In Vivo Synthesis of Diverse Metal Nanoparticles by Recombinant Escherichia coli

Abstract

Nanometer-scale metal particles are finding many applications in the fields of biology and nanotechnology owing to their unique optical and magnetic properties. Phytochelatin (PC) and other metal-binding proteins have an ability to bind heavy metals and have been used for heavy-metal removal. Thus, we reasoned that they might be employed for the synthesis of metal nanoparticles (NPs). Herein, we report the in vivo biosynthesis of diverse NPs by recombinant Escherichia coli expressing phytochelatin synthase (PCS) and/or metallothionein (MT). NPs of various metal elements, including semiconducting, alkali-earth, magnetic, and noble metals and rare-earth fluorides, could be synthesized in E. coli. The size of NPs could be tuned on the nanoscale by changing the concentration of metal ions in the medium. Thus, the controlled synthesis of NPs with desirable characteristics for in vitro assays and cellular imaging was possible. Paramagnetic NPs could also be synthesized by using the same system. The strategy of employing recombinant E. coli as an NP factory is generally applicable for the combinatorial synthesis of diverse NPs with a wide range of characteristics.Metal NPs exhibit unique optical, electronic, and magnetic properties, which depend on their composition, size, and structure, and have therefore been explored extensively for various applications in bio-and nanotechnology.

Nanoparticle biosynthesis using unicellular and subcellular supports

“…7 The cysteines in phytochelatin synthase (PC) and metallothionein (MT) were responsible for metal ion interaction. Using plasmids, PC and MT genes were transformed individually or in combination into the E. coli bacteria.…”

“…Consequently, the upregulation of specific proteins causes other functional proteins to remain in a less active state, and control of the reactant supply could have a role in controlling the nucleation and growth of metal nanoparticles. 3,[5][6][7] These strategies facilitate the formation of nanoparticles of homogeneous sizes and shapes. A study using microfluidics showed promising results for potential scale-up.…”

Biosynthesis and display of diverse metal nanoparticles by recombinant Escherichia coli

“…To further validate the formation of gold nanoparticles in R. etli cells, we performed TEM analysis for R. etli cells. Notably, extracellular gold nanoparticles appeared when incubating cells 10 with L-DOPA and gold ions for 12 h (Fig. 1C, arrows).…”

“…These findings demonstrate the effectiveness of the proposed method in the synthesis and display of metal nanoparticles. 10 In summary, this paper presents a simple, room-temperature, and the green chemistry synthetic method for the biosynthesis of nanoparticles. We illustrated how the EuMel biosynthesis pathway in R. etli can be exploited for the synthesis of metal nanoparticles through the use of recombinant E. coli with L- 15 DOPA.…”

In Vivo Synthesis of EuSe Nanoparticles and its Cytotoxicity against Cancer Cells

“…Recombinant E. coli BL21(DE3) co-expressing AtPCS and PpMT was prepared according to the methods described in a previous work [9]. Briefly, recombinant E. coli cells expressing pTJ1-PpMT-AtPCS were grown at 37°C for 2 h in 100 mL of Luria-Bertani (LB) medium.…”