometer with a Cu K_α radiation. A Nano-ZS90 Zeta Sizer was used to determine zeta potentials of UCNPs and AuNRs. AFM was performed using a DI Innova AFM (Bruker) in light tapping mode. Optical absorption spectra were recorded using a UV-3600 UV-Vis-NIR absorption spectrophotometer. Upconversion fluorescent spectrum was measured via QuantaMasterTM40 spectrofluorometer equipped with a 250 mW 980 nm NIR laser diode. Fluorescence lifetime measurements were recorded on an FLsp920 spectrofluorometer (Edinburgh) with 980 nm laser light as the excitation source, which is a time-gated method compatible with the long lifetime of UCNPs. Upconversion luminescence images were achieved by a camera for 30 sec under the excitation for the tissue penetration depth test.