Scientific highlights

 

Characterisation of self-assembly of structures on nanoparticles
Small angle neutron scattering, along with chemical deuteration has been used to support the challenging task of characterising the structure of self-assembling organic molecules on the surface of nanoparticles.

Self-assembled monolayer-protected nanoparticles are being increasingly used in electronics, drug delivery, catalysis and sensing devices. The composition and structure of the ligands that make up the shell layer is important because they are thought to determine the properties of the nanoparticles, such as the chemical, biological and interfacial behaviour.

The study shows that quantitative description of the morphology of the self-assembly on nanoparticles can be obtained by using small-angle neutron scattering (SANS) and deuterated organic molecules. This approach is able to distinguish very similar structures and the methodology used is versatile for nanoparticles with different type of core elements as well as ligand chemistry.

Surface of nanoparticles news imageChemistry deuterated nanoparticles

Luo, Z, et al. Quantitative 3D determination of self-assembled structures on nanoparticles using small angle neutron scattering. Nature Communications 2018. http://doi.org/10.1038/s41467-018-03699-7
 


Invisible deuterated detergents for studying structures of membrane proteins
Membrane proteins play a vital role in many critical biological processes. Detergents are commonly used to stabilise membrane proteins to study their structure. The Chemical Deuteration team has developed a new method for the selective deuteration of common detergents octyl β-D-glucopyranoside (OG) and n-dodecyl-β-D-maltopyranoside (DDM) so that only the signal from the membrane protein remains in the small angle neutron scattering (SANS) data. The applicability of this method has been demonstrated for five different membrane proteins using SANS.

OG and DDM surfactants

Midtgaard S, et al. Invisible detergents for structure determination of membrane proteins by small‐angle neutron scattering. The FEBS Journal 2018, 285, 357. http://doi.org/10.1111/febs.14345


Deuterated fibronectin and Neutron Reflectivity 
Extracellular matrix (ECM) proteins such as fibronectin (FN), laminin and collagen can be used to create biomimetic surfaces for cell adhesion and tissue engineering. By immobilising biocompatible ECM proteins on a biomaterial surface the interaction between it and the host cells can be influenced. 
 
Hydrogenous and deuterated (at NDF) variants of the fibronectin fragment, 9th-10th type III domains (FIII9-10) were investigated for their ability to mediate adhesion of cultured cells to TiO2 surface by neutron reflectivity on Platypus at the Australian Centre for Neutron Scattering.
 
NDF case study: Deuterated protein and Neutron Reflectivity graph
 

McIntosh L, Whitelaw C, Rekas A, Holt SA, van der Walle CF. Interrogating protonated/deuterated fibronectin fragment layers adsorbed to titania by neutron reflectivity and their concomitant control over cell adhesion. Interface, 2015, 12(107). http://dx.doi.org/10.1098/rsif.2015.0164 

Storage in solid Metal-Organic Frameworks (MOF)
Neutron diffraction experiments are used to unveil the site-specific binding properties of CO2 within MOF materials while systematically varying both the amount of CO2 and the temperature. Deuterated materials enabled a comprehensive study of carbon dioxide adsorption in the metal-organic frameworks M2 (dobdc) (M = Mg, Mn, Fe, Co, Ni, Cu, Zn).
 
NDF case study: MOF graph

Deuterated biopolymer and Infrared (IR) Microspectroscopy
Deuteration of bacterial biopolyesters to probe phase separation using the Infrared Microspectroscopy beamline at the Australian Synchrotron.
 
NDF case study: Deuterated biopolymer graph
Russell RA, Darwish TA, Puskar L, Martin DE, Holden PJ, Foster LJR.  Deuterated polymers for probing phase separation using infrared microspectroscopy. Biomacromolecules, 2014, 15(2): 644-649. http://dx.doi.org/10.1021/bm4017012 
 

Biomembrane research 
Dr. Anton Le Brun uses neutron scattering techniques in combination with deuteration to research phenomena that occur at biological membranes. This has included production of deuterated lipopolysaccharide (LPS) from E. coli for studying structural aspects of the Gram-negative bacterial outer membrane using neutron reflectometry.
 
 
NDF case study: Biomembrane graph
Le Brun AP, Clifton LA, Halbert CE, Lin B, Meron M, Holden PJ, Lakey JH, Holt SA: Structural Characterisation of a Model Gram-negative Bacterial Surface using Lipopolysaccharides from Rough Strains of Escherichia coli. Biomacromolecules, 2013, 14(6):2014-2022. http://dx.doi.org/10.1021/bm400356m 

Structural characterisation of an HIV coat protein - calmodulin interation
Structural characterisation of the interaction between:
  • HIV-1 structural matrix protein (MA)
  • The intracellular mediator protein, calmodulin (CaM)

Binding of HIV-1 MA protein to deuterated calmodulin, modelled from small-angle neutron scattering (SANS) conducted at multiple solvent contrasts.
 
NDF case study: Structural characterisation graph
 

Triple-labelled hydrophobin (2H/15N/ 13C) and NMR 
Investigation of a fungal hydrophobin (EAS∆15) rodlet structure using recombinantly expressed 2H/15N/13C labelled EAS∆15 and solid-state NMR. 

NDF case study: Triple labelled protein graph 
 
Morris VK, Linser R, Wilde KL, Duff AP, Sunde M, Kwan AH. Solid-state NMR spectroscopy of functional amyloid from a fungal hydrophobin: a well-ordered β–sheet core amidst structural heterogeneity. Angew Chem Int Ed, 2012, 51:12621 –12625. http://dx.doi.org/10.1002/anie.201205625

The morphology and structure of Organic Light Emitting Diodes (OLED)
Deuteration of the organic compounds provided the contrast, enabling detection of diffusion between two layers of an OLED when heated, using neutron reflectometry.

 NDF case study: OLED graph
 


Proposals for molecular deuteration should be submitted at http://neutron.ansto.gov.au. You can email ndf-enquiries@ansto.gov.au or contact Professor Peter Holden on + 61 (2) 9717 3991 or other NDF staff at any time.