Thursday 11 July 2013, Sidlaw Room, 11:00-13:00
Bio-relevant LSS
Neutron diffraction studies of collagen behaviour in human bone for patients suffering from osteoporosis and
osteoarthritis
F Harden, R Aspden and J Skakle
Aberdeen University, UK
Understanding the working of collagen within the bone is important because this will enable greater understanding
of the intricate workings of the organic phase of bone. Bone is known to be affected by several factors including a
person’s age, sex and diet. However, studying collagen in situ is challenging due to the many factors involved,
including maintaining the collagen within the bone at a body-like temperature, keeping the overall bone moist
throughout the experiments and similarly obtaining samples at a decent quality to analyse. This study expands on
previous work with the aim of finding a model for the collagen behaviour. The following study looked at trabecular
bone from femoral heads obtained from human patients suffering from either osteoporosis or osteoarthritis. These
specimens were then sliced into approximately 2 mm slices and neutron diffraction performed on each. A humidity
chamber was used to maintain the ‘natural’ environment of the bone allowing relatively good in situ results of the
interfibrillar spacing of collagen to be achieved. The results from the neutron diffraction studies will enable
comparisons of the interfibrillar spacing of collagen to be made and will also enable a greater understanding of how
these spacings are affected due to bone degenerative diseases. It is the authors aim to use this model to determine
if the interfibrillar spacings of collagen are influenced by degenerative diseases. These results will aid further
understanding on how collagen behaves, specifically within patients suffering from common degenerative diseases.
Nanodevices for neoplastic diagnosis or therapy
L Paduano1, G Mangiapia1, G D'errico1, C Irace1, A Radulescu2, H Frielinghaus2, G Fragneto3 and D Montesarchio1
1
University of Naples, Italy, 2JCNS, Germany 3ILL, France
Amphiphilic molecules of appropriate design can form a variety of supramolecular aggregates such as micelles,
vesicles and inverse bicontinuous cubic phases that may be exploited in several applications such as in medical
diagnostic and therapy. Here the update development and improvement of potential tumor–specific supramolecular
contrast agents for magnetic resonance imaging (MRI) applications or chemotherapy is presented.
In the field of tumor diagnosis nanodevices contrast agents, based on gadolinium complexes and peptides, were
prepared. In the field of tumor therapy new classes of potential antineoplastic agents based on ruthenium
amphiphilic complexes were proposed.
The study has been carried out by means of small-angle neutron scattering, dynamic light scattering, electron
paramagnetic resonance spectroscopy and electron cryo-microscopy. The systems presented are stimuli-responsive
can switch from one structure to other depending on the environmental condition. Finally in vitro and in vivo tests, of
these nanoaggregates on live cultures of human cancer cells were performed, demonstrating high efficiency of these
tools both in diagnosis and therapy.
ICNS 2013 International Conference on Neutron Scattering
Dynamic cluster formation in therapeutic monoclonal antibody solutions
P D Godfrin2 , Y Liu1, E Yearley2, Y Gokarn3, I Zaaraga3 and N Wagner2
1
University of Delaware/NCNR,USA, 2University of Delaware, USA, 3Genentech Inc, USA
Concentrated therapeutic protein formulations for subcutaneous injection provide a favorable route for drug therapy;
however, numerous challenges arise with regards to their delivery and stability, such as the undesirable increase of
viscosity. It has long been speculated the reason for increased viscosity in some concentrated monoclonal antibody
(mAb) is due to the formation of reversible clusters. However, the nature of the possible formation of dynamic
protein clusters and its microstructure in concentrated mAb solutions is still not fully understood. We have applied
small angle neutron/x-ray scattering (SANS/SAXS), neutron spin echo (NSE), dynamic light scattering (DLS), and
rheological measurements to investigate a few therapeutic IgG1 mAbs. The experimental results show conclusive
evidence of the existence of the dynamic clusters in solution whose size is clearly correlated with the change of
viscosity in solutions. The results have further revealed the driving force responsible for cluster formation.
Purifying water with proteins - How this works: a study with neutrons
M Hellsing1, A Rennie1 and H Kwaambwa2
1
Uppsala University, Sweden, 2Polytechnic of Namibia, South Africa
An extract from the seeds of the Moringa oleifera tree that is principally a low molecular mass protein is known to be
efficient as a coagulating agent for water purification. The purification process that is based on traditional methods
used in tropical and sub-tropical Africa is attracting interest for larger scale use as a sustainable, environmentally
friendly technology. The structure of adsorbed layers at different oxide surfaces such as silica and alumina has
been investigated by neutron reflection [1]. At silica surfaces adsorption of 5 mg m-2 at concentrations as low as
0.025% wt. has been observed. The association with surfactants and the conditions under which the protein can
desorb have also been studied. The strong adsorption, in combination with the tendency for the protein molecules
to associate suggests a mechanism for destabilizing particulate dispersions so as to sediment impurities and to
provide water that is filterable. This mechanism occurs even for protein that has previously been identified as being
of low mass (about 7 kDaltons) and thus is unlikely to be efficient in bridging or depletion flocculation.
