Fig. 1

UV spectroscopy analysis. a GNP spectrum shows maximum absorbance and peak at 520 nm, b GNP–Cys at 520 nm, c GNP–Cys–Dox at 510 nm and at 290 nm. d UV spectrum of GNP theranostic nanomedicines shows a red shift in peak and now the inorganic peak with maximum absorption is at 525 nm with absorption 0.650 and organic peak is at 340 with absorption 0.573. e Optical properties of gold nanoparticles with different sizes: a10, b 25, c 50, d 70, e 100, f > 100, g > 500. f Final GNP theranostic nanomedicine shows the fluorescence under UV excitation, blue excitation and green excitation filters with strong fluorescence in blue filter. g, h Excitation and emission spectra of GNP and nanomedicine show emission at 362.3 nm with different intensities 168.9 for GNP and 116.2 for GNP theranostic nanomedicine