February 26, 2024

Princeton Chemists Create Quantum Dots at Room Temperature Using Custom Protein

An image of quantum dots taken under an electron microscope. These quantum dots were produced in the Hecht Lab using de novo proteins.
Thats the terrain where Michael Hecht, professor of chemistry, deals with his research study group. And just recently, their interest for creating their own sequences settled.
They found the first recognized de novo (newly produced) protein that catalyzes, or drives, the synthesis of quantum dots. Quantum dots are fluorescent nanocrystals used in electronic applications from LED screens to photovoltaic panels.
Their work opens the door to making nanomaterials in a more sustainable way by demonstrating that protein sequences not originated from nature can be used to synthesize functional materials– with pronounced benefits to the environment.

Teacher Michael Hecht and his research group at Princeton have made a significant discovery in the field of chemistry by creating the first known de novo protein that catalyzes the synthesis of quantum dots. Quantum dots are nanocrystals with fluorescent residential or commercial properties that are used in a variety of electronic applications, including LED screens and photovoltaic panels. This brand-new approach of producing quantum dots has the prospective to be more sustainable and eco-friendly than current approaches, as it shows that functional materials can be manufactured utilizing protein series that are not originated from nature.
Researchers at Princetons Department of Chemistry found the first recognized de novo protein that catalyzes, or drives, the synthesis of quantum dots.
Nature uses 20 canonical amino acids as foundation to make proteins, integrating their sequences to create intricate molecules that carry out biological functions.
What occurs with the sequences not picked by nature? And what possibilities depend on building entirely new series to make unique, or de novo, proteins bearing little resemblance to anything in nature?

Quantum dots are generally made in commercial settings with heats and poisonous, expensive solvents– a procedure that is neither affordable nor eco-friendly. However Hecht and his research group managed the procedure in the laboratory utilizing water as a solvent, making a stable end-product at room temperature.
” Were interested in making life molecules, proteins, that did not emerge in life,” said Hecht, who led the research with Greg Scholes, the William S. Tod Professor of Chemistry and chair of the department. If we make lifelike particles that did not emerge from typical origins, can they do cool things?
” So here, were making novel proteins that never developed in life doing things that do not exist in life.”
The teams process can also tune nanoparticle size, which identifies the color quantum dots radiance, or fluoresce, in. That holds possibilities for tagging particles within a biological system, like staining cancer cells in vivo.
Professor Michael Hecht, and fifth-year graduate trainee and co-author on the quantum dot research study Yueyu Yao, in Frick Laboratory. Credit: Photo by Jesse Condon
” Quantum dots have really interesting optical properties due to their sizes,” stated Yueyu Yao, co-author on the paper and a fifth-year graduate trainee in Hechts lab. “Theyre extremely great at absorbing light and transforming it to chemical energy– that makes them helpful for being made into photovoltaic panels or any sort of photo sensing unit.
” But on the other hand, theyre also great at giving off light at a specific desired wavelength, which makes them ideal for making LED screens.”
And because theyre little– composed of only about 100 atoms and maybe 2 nanometers across– theyre able to penetrate some biological barriers, making their energy in medicines and biological imaging specifically appealing.
Why utilize de novo proteins?
” I believe using de novo proteins opens a method for designability,” said Leah Spangler, lead author on the research study and a former postdoc in the Scholes Lab. “A key word for me is engineering. I desire to be able to engineer proteins to do something particular, and this is a type of protein you can do that with.
” The quantum dots were making arent terrific quality yet, however that can be enhanced by tuning the synthesis,” she added. “We can attain much better quality by crafting the protein to affect quantum dot formation in various ways.”
Leah Spangler, lead author on the paper, in Frick Lab last year. Credit: Photo byC. Todd Reichart, Department of Chemistry
Based on work done by corresponding author Sarangan Chari, a senior chemist in Hechts laboratory, the team utilized a de novo protein it created named ConK to catalyze the response. Scientist first separated ConK in 2016 from a large combinatorial library of proteins. Its still made from natural amino acids, but it qualifies as “de novo” since its series doesnt have any similarity to a natural protein.
Scientists found that ConK made it possible for the survival of E. coli in otherwise hazardous concentrations of copper, suggesting it may be beneficial for metal binding and sequestration. The quantum dots used in this research are constructed of cadmium sulfide. Cadmium is a metal, so researchers wondered if ConK could be utilized to manufacture quantum dots.
Their inkling paid off. ConK breaks down cysteine, one of the 20 amino acids, into several products, consisting of hydrogen sulfide. That serves as the active sulfur source that will then go on to react with the metal cadmium. The outcome is CdS quantum dots.
” To make a cadmium sulfide quantum dot, you require the cadmium source and the sulfur source to react in option,” said Spangler. “What the protein does is make the sulfur source gradually over time. We add the cadmium at first but the protein creates the sulfur, which then responds to make distinct sizes of quantum dots.”
Referral: “A de novo protein catalyzes the synthesis of semiconductor quantum dots” by Leah C. Spangler, Yueyu Yao, Guangming Cheng, Nan Yao, Sarangan L. Chari, Gregory D. Scholes and Michael H. Hecht, 12 December 2022, Proceedings of the National Academy of Sciences.DOI: 10.1073/ pnas.2204050119.
This research was supported by the National Science Foundation MRSEC program (DMR-2011750), the Princeton University Writing Center and the Canadian Institute for Advanced Research. The research was likewise supported by NSF grant MCB-1947720 to MH.

Professor Michael Hecht and his research study group at Princeton have made a significant discovery in the field of chemistry by producing the first known de novo protein that catalyzes the synthesis of quantum dots. These quantum dots were produced in the Hecht Lab utilizing de novo proteins. The quantum dots utilized in this research are made out of cadmium sulfide.” To make a cadmium sulfide quantum dot, you require the cadmium source and the sulfur source to respond in service,” said Spangler. We add the cadmium initially but the protein creates the sulfur, which then responds to make distinct sizes of quantum dots.”