Self-Assembled Multivalent (SAMul) Polyanion Binding – Impact of Hydrophobic Modifications in the Micellar Core on DNA and Heparin Binding at the Peripheral Cationic Ligands

This paper reports a small family of cationic surfactants designed to bind polyanions such as DNA and heparin. Each molecule has the same hydrophilic cationic ligand, and a hydrophobic aliphatic group with eighteen carbon atoms with either one, two or three alkene groups within the hydrophobic chain (C18-1, C18-2 and C18-3). Dynamic light scattering indicates that more alkenes lead to geometric distortion, giving rise to larger self-assembled multivalent (SAMul) nanostructures. Mallard Blue and Ethidium Bromide dye displacement assays demonstrate that heparin and DNA have markedly different binding preferences, with heparin binding most effectively to C18-1, and DNA to C18-3, even though the molecular structural differences of these SAMul systems are buried in the hydrophobic core. Multiscale modelling suggests that adaptive heparin maximises enthalpically-favourable interactions with C18-1, while shape-persistent DNA forms a similar number of interactions with each ligand display, but with slightly less entropic cost for binding to C18-3 – fundamental thermodynamic differences in SAMul binding of heparin or DNA. This study therefore provides unique insight into electrostatic molecular recognition between highly charged nanoscale surfaces in biologically-relevant systems

Chiral recognition at self-assembled multivalent (SAMul) nanoscale interfaces – enantioselectivity in polyanion binding

Self-assembled multivalent (SAMul) ligands based on palmitic acid functionalised with cationic L/D-lysine bind polyanionic heparin or DNA with no chiral preference. Inserting a glycine spacer unit switches on chiral discrimination – a rare example of controlled chiral recognition at a SAMul nanoscale interface

Promoting Muslim Nationalism in Turkish Museums: A study of visitors’ responses to the Panorama Museum 1453

In recent years, studies have shown that the institutional representation of Turkey’s national history and identity has undergone a shift closely linked to the rise of the Justice and Development Party (AKP), led by President Recep Tayyip Erdoğan. Since the AKP came to power, the government supported the building of new state-sponsored museums reflecting the party’s national ideology, which recent literature dubbed “Turkish Muslim Nationalism.” These museums prioritize the Ottoman Empire’s past and its Islamic heritage as the grand narrative of Turkey’s national history, putting other equally important narratives in the background, e.g. the Roman, Byzantine, Greek, and the more recent Kemalist past of the country. One such museum is the Panorama Museum 1453, which has become a popular tourist attraction in Istanbul. This article examines how the visitors respond to the national identity promoted by the Panorama. It draws on fifty video-based interviews as well as visual elements of the museum. The data collected in this study has been analysed using a theoretical framework based on theories of nationalism. This research findings provide material supporting the thesis that the museum is successful in promoting a distinct version of Turkish Muslim Nationalism. It effectively conveys a national identity that emphasizes the characteristics of a Muslim Turk whose identity can be (and is) still influenced by the Ottoman Empire’s historical legacy. This legacy drives Turkish identity as an identity inextricably linked to Islam as the religion of the state, connected with other characteristics such as military power and technological progress. The museum’s presentation of this identity in the Panorama is compelling and immersive, which helps to solidify visitors’ understanding and acceptance

Introduction: anthropology's queer sensibilities

This special issue addresses vital epistemological, methodological, ethical and political issues at the intersections of queer theory and anthropology as they speak to the study of sexual and gender diversity in the contemporary world. The special issue centres on explorations of anthropology’s queer sensibilities, that is, experimental thinking in ethnographically informed investigations of gender and sexual difference, and related connections, disjunctures and tensions in their situated and abstract dimensions. The articles consider the possibilities and challenges of anthropology’s queer sensibilities that anthropologise queer theory whilst queering anthropology in ethnographically informed analyses. Contributors focus on anthropologising queer theory in research on same-sex desire in the Congo; LGBT migrant and asylum experience in the UK and France; same-sex intimacies within opposite gender oriented sexualities in Kenya and Ghana; secret and ambiguous intimacies and sensibilities beyond an identifiable ‘queer subject’ of rights and recognition in India; migrant imaginings of home in Indonesian lesbian relationships in Hong Kong; and cross-generational perspectives on ‘coming out’ in Taiwan and their implications for theories of kinship and relatedness. An extensive interview with Esther Newton, the prominent figure in gay and lesbian and queer anthropology concludes the collection

Electrostatic binding of polyanions using self-assembled multivalent (SAMul) ligand displays-structure-activity effects on DNA/heparin binding

This paper reports that modifying the ligands in self-assembled multivalent (SAMul) displays has an impact on apparent binding selectivity towards two nanoscale biological polyanions-heparin and DNA. For the nanostructures assayed here, spermidine ligands are optimal for heparin binding but spermine ligands are preferred for DNA. Probing subtle differences in such nanoscale binding interfaces is a significant challenge, and as such, several experimental binding assays-competition assays and isothermal calorimetry-are employed to confirm differences in affinity and provide thermodynamic insights. Given the dynamic nature and hierarchical binding processes involved in SAMul systems, we employed multiscale modelling to propose reasons for the origins of polyanion selectivity differences. The modelling results, when expressed in thermodynamic terms and compared with the experimental data, suggest that DNA is a shape-persistent polyanion, and selectivity originates only from ligand preferences, whereas heparin is more flexible and adaptive, and as such, actively reinforces ligand preferences. As such, this study suggests that inherent differences between polyanions may underpin subtle binding selectivity differences, and that even simple electrostatic interfaces such as these can have a degree of tunability, which has implications for biological control and regulation on the nanoscale

Patchy and Janus Nanoparticles by Self-Organization of Mixtures of Fluorinated and Hydrogenated Alkanethiolates on the Surface of a Gold Core

The spontaneous self-organization of dissimilar ligands on the surface of metal nanoparticles is a very appealing approach to obtain anisotropic "spherical". systems. In addition to differences in ligand length and end groups, a further thermodynamic driving force to control the self-assembled monolayer organization may become available if the ligands are inherently immiscible, as is the case of hydrogenated (H-) and fluorinated (F-) species. Here, we validate the viability of this approach by combining F-19 NMR experiments and multiscale molecular simulations on large sets of mixed-monolayer-protected gold nanoparticles (NPs). The phase segregation of blends of F- and H-thiolates grafted on the surface of gold NPs allows a straightforward approach to patterned mixed monolayers, with the shapes of the monolayer domains being encoded in the structure of the F/H-thiolate ligands. The results obtained from this comprehensive study offer molecular design rules to achieve a precise control of inorganic nanoparticles protected by specifically patterned monolayers

Emergence of highly-ordered hierarchical nanoscale aggregates on electrostatic binding of self-assembled multivalent (SAMul) cationic micelles with polyanionic heparin

We report three surfactants, with cationic N,N-di-(3-aminopropyl)-N-methylamine (DAPMA) head groups and aliphatic chains connected via an amide linkage, and investigate their ability to self-assemble and bind polyanionic heparin – a process of potential clinical importance in coagulation control. Modifying the hydrophobic chain length tunes the self-assembly event, with C16-DAPMA having the lowest critical micelle concentration and also being the optimal heparin binder. Remarkably highly structured hierarchical nanoscale aggregates are formed on binding between the spherical cationic micelles and linear polyanionic heparin. C14-DAPMA and C16-DAPMA yield organized polycrystalline assemblies as observed by transmission electron microscopy (TEM), predicted in solution by mesoscale simulations and characterized by small-angle X-ray scattering (SAXS). This confirms that the micelles remain intact during the hierarchical assembly process and become packed in a face-centered cubic manner. The nanoscale assembly formed by C16-DAPMA showed the highest degree of order. Importantly, these studies indicate the impact of hydrophobic modification on self-assembly and heparin binding, demonstrate remarkably high stability of these self-assembled micelles even when forming strong electrostatic interactions with heparin, and provide structural insights into nanoscale hierarchical electrostatic assemblies

Molecular Features for Probing Small Amphiphilic Molecules with Self-Assembled Monolayer Protected Nanoparticles

The sensing of small molecules poses the challenge to develop devices able to discriminate between compounds that may be structurally very similar. Here, attention has been paid to the use of self-assembled monolayer (SAM)-protected gold nanoparticles since they enable a modular approach to tune single-molecule affinity and selectivity simply by changing functional moieties (i.e. covering ligands), alongside with multivalent molecular recognition. To date, the discovery of monolayers suitable for a specific molecular target relies on trial-and-error approaches, with ligand chemistry being the main criteria used to modulate selectivity and sensitivity. By using molecular dynamics, we showcase that either individual molecular characteristics and/or collective features such as ligand flexibility, monolayer organization, ligand local ordering, and interfacial solvent properties can also be exploited conveniently. The knowledge of the molecular mechanisms that drive the recognition of small molecules on SAM covered nanoparticles will critically expand our ability to manipulate and control such supramolecular systems

Curating a Nation: The Interplay of Museums and Muslim Nationalism in Modern Turkey

Over the past two decades, the Justice and Development Party (AKP) has held power in Turkey through five different governments, with Recep Tayyip Erdoğan at the helm throughout. This AKP has brought about significant changes for both the Turkish State and society, including the emergence of a new national ideology that Jenny White epitomized Muslim Nationalism. Muslim Nationalism in its Turkish specificity brought forth a new Turkey and “new Turks”, with state-sponsored institutions playing a key role, largely driven by top-down efforts to build a cohesive national identity. Museums have played a significant role in the process of nation-building with many new institutions featuring stories of sultans, Islamic scientists, and Ottoman warriors while neglecting other equally important symbols and heritages of Turkey, such as the Greek, Roman, and Byzantine heritages. These museums are important state-sponsored rituals that promote the vision of the "new Turkey" envisioned by the ruling class. This study focuses on four museums: the Istanbul Museum of the History of Science and Technology in Islam, the Panorama Museum 1453, the Kabatepe Simulation Centre and Museum, and the newly renovated Topkapı Museum. By examining the connections between these museums, we can gain a better understanding of how this ideology is exhibited and perpetuated through cultural institutions, and what image of Turkey and Turks emerges from them

Perceptions and Misconceptions in Molecular Recognition: Key Factors in Self-Assembling Multivalent (SAMul) Ligands/Polyanions Selectivity

Biology is dominated by polyanions (cell membranes, nucleic acids, and polysaccharides just to name a few), and achieving selective recognition between biological polyanions and synthetic systems currently constitutes a major challenge in many biomedical applications, nanovectors-assisted gene delivery being a prime example. This review work summarizes some of our recent efforts in this field; in particular, by using a combined experimental/computation approach, we investigated in detail some critical aspects in self-assembled nanomicelles and two major polyanions-DNA and heparin