Researchers at the Institute of Science Tokyo and the University of Leeds discovered that positioning biomineralization peptides inside liposomes controls how gold nanoparticles grow. Published on August 18, 2026, the study reveals that membrane-localized peptides promote branched structures, while internally confined peptides favor spherical nanoparticles.
Controlling Gold Nanoparticle Growth Inside Liposomal Nanoreactors
Controlling the size and shape of gold nanoparticles is vital for applications in optical sensing, catalysis, imaging, and other advanced technologies. However, directing nucleation and growth under mild, environmentally friendly conditions has persistently challenged materials scientists. To tackle this, a research team investigated how local reaction environments within liposomes alter nanoparticle formation. The work was led by Associate Professor Masayoshi Tanaka and Graduate Student Yuya Abe from the Department of Chemical Science & Engineering at the Institute of Science Tokyo, alongside Professor Stephen D. Evans from the University of Leeds.
Liposomes provide two distinct spatial zones: the internal aqueous compartment and the membrane interface. By manipulating where peptides settle inside these nanoscale reaction compartments, researchers can program the resulting gold structures. Biomineralization peptides, which are brief chains of amino acids, present a viable approach for facilitating metal reduction and guiding the development of nanoparticles.
Membrane Interfaces Versus Aqueous Interiors Using Peptide B3
To examine spatial arrangement, the investigators added a gold precursor, HAuCl4, into liposomal nanoreactors that held distinct peptide sequences. Their preliminary trials centered on B3, a specific peptide capable of both reducing gold ions and altering nanoparticle geometry.
Transmission electron microscopy and elemental mapping demonstrated that when B3 concentrated mostly close to the liposome membrane, it generated intricate, branched, anisotropic Au/liposome assemblies featuring a high accumulation of gold at the outer edges. When the team altered the liposome chemistry by introducing the cationic lipid DOTAP, the spatial orientation shifted. This relocation pushed the B3 peptide toward the aqueous interior, resulting in the formation of spherical gold nanoparticles rather than highly branched structures.
Peptide Sequence Specificity and Spatial Organization with Peptide G1
The resulting shape relies on a combination of the specific peptide sequence and the spatial arrangement of the peptide inside the restricted reaction space. When researchers tested a second biomineralization peptide, G1, it behaved differently from B3. G1 remained predominantly localized within the aqueous interior, even after the membrane composition was altered.
Because G1 was confined internally in this manner, it led to the creation of small, nearly spherical gold nanoparticles with an average diameter of about 2.7 nanometers. In the end, this comparison shows that designing bio-inspired nanomaterials successfully demands control over both sequence configuration and membrane makeup to govern how reactions proceed within nanoscale settings.