Surface chemistry-mediated penetration and gold nanorod thermotherapy in multicellular tumor spheroids

Abstract

We investigated the penetration and thermotherapy efficiency of different surface coated gold nanorods (Au NRs) in multicellular tumor spheroids. The current data show that negatively charged Au NRs, other than positively charged Au NRs, can penetrate deep into the tumor spheroids and achieve a significant thermal therapeutic benefit.

Fig. 1

Characterization of Au NRs. (a) TEM image of the CTAB-coated Au NRs. (b) UV-Vis-NIR absorption spectra of PDDAC-coated Au NRs, PSS-coated Au NRs and CTAB-coated Au NRs. (c) Suspension of Au NRs. (d-f) Zeta potential distribution of PDDAC (d), PSS (e) and CTAB-coated Au NRs (f).

Fig. 2

(A) ESEM images of MCF-7S spheroids after 7 days of culturing taken under a series of magnifications (Scale bar from left to right, 300 μm, 50 μm, 5 μm, 2 μm). (B) TEM images of cells on the outside (a) and inside (b) of the MCF-7 tumor spheroid (Scale bar, 2.0 μm).

Fig. 3

NIR thermal therapy effect. (A) Tumor spheroid viability after treatment with different Au NRs at 150 pM for 24 h. (B) The number of Au NRs per tumor spheroid after 24 h of treatment. (C) Thermal therapy efficiency of different Au NR calculated by the following formula: Thermal therapy efficiency = Viability loss/The number of Au NRs per MCTS. (D) HE staining. MCTSs were sectioned and stained after NIR laser radiation (Scale bar, 100 μm).

Fig. 4

Distribution of Au NRs in MCTSs. HE staining of the tumor spheroid treated with different Au NRs for 24 h (a, c. e). DF images of tumor spheroid treated with different Au NRs for 24 h (b. d. f). The bright spots in the DF images represent for the existence of Au NRs. In b and f, Au NRs are distributed mainly outside. In d, Au NRs are distributed both outside and inside (Scale bar, 100 μm).