[1]
H. M. Kwaambwa, M. S. Hellsing and A. R. Rennie (2010) Langmuir 26, 3902-3910.
Using neutron reflection to study the atmospheric oxidation mechanism of an organic monolayer by chlorine atoms
S Jones1, M King1, A Ward2, A Rennie3, A Hughes4 and R Campbell5
1
Royal Holloway, University of London, UK, 2Lasers for Science Facility, Science and Technology Facilities Council,
UK, 3Uppsala University, Sweden, 4ISIS, UK, 5ILL, France
Aerosols in the atmosphere are known to affect the climate of the Earth directly by scattering and absorbing solar
radiation and also indirectly by acting as cloud condensation nuclei (CCN) which influence cloud formation and
cloud radiative properties.The presence of monolayer organic films on the surface of atmospheric aerosol can affect
CCN formation. Gaseous and liquid phase oxidants are prevalent in the atmosphere and have the potential to
oxidise monolayer films, thus causing a change in aerosol chemical composition and a resultant change in aerosol
cloud formation potential.
The gas phase chlorine atom is important in the marine lower atmosphere. It has recently been shown (Liu et al.,
2011) not to equilibrate with surfaces before reaction unlike gas phase ozone. We have shown that the oxidation of
a monolayer of the lipid DSPC (1,2-distearoyl-sn-glycero-3-phosphocholine) at the air water interface by the gas
phase chlorine atom occurs in a stepwise degradation mechanism (A to B to C to…). DSPC is a realistic proxy of
organic detrital matter found in atmospheric aerosol.
ICNS 2013 International Conference on Neutron Scattering
Neutron reflection has been used to investigate the organic film as it is oxidised by gaseous chlorine atoms. Both
the surface coverage and film thickness were found to decrease as the reaction proceeds. However, the oxidation
reaction did not completely remove the film from the interface.
A stepwise degradation mechanism may present opportunities for the organic film to react further with other
atmospheric chemicals. In which case, organic films present on aerosols in the lower marine atmosphere may not
completely inhibit water uptake thus allowing aerosol growth and CCN formation.
Size control of squalenoide nanomedicine obtained by nanoprecipitation method
D Saha1, O Spalla2, F Testard2, P Couvreur3 and D Desmalele3
1
CEA Saclay, France, 2LIONS, DSM/IRAMIS, CEA Saclay, France, 3Universite Paris-Sud, France
Nucleoside analogues are a class of therapeutic agents with significant anticancer or antiviral properties. However,
these molecules possess some limitations that often restrict their use. Recently, Couvreur et al.1 have developed a
new strategy to increase the therapeutic index of these molecules by coupling them to the acyclic isoprenoid chain
of squalene. The coupling of squalene moieties and nucleoside analogues allows the formation of spherical nanoassemblies using the well-known nanoprecipitation method1. The major drawback of this very promising strategy is
the lack of control in size and polydispersity of the obtained nanoparticles. There is thus a strong interest to have a
better understanding of the mechanism of formation of these drug nanoparticles to control, their size, polydispersity
and internal structure. Taking the benefit of recently developed millifluidic setup, we were able to control the
polidispersity and reproducibility of the squalene derivatives nanoparticles formation to some extent. Small Angle
Neutron Scattering (SANS) experiment reveals the growth of the particles by increasing concentration. The internal
structure of the particles were obtained at large angle whereas, the information about the specific surface and the
size of this particles were obtained at small angle by using SANS. To our knowledge, this is the first demonstration of
nanomedicine formation by using SANS.
[1]
Couvreur P. et al, Nanoletter (2006), 6, 2544
Characterizing the structure of the solid-liquid interface of dispersed tripalmitin nanoparticles with a combination of
small angle neutron and x-ray scattering
M Schmiele and T Unruh
Friedrich-Alexander-University Erlangen-Nuremberg, Germany
Suspensions of solid triglyceride nanoparticles play an important role in modern pharmaceutical research (drug
delivery systems) [1] and food science (functional food) [2]. To obtain stable colloidal suspensions stabilizers like
polysorbates, polymers and phospholipids are used. In a recent study we focused on suspensions of crystalline
tripalmitin nanoparticles stabilized by phospholipids in an aqueous dispersion medium [3]. The aim of this study
was to characterize the molecular arrangement of the phospholipid molecules at the solid-liquid interface between
the tripalmitin core and the aqueous phase. The structure of this stabilizer layer is important to understand the
stabilization mechanism and to control the polymorphic transitions of the particles and their encapsulation and
adsorption ability of drugs and other bioactive molecules. By a simultaneous evaluation of small angle neutron and
X-ray scattering (SANS, SAXS) patterns with the "X-Ray Powder Pattern Simulation Analysis" (XPPSA) method [4]
that has been extended to neutron scattering it has been shown that the phospholipids arrange flatly and densely
packed in a monolayer with a total thickness of about 12 Angström on the particle surface. Furthermore the
simulation method has been successfully used in a recent SANS and SAXS study to characterize the adsorption of
DNA at the solid-liquid interface of cationically modified tripalmitin nanoparticles [5].
[1]
[2]
H. Bunjes. Curr. Opin. Colloid & Interface Sci., 16, 405-411 (2011).
L. Sagalowicz and M. Leser. Curr. Opin. Colloid & Interface Sci., 15, 61-72 (2010).
ICNS 2013 International Conference on Neutron Scattering
[3]
[4]
[5]
M. Schmiele, T. Unruh et al., submitted to Phys. Rev. E (2013).
T. Unruh. J. Appl. Cryst., 40, 1008-1018 (2007).
M. Schmiele et al., in prep.
ICNS 2013 International Conference on Neutron Scattering