Single enzyme direct biomineralization of ZnS, Zn_xCd_1−xS and Zn_xCd_1−xS–ZnS quantum confined nanocrystals

Abstract

ZnS, ZnxCd1−xS, and ZnxCd1−xS–ZnS quantum dots were synthesized in the aqueous phase at room temperature via biomineralization enabled by a single enzyme in solution.

In Situ Biomineralization of CuxZnySnzS4 Nanocrystals within TiO2-Based Quantum Dot Sensitized Solar Cell Anodes

“…Therefore, optical, structural, and compositional analysis results are all consistent with the formation of quantum confined SnS nanocrystals, confirming that our single enzyme biomineralization approach can be extended for SnS biomineralization. As noted above, we have reported the application of our enzymatic direct biomineralization synthesis method to the formation of CuS and ZnS quantum confined nanocrystals, , and in combination, these results point to the feasibility of CZTS biomineralization.…”

“…Therefore, optical, structural, and compositional analysis results are all consistent with the formation of quantum confined SnS nanocrystals, confirming that our single enzyme biomineralization approach can be extended for SnS biomineralization. As noted above, we have reported the application of our enzymatic direct biomineralization synthesis method to the formation of CuS and ZnS quantum confined nanocrystals, 34,35 and in combination, these results point to the feasibility of CZTS biomineralization. Incubation of a buffered mixture of Cu acetate, Zn acetate, tin chloride (Cu:Zn:Sn = 1:2:2 molar ratios), L-cysteine, and smCSE for 6 h yields solutions and nanocrystals with significantly different optical properties to those where only one of the metal precursors is present, Figure 3a.…”

“…Biomineralization of quantum confined metal sulfide nanocrystals via the smCSE enzyme has been described in detail in previous publications. ,− Briefly, the expression of smSCE cloned within a BL21 strain of E. coli was started by subculturing the plasmid in 200 mL of LB broth at 37 °C for 16 h. The main expression was induced at dilution of OD 600 = 0.8 by adding an additional 800 mL of LB broth and 1 mM IPTG at 20 °C and incubating for 16 h. The solution was then centrifuged at 3225 g for 10 min, and the pellet was resuspended in lysis buffer and sonicated for 30 min. The sonicated solution was centrifuged at 3225 g for 10 min prior to enzyme purification via immobilized metal affinity chromatography with 500 mM imidazole buffer.…”

Scalable Biomineralization of CdS Quantum Dots by Immobilized Cystathionine γ-Lyase

“…Low-temperature, aqueous phase biosynthetic routes, which rely on intracellular or extracellular enzymatic turnover of QD precursors, offer the potential for improved sustainability and satisfaction of numerous principles of green engineering owing to the use of an intrinsically “green” solvent, ambient reaction temperatures, water-soluble ligands, and the catalytic precision of enzymes. ,− Among biosynthetic approaches, environmentally benign and low-cost extracellular single-enzyme biomineralization of size-controllable QDs of a range of material compositions is possible, including CdS, CdSe, ZnS, PbS, CuInS 2 , CuZnSnS 4 , and Ag 2 S. − Specifically, pyridoxal phosphate (PLP)-dependent cystathionine γ-lyase (CSE) catalyzes the reaction of a variety of amino acid substrates, including l -cysteine, l -homocysteine, and l -cystine, leading to endogenous production of H 2 S and thus reactive HS – species. , For example, l -cysteine serves as both the sulfur source and QD capping agent for the biomineralization approach. Recent detailed quantitative assessment of the commercial viability of a number of common colloidal QD synthesis strategies for solar photovoltaics, which has carefully accounted for uncertainties in numerous processing variables, estimates that ca.…”

Tailored Coupling of Biomineralized CdS Quantum Dots to rGO to Realize Ambient Aqueous Synthesis of a High-Performance Hydrogen Evolution Photocatalyst

“…We have previously demonstrated a single-enzyme-based aqueous route for the synthesis of a variety of quantum-confined, semiconducting nanocrystals, including CdS and the reduction of graphene oxide to rGO. − Both CdS and CdS/rGO photocatalysts, although unstable over long periods of use, have been widely studied for water splitting, providing a basis for this demonstration of the potential for bioinspired and biological synthesis. rGO is often used in chemically synthesized photocatalysts as a support that can accept photoexcited electrons from CdS to suppress charge recombination, increase exciton lifetime, and ultimately increase H 2 production rates .…”