**Abbreviations**

AuNCs: gold nanoclusters; AuBSA: abbreviation used in this study for the particular AuNCs embedded in BSA being prepared by the described synthetic procedure; BSA: bovine serum albumin; BSA-AuNCs: general abbreviation for AuNCs embedded in BSA being published within the scientific literature, i.e., regardless the consideration of the exact experimental conditions; CW-EPR: continuous wave electron paramagnetic resonance; DFT: density functional theory; EDS: energy dispersive X-ray analysis; EX/EM: excitation/emission; EXAFS: extended X-ray absorption fine structure; HAADF: high-angle annular dark field; HR-TEM: high resolution transmission electron microscopy; l-DOS: local density of states; LEPR: light-induced electron paramagnetic resonance; MS: mass spectrometry; MW: microwaves; NCs: nanoclusters; SPR: surface plasmon resonance; STEM: scanning transmission electron microscopy; UV: ultraviolet; vis: visible; XANES: X-ray absorption near-edge structure; XAS: X-ray absorption spectroscopy; XPS: X-ray photoelectron spectroscopy; XRD: X-ray diffraction.
