Size-controlled synthesis and characterization of CoPt nanoparticles using protein shells

Area of Science:

• Materials Science
• Nanotechnology
• Biotechnology

Background:

• Nanostructured magnetic materials like iron oxide and bimetallic nanoparticles have potential applications in electronics and nanomedicine.
• Controlling particle size is crucial for tailoring magnetic properties and achieving high reproducibility in nanoparticle synthesis, which remains a significant challenge.

Purpose of the Study:

• To synthesize cobalt-platinum nanoparticles (CoPt NPs) using PepA, a bacterial aminopeptidase, as a protein shell.
• To investigate the physicochemical and magnetic properties of CoPt NPs with and without protein encapsulation.
• To demonstrate the control over CoPt NP size and magnetic properties using PepA.

Main Methods:

• Synthesis of CoPt NPs in ambient solution phase using PepA as a protein shell.
• Characterization of CoPt NP size, ranging from 1.1 to 2.8 nm.
• Investigation of magnetic properties, including superparamagnetism and ferromagnetism, in relation to particle size and PepA encapsulation.

Main Results:

• PepA enabled stringent control over CoPt NP size (1.1–2.8 nm).
• Magnetic properties were size-dependent: 1.1 nm CoPt NPs exhibited low-temperature superparamagnetism, while 2.1 and 2.8 nm NPs showed ferromagnetism below the blocking temperature.
• PepA encapsulation had a negligible effect on the coercivity of CoPt NPs.

Conclusions:

• PepA serves as an effective protein shell for controlling the size and magnetic properties of CoPt NPs.
• The biocompatibility and modification capabilities of PepA can be integrated with CoPt NP functionalities for developing advanced multifunctional materials.
• This approach facilitates the development of novel magnetic nanomaterials for diverse applications.