Detoxification of gold nanorods by treatment with polystyrenesulfonate.
We address an outstanding issue associated with the biocompatibility of gold nanorods (GNRs), a promising agent for biomedical imaging and theragnostics. GNRs are typically prepared in the presence of cetyltrimethylammonium bromide (CTAB), a cationic surfactant whose rigorous removal is necessary due to its cytotoxicity and membrane-compromising properties. CTAB-stabilized GNRs can be partially purified by treatment with polystyrenesulfonate (PSS), an anionic polyelectrolyte often used as a surrogate peptizing agent, followed by chloroform extraction and ultrafiltration with minimal loss of dispersion stability. However, in vitro cytotoxicity assays of PSS-coated GNRs revealed IC(50) values in the low to submicromolar range, with subsequent studies indicating the source of toxicity to be associated with a persistent PSS-CTAB complex. Further exchange of CTAB-laden PSS with fresh polyelectrolyte greatly improves biocompatibility, to the extent that 85 microg/mL of "CTAB-free" GNRs (the highest level evaluated) has comparable toxicity to a standard phosphate buffer solution. Ironically, PSS is not effective by itself at stabilizing GNRs in CTAB-depleted suspensions: while useful as a detergent for GNR detoxification, it should be replaced by more robust coatings for long-term stability under physiological conditions.
Leonov
Alexei P
AP
Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
Zheng
Jiwen
J
Clogston
Jeffrey D
JD
Stern
Stephan T
ST
Patri
Anil K
AK
Wei
Alexander
A
D045744:Cell Line, Tumor; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry
D002593:Cetrimonium Compounds; D011137:Polystyrenes; C071389:polystyrene sulfate; D006046:Gold; D000077286:Cetrimonium