Polymer decorated gold nanoparticles as switchable delivery tools.

Purpose: Thermosensitive polymers decorated gold nanoparticles have been investigated as potential systems for intracellular controlled penetration. Results: Polymer conjugation induced reversible nanoparticles aggregation above the LCST. When MCF7 cells were treated with PNIPAM-gold at 40°C the penetration of nanoparticles was 88 times higher as compared to cells treated at 34°C. No temperature dependence was noted for naked nanoparticles. Cells treated at 40°C with PNIPAM-gold were susceptible to laser induced nano thermolysis. No sensitivity to irradiation was found for cells treated with naked nanoparticles or PNIPAM-gold at 34°C. Conclusions: Thermosensitive gold nanoparticles can be successfully used as stimuli induced cell penetrating agents with potential exploitation as therapeutic and diagnostic tools either fro in vivo or in vitro applications. These systems can be used to target selectively tumour tissues which undergo physiologic temperature increasing.