Thermostable iron oxide nanoparticle synthesis within recombinant ferritins from the hyperthermophile Pyrococcus yayanosii CH1

Abstract

Thermostable nanoparticles have numerous applications in catalysis and in the oil/gas industry. However, synthesizing these nanoparticles requires expensive polymers. Here, a novel thermostable ferritin named PcFn, originally from the hyperthermophilic archaeon Pyrococcus yayanosii CH1, was overexpressed in Escherichia coli, purified and characterized, which could successfully direct the synthesis of thermostable magnetoferritins (M-PcFn) with monodispersed iron oxide nanoparticles in one step. Transmission electron microscopy and magnetic measurements show that the cores of the M-PcFn have an average diameter of 4.7 nm, are well-crystalline and superparamagnetic. Both the PcFn and M-PcFn can resist temperatures up to 110 C, which is significantly higher than for human H-chain ferritin (HFn) and M-HFn, and comparable to temperatures previously reported for Pyrococcus furiosus ferritin (PfFn) and M-PfFn. After heating at 110 C for 30 minutes, PcFn and M-PcFn maintained their secondary structures and PcFn retained 87.4% of its iron uptake activity. This remarkable thermostability of PcFn and M-PcFn suggests potential applications in elevated temperature environments.

Magnetite Nanoparticles: Synthesis and Applications in Optics and Nanophotonics

“…One of the ways to produce magnetite nanoparticles with uniform dimensions is to perform the reaction in constrained environments. Different synthetic and biological reactors could be used for this synthesis, such as apoferritin protein cages [ 50 ], phospholipid membranes (micelles) [ 51 ], mesoporous materials [ 52 ], microemulsions [ 53 ], etc. Here, we would focus on apoferritin protein cages as constrained environments for magnetite nanoparticles synthesis.…”

“…Ferritin is an iron storage protein and has a spherical protein cage with an exterior diameter of 12 nm and an interior cavity diameter of 6–8 nm. Yu et al [ 50 ] have a reported novel thermostable ferritin (PcFn), purified and characterized, that could successfully direct the synthesis of thermostable magnetoferritins (M-PcFn) with monodispersed iron oxide nanoparticles in one step. They obtained good crystalline and superparamagnetic magnetite nanoparticles with an average diameter of 4.7 nm ( Figure 4 ).…”

“… High-resolution Transmission Electron Microscopy (TEM) images showing lattice fringes of the magnetite cores (adapted from [ 50 ] with permission from The Royal Society of Chemistry 2019). …”

Enhanced Magnetic Hyperthermia of Magnetoferritin through Synthesis at Elevated Temperature

“…In this work, we synthesized magnetoferritin within a ferritin cage (PfFn) from the hyperthermophilic archaeon Pyrococcus furiosus by adding theoretical loading factors of 10,000 Fe/cage at temperatures of 45 °C, 65 °C, 90 °C, and 95 °C, named MPfFn-45, MPfFn-65, MPfFn-90, and MPfFn-95, respectively. PfFn is considered to be the most thermostable ferritin so far, with a melting temperature (T m ) of >120 °C or 116.8 °C measured under different conditions [ 20 , 21 ]. Compared with mammalian ferritins, such as recombinant human H chain ferritin (T m = 77 °C) [ 22 ], PfFn has a much higher thermostability as well as a different inner structure.…”

A novel method forin situvisualization of the growth kinetics, structures and behaviours of gas-phase fabricated metallic alloy nanoparticles

“…1,[5][6][7] Therefore, researchers have spent great effort to develop fabrication methods to obtain nanoparticles with controllable size, shape, phase and elemental distribution. 4,[8][9][10][11][12][13][14][15] Among all the methods, chemical synthesis and gas-phase deposition are two outstanding ways as they show signicant efficiency, controllability, and exibility on the design and tuning of the nanoparticle structures. Although the chemical synthesis has gained big success in fabricating a large variety of functional nanoparticles with well-designed structures and morphologies, the use of surfactants frequently leads to a critical problem that the synthesized nanoparticles inevitably have organic molecules covered on the surfaces, largely weakening their activities in a lot of sensor applications.…”