Studies on Urease Mediated Nanoparticle Formation

Urease is a protein that is found in the Jack Bean, and is commercially purified. It has been reported that urease aids in the process of nanoparticle synthesis¹_. In Dr. Bhagwati Sharma’s experiments, urease was found to be catalytic in the synthesis of gold, silver, platinum, and gold-silver alloy particles.¹ Urease is also known to synthesize particles of magnetite, zinc oxide⁵, and iron oxide³. Dr. Sharma’s methods will be tested in these studies in effort to confirm the capability of urease to synthesize silver, gold, and platinum nanoparticles, with the end goal of solving the chemical structure of urease in order to learn more about its properties on a molecular level.

In order to perform the methods that were employed by Dr. Sharma, several different purities of urease will be tested for their effects on the reduction of ionic metals by potassium carbonate. When the correct concentration of urease is used, incubation of each solution will change its color, according to the spectrum of the nanoparticle present: red for gold particles, yellow for silver nanoparticles, and black/brown for platinum nanoparticles. There will be limited or no precipitate present in solution, and the solution will be homogenous. Thus far, Ag(NO)₃ has been put through several solutions containing ranges of 2mg/mL Urease to 20mg/mL Urease solution. In some cases, precipitate was formed almost immediately. Since then, the pH has been scaled down to match that of Dr. Sharma’s procedure. It is believed that the high alkalinity due to potassium carbonate catalyzed the formation of a precipitate, preventing the solution any opportunity to slowly form nanoparticles.

At the time that the methods have been successfully recreated and the nanoparticles have been formed, the particles will be tested by several methods including cryo-electron microscopy. This will be performed in order to solve for the structure of urease, as well as urease after the particles have been captured. The two structures will be compared in order to evaluate what about the enzyme’s structure has facilitated the nanoparticle capture. This will serve to reveal the mechanism of the reaction.

Nanoparticles have been utilized in the creation of microstructures¹, and are an essential building block for the future of nanotechnology. Cost efficiency of nanoparticle synthesis is extremely crucial for the branching of nanotechnology into other fields of science and technology. The information provided by structural analysis of urease will ideally be beneficial towards the synthesis of more cost efficient enzymes, making particle synthesis less expensive, and therefore making nanoparticles more available to the scientific and industrial communities.

References

1. Sharma, Bhagwati, Sonam Mandani, and Tridib K. Sarma. "Biogenic Growth of Alloys and Core-Shell Nanostructures Using Urease as a Nanoreactor at Ambient Conditions." Nature.com. Scientific Reports, 10 Sept. 2013. Web. 2 Oct. 2016.
2. Liang, Zhenpeng, Chaoyang Wang, Zhen Tong, Weihua Ye, and Shiqu Ye. "Bio-catalytic Nanoparticles with Urease Immobilized in Multilayer Assembled through Layer-by-layer Technique." Science Direct. Elsevier B.V., Apr. 2005. Web. 2 Oct. 2016.
3. Sahoo, Banalata, Sumanta Kumar Sahu, and Panchanan Pramanik. "A Novel Method for the Immobilization of Urease on Phosphonate Grafted Iron Oxide Nanoparticle." Science Direct. Elsevier B.V., May 2011. Web. 2 Oct. 2016.
4. Parashar, Nirala, Upadhyay, Saxena, and Srivastava. "Urease Immobilized Fluorescent Gold Nanoparticles for Urea Sensing." NCBI. N.p., May 2015. Web. 2 Oct. 2016.
5. Eghbali M, Farahbakhsh A, Rohani A, Pour A. N. Urea biosensor based on immobilization of urease on ZnO nanoparticles. Orient J Chem 2015;31(2)