Anisotropic metal growth on phospholipid nanodiscs via lipid bilayer expansion

Abstract

Self-assembling biomolecules provide attractive templates for the preparation of metallic nanostructures. However, the intuitive transfer of the “outer shape” of the assembled macromolecules to the final metallic particle depends on the intermolecular forces among the biomolecules which compete with interactions between template molecules and the metal during metallization. The shape of the bio-template may thus be more dynamic than generally assumed. Here, we have studied the metallization of phospholipid nanodiscs which are discoidal particles of ~10 nm diameter containing a lipid bilayer ~5 nm thick. Using negatively charged lipids, electrostatic adsorption of amine-coated Au nanoparticles was achieved and followed by electroless gold deposition. Whereas Au nanoparticle adsorption preserves the shape of the bio-template, metallization proceeds via invasion of Au into the hydrophobic core of the nanodisc. Thereby, the lipidic phase induces a lateral growth that increases the diameter but not the original thickness of the template. Infrared spectroscopy reveals lipid expansion and suggests the existence of internal gaps in the metallized nanodiscs, which is confirmed by surface-enhanced Raman scattering from the encapsulated lipids. Interference of metallic growth with non-covalent interactions can thus become itself a shape-determining factor in the metallization of particularly soft and structurally anisotropic biomaterials.

Nanodiscs in Membrane Biochemistry and Biophysics

“…480 Deposition of colloidal Au particles resulted in rapid lateral growth of Nanodiscs during the first few minutes. At the same time appearance of optical absorption in the near-UV region below 440 nm was observed.…”

“…Negatively charged nanodiscs assembled using MSP1D1 and DMPG lipids were used as templates for making composite nanoparticles by electrostatic absorption of positively charged 1.4 nm amine coated gold nanoparticles. 494 Deposition of colloidal Au particles resulted in rapid lateral growth of nanodiscs during the first few minutes. At the same time, appearance of optical absorption in the near-UV region below 440 nm was observed.…”

Toxicity of metal-based nanoparticles: Challenges in the nano era

“…Recent studies demonstrated that NPprotein corona formation could interact with many immune system components to either stimulate or suppress the immune response and cytotoxic effects (Hu et al, 2011a;Ruge et al, 2011;Lee et al, 2015;Lu et al, 2018). In addition, various coating materials like polyethylene glycol (PEG), poly (lactic-co-glycolic acid) (PLGA), polylactic acid (PLA), lipids, and others have been used to modify the metalbased NP surface, which considerably changes the physicochemical properties of NPs (Tefft et al, 2015;Oertel et al, 2016;Guerrero et al, 2019;Jiao et al, 2020;Murphy et al, 2021). Surface modifications of NPs not only affect their pharmacokinetics and change their biodistribution, clearance, and elimination, which are closely related to their toxicity in the body (Arami et al, 2015;Das et al, 2017;Yu et al, 2018a).…”

Auric Chloride Induced Micellization on Fractal Patterned Dicationic Amphiphiles and Stabilization of Gold Nanoparticles

“…Self-assembly of hierarchically ordered structures is a fascinating subject, in which small entities into larger two- or three-dimensional (3D) structures exhibiting new features that cannot be achieved by the isolated building blocks. , Nature uses a highly ordered self-assembled structure to construct the functional hybrid materials from inorganic and organic building blocks. , The artificial synthesis of hierarchically self-assembled nanoscale building blocks such as nanoclusters, nanowires, nanobelts, and nanotubes is the versatile technique available for the fabrication of functional electronic and photonic nanodevices. , Fractal structures are extremely familiar in nature with different scales of lengths from self-assembled molecules, to the shapes of coastlines, to the distribution of galaxies, and even to the 3D shapes of clouds . They are never-ending patterns and are attained by repeating a simple process over and over in an ongoing reaction loop driven by recursion.…”

“…3,4 The artificial synthesis of hierarchically self-assembled nanoscale building blocks such as nanoclusters, nanowires, nanobelts, and nanotubes is the versatile technique available for the fabrication of functional electronic and photonic nanodevices. 5,6 Fractal structures are extremely familiar in nature with different scales of lengths from self-assembled molecules, to the shapes of coastlines, to the distribution of galaxies, and even to the 3D shapes of clouds. 7 They are never-ending patterns and are attained by repeating a simple process over and over in an ongoing reaction loop driven by recursion.…”