Bioeffects of Gold Nanorods as a Function of Aspect Ratio and Surface Chemistry
Interim rept. May 2011-Nov 2012
OAK RIDGE INST FOR SCIENCE AND EDUCATION WRIGHT-PATTERSON AFB OH
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One of the major challenges to the use of nanoparticles as drug delivery agents is that nanoparticles often become trapped in endosomes unable to reach their desired target. Functionalization of gold nanorods GNRs was used in this study to attempt delivery outside of endosomes as well as study the role of surface chemistry and aspect ratio AR on bio-effects relevant to delivery applications. GNRs were used in this study due to their unique optical properties and enhanced delivery abilities. GNRs were synthesized with ARs 3 and 6 and functionalized with negatively charged tannic acid TA and carboxylic acid COOH as well as positively charged TAT transactivator of transcription peptide with the sequence GRKKRRQRRRPQ and TAT HA2 hemaglutanin peptide with the sequence RRRQRRKKRGGDIMGEWGNEIFGAIAGFLG. After functionalization all the GNRs used in the study were biocompatible, making them applicable for biological applications. The cellular uptake of GNRs into keratinocytes was dependent on both AR and surface charge. AR 6 GNRs showed quantitatively higher uptake than AR 3 GNRs. Additionally, positively charged GNRs had higher uptake than negatively charged GNRs. Further studies showed that surface chemistry played a role in the uptake pathway used. TAT, TAT HA2, and COOH GNRs were uptaken by a variety of mechanisms of endocytosis. TA GNRs, however, were uptaken independently of endocytosis resulting in a unique orientation of TA GNRs within cells. This result makes TA GNRs extremely useful for the development of delivery, bio-imaging, and therapeutic applications.
- Anatomy and Physiology
- Physical Chemistry