To investigate the morphology of CUR-NP and to confirm size data obtained by DLS measurements, AFM was performed using a Nanowizard 3® (JPK Instruments, Berlin, Germany) and a Digital Nanoscope IV Bioscope (Veeco Instruments, Santa Barbara, CA, USA), respectively. Formulations were diluted 1:100 with water and 20 µL of the diluted sample were placed onto a silica wafer or an untreated microscopic glass slide. The samples were left to settle onto the surface for a few minutes and the remaining fluid was absorbed by a lint-free wipe (Kimtech Precision Wipes, Kimberly-Clark, Fullerton, CA, USA). Measurements were performed in tapping mode, in which the cantilever oscillated with determined amplitude close to its resonance frequency, with scan rates from 0.5 to 1 Hz. A HQ:NSC16/AL_BS (Anfatec Instruments, Oelsnitz, Germany) cantilever was used [37 (link)]. Data were processed using JPKSPM data processing software (v. 5.1.8, JPK instruments).
For the TEM analysis, the nanoparticle suspension was applied onto 300-mesh copper grids. Samples were then negative stained thrice with 2% uranyl acetate (pH 4.2), which was alternated by washing steps with water. The samples were then allowed to dry overnight before being examined under the TEM (LEO 912 AB, Carl Zeiss, Jena, Germany) [22 (link)].
For the TEM analysis, the nanoparticle suspension was applied onto 300-mesh copper grids. Samples were then negative stained thrice with 2% uranyl acetate (pH 4.2), which was alternated by washing steps with water. The samples were then allowed to dry overnight before being examined under the TEM (LEO 912 AB, Carl Zeiss, Jena, Germany) [22 (link)].