Page 50 - ILL Annual Report 2019

SOFT CONDENSED MATTER
Andrea Lassenberger. Austrian
The ILL
‘Multidisciplinarity is the key to understanding and progress in modern research. This approach is reflected in my research, which is driven by curiosity and an interest in how molecules and atoms assemble on the nanoscale. My main
interests are the synthesis, growth mechanisms and characterisation of metal oxide and organic nanoparticles, and the combination of these with biomaterials’.
Yeast-derived glycolipids make superparamagnetic iron oxide nanoparticles behave in biological systems
Vertical reflectometer D17 and small-angle scattering instrument D33
DUBBLE beamline at ESRF
Superparamagnetic iron oxide nanoparticles (SPIONs) smaller than ∼20 nm in diameter are used in applications such as drug delivery, MRI and hyperthermia. The iron oxide cores must be coated with a defined hydrophilic shell in order to render them colloidally stable and biocompatible.
We synthesised monodisperse SPIONs
with a single layer of irreversibly linked sophorolipids, a natural glycolipid produced in large amounts by the yeast S. bombicola. The core-shell structure of these nanoparticles can be resolved using a combination of SAXS and SANS: while X-rays are sensitive to the metal core of the nanoparticles, neutrons probe the highly hydrated
polymer shell. This study demonstrates how the two complementary techniques are indispensable in nanomaterials research.
AUTHORS
A. Lassenberger, V. Cristiglio, I. Grillo and K. Batchu (ILL)
E. Reimhult and A. Scheberl (University of Natural Resources and Life Sciences, Vienna, Austria)
N. Baccile (Sorbonne Université, Paris, France)
D. Hermida-Merino (ESRF)
ARTICLE FROM
ACS Appl. Bio Mater. (2019)—doi: 10.1021/acsabm.9b00427
REFERENCES
[1] N. Lee, D. Yoo, D. Ling, M.H. Cho, T. Hyeon and J. Cheon, J. Chem. Rev. 115:19 (2015) 10637
[2] E. Amstad, T. Gillich, I. Bilecka, M. Textor and E. Reimhult, Nano Lett. 9:12 (2009) 4042
[3] S. Singh, P. Patel, S. Jaiswal, A. Prabhune, C.V. Ramana and B.L.V. Prasad, New J. Chem. 33:3 (2009) 646
[4] N. Baccile, R. Noiville, L. Stievano and I. Van Bogaert, Phys. Chem. Chem. Phys. 15:5 (2013) 1606
Magnetic nanoparticles, in particular, superparamagnetic iron oxide nanoparticles (NPs), have received increasing attention for biomedical applications due to their responsiveness to magnetic fields and negligible toxicity. While these properties are governed by their inorganic core, their surface properties play a crucial role in interfacing with biological systems such as cells and proteins [1]. This becomes particularly important for applications that require the targeting of tissue, for which NPs must be invisible to cells of the reticuloendothelial system while interacting with the cells of the target tissue. Thus, the surface of these NPs must be designed in a way that a) provides colloidal stability to the system, b) renders the NPs biocompatible and non-toxic and c) defines the specific interaction of the NPs with the target [2].
Sophorolipids (SL) are non-toxic, bio-based glycolipids produced by the yeast S. bombicola that can fulfill the functions required of a surface coating for nanoparticles. They are characterised by a bolaform structure, where one side is composed of a bulky sophorose headgroup and the other by a free carboxylic acid, separated by an oleyl C18:1 fatty chain. These molecules have been reported to have natural targeting abilities as well as anti-cancer and anti-bacterial properties. Because of these attractive properties, they have already been explored as dispersants for SPIONs [3, 4]. However, in this demonstration the SL was not engineered
to bind irreversibly as a monolayer shell that ensures control over size and long-term structure in a biomedical application. Therefore, with the goal of stabilising biocompatible, core-shell, monodisperse SPION glyconanoparticles (figure 1) using a single, grafted sophorolipid layer, we modified the COOH endgroup of SL with nitrodopamine (NDA). NDA binds strongly to iron oxide and has been used to graft irreversibly bound dispersant shells to SPIONs [2].
We demonstrated the grafting of an SL monolayer onto
the monodisperse SPION surface using a combination
of synchrotron SAXS and SANS. Colloidal stability, biocompatibility and the absence of toxicity resulting from such a defined core-shell architecture were shown using a combination of cryo-TEM, dynamic light scattering (DLS) and thermal gravimetric analyses (TGA), as well as by cellular uptake and toxicity tests.
ANNUAL REPORT 2019