Figure 1.

Protein-aided synthesis of Mn-doped ZnS nanocrystals. (A) Schematic illustration of the biomineralization process mediated by the BB-TrxA::CT43 fusion protein. The antibody-binding BB domain (red), ZnS-binding loop (green) and TrxA framework (blue) are shown. (B) Influence of the Mn²⁺ concentration on the fluorescence of UV-excited biofabricated QDs. A no protein control is included. (C) Emission intensity at 590 nm of QDs mineralized in the presence of the indicated amount of Mn²⁺ (λ _ex = 280 nm). Error bars correspond to triplicate experiments. Absorption (D) and emission (E) spectra of QD mineralized in the absence (blue) or presence of 7.5% Mn (orange). A no protein control (black) is included. The peak centered at 670 nm that is visible in the blue curve and convoluted in the orange spectrum corresponds to the second order diffraction of the proteins’ tryptophan emission peak. The inset of Fig. D shows a HRTEM image of an Mn-doped (7.5%) ZnS nanocrystals bounded by a dashed line to facilitate visualization.