(a)
(b)
(c)
(d)
Figure 2: (a) TEM image of GO-AuNS-DOTA-Gd nanoparticles; (b) distribution of the nanoparticles analyzed by DLS; (c) increased UV-Vis-NIR absorption spectra of various concentrations of GO-AuNS-DOTA nanoparticles in RPMI-1640 culture medium; (d) the absorbance of GO-AuNS-DOTA-Gd nanoparticles dispersed in RPMI-1640 culture medium at 808 nm increased as the concentration increased.