Abstract:† Electronic supplementary information (ESI) available: Synthesis of organic compounds and their characterisations (NMR spectra ( 1 H and 13 C), FTIR, SMHR-ESI). Chemical modication of the surfaces (PM-IRRAS, contact angles and AFM). See
BackgroundSynchrotron radiation facilities are pillars of modern structural biology. Small-Angle X-ray scattering performed at synchrotron sources is often used to characterize the shape of biological macromolecules. A major challenge with high-energy X-ray beam on such macromolecules is the perturbation of sample due to radiation damage.ResultsBy employing atomic force microscopy, another common technique to determine the shape of biological macromolecules when deposited on flat substrates, we present a protocol to evaluate and characterize consequences of radiation damage. It requires the acquisition of images of irradiated samples at the single molecule level in a timely manner while using minimal amounts of protein. The protocol has been tested on two different molecular systems: a large globular tetremeric enzyme (β-Amylase) and a rod-shape plant virus (tobacco mosaic virus). Radiation damage on the globular enzyme leads to an apparent increase in molecular sizes whereas the effect on the long virus is a breakage into smaller pieces resulting in a decrease of the average long-axis radius.ConclusionsThese results show that radiation damage can appear in different forms and strongly support the need to check the effect of radiation damage at synchrotron sources using the presented protocol.
BackgroundSynchrotron radiation facilities are pillars of modern structural biology. Small-Angle X-ray scattering performed at synchrotron sources is often used to characterize the shape of biological macromolecules. A major challenge with high-energy X-ray beam on such macromolecules is the perturbation of sample due to radiation damage.ResultsBy employing atomic force microscopy, another common technique to determine the shape of biological macromolecules when deposited on flat substrates, we present a protocol to evaluate and characterize consequences of radiation damage. It requires the acquisition of images of irradiated samples at the single molecule level in a timely manner while using minimal amounts of protein. The protocol has been tested on two different molecular systems: a large globular tetremeric enzyme (β-Amylase) and a rod-shape plant virus (tobacco mosaic virus). Radiation damage on the globular enzyme leads to an apparent increase in molecular sizes whereas the effect on the long virus is a breakage into smaller pieces resulting in a decrease of the average long-axis radius.ConclusionsThese results show that radiation damage can appear in different forms and strongly support the need to check the effect of radiation damage at synchrotron sources using the presented protocol.
“…Meillan et al (2014) developed a method for Tobacco mosaic virus detection. The virus was immobilised using organic self-assembled monolayer (SAM) followed by analysis with atomic force microscopy (AFM).…”
Section: Comparison Of Outputs For Plastic and Natural Antibodiesmentioning
confidence: 99%
“…Efforts have been made to develop novel diagnosis methods for viruses, using techniques such as atomic force microscopy (Meillan et al, 2014), interferometry (Ymeti et al, 2007) and electrochemistry (Lee et al, 2013;Wei et al, 2013), or by implementing components such as carbon nanotubes (Dias et al, 2013;Tam et al, 2009), silicon nanowires (Svendsen et al, 2011), liquid crystals (Han et al, 2014), microcavities (Dantham et al, 2012) and microfluidics (Connelly et al, 2012;Matatagui et al, 2013) into sensor systems. Many of these studies, as well as others in the field, have used antibodies as the recognition material for virus detection exploiting the high specificity between an antibody and its analyte as a detection system (Bianco et al, 2013;Altintas et al, 2011).…”
“…The ureido silylated compound (3) , terminated with a carboxylic acid function protected with a photolabile group, was obtained using a previously described procedure …”
Section: Resultsmentioning
confidence: 99%
“…Only a few studies described the preparation of mixed silane monolayers using internal functional group like amide, carbamate, or urea groups in the alkyl chains able to self‐assemble by hydrogen‐bonding. Recently, we have developed functionalized SAMs containing internal urea or amide moiety in the linear alkyl chains . The molecular assembly in the monolayers is mainly driven by the intermolecular hydrogen‐bonding between amide or urea groups.…”
In this study, we report the successful grafting on silica surfaces by the coadsorption method, of mixed nitrobenzyl ester‐/methyl‐terminated self‐assembled monolayers (SAMs), with ratios of two coupling agents (30/70) and (10/90). We show that the preparation of mixed monolayers using two organosilanes with internal urea groups in the alkyl chain seems to be appropriate to obtain a monolayer composition similar to the molar ratio of the two silanes in the deposition solution. This behavior could be due to the presence of the polar urea groups in the molecular structure of both organosilanes which allows them to have the same ability of self‐assembly by hydrogen‐bonding and also the same affinity with the hydrophilic surface. To locate the ester functions at the surface of the mixed monolayers, we investigated the covalent immobilization of amino functionalized gold nanoparticles (GNPs) as nanoscale marker. Polarization modulation infrared reflection‐adsorption spectroscopy (PM‐IRRAS) and atomic force microscopy (AFM) were used to monitor the chemical modifications of the silica surfaces and to demonstrate the successful attachment of gold nanoparticles onto the modified surfaces. Finally, we show that the mixed SAMs were grafted with a phase separation.
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