In vitrotoxicity studies of polymer-coated gold nanorods

Abstract

We evaluated cellular responses to polymer-treated gold nanorods, which were synthesized using the standard wet-chemistry method that utilizes hexadecyltrimethylammonium bromide (CTAB). The nanorod dispersions were coated with either polystyrene sulfonate (PSS) or polyethylene glycol (PEG). Two sizes of nanorods were tested, with optical responses peaking at 628 and 773 nm. The cells were from mammary adenocarcinoma (SKBR3), Chinese Hamster Ovary (CHO), mouse myoblast (C2C12) and Human Leukemia (HL60) cell lines. Their mitochondrial function following exposure to the nanorods were assessed using the MTS assay. We found PEGylated particles to have superior biocompatibility compared with PSS-coated nanorods, which showed substantial cytotoxicity. Electron microscopy showed no cellular uptake of PEGylated particles compared with their PSS counterparts. PEGylated gold nanorods also exhibited better dispersion stability in the presence of cell growth medium; PSS-coated rods tended to flocculate or cluster. In the case of the PSS particles, toxicity correlated with surface area across the two sizes of nanorods studied.

On Biodecorated Gold Nanoparticles Distributed within Tissues and Cells

“…It has been shown that the gold nanorods coated with PEG display a lower cytotoxicity, penetrate into cells to a lesser degree, and are more stable in culture medium when compared with the AuNRs modified with poly(sodium styrene sulfonate) (PSS) [35]. In addition to PEG and PSS, other substances are also used to decrease nanorod cytotoxicity via CTAB substitution or the creation of an additional surface layer, namely, phosphatidylcholine [36].…”

“…Nanoparticles have high surface-to-volume ratios when compared with large particles and are usually smaller than several hundred nanometers in size, comparable to large biological molecules, of a size about 100 to 10,000 times smaller than human cells. The range of studied gold nanoparticles covers more than two orders of magnitude from the minimal size of 1.0, 1.2 or 1.4 nm (atomic cluster Au 15 , Au 35 or Au 55 ) [2] to the maximal size of 250 nm [3].…”

Microspectroscopic characterisation of gold nanorods for cancer detection

“…Q ext is the extinction efficiency of a particle calculated using the Discrete Dipole Approximation method, DDSCAT, 151,152 and r is the radius of an equivalent sphere obtained from actual size determination from SEM images (data not shown, see Rayavarapu et al 81 ). The PEG-GNR aspect ratio of 2.4 ± 0.2 was derived from analysis of at least 250 particles in each case from SEM images, as was shown by Rayavarapu et al 81 …”

“…22,150 In the GNR synthesis, gold seeds are added to a growth solution, which contains the shape directing surfactant hexadecyltrimethylammonium bromide (CTAB). CTAB is cytotoxic 37,81,144 and therefore, in general, GNR are PEGylated. 44,78,81,144 Here, we PEGylated all but one GNR sample, in the manner previously described.…”

“…CTAB is cytotoxic 37,81,144 and therefore, in general, GNR are PEGylated. 44,78,81,144 Here, we PEGylated all but one GNR sample, in the manner previously described. 81,170 In biomedical applications, PEG-GNR are directed to the cell surface using antibodies.…”