1 research outputs found
Effect of Gold Nanoparticle Size and Coating on Labeling Monocytes for CT Tracking
With advances in cell therapies,
interest in cell tracking techniques
to monitor the migration, localization, and viability of these cells
continues to grow. X-ray computed tomography (CT) is a cornerstone
of medical imaging but has been limited in cell tracking applications
due to its low sensitivity toward contrast media. In this study, we
investigate the role of size and surface functionality of gold nanoparticles
for monocyte uptake to optimize the labeling of these cells for tracking
in CT. We synthesized gold nanoparticles (AuNP) that range from 15
to 150 nm in diameter and examined several capping ligands, generating
44 distinct AuNP formulations. In vitro cytotoxicity and uptake experiments
were performed with the RAW 264.7 monocyte cell line. The majority
of formulations at each size were found to be biocompatible, with
only certain 150 nm PEG functionalized particles reducing viability
at high concentrations. High uptake of AuNP was found using small
capping ligands with distal carboxylic acids (11-MUA and 16-MHA).
Similar uptake values were found with intermediate sizes (50 and 75
nm) of AuNP when coated with 2000 MW polyÂ(ethylene-glycol) carboxylic
acid ligands (PCOOH). Low uptake values were observed with 15, 25,
100, and 150 nm PCOOH AuNP, revealing interplay between size and surface
functionality. Transmission electron microscopy (TEM) and CT performed
on cells revealed similar patterns of high gold uptake for 50 nm PCOOH
and 75 nm PCOOH AuNP. These results demonstrate that highly negatively
charged carboxylic acid coatings for AuNP provide the greatest internalization
of AuNP in monocytes, with a complex dependency on size