Understanding dynamic changes in live cell adhesion with neutron reflectometry

Abstract

Neutron reflectometry (NR) was used to examine various live cells adhesion to quartz substrates under different environmental conditions, including flow stress. To the best of our knowledge, these measurements represent the first successful visualization and quantization of the interface between live cells and a substrate with sub-nanometer resolution. In our first experiments, we examined live mouse fibroblast cells as opposed to past experiments using supported lipids, proteins, or peptide layers with no associated cells. We continued the NR studies of cell adhesion by investigating endothelial monolayers and glioblastoma cells under dynamic flow conditions. We demonstrated that neutron reflectometry is a powerful tool to study the strength of cellular layer adhesion in living tissues, which is a key factor in understanding the physiology of cell interactions and conditions leading to abnormal or disease circumstances. Continuative measurements, such as investigating changes in tumor cell – surface contact of various glioblastomas, could impact advancements in tumor treatments. In principle, this can help us to identify changes that correlate with tumor invasiveness. Pursuit of these studies can have significant medical impact on the understanding of complex biological problems and their effective treatment, e.g. for the development of targeted anti-invasive therapies.

Stratified Temperature-Responsive Multilayer Hydrogels of Poly(N-vinylpyrrolidone) and Poly(N-vinylcaprolactam): Effect of Hydrogel Architecture on Properties

“…The internal organization of nanoscale films has been resolved by probing their interfacial properties using neutron reflectivity (NR). − The layering in hydrogen-bonded and ionically paired multilayers has been shown to depend on polymer type, deposition conditions, film thickness, and charge balance. − Using deuterium-containing components such as D 2 O or deuterated (labeled) polymers allows contrast between various polymeric labeled and nonlabeled strata to be achieved for the resolution of polymer structure and internal water distribution. − The layered structure of endothelial cell and tumor cell adherence explored by Junghans et al demonstrated the nondestructive yet deeply penetrating characterization afforded by NR measurements . Nondeuterated polymer films have been characterized through the amount of D 2 O absorbed by constituent chains, allowing various properties to be determined from the difference in scattering density and allowing determinations of a hydrogel film’s varied hydration throughout its thickness as well as the thickness of layers and the structure. ,, …”

“…52−57 The layered structure of endothelial cell and tumor cell adherence explored by Junghans et al demonstrated the nondestructive yet deeply penetrating characterization afforded by NR measurements. 58 Nondeuterated polymer films have been characterized through the amount of D 2 O absorbed by constituent chains, allowing various properties to be determined from the difference in scattering density 59 and allowing determinations of a hydrogel film's varied hydration throughout its thickness as well as the thickness of layers and the structure. 53,59,60 Although stratified hydrogels have been mostly limited to bulk systems with dimensions of several micrometers or centimeters, 8,25−27 LbL assembly allows integration of various chemically diverse strata within a single multilayer construct.…”

Neutron scattering in the biological sciences: progress and prospects

“…The association of proteins with fluid lipid bilayers can now be routinely studied by NR, and their conformational changes in response to external triggers (pH changes, voltage pulses or the addition of small-molecule ligands, partner proteins or nucleic acids) can be characterized on the molecular level, including the effect that a protein can have on a lipid bilayer (Kent et al, 2010;Jones et al, 2012). It should also be pointed out that living cells have been interrogated by NR, specifically their adhesion properties on substrates (Junghans et al, 2014).…”

Analysis of biosurfaces by neutron reflectometry: From simple to complex interfaces

“…In this spirit, we have started to expand those studies to glioblastoma (GBM), 45 one of the most common and aggressive type of brain tumors. 100 Under static conditions, we have observed profound differences in noninvasive U251 cells, compared to the invasive CNS1 and GL261 cells.…”

“…NR can be applied in the study of living tissue to better understand biological mechanisms such as cellular adhesion within the vascular system and the differences that may be specifically associated with brain tumor invasion. [45][46][47] …”