Further to confirm the successful conjugation of Cyt C and Zn Porph to AuNPs, they were characterized using UV-visible absorption absorption spectroscopy. UV-visible absorption spectroscopy is a widely used technique used when working with AuNPs as the absorption spectrum can determine both their size and concentration. The maximum absorbance of the surface plasmon resonance (SPR) peak in the spectra, located between 500 and 600 nm, is indicative of their size. Once the size and the extinction coefficient of the AuNPs are known, their concentration can be calculated using the Beer-Lambert law. , On the other hand, porphyrins are commonly conjugated in located within the peak and that the deconvolution accurately can determine the heights of the hidden peaks.