AuNP and its
dendrimer nanoconjugates were imaged using a MultiMode Atomic Force
Microscope (Bruker, Santa Barbara, CA). Bruker
SCANASYST cantilevers
of nominal 0.7 N/m spring constant and 120–180 kHz resonance
frequency were used for AFM imaging in PBS buffer. Prior to imaging,
the vertically engaging E-scanner was calibrated for accuracy in the
x,
y,
z direction by using
a 1 μm grid with a depth of 20 nm. Mica substrates were prepared
for imaging as follows. Freshly cleaved mica was modified with a 100
μL deposit of 0.01% 3-(aminopropyl)triethoxysilane (APTES) solution.
After a 20 min incubation period, the mica surface was rinsed six
times with 1 mL aliquots of nanopure water and dried with compressed
nitrogen. The modified mica substrate was incubated for 5 min with
10 μL of conjugate AuNP and placed in the AFM fluid cell holder
for imaging. All images were collected in fluid
SCANASYST mode under
PBS buffer (pH 7.4) with a scan rate of 1 Hz. Digital resolution of
each image was 512 × 512 pixels.
Witte A.B., Leistra A.N., Wong P.T., Bharathi S., Refior K., Smith P., Kaso O., Sinniah K, & Choi S.K. (2014). Atomic Force Microscopy Probing of Receptor–Nanoparticle Interactions for Riboflavin Receptor Targeted Gold–Dendrimer Nanocomposites. The Journal of Physical Chemistry. B, 118(11), 2872-2882.