(193h) Increasing Single Wall Carbon Nanotube Delivery to Macrophages by Independent Modifications of the Material and Cellular Activity

Single wall carbon
nanotubes (SWCNTs) are a class of nanomaterials with unique physical and
optical properties which make SWCNTs well-suited for biomedical applications.
Recent studies have shown the potential for SWCNT use as drug and gene delivery
vectors, imaging probes for cellular labeling and tracking, molecular sensors, and
for thermal ablation of cells in situ. SWCNTs are routinely dispersed in
aqueous solution using polyethylene glycol (PEG) copolymers, lipids, and
proteins. Yet, there remains a limited mechanistic understanding of how different
molecular SWCNT surface coatings interact with a complex, dynamic cellular
state, such as those found in immune cells. Nanomaterial interactions with
cells of the immune system, such as macrophages, are particularly important for
determining mechanisms of toxicity and developing specific medical therapeutics
for inflammation and cancer detection. We investigated the differential effects
of SWNCT dispersion with bioinert Pluronic F-127 (PF127) polymer and bioactive
bovine serum albumin (BSA) protein on SWCNT uptake and localization in J774A.1
macrophages and NIH-3T3 fibroblasts. We also examined stimulation of
macrophages with lipopolysaccharide (LPS) to measure effects of cell state on SWCNT
uptake.

We quantified cellular
uptake of SWCNTs over three orders of magnitude (1-100 μg/ml) using
Raman spectroscopy. Macrophages exhibited a steady dose dependent increase in
cell associated SWCNTs with approximately double the effect for BSA-SWCNTs
compared to PF127-SWCNTs. Cells treated with BSA-SWCNTs showed gross changes in
size, morphology, proliferation capability and other phenotypic changes. In
contrast, these cellular changes were not observed for macrophages with
PF127-SWCNTs or fibroblasts with either PF127-SWCNTs or BSA-SWCNTs.  Cellular
stimulation with LPS increased uptake, and an additive effect was observed for
pre-stimulated macrophages with increasing SWCNTs, but the uptake of BSA-SWCNTs
plateaued at higher exposure concentrations.  Taken together, these results
indicate the sensitivity of macrophage uptake to bioactive SWCNT coatings and
cellular stimulation, as well as the ability of macrophages to adapt for
increased uptake of bioactive coated SWCNTs